diff --git a/vendor/code.ivysaur.me/imagequant/.hgignore b/vendor/code.ivysaur.me/imagequant/.hgignore
new file mode 100644
index 0000000..2305450
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/.hgignore
@@ -0,0 +1,4 @@
+mode:regex
+
+^_dist/
+\.exe$
diff --git a/vendor/code.ivysaur.me/imagequant/.hgtags b/vendor/code.ivysaur.me/imagequant/.hgtags
new file mode 100644
index 0000000..cc08773
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/.hgtags
@@ -0,0 +1,2 @@
+795de1317b3afb38cbc638a95f4324a694f0c5e8 release-2.8go1.0
+2a725298492495e5ac694550b41112f00782850b release-2.9go1.1
diff --git a/vendor/code.ivysaur.me/imagequant/Attributes.go b/vendor/code.ivysaur.me/imagequant/Attributes.go
new file mode 100644
index 0000000..f2ca262
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/Attributes.go
@@ -0,0 +1,114 @@
+/*
+Copyright (c) 2016, The go-imagequant author(s)
+
+Permission to use, copy, modify, and/or distribute this software for any purpose
+with or without fee is hereby granted, provided that the above copyright notice
+and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD TO
+THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
+IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA
+OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+SOFTWARE.
+*/
+
+package imagequant
+
+import (
+ "errors"
+)
+
+/*
+#include "libimagequant.h"
+*/
+import "C"
+
+type Attributes struct {
+ p *C.struct_liq_attr
+}
+
+// Callers MUST call Release() on the returned object to free memory.
+func NewAttributes() (*Attributes, error) {
+ pAttr := C.liq_attr_create()
+ if pAttr == nil { // nullptr
+ return nil, errors.New("Unsupported platform")
+ }
+
+ return &Attributes{p: pAttr}, nil
+}
+
+const (
+ COLORS_MIN = 2
+ COLORS_MAX = 256
+)
+
+func (this *Attributes) SetMaxColors(colors int) error {
+ return translateError(C.liq_set_max_colors(this.p, C.int(colors)))
+}
+
+func (this *Attributes) GetMaxColors() int {
+ return int(C.liq_get_max_colors(this.p))
+}
+
+const (
+ QUALITY_MIN = 0
+ QUALITY_MAX = 100
+)
+
+func (this *Attributes) SetQuality(minimum, maximum int) error {
+ return translateError(C.liq_set_quality(this.p, C.int(minimum), C.int(maximum)))
+}
+
+func (this *Attributes) GetMinQuality() int {
+ return int(C.liq_get_min_quality(this.p))
+}
+
+func (this *Attributes) GetMaxQuality() int {
+ return int(C.liq_get_max_quality(this.p))
+}
+
+const (
+ SPEED_SLOWEST = 1
+ SPEED_DEFAULT = 3
+ SPEED_FASTEST = 10
+)
+
+func (this *Attributes) SetSpeed(speed int) error {
+ return translateError(C.liq_set_speed(this.p, C.int(speed)))
+}
+
+func (this *Attributes) GetSpeed() int {
+ return int(C.liq_get_speed(this.p))
+}
+
+func (this *Attributes) SetMinOpacity(min int) error {
+ return translateError(C.liq_set_min_opacity(this.p, C.int(min)))
+}
+
+func (this *Attributes) GetMinOpacity() int {
+ return int(C.liq_get_min_opacity(this.p))
+}
+
+func (this *Attributes) SetMinPosterization(bits int) error {
+ return translateError(C.liq_set_min_posterization(this.p, C.int(bits)))
+}
+
+func (this *Attributes) GetMinPosterization() int {
+ return int(C.liq_get_min_posterization(this.p))
+}
+
+func (this *Attributes) SetLastIndexTransparent(is_last int) {
+ C.liq_set_last_index_transparent(this.p, C.int(is_last))
+}
+
+func (this *Attributes) CreateHistogram() *Histogram {
+ ptr := C.liq_histogram_create(this.p)
+ return &Histogram{p: ptr}
+}
+
+// Free memory. Callers must not use this object after Release has been called.
+func (this *Attributes) Release() {
+ C.liq_attr_destroy(this.p)
+}
diff --git a/vendor/code.ivysaur.me/imagequant/COPYRIGHT b/vendor/code.ivysaur.me/imagequant/COPYRIGHT
new file mode 100644
index 0000000..3514d66
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/COPYRIGHT
@@ -0,0 +1,641 @@
+
+libimagequant is derived from code by Jef Poskanzer and Greg Roelofs
+licensed under pngquant's original license (at the end of this file),
+and contains extensive changes and additions by Kornel Lesiński
+licensed under GPL v3.
+
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+libimagequant © 2009-2016 by Kornel Lesiński.
+
+ GNU GENERAL PUBLIC LICENSE
+ Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc.
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+ Preamble
+
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+
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+any other work released this way by its authors. You can apply it to
+your programs, too.
+
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+sue for patent infringement). To "grant" such a patent license to a
+party means to make such an agreement or commitment not to enforce a
+patent against the party.
+
+ If you convey a covered work, knowingly relying on a patent license,
+and the Corresponding Source of the work is not available for anyone
+to copy, free of charge and under the terms of this License, through a
+publicly available network server or other readily accessible means,
+then you must either (1) cause the Corresponding Source to be so
+available, or (2) arrange to deprive yourself of the benefit of the
+patent license for this particular work, or (3) arrange, in a manner
+consistent with the requirements of this License, to extend the patent
+license to downstream recipients. "Knowingly relying" means you have
+actual knowledge that, but for the patent license, your conveying the
+covered work in a country, or your recipient's use of the covered work
+in a country, would infringe one or more identifiable patents in that
+country that you have reason to believe are valid.
+
+ If, pursuant to or in connection with a single transaction or
+arrangement, you convey, or propagate by procuring conveyance of, a
+covered work, and grant a patent license to some of the parties
+receiving the covered work authorizing them to use, propagate, modify
+or convey a specific copy of the covered work, then the patent license
+you grant is automatically extended to all recipients of the covered
+work and works based on it.
+
+ A patent license is "discriminatory" if it does not include within
+the scope of its coverage, prohibits the exercise of, or is
+conditioned on the non-exercise of one or more of the rights that are
+specifically granted under this License. You may not convey a covered
+work if you are a party to an arrangement with a third party that is
+in the business of distributing software, under which you make payment
+to the third party based on the extent of your activity of conveying
+the work, and under which the third party grants, to any of the
+parties who would receive the covered work from you, a discriminatory
+patent license (a) in connection with copies of the covered work
+conveyed by you (or copies made from those copies), or (b) primarily
+for and in connection with specific products or compilations that
+contain the covered work, unless you entered into that arrangement,
+or that patent license was granted, prior to 28 March 2007.
+
+ Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+ 12. No Surrender of Others' Freedom.
+
+ If conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License. If you cannot convey a
+covered work so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you may
+not convey it at all. For example, if you agree to terms that obligate you
+to collect a royalty for further conveying from those to whom you convey
+the Program, the only way you could satisfy both those terms and this
+License would be to refrain entirely from conveying the Program.
+
+ 13. Use with the GNU Affero General Public License.
+
+ Notwithstanding any other provision of this License, you have
+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU Affero General Public License into a single
+combined work, and to convey the resulting work. The terms of this
+License will continue to apply to the part which is the covered work,
+but the special requirements of the GNU Affero General Public License,
+section 13, concerning interaction through a network will apply to the
+combination as such.
+
+ 14. Revised Versions of this License.
+
+ The Free Software Foundation may publish revised and/or new versions of
+the GNU General Public License from time to time. Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+ Each version is given a distinguishing version number. If the
+Program specifies that a certain numbered version of the GNU General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation. If the Program does not specify a version number of the
+GNU General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+ If the Program specifies that a proxy can decide which future
+versions of the GNU General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+ Later license versions may give you additional or different
+permissions. However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+ 15. Disclaimer of Warranty.
+
+ THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+ 16. Limitation of Liability.
+
+ IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+ 17. Interpretation of Sections 15 and 16.
+
+ If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+© 1989, 1991 by Jef Poskanzer.
+© 1997, 2000, 2002 by Greg Roelofs.
+
+Permission to use, copy, modify, and distribute this software and its
+documentation for any purpose and without fee is hereby granted, provided
+that the above copyright notice appear in all copies and that both that
+copyright notice and this permission notice appear in supporting
+documentation. This software is provided "as is" without express or
+implied warranty.
diff --git a/vendor/code.ivysaur.me/imagequant/Histogram.go b/vendor/code.ivysaur.me/imagequant/Histogram.go
new file mode 100644
index 0000000..183cbce
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/Histogram.go
@@ -0,0 +1,45 @@
+/*
+Copyright (c) 2016, The go-imagequant author(s)
+
+Permission to use, copy, modify, and/or distribute this software for any purpose
+with or without fee is hereby granted, provided that the above copyright notice
+and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD TO
+THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
+IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA
+OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+SOFTWARE.
+*/
+
+package imagequant
+
+/*
+#include "libimagequant.h"
+*/
+import "C"
+
+type Histogram struct {
+ p *C.struct_liq_histogram
+}
+
+func (this *Histogram) AddImage(attr *Attributes, img *Image) error {
+ return translateError(C.liq_histogram_add_image(this.p, attr.p, img.p))
+}
+
+func (this *Histogram) Quantize(attr *Attributes) (*Result, error) {
+ res := Result{}
+ liqerr := C.liq_histogram_quantize(this.p, attr.p, &res.p)
+ if liqerr != C.LIQ_OK {
+ return nil, translateError(liqerr)
+ }
+
+ return &res, nil
+}
+
+// Free memory. Callers must not use this object after Release has been called.
+func (this *Histogram) Release() {
+ C.liq_histogram_destroy(this.p)
+}
diff --git a/vendor/code.ivysaur.me/imagequant/Image.go b/vendor/code.ivysaur.me/imagequant/Image.go
new file mode 100644
index 0000000..38a5f3d
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/Image.go
@@ -0,0 +1,66 @@
+/*
+Copyright (c) 2016, The go-imagequant author(s)
+
+Permission to use, copy, modify, and/or distribute this software for any purpose
+with or without fee is hereby granted, provided that the above copyright notice
+and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD TO
+THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
+IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA
+OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+SOFTWARE.
+*/
+
+package imagequant
+
+import (
+ "errors"
+ "unsafe"
+)
+
+/*
+#include "libimagequant.h"
+*/
+import "C"
+
+type Image struct {
+ p *C.struct_liq_image
+ w, h int
+ released bool
+}
+
+// Callers MUST call Release() on the returned object to free memory.
+func NewImage(attr *Attributes, rgba32data string, width, height int, gamma float64) (*Image, error) {
+ pImg := C.liq_image_create_rgba(attr.p, unsafe.Pointer(C.CString(rgba32data)), C.int(width), C.int(height), C.double(gamma))
+ if pImg == nil {
+ return nil, errors.New("Failed to create image (invalid argument)")
+ }
+
+ return &Image{
+ p: pImg,
+ w: width,
+ h: height,
+ released: false,
+ }, nil
+}
+
+// Free memory. Callers must not use this object after Release has been called.
+func (this *Image) Release() {
+ C.liq_image_destroy(this.p)
+ this.released = true
+}
+
+func (this *Image) Quantize(attr *Attributes) (*Result, error) {
+ res := Result{
+ im: this,
+ }
+ liqerr := C.liq_image_quantize(this.p, attr.p, &res.p)
+ if liqerr != C.LIQ_OK {
+ return nil, translateError(liqerr)
+ }
+
+ return &res, nil
+}
diff --git a/vendor/code.ivysaur.me/imagequant/Result.go b/vendor/code.ivysaur.me/imagequant/Result.go
new file mode 100644
index 0000000..d084c95
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/Result.go
@@ -0,0 +1,110 @@
+/*
+Copyright (c) 2016, The go-imagequant author(s)
+
+Permission to use, copy, modify, and/or distribute this software for any purpose
+with or without fee is hereby granted, provided that the above copyright notice
+and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD TO
+THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
+IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA
+OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+SOFTWARE.
+*/
+
+package imagequant
+
+import (
+ "image/color"
+ "unsafe"
+)
+
+/*
+#include "libimagequant.h"
+*/
+import "C"
+
+// Callers must not use this object once Release has been called on the parent
+// Image struct.
+type Result struct {
+ p *C.struct_liq_result
+ im *Image
+}
+
+func (this *Result) SetDitheringLevel(dither_level float32) error {
+ return translateError(C.liq_set_dithering_level(this.p, C.float(dither_level)))
+}
+
+func (this *Result) GetQuantizationError() float64 {
+ return float64(C.liq_get_quantization_error(this.p))
+}
+
+func (this *Result) GetRemappingError() float64 {
+ return float64(C.liq_get_remapping_error(this.p))
+}
+
+func (this *Result) GetQuantizationQuality() float64 {
+ return float64(C.liq_get_quantization_quality(this.p))
+}
+
+func (this *Result) GetRemappingQuality() float64 {
+ return float64(C.liq_get_remapping_quality(this.p))
+}
+
+func (this *Result) SetOutputGamma(gamma float64) error {
+ return translateError(C.liq_set_output_gamma(this.p, C.double(gamma)))
+}
+
+func (this *Result) GetImageWidth() int {
+ // C.liq_image_get_width
+ return this.im.w
+}
+
+func (this *Result) GetImageHeight() int {
+ // C.liq_image_get_height
+ return this.im.h
+}
+
+func (this *Result) GetOutputGamma() float64 {
+ return float64(C.liq_get_output_gamma(this.p))
+}
+
+func (this *Result) WriteRemappedImage() ([]byte, error) {
+ if this.im.released {
+ return nil, ErrUseAfterFree
+ }
+
+ buff_size := this.im.w * this.im.h
+ buff := make([]byte, buff_size)
+
+ iqe := C.liq_write_remapped_image(this.p, this.im.p, unsafe.Pointer(&buff[0]), C.size_t(buff_size))
+ if iqe != C.LIQ_OK {
+ return nil, translateError(iqe)
+ }
+
+ return buff, nil
+}
+
+func (this *Result) GetPalette() color.Palette {
+ ptr := C.liq_get_palette(this.p) // copy struct content
+ max := int(ptr.count)
+
+ ret := make([]color.Color, max)
+ for i := 0; i < max; i += 1 {
+ ret[i] = color.RGBA{
+ R: uint8(ptr.entries[i].r),
+ G: uint8(ptr.entries[i].g),
+ B: uint8(ptr.entries[i].b),
+ A: uint8(ptr.entries[i].a),
+ }
+ }
+
+ return ret
+}
+
+// Free memory. Callers must not use this object after Release has been called.
+func (this *Result) Release() {
+ C.liq_result_destroy(this.p)
+}
diff --git a/vendor/code.ivysaur.me/imagequant/blur.c b/vendor/code.ivysaur.me/imagequant/blur.c
new file mode 100644
index 0000000..7f0a716
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/blur.c
@@ -0,0 +1,132 @@
+/*
+© 2011-2015 by Kornel Lesiński.
+
+This file is part of libimagequant.
+
+libimagequant is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+libimagequant is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with libimagequant. If not, see .
+*/
+
+#include "libimagequant.h"
+#include "pam.h"
+#include "blur.h"
+
+/*
+ Blurs image horizontally (width 2*size+1) and writes it transposed to dst (called twice gives 2d blur)
+ */
+static void transposing_1d_blur(unsigned char *restrict src, unsigned char *restrict dst, unsigned int width, unsigned int height, const unsigned int size)
+{
+ assert(size > 0);
+
+ for(unsigned int j=0; j < height; j++) {
+ unsigned char *restrict row = src + j*width;
+
+ // accumulate sum for pixels outside line
+ unsigned int sum;
+ sum = row[0]*size;
+ for(unsigned int i=0; i < size; i++) {
+ sum += row[i];
+ }
+
+ // blur with left side outside line
+ for(unsigned int i=0; i < size; i++) {
+ sum -= row[0];
+ sum += row[i+size];
+
+ dst[i*height + j] = sum / (size*2);
+ }
+
+ for(unsigned int i=size; i < width-size; i++) {
+ sum -= row[i-size];
+ sum += row[i+size];
+
+ dst[i*height + j] = sum / (size*2);
+ }
+
+ // blur with right side outside line
+ for(unsigned int i=width-size; i < width; i++) {
+ sum -= row[i-size];
+ sum += row[width-1];
+
+ dst[i*height + j] = sum / (size*2);
+ }
+ }
+}
+
+/**
+ * Picks maximum of neighboring pixels (blur + lighten)
+ */
+LIQ_PRIVATE void liq_max3(unsigned char *src, unsigned char *dst, unsigned int width, unsigned int height)
+{
+ for(unsigned int j=0; j < height; j++) {
+ const unsigned char *row = src + j*width,
+ *prevrow = src + (j > 1 ? j-1 : 0)*width,
+ *nextrow = src + MIN(height-1,j+1)*width;
+
+ unsigned char prev,curr=row[0],next=row[0];
+
+ for(unsigned int i=0; i < width-1; i++) {
+ prev=curr;
+ curr=next;
+ next=row[i+1];
+
+ unsigned char t1 = MAX(prev,next);
+ unsigned char t2 = MAX(nextrow[i],prevrow[i]);
+ *dst++ = MAX(curr,MAX(t1,t2));
+ }
+ unsigned char t1 = MAX(curr,next);
+ unsigned char t2 = MAX(nextrow[width-1],prevrow[width-1]);
+ *dst++ = MAX(t1,t2);
+ }
+}
+
+/**
+ * Picks minimum of neighboring pixels (blur + darken)
+ */
+LIQ_PRIVATE void liq_min3(unsigned char *src, unsigned char *dst, unsigned int width, unsigned int height)
+{
+ for(unsigned int j=0; j < height; j++) {
+ const unsigned char *row = src + j*width,
+ *prevrow = src + (j > 1 ? j-1 : 0)*width,
+ *nextrow = src + MIN(height-1,j+1)*width;
+
+ unsigned char prev,curr=row[0],next=row[0];
+
+ for(unsigned int i=0; i < width-1; i++) {
+ prev=curr;
+ curr=next;
+ next=row[i+1];
+
+ unsigned char t1 = MIN(prev,next);
+ unsigned char t2 = MIN(nextrow[i],prevrow[i]);
+ *dst++ = MIN(curr,MIN(t1,t2));
+ }
+ unsigned char t1 = MIN(curr,next);
+ unsigned char t2 = MIN(nextrow[width-1],prevrow[width-1]);
+ *dst++ = MIN(t1,t2);
+ }
+}
+
+/*
+ Filters src image and saves it to dst, overwriting tmp in the process.
+ Image must be width*height pixels high. Size controls radius of box blur.
+ */
+LIQ_PRIVATE void liq_blur(unsigned char *src, unsigned char *tmp, unsigned char *dst, unsigned int width, unsigned int height, unsigned int size)
+{
+ assert(size > 0);
+ if (width < 2*size+1 || height < 2*size+1) {
+ return;
+ }
+ transposing_1d_blur(src, tmp, width, height, size);
+ transposing_1d_blur(tmp, dst, height, width, size);
+}
diff --git a/vendor/code.ivysaur.me/imagequant/blur.h b/vendor/code.ivysaur.me/imagequant/blur.h
new file mode 100644
index 0000000..06ae8cb
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/blur.h
@@ -0,0 +1,4 @@
+
+LIQ_PRIVATE void liq_blur(unsigned char *src, unsigned char *tmp, unsigned char *dst, unsigned int width, unsigned int height, unsigned int size);
+LIQ_PRIVATE void liq_max3(unsigned char *src, unsigned char *dst, unsigned int width, unsigned int height);
+LIQ_PRIVATE void liq_min3(unsigned char *src, unsigned char *dst, unsigned int width, unsigned int height);
diff --git a/vendor/code.ivysaur.me/imagequant/cflags_linux.go b/vendor/code.ivysaur.me/imagequant/cflags_linux.go
new file mode 100644
index 0000000..fd11792
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/cflags_linux.go
@@ -0,0 +1,9 @@
+//+build !windows
+
+package imagequant
+
+/*
+#cgo CFLAGS: -O3 -fno-math-errno -fopenmp -funroll-loops -fomit-frame-pointer -Wall -Wno-attributes -std=c99 -DNDEBUG -DUSE_SSE=1 -msse -fexcess-precision=fast
+#cgo LDFLAGS: -lm -fopenmp -ldl
+*/
+import "C"
diff --git a/vendor/code.ivysaur.me/imagequant/cflags_windows.go b/vendor/code.ivysaur.me/imagequant/cflags_windows.go
new file mode 100644
index 0000000..0800274
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/cflags_windows.go
@@ -0,0 +1,9 @@
+//+build windows
+
+package imagequant
+
+/*
+#cgo CFLAGS: -O3 -fno-math-errno -fopenmp -funroll-loops -fomit-frame-pointer -Wall -Wno-attributes -std=c99 -DNDEBUG -DUSE_SSE=1 -msse -fexcess-precision=fast
+#cgo LDFLAGS: -fopenmp -static
+*/
+import "C"
\ No newline at end of file
diff --git a/vendor/code.ivysaur.me/imagequant/cmd/gopngquant/Makefile.cygwin b/vendor/code.ivysaur.me/imagequant/cmd/gopngquant/Makefile.cygwin
new file mode 100644
index 0000000..af174af
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/cmd/gopngquant/Makefile.cygwin
@@ -0,0 +1,10 @@
+
+.PHONY: all clean
+
+all: gopngquant.exe
+
+clean:
+ rm ./gopngquant.exe || true
+
+gopngquant.exe: main.go
+ ( source ~/.cygwin-toolchain-switcher/use-toolchain-x86_64-w64-mingw32.sh && go build -a -ldflags '-s -w' )
diff --git a/vendor/code.ivysaur.me/imagequant/cmd/gopngquant/main.go b/vendor/code.ivysaur.me/imagequant/cmd/gopngquant/main.go
new file mode 100644
index 0000000..cbfa94a
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/cmd/gopngquant/main.go
@@ -0,0 +1,156 @@
+/*
+Copyright (c) 2016, The go-imagequant author(s)
+
+Permission to use, copy, modify, and/or distribute this software for any purpose
+with or without fee is hereby granted, provided that the above copyright notice
+and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD TO
+THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
+IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA
+OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+SOFTWARE.
+*/
+
+package main
+
+import (
+ "flag"
+ "fmt"
+ "image"
+ "image/color"
+ "image/png"
+ "os"
+
+ "code.ivysaur.me/imagequant"
+)
+
+func GoImageToRgba32(im image.Image) []byte {
+ w := im.Bounds().Max.X
+ h := im.Bounds().Max.Y
+ ret := make([]byte, w*h*4)
+
+ p := 0
+
+ for y := 0; y < h; y += 1 {
+ for x := 0; x < w; x += 1 {
+ r16, g16, b16, a16 := im.At(x, y).RGBA() // Each value ranges within [0, 0xffff]
+
+ ret[p+0] = uint8(r16 >> 8)
+ ret[p+1] = uint8(g16 >> 8)
+ ret[p+2] = uint8(b16 >> 8)
+ ret[p+3] = uint8(a16 >> 8)
+ p += 4
+ }
+ }
+
+ return ret
+}
+
+func Rgb8PaletteToGoImage(w, h int, rgb8data []byte, pal color.Palette) image.Image {
+ rect := image.Rectangle{
+ Max: image.Point{
+ X: w,
+ Y: h,
+ },
+ }
+
+ ret := image.NewPaletted(rect, pal)
+
+ for y := 0; y < h; y += 1 {
+ for x := 0; x < w; x += 1 {
+ ret.SetColorIndex(x, y, rgb8data[y*w+x])
+ }
+ }
+
+ return ret
+}
+
+func Crush(sourcefile, destfile string, speed int) error {
+
+ fh, err := os.OpenFile(sourcefile, os.O_RDONLY, 0444)
+ if err != nil {
+ return fmt.Errorf("os.OpenFile: %s", err.Error())
+ }
+ defer fh.Close()
+
+ img, err := png.Decode(fh)
+ if err != nil {
+ return fmt.Errorf("png.Decode: %s", err.Error())
+ }
+
+ width := img.Bounds().Max.X
+ height := img.Bounds().Max.Y
+
+ attr, err := imagequant.NewAttributes()
+ if err != nil {
+ return fmt.Errorf("NewAttributes: %s", err.Error())
+ }
+ defer attr.Release()
+
+ err = attr.SetSpeed(speed)
+ if err != nil {
+ return fmt.Errorf("SetSpeed: %s", err.Error())
+ }
+
+ rgba32data := GoImageToRgba32(img)
+
+ iqm, err := imagequant.NewImage(attr, string(rgba32data), width, height, 0)
+ if err != nil {
+ return fmt.Errorf("NewImage: %s", err.Error())
+ }
+ defer iqm.Release()
+
+ res, err := iqm.Quantize(attr)
+ if err != nil {
+ return fmt.Errorf("Quantize: %s", err.Error())
+ }
+ defer res.Release()
+
+ rgb8data, err := res.WriteRemappedImage()
+ if err != nil {
+ return fmt.Errorf("WriteRemappedImage: %s", err.Error())
+ }
+
+ im2 := Rgb8PaletteToGoImage(res.GetImageWidth(), res.GetImageHeight(), rgb8data, res.GetPalette())
+
+ fh2, err := os.OpenFile(destfile, os.O_WRONLY|os.O_CREATE, 0644)
+ if err != nil {
+ return fmt.Errorf("os.OpenFile: %s", err.Error())
+ }
+ defer fh2.Close()
+
+ penc := png.Encoder{
+ CompressionLevel: png.BestCompression,
+ }
+ err = penc.Encode(fh2, im2)
+ if err != nil {
+ return fmt.Errorf("png.Encode: %s", err.Error())
+ }
+
+ return nil
+}
+
+func main() {
+ ShouldDisplayVersion := flag.Bool("Version", false, "")
+ Infile := flag.String("In", "", "Input filename")
+ Outfile := flag.String("Out", "", "Output filename")
+ Speed := flag.Int("Speed", 3, "Speed (1 slowest, 10 fastest)")
+
+ flag.Parse()
+
+ if *ShouldDisplayVersion {
+ fmt.Printf("libimagequant '%s' (%d)\n", imagequant.GetLibraryVersionString(), imagequant.GetLibraryVersion())
+ os.Exit(1)
+ }
+
+ err := Crush(*Infile, *Outfile, *Speed)
+ if err != nil {
+ fmt.Println(err.Error())
+ os.Exit(1)
+ }
+
+ os.Exit(0)
+}
diff --git a/vendor/code.ivysaur.me/imagequant/imagequant.go b/vendor/code.ivysaur.me/imagequant/imagequant.go
new file mode 100644
index 0000000..d121883
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/imagequant.go
@@ -0,0 +1,74 @@
+/*
+Copyright (c) 2016, The go-imagequant author(s)
+
+Permission to use, copy, modify, and/or distribute this software for any purpose
+with or without fee is hereby granted, provided that the above copyright notice
+and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD TO
+THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
+IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA
+OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+SOFTWARE.
+*/
+
+package imagequant
+
+import (
+ "errors"
+)
+
+/*
+#include "libimagequant.h"
+
+const char* liqVersionString() {
+ return LIQ_VERSION_STRING;
+}
+
+*/
+import "C"
+
+var (
+ ErrQualityTooLow = errors.New("Quality too low")
+ ErrValueOutOfRange = errors.New("Value out of range")
+ ErrOutOfMemory = errors.New("Out of memory")
+ ErrAborted = errors.New("Aborted")
+ ErrBitmapNotAvailable = errors.New("Bitmap not available")
+ ErrBufferTooSmall = errors.New("Buffer too small")
+ ErrInvalidPointer = errors.New("Invalid pointer")
+
+ ErrUseAfterFree = errors.New("Use after free")
+)
+
+func translateError(iqe C.liq_error) error {
+ switch iqe {
+ case C.LIQ_OK:
+ return nil
+ case (C.LIQ_QUALITY_TOO_LOW):
+ return ErrQualityTooLow
+ case (C.LIQ_VALUE_OUT_OF_RANGE):
+ return ErrValueOutOfRange
+ case (C.LIQ_OUT_OF_MEMORY):
+ return ErrOutOfMemory
+ case (C.LIQ_ABORTED):
+ return ErrAborted
+ case (C.LIQ_BITMAP_NOT_AVAILABLE):
+ return ErrBitmapNotAvailable
+ case (C.LIQ_BUFFER_TOO_SMALL):
+ return ErrBufferTooSmall
+ case (C.LIQ_INVALID_POINTER):
+ return ErrInvalidPointer
+ default:
+ return errors.New("Unknown error")
+ }
+}
+
+func GetLibraryVersion() int {
+ return int(C.liq_version())
+}
+
+func GetLibraryVersionString() string {
+ return C.GoString(C.liqVersionString())
+}
diff --git a/vendor/code.ivysaur.me/imagequant/kmeans.c b/vendor/code.ivysaur.me/imagequant/kmeans.c
new file mode 100644
index 0000000..f596009
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/kmeans.c
@@ -0,0 +1,107 @@
+/*
+© 2011-2016 by Kornel Lesiński.
+
+This file is part of libimagequant.
+
+libimagequant is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+libimagequant is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with libimagequant. If not, see .
+*/
+
+#include "libimagequant.h"
+#include "pam.h"
+#include "kmeans.h"
+#include "nearest.h"
+#include
+#include
+
+#ifdef _OPENMP
+#include
+#else
+#define omp_get_max_threads() 1
+#define omp_get_thread_num() 0
+#endif
+
+/*
+ * K-Means iteration: new palette color is computed from weighted average of colors that map to that palette entry.
+ */
+LIQ_PRIVATE void kmeans_init(const colormap *map, const unsigned int max_threads, kmeans_state average_color[])
+{
+ memset(average_color, 0, sizeof(average_color[0])*(KMEANS_CACHE_LINE_GAP+map->colors)*max_threads);
+}
+
+LIQ_PRIVATE void kmeans_update_color(const f_pixel acolor, const float value, const colormap *map, unsigned int match, const unsigned int thread, kmeans_state average_color[])
+{
+ match += thread * (KMEANS_CACHE_LINE_GAP+map->colors);
+ average_color[match].a += acolor.a * value;
+ average_color[match].r += acolor.r * value;
+ average_color[match].g += acolor.g * value;
+ average_color[match].b += acolor.b * value;
+ average_color[match].total += value;
+}
+
+LIQ_PRIVATE void kmeans_finalize(colormap *map, const unsigned int max_threads, const kmeans_state average_color[])
+{
+ for (unsigned int i=0; i < map->colors; i++) {
+ double a=0, r=0, g=0, b=0, total=0;
+
+ // Aggregate results from all threads
+ for(unsigned int t=0; t < max_threads; t++) {
+ const unsigned int offset = (KMEANS_CACHE_LINE_GAP+map->colors) * t + i;
+
+ a += average_color[offset].a;
+ r += average_color[offset].r;
+ g += average_color[offset].g;
+ b += average_color[offset].b;
+ total += average_color[offset].total;
+ }
+
+ if (total && !map->palette[i].fixed) {
+ map->palette[i].acolor = (f_pixel){
+ .a = a / total,
+ .r = r / total,
+ .g = g / total,
+ .b = b / total,
+ };
+ map->palette[i].popularity = total;
+ }
+ }
+}
+
+LIQ_PRIVATE double kmeans_do_iteration(histogram *hist, colormap *const map, kmeans_callback callback)
+{
+ const unsigned int max_threads = omp_get_max_threads();
+ kmeans_state average_color[(KMEANS_CACHE_LINE_GAP+map->colors) * max_threads];
+ kmeans_init(map, max_threads, average_color);
+ struct nearest_map *const n = nearest_init(map);
+ hist_item *const achv = hist->achv;
+ const int hist_size = hist->size;
+
+ double total_diff=0;
+ #pragma omp parallel for if (hist_size > 3000) \
+ schedule(static) default(none) shared(average_color,callback) reduction(+:total_diff)
+ for(int j=0; j < hist_size; j++) {
+ float diff;
+ unsigned int match = nearest_search(n, &achv[j].acolor, achv[j].tmp.likely_colormap_index, &diff);
+ achv[j].tmp.likely_colormap_index = match;
+ total_diff += diff * achv[j].perceptual_weight;
+
+ kmeans_update_color(achv[j].acolor, achv[j].perceptual_weight, map, match, omp_get_thread_num(), average_color);
+
+ if (callback) callback(&achv[j], diff);
+ }
+
+ nearest_free(n);
+ kmeans_finalize(map, max_threads, average_color);
+
+ return total_diff / hist->total_perceptual_weight;
+}
diff --git a/vendor/code.ivysaur.me/imagequant/kmeans.h b/vendor/code.ivysaur.me/imagequant/kmeans.h
new file mode 100644
index 0000000..c51d7bb
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/kmeans.h
@@ -0,0 +1,19 @@
+
+#ifndef KMEANS_H
+#define KMEANS_H
+
+// Spread memory touched by different threads at least 64B apart which I assume is the cache line size. This should avoid memory write contention.
+#define KMEANS_CACHE_LINE_GAP ((64+sizeof(kmeans_state)-1)/sizeof(kmeans_state))
+
+typedef struct {
+ double a, r, g, b, total;
+} kmeans_state;
+
+typedef void (*kmeans_callback)(hist_item *item, float diff);
+
+LIQ_PRIVATE void kmeans_init(const colormap *map, const unsigned int max_threads, kmeans_state state[]);
+LIQ_PRIVATE void kmeans_update_color(const f_pixel acolor, const float value, const colormap *map, unsigned int match, const unsigned int thread, kmeans_state average_color[]);
+LIQ_PRIVATE void kmeans_finalize(colormap *map, const unsigned int max_threads, const kmeans_state state[]);
+LIQ_PRIVATE double kmeans_do_iteration(histogram *hist, colormap *const map, kmeans_callback callback);
+
+#endif
diff --git a/vendor/code.ivysaur.me/imagequant/libimagequant.c b/vendor/code.ivysaur.me/imagequant/libimagequant.c
new file mode 100644
index 0000000..08f6962
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/libimagequant.c
@@ -0,0 +1,2032 @@
+/*
+** © 2009-2016 by Kornel Lesiński.
+**
+** This file is part of libimagequant.
+**
+** libimagequant is free software: you can redistribute it and/or modify
+** it under the terms of the GNU General Public License as published by
+** the Free Software Foundation, either version 3 of the License, or
+** (at your option) any later version.
+**
+** libimagequant is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+** GNU General Public License for more details.
+**
+** You should have received a copy of the GNU General Public License
+** along with libimagequant. If not, see .
+*/
+/* Copyright (C) 1989, 1991 by Jef Poskanzer.
+** Copyright (C) 1997, 2000, 2002 by Greg Roelofs; based on an idea by
+** Stefan Schneider.
+**
+** Permission to use, copy, modify, and distribute this software and its
+** documentation for any purpose and without fee is hereby granted, provided
+** that the above copyright notice appear in all copies and that both that
+** copyright notice and this permission notice appear in supporting
+** documentation. This software is provided "as is" without express or
+** implied warranty.
+*/
+
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+
+#if !(defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199900L) && !(defined(_MSC_VER) && _MSC_VER >= 1800)
+#error "This program requires C99, e.g. -std=c99 switch in GCC or it requires MSVC 18.0 or higher."
+#error "Ignore torrent of syntax errors that may follow. It's only because compiler is set to use too old C version."
+#endif
+
+#ifdef _OPENMP
+#include
+#else
+#define omp_get_max_threads() 1
+#define omp_get_thread_num() 0
+#endif
+
+#include "libimagequant.h"
+
+#include "pam.h"
+#include "mediancut.h"
+#include "nearest.h"
+#include "blur.h"
+#include "kmeans.h"
+
+#define LIQ_HIGH_MEMORY_LIMIT (1<<26) /* avoid allocating buffers larger than 64MB */
+
+// each structure has a pointer as a unique identifier that allows type checking at run time
+static const char liq_attr_magic[] = "liq_attr";
+static const char liq_image_magic[] = "liq_image";
+static const char liq_result_magic[] = "liq_result";
+static const char liq_histogram_magic[] = "liq_histogram";
+static const char liq_remapping_result_magic[] = "liq_remapping_result";
+static const char liq_freed_magic[] = "free";
+#define CHECK_STRUCT_TYPE(attr, kind) liq_crash_if_invalid_handle_pointer_given((const liq_attr*)attr, kind ## _magic)
+#define CHECK_USER_POINTER(ptr) liq_crash_if_invalid_pointer_given(ptr)
+
+struct liq_attr {
+ const char *magic_header;
+ void* (*malloc)(size_t);
+ void (*free)(void*);
+
+ double target_mse, max_mse, kmeans_iteration_limit;
+ float min_opaque_val;
+ unsigned int max_colors, max_histogram_entries;
+ unsigned int min_posterization_output /* user setting */, min_posterization_input /* speed setting */;
+ unsigned int kmeans_iterations, feedback_loop_trials;
+ bool last_index_transparent, use_contrast_maps, use_dither_map;
+ unsigned char speed;
+
+ unsigned char progress_stage1, progress_stage2, progress_stage3;
+ liq_progress_callback_function *progress_callback;
+ void *progress_callback_user_info;
+
+ liq_log_callback_function *log_callback;
+ void *log_callback_user_info;
+ liq_log_flush_callback_function *log_flush_callback;
+ void *log_flush_callback_user_info;
+};
+
+struct liq_image {
+ const char *magic_header;
+ void* (*malloc)(size_t);
+ void (*free)(void*);
+
+ f_pixel *f_pixels;
+ rgba_pixel **rows;
+ double gamma;
+ unsigned int width, height;
+ unsigned char *noise, *edges, *dither_map;
+ rgba_pixel *pixels, *temp_row;
+ f_pixel *temp_f_row;
+ liq_image_get_rgba_row_callback *row_callback;
+ void *row_callback_user_info;
+ float min_opaque_val;
+ f_pixel fixed_colors[256];
+ unsigned short fixed_colors_count;
+ bool free_pixels, free_rows, free_rows_internal;
+};
+
+typedef struct liq_remapping_result {
+ const char *magic_header;
+ void* (*malloc)(size_t);
+ void (*free)(void*);
+
+ unsigned char *pixels;
+ colormap *palette;
+ liq_progress_callback_function *progress_callback;
+ void *progress_callback_user_info;
+
+ liq_palette int_palette;
+ double gamma, palette_error;
+ float dither_level;
+ bool use_dither_map; unsigned char progress_stage1;
+} liq_remapping_result;
+
+struct liq_result {
+ const char *magic_header;
+ void* (*malloc)(size_t);
+ void (*free)(void*);
+
+ liq_remapping_result *remapping;
+ colormap *palette;
+ liq_progress_callback_function *progress_callback;
+ void *progress_callback_user_info;
+
+ liq_palette int_palette;
+ float dither_level;
+ double gamma, palette_error;
+ int min_posterization_output;
+ bool use_dither_map;
+};
+
+struct liq_histogram {
+ const char *magic_header;
+ void* (*malloc)(size_t);
+ void (*free)(void*);
+
+ struct acolorhash_table *acht;
+ double gamma;
+ f_pixel fixed_colors[256];
+ unsigned short fixed_colors_count;
+ unsigned short ignorebits;
+ bool had_image_added;
+};
+
+static void modify_alpha(liq_image *input_image, rgba_pixel *const row_pixels) LIQ_NONNULL;
+static void contrast_maps(liq_image *image) LIQ_NONNULL;
+static liq_error finalize_histogram(liq_histogram *input_hist, liq_attr *options, histogram **hist_output) LIQ_NONNULL;
+static const rgba_pixel *liq_image_get_row_rgba(liq_image *input_image, unsigned int row) LIQ_NONNULL;
+static const f_pixel *liq_image_get_row_f(liq_image *input_image, unsigned int row) LIQ_NONNULL;
+static void liq_remapping_result_destroy(liq_remapping_result *result) LIQ_NONNULL;
+static liq_error pngquant_quantize(histogram *hist, const liq_attr *options, const int fixed_colors_count, const f_pixel fixed_colors[], const double gamma, bool fixed_result_colors, liq_result **) LIQ_NONNULL;
+static liq_error liq_histogram_quantize_internal(liq_histogram *input_hist, liq_attr *attr, bool fixed_result_colors, liq_result **result_output) LIQ_NONNULL;
+
+LIQ_NONNULL static void liq_verbose_printf(const liq_attr *context, const char *fmt, ...)
+{
+ if (context->log_callback) {
+ va_list va;
+ va_start(va, fmt);
+ int required_space = vsnprintf(NULL, 0, fmt, va)+1; // +\0
+ va_end(va);
+
+ char buf[required_space];
+ va_start(va, fmt);
+ vsnprintf(buf, required_space, fmt, va);
+ va_end(va);
+
+ context->log_callback(context, buf, context->log_callback_user_info);
+ }
+}
+
+LIQ_NONNULL inline static void verbose_print(const liq_attr *attr, const char *msg)
+{
+ if (attr->log_callback) {
+ attr->log_callback(attr, msg, attr->log_callback_user_info);
+ }
+}
+
+LIQ_NONNULL static void liq_verbose_printf_flush(liq_attr *attr)
+{
+ if (attr->log_flush_callback) {
+ attr->log_flush_callback(attr, attr->log_flush_callback_user_info);
+ }
+}
+
+LIQ_NONNULL static bool liq_progress(const liq_attr *attr, const float percent)
+{
+ return attr->progress_callback && !attr->progress_callback(percent, attr->progress_callback_user_info);
+}
+
+LIQ_NONNULL static bool liq_remap_progress(const liq_remapping_result *quant, const float percent)
+{
+ return quant->progress_callback && !quant->progress_callback(percent, quant->progress_callback_user_info);
+}
+
+#if USE_SSE
+inline static bool is_sse_available()
+{
+#if (defined(__x86_64__) || defined(__amd64))
+ return true;
+#else
+ int a,b,c,d;
+ cpuid(1, a, b, c, d);
+ return d & (1<<25); // edx bit 25 is set when SSE is present
+#endif
+}
+#endif
+
+/* make it clear in backtrace when user-supplied handle points to invalid memory */
+NEVER_INLINE LIQ_EXPORT bool liq_crash_if_invalid_handle_pointer_given(const liq_attr *user_supplied_pointer, const char *const expected_magic_header);
+LIQ_EXPORT bool liq_crash_if_invalid_handle_pointer_given(const liq_attr *user_supplied_pointer, const char *const expected_magic_header)
+{
+ if (!user_supplied_pointer) {
+ return false;
+ }
+
+ if (user_supplied_pointer->magic_header == liq_freed_magic) {
+ fprintf(stderr, "%s used after being freed", expected_magic_header);
+ // this is not normal error handling, this is programmer error that should crash the program.
+ // program cannot safely continue if memory has been used after it's been freed.
+ // abort() is nasty, but security vulnerability may be worse.
+ abort();
+ }
+
+ return user_supplied_pointer->magic_header == expected_magic_header;
+}
+
+NEVER_INLINE LIQ_EXPORT bool liq_crash_if_invalid_pointer_given(const void *pointer);
+LIQ_EXPORT bool liq_crash_if_invalid_pointer_given(const void *pointer)
+{
+ if (!pointer) {
+ return false;
+ }
+ // Force a read from the given (potentially invalid) memory location in order to check early whether this crashes the program or not.
+ // It doesn't matter what value is read, the code here is just to shut the compiler up about unused read.
+ char test_access = *((volatile char *)pointer);
+ return test_access || true;
+}
+
+LIQ_NONNULL static void liq_log_error(const liq_attr *attr, const char *msg)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return;
+ liq_verbose_printf(attr, " error: %s", msg);
+}
+
+static double quality_to_mse(long quality)
+{
+ if (quality == 0) {
+ return MAX_DIFF;
+ }
+ if (quality == 100) {
+ return 0;
+ }
+
+ // curve fudged to be roughly similar to quality of libjpeg
+ // except lowest 10 for really low number of colors
+ const double extra_low_quality_fudge = MAX(0,0.016/(0.001+quality) - 0.001);
+ return extra_low_quality_fudge + 2.5/pow(210.0 + quality, 1.2) * (100.1-quality)/100.0;
+}
+
+static unsigned int mse_to_quality(double mse)
+{
+ for(int i=100; i > 0; i--) {
+ if (mse <= quality_to_mse(i) + 0.000001) { // + epsilon for floating point errors
+ return i;
+ }
+ }
+ return 0;
+}
+
+/** internally MSE is a sum of all channels with pixels 0..1 range,
+ but other software gives per-RGB-channel MSE for 0..255 range */
+static double mse_to_standard_mse(double mse) {
+ return mse * 65536.0/6.0;
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_error liq_set_quality(liq_attr* attr, int minimum, int target)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return LIQ_INVALID_POINTER;
+ if (target < 0 || target > 100 || target < minimum || minimum < 0) return LIQ_VALUE_OUT_OF_RANGE;
+
+ attr->target_mse = quality_to_mse(target);
+ attr->max_mse = quality_to_mse(minimum);
+ return LIQ_OK;
+}
+
+LIQ_EXPORT LIQ_NONNULL int liq_get_min_quality(const liq_attr *attr)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return -1;
+ return mse_to_quality(attr->max_mse);
+}
+
+LIQ_EXPORT LIQ_NONNULL int liq_get_max_quality(const liq_attr *attr)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return -1;
+ return mse_to_quality(attr->target_mse);
+}
+
+
+LIQ_EXPORT LIQ_NONNULL liq_error liq_set_max_colors(liq_attr* attr, int colors)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return LIQ_INVALID_POINTER;
+ if (colors < 2 || colors > 256) return LIQ_VALUE_OUT_OF_RANGE;
+
+ attr->max_colors = colors;
+ return LIQ_OK;
+}
+
+LIQ_EXPORT LIQ_NONNULL int liq_get_max_colors(const liq_attr *attr)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return -1;
+
+ return attr->max_colors;
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_error liq_set_min_posterization(liq_attr *attr, int bits)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return LIQ_INVALID_POINTER;
+ if (bits < 0 || bits > 4) return LIQ_VALUE_OUT_OF_RANGE;
+
+ attr->min_posterization_output = bits;
+ return LIQ_OK;
+}
+
+LIQ_EXPORT LIQ_NONNULL int liq_get_min_posterization(const liq_attr *attr)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return -1;
+
+ return attr->min_posterization_output;
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_error liq_set_speed(liq_attr* attr, int speed)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return LIQ_INVALID_POINTER;
+ if (speed < 1 || speed > 10) return LIQ_VALUE_OUT_OF_RANGE;
+
+ unsigned int iterations = MAX(8-speed, 0); iterations += iterations * iterations/2;
+ attr->kmeans_iterations = iterations;
+ attr->kmeans_iteration_limit = 1.0/(double)(1<<(23-speed));
+ attr->feedback_loop_trials = MAX(56-9*speed, 0);
+
+ attr->max_histogram_entries = (1<<17) + (1<<18)*(10-speed);
+ attr->min_posterization_input = (speed >= 8) ? 1 : 0;
+ attr->use_dither_map = (speed <= (omp_get_max_threads() > 1 ? 7 : 5)); // parallelized dither map might speed up floyd remapping
+ attr->use_contrast_maps = (speed <= 7) || attr->use_dither_map;
+ attr->speed = speed;
+
+ attr->progress_stage1 = attr->use_contrast_maps ? 20 : 8;
+ if (attr->feedback_loop_trials < 2) attr->progress_stage1 += 30;
+ attr->progress_stage3 = 50 / (1+speed);
+ attr->progress_stage2 = 100 - attr->progress_stage1 - attr->progress_stage3;
+ return LIQ_OK;
+}
+
+LIQ_EXPORT LIQ_NONNULL int liq_get_speed(const liq_attr *attr)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return -1;
+
+ return attr->speed;
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_error liq_set_output_gamma(liq_result* res, double gamma)
+{
+ if (!CHECK_STRUCT_TYPE(res, liq_result)) return LIQ_INVALID_POINTER;
+ if (gamma <= 0 || gamma >= 1.0) return LIQ_VALUE_OUT_OF_RANGE;
+
+ if (res->remapping) {
+ liq_remapping_result_destroy(res->remapping);
+ res->remapping = NULL;
+ }
+
+ res->gamma = gamma;
+ return LIQ_OK;
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_error liq_set_min_opacity(liq_attr* attr, int min)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return LIQ_INVALID_POINTER;
+ if (min < 0 || min > 255) return LIQ_VALUE_OUT_OF_RANGE;
+
+ attr->min_opaque_val = (double)min/255.0;
+ return LIQ_OK;
+}
+
+LIQ_EXPORT LIQ_NONNULL int liq_get_min_opacity(const liq_attr *attr)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return -1;
+
+ return MIN(255, 256.0 * attr->min_opaque_val);
+}
+
+LIQ_EXPORT LIQ_NONNULL void liq_set_last_index_transparent(liq_attr* attr, int is_last)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return;
+
+ attr->last_index_transparent = !!is_last;
+}
+
+LIQ_EXPORT void liq_attr_set_progress_callback(liq_attr *attr, liq_progress_callback_function *callback, void *user_info)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return;
+
+ attr->progress_callback = callback;
+ attr->progress_callback_user_info = user_info;
+}
+
+LIQ_EXPORT void liq_result_set_progress_callback(liq_result *result, liq_progress_callback_function *callback, void *user_info)
+{
+ if (!CHECK_STRUCT_TYPE(result, liq_result)) return;
+
+ result->progress_callback = callback;
+ result->progress_callback_user_info = user_info;
+}
+
+LIQ_EXPORT void liq_set_log_callback(liq_attr *attr, liq_log_callback_function *callback, void* user_info)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return;
+
+ liq_verbose_printf_flush(attr);
+ attr->log_callback = callback;
+ attr->log_callback_user_info = user_info;
+}
+
+LIQ_EXPORT void liq_set_log_flush_callback(liq_attr *attr, liq_log_flush_callback_function *callback, void* user_info)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return;
+
+ attr->log_flush_callback = callback;
+ attr->log_flush_callback_user_info = user_info;
+}
+
+LIQ_EXPORT liq_attr* liq_attr_create()
+{
+ return liq_attr_create_with_allocator(NULL, NULL);
+}
+
+LIQ_EXPORT LIQ_NONNULL void liq_attr_destroy(liq_attr *attr)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) {
+ return;
+ }
+
+ liq_verbose_printf_flush(attr);
+
+ attr->magic_header = liq_freed_magic;
+ attr->free(attr);
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_attr* liq_attr_copy(const liq_attr *orig)
+{
+ if (!CHECK_STRUCT_TYPE(orig, liq_attr)) {
+ return NULL;
+ }
+
+ liq_attr *attr = orig->malloc(sizeof(liq_attr));
+ if (!attr) return NULL;
+ *attr = *orig;
+ return attr;
+}
+
+static void *liq_aligned_malloc(size_t size)
+{
+ unsigned char *ptr = malloc(size + 16);
+ if (!ptr) {
+ return NULL;
+ }
+
+ uintptr_t offset = 16 - ((uintptr_t)ptr & 15); // also reserves 1 byte for ptr[-1]
+ ptr += offset;
+ assert(0 == (((uintptr_t)ptr) & 15));
+ ptr[-1] = offset ^ 0x59; // store how much pointer was shifted to get the original for free()
+ return ptr;
+}
+
+LIQ_NONNULL static void liq_aligned_free(void *inptr)
+{
+ unsigned char *ptr = inptr;
+ size_t offset = ptr[-1] ^ 0x59;
+ assert(offset > 0 && offset <= 16);
+ free(ptr - offset);
+}
+
+LIQ_EXPORT liq_attr* liq_attr_create_with_allocator(void* (*custom_malloc)(size_t), void (*custom_free)(void*))
+{
+#if USE_SSE
+ if (!is_sse_available()) {
+ return NULL;
+ }
+#endif
+ if (!custom_malloc && !custom_free) {
+ custom_malloc = liq_aligned_malloc;
+ custom_free = liq_aligned_free;
+ } else if (!custom_malloc != !custom_free) {
+ return NULL; // either specify both or none
+ }
+
+ liq_attr *attr = custom_malloc(sizeof(liq_attr));
+ if (!attr) return NULL;
+ *attr = (liq_attr) {
+ .magic_header = liq_attr_magic,
+ .malloc = custom_malloc,
+ .free = custom_free,
+ .max_colors = 256,
+ .min_opaque_val = 1, // whether preserve opaque colors for IE (1.0=no, does not affect alpha)
+ .last_index_transparent = false, // puts transparent color at last index. This is workaround for blu-ray subtitles.
+ .target_mse = 0,
+ .max_mse = MAX_DIFF,
+ };
+ liq_set_speed(attr, 3);
+ return attr;
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_error liq_image_add_fixed_color(liq_image *img, liq_color color)
+{
+ if (!CHECK_STRUCT_TYPE(img, liq_image)) return LIQ_INVALID_POINTER;
+ if (img->fixed_colors_count > 255) return LIQ_UNSUPPORTED;
+
+ float gamma_lut[256];
+ to_f_set_gamma(gamma_lut, img->gamma);
+ img->fixed_colors[img->fixed_colors_count++] = rgba_to_f(gamma_lut, (rgba_pixel){
+ .r = color.r,
+ .g = color.g,
+ .b = color.b,
+ .a = color.a,
+ });
+ return LIQ_OK;
+}
+
+LIQ_NONNULL static liq_error liq_histogram_add_fixed_color_internal(liq_histogram *hist, f_pixel color)
+{
+ if (hist->fixed_colors_count > 255) return LIQ_UNSUPPORTED;
+
+ hist->fixed_colors[hist->fixed_colors_count++] = color;
+ return LIQ_OK;
+}
+
+LIQ_NONNULL static bool liq_image_use_low_memory(liq_image *img)
+{
+ img->temp_f_row = img->malloc(sizeof(img->f_pixels[0]) * img->width * omp_get_max_threads());
+ return img->temp_f_row != NULL;
+}
+
+LIQ_NONNULL static bool liq_image_should_use_low_memory(liq_image *img, const bool low_memory_hint)
+{
+ return img->width * img->height > (low_memory_hint ? LIQ_HIGH_MEMORY_LIMIT/8 : LIQ_HIGH_MEMORY_LIMIT) / sizeof(f_pixel); // Watch out for integer overflow
+}
+
+static liq_image *liq_image_create_internal(const liq_attr *attr, rgba_pixel* rows[], liq_image_get_rgba_row_callback *row_callback, void *row_callback_user_info, int width, int height, double gamma)
+{
+ if (gamma < 0 || gamma > 1.0) {
+ liq_log_error(attr, "gamma must be >= 0 and <= 1 (try 1/gamma instead)");
+ return NULL;
+ }
+
+ if (!rows && !row_callback) {
+ liq_log_error(attr, "missing row data");
+ return NULL;
+ }
+
+ liq_image *img = attr->malloc(sizeof(liq_image));
+ if (!img) return NULL;
+ *img = (liq_image){
+ .magic_header = liq_image_magic,
+ .malloc = attr->malloc,
+ .free = attr->free,
+ .width = width, .height = height,
+ .gamma = gamma ? gamma : 0.45455,
+ .rows = rows,
+ .row_callback = row_callback,
+ .row_callback_user_info = row_callback_user_info,
+ .min_opaque_val = attr->min_opaque_val,
+ };
+
+ if (!rows || attr->min_opaque_val < 1.f) {
+ img->temp_row = attr->malloc(sizeof(img->temp_row[0]) * width * omp_get_max_threads());
+ if (!img->temp_row) return NULL;
+ }
+
+ // if image is huge or converted pixels are not likely to be reused then don't cache converted pixels
+ if (liq_image_should_use_low_memory(img, !img->temp_row && !attr->use_contrast_maps && !attr->use_dither_map)) {
+ verbose_print(attr, " conserving memory");
+ if (!liq_image_use_low_memory(img)) return NULL;
+ }
+
+ if (img->min_opaque_val < 1.f) {
+ verbose_print(attr, " Working around IE6 bug by making image less transparent...");
+ }
+
+ return img;
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_error liq_image_set_memory_ownership(liq_image *img, int ownership_flags)
+{
+ if (!CHECK_STRUCT_TYPE(img, liq_image)) return LIQ_INVALID_POINTER;
+ if (!img->rows || !ownership_flags || (ownership_flags & ~(LIQ_OWN_ROWS|LIQ_OWN_PIXELS))) {
+ return LIQ_VALUE_OUT_OF_RANGE;
+ }
+
+ if (ownership_flags & LIQ_OWN_ROWS) {
+ if (img->free_rows_internal) return LIQ_VALUE_OUT_OF_RANGE;
+ img->free_rows = true;
+ }
+
+ if (ownership_flags & LIQ_OWN_PIXELS) {
+ img->free_pixels = true;
+ if (!img->pixels) {
+ // for simplicity of this API there's no explicit bitmap argument,
+ // so the row with the lowest address is assumed to be at the start of the bitmap
+ img->pixels = img->rows[0];
+ for(unsigned int i=1; i < img->height; i++) {
+ img->pixels = MIN(img->pixels, img->rows[i]);
+ }
+ }
+ }
+
+ return LIQ_OK;
+}
+
+LIQ_NONNULL static bool check_image_size(const liq_attr *attr, const int width, const int height)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) {
+ return false;
+ }
+
+ if (width <= 0 || height <= 0) {
+ liq_log_error(attr, "width and height must be > 0");
+ return false;
+ }
+
+ if (width > INT_MAX/sizeof(rgba_pixel)/height || width > INT_MAX/16/sizeof(f_pixel) || height > INT_MAX/sizeof(size_t)) {
+ liq_log_error(attr, "image too large");
+ return false;
+ }
+ return true;
+}
+
+LIQ_EXPORT liq_image *liq_image_create_custom(const liq_attr *attr, liq_image_get_rgba_row_callback *row_callback, void* user_info, int width, int height, double gamma)
+{
+ if (!check_image_size(attr, width, height)) {
+ return NULL;
+ }
+ return liq_image_create_internal(attr, NULL, row_callback, user_info, width, height, gamma);
+}
+
+LIQ_EXPORT liq_image *liq_image_create_rgba_rows(const liq_attr *attr, void *const rows[], int width, int height, double gamma)
+{
+ if (!check_image_size(attr, width, height)) {
+ return NULL;
+ }
+
+ for(int i=0; i < height; i++) {
+ if (!CHECK_USER_POINTER(rows+i) || !CHECK_USER_POINTER(rows[i])) {
+ liq_log_error(attr, "invalid row pointers");
+ return NULL;
+ }
+ }
+ return liq_image_create_internal(attr, (rgba_pixel**)rows, NULL, NULL, width, height, gamma);
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_image *liq_image_create_rgba(const liq_attr *attr, const void* bitmap, int width, int height, double gamma)
+{
+ if (!check_image_size(attr, width, height)) {
+ return NULL;
+ }
+ if (!CHECK_USER_POINTER(bitmap)) {
+ liq_log_error(attr, "invalid bitmap pointer");
+ return NULL;
+ }
+
+ rgba_pixel *const pixels = (rgba_pixel *const)bitmap;
+ rgba_pixel **rows = attr->malloc(sizeof(rows[0])*height);
+ if (!rows) return NULL;
+
+ for(int i=0; i < height; i++) {
+ rows[i] = pixels + width * i;
+ }
+
+ liq_image *image = liq_image_create_internal(attr, rows, NULL, NULL, width, height, gamma);
+ if (!image) {
+ attr->free(rows);
+ return NULL;
+ }
+ image->free_rows = true;
+ image->free_rows_internal = true;
+ return image;
+}
+
+NEVER_INLINE LIQ_EXPORT void liq_executing_user_callback(liq_image_get_rgba_row_callback *callback, liq_color *temp_row, int row, int width, void *user_info);
+LIQ_EXPORT void liq_executing_user_callback(liq_image_get_rgba_row_callback *callback, liq_color *temp_row, int row, int width, void *user_info)
+{
+ assert(callback);
+ assert(temp_row);
+ callback(temp_row, row, width, user_info);
+}
+
+LIQ_NONNULL inline static bool liq_image_has_rgba_pixels(const liq_image *img)
+{
+ if (!CHECK_STRUCT_TYPE(img, liq_image)) {
+ return false;
+ }
+ return img->rows || (img->temp_row && img->row_callback);
+}
+
+LIQ_NONNULL inline static bool liq_image_can_use_rgba_rows(const liq_image *img)
+{
+ assert(liq_image_has_rgba_pixels(img));
+
+ const bool iebug = img->min_opaque_val < 1.f;
+ return (img->rows && !iebug);
+}
+
+LIQ_NONNULL static const rgba_pixel *liq_image_get_row_rgba(liq_image *img, unsigned int row)
+{
+ if (liq_image_can_use_rgba_rows(img)) {
+ return img->rows[row];
+ }
+
+ assert(img->temp_row);
+ rgba_pixel *temp_row = img->temp_row + img->width * omp_get_thread_num();
+ if (img->rows) {
+ memcpy(temp_row, img->rows[row], img->width * sizeof(temp_row[0]));
+ } else {
+ liq_executing_user_callback(img->row_callback, (liq_color*)temp_row, row, img->width, img->row_callback_user_info);
+ }
+
+ if (img->min_opaque_val < 1.f) modify_alpha(img, temp_row);
+ return temp_row;
+}
+
+LIQ_NONNULL static void convert_row_to_f(liq_image *img, f_pixel *row_f_pixels, const unsigned int row, const float gamma_lut[])
+{
+ assert(row_f_pixels);
+ assert(!USE_SSE || 0 == ((uintptr_t)row_f_pixels & 15));
+
+ const rgba_pixel *const row_pixels = liq_image_get_row_rgba(img, row);
+
+ for(unsigned int col=0; col < img->width; col++) {
+ row_f_pixels[col] = rgba_to_f(gamma_lut, row_pixels[col]);
+ }
+}
+
+LIQ_NONNULL static const f_pixel *liq_image_get_row_f(liq_image *img, unsigned int row)
+{
+ if (!img->f_pixels) {
+ if (img->temp_f_row) {
+ float gamma_lut[256];
+ to_f_set_gamma(gamma_lut, img->gamma);
+ f_pixel *row_for_thread = img->temp_f_row + img->width * omp_get_thread_num();
+ convert_row_to_f(img, row_for_thread, row, gamma_lut);
+ return row_for_thread;
+ }
+
+ assert(omp_get_thread_num() == 0);
+ if (!liq_image_should_use_low_memory(img, false)) {
+ img->f_pixels = img->malloc(sizeof(img->f_pixels[0]) * img->width * img->height);
+ }
+ if (!img->f_pixels) {
+ if (!liq_image_use_low_memory(img)) return NULL;
+ return liq_image_get_row_f(img, row);
+ }
+
+ float gamma_lut[256];
+ to_f_set_gamma(gamma_lut, img->gamma);
+ for(unsigned int i=0; i < img->height; i++) {
+ convert_row_to_f(img, &img->f_pixels[i*img->width], i, gamma_lut);
+ }
+ }
+ return img->f_pixels + img->width * row;
+}
+
+LIQ_EXPORT LIQ_NONNULL int liq_image_get_width(const liq_image *input_image)
+{
+ if (!CHECK_STRUCT_TYPE(input_image, liq_image)) return -1;
+ return input_image->width;
+}
+
+LIQ_EXPORT LIQ_NONNULL int liq_image_get_height(const liq_image *input_image)
+{
+ if (!CHECK_STRUCT_TYPE(input_image, liq_image)) return -1;
+ return input_image->height;
+}
+
+typedef void free_func(void*);
+
+LIQ_NONNULL static free_func *get_default_free_func(liq_image *img)
+{
+ // When default allocator is used then user-supplied pointers must be freed with free()
+ if (img->free_rows_internal || img->free != liq_aligned_free) {
+ return img->free;
+ }
+ return free;
+}
+
+LIQ_NONNULL static void liq_image_free_rgba_source(liq_image *input_image)
+{
+ if (input_image->free_pixels && input_image->pixels) {
+ get_default_free_func(input_image)(input_image->pixels);
+ input_image->pixels = NULL;
+ }
+
+ if (input_image->free_rows && input_image->rows) {
+ get_default_free_func(input_image)(input_image->rows);
+ input_image->rows = NULL;
+ }
+}
+
+LIQ_EXPORT LIQ_NONNULL void liq_image_destroy(liq_image *input_image)
+{
+ if (!CHECK_STRUCT_TYPE(input_image, liq_image)) return;
+
+ liq_image_free_rgba_source(input_image);
+
+ if (input_image->noise) {
+ input_image->free(input_image->noise);
+ }
+
+ if (input_image->edges) {
+ input_image->free(input_image->edges);
+ }
+
+ if (input_image->dither_map) {
+ input_image->free(input_image->dither_map);
+ }
+
+ if (input_image->f_pixels) {
+ input_image->free(input_image->f_pixels);
+ }
+
+ if (input_image->temp_row) {
+ input_image->free(input_image->temp_row);
+ }
+
+ if (input_image->temp_f_row) {
+ input_image->free(input_image->temp_f_row);
+ }
+
+ input_image->magic_header = liq_freed_magic;
+ input_image->free(input_image);
+}
+
+LIQ_EXPORT liq_histogram* liq_histogram_create(const liq_attr* attr)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) {
+ return NULL;
+ }
+
+ liq_histogram *hist = attr->malloc(sizeof(liq_histogram));
+ if (!hist) return NULL;
+ *hist = (liq_histogram) {
+ .magic_header = liq_histogram_magic,
+ .malloc = attr->malloc,
+ .free = attr->free,
+
+ .ignorebits = MAX(attr->min_posterization_output, attr->min_posterization_input),
+ };
+ return hist;
+}
+
+LIQ_EXPORT LIQ_NONNULL void liq_histogram_destroy(liq_histogram *hist)
+{
+ if (!CHECK_STRUCT_TYPE(hist, liq_histogram)) return;
+ hist->magic_header = liq_freed_magic;
+
+ pam_freeacolorhash(hist->acht);
+ hist->free(hist);
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_result *liq_quantize_image(liq_attr *attr, liq_image *img)
+{
+ liq_result *res;
+ if (LIQ_OK != liq_image_quantize(img, attr, &res)) {
+ return NULL;
+ }
+ return res;
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_error liq_image_quantize(liq_image *const img, liq_attr *const attr, liq_result **result_output)
+{
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return LIQ_INVALID_POINTER;
+ if (!liq_image_has_rgba_pixels(img)) {
+ return LIQ_UNSUPPORTED;
+ }
+
+ liq_histogram *hist = liq_histogram_create(attr);
+ if (!hist) {
+ return LIQ_OUT_OF_MEMORY;
+ }
+ liq_error err = liq_histogram_add_image(hist, attr, img);
+ if (LIQ_OK != err) {
+ return err;
+ }
+
+ err = liq_histogram_quantize_internal(hist, attr, false, result_output);
+ liq_histogram_destroy(hist);
+
+ return err;
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_error liq_histogram_quantize(liq_histogram *input_hist, liq_attr *attr, liq_result **result_output) {
+ return liq_histogram_quantize_internal(input_hist, attr, true, result_output);
+}
+
+LIQ_NONNULL static liq_error liq_histogram_quantize_internal(liq_histogram *input_hist, liq_attr *attr, bool fixed_result_colors, liq_result **result_output)
+{
+ if (!CHECK_USER_POINTER(result_output)) return LIQ_INVALID_POINTER;
+ *result_output = NULL;
+
+ if (!CHECK_STRUCT_TYPE(attr, liq_attr)) return LIQ_INVALID_POINTER;
+ if (!CHECK_STRUCT_TYPE(input_hist, liq_histogram)) return LIQ_INVALID_POINTER;
+
+ if (liq_progress(attr, 0)) return LIQ_ABORTED;
+
+ histogram *hist;
+ liq_error err = finalize_histogram(input_hist, attr, &hist);
+ if (err != LIQ_OK) {
+ return err;
+ }
+
+ err = pngquant_quantize(hist, attr, input_hist->fixed_colors_count, input_hist->fixed_colors, input_hist->gamma, fixed_result_colors, result_output);
+ pam_freeacolorhist(hist);
+
+ return err;
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_error liq_set_dithering_level(liq_result *res, float dither_level)
+{
+ if (!CHECK_STRUCT_TYPE(res, liq_result)) return LIQ_INVALID_POINTER;
+
+ if (res->remapping) {
+ liq_remapping_result_destroy(res->remapping);
+ res->remapping = NULL;
+ }
+
+ if (res->dither_level < 0 || res->dither_level > 1.0f) return LIQ_VALUE_OUT_OF_RANGE;
+ res->dither_level = dither_level;
+ return LIQ_OK;
+}
+
+LIQ_NONNULL static liq_remapping_result *liq_remapping_result_create(liq_result *result)
+{
+ if (!CHECK_STRUCT_TYPE(result, liq_result)) {
+ return NULL;
+ }
+
+ liq_remapping_result *res = result->malloc(sizeof(liq_remapping_result));
+ if (!res) return NULL;
+ *res = (liq_remapping_result) {
+ .magic_header = liq_remapping_result_magic,
+ .malloc = result->malloc,
+ .free = result->free,
+ .dither_level = result->dither_level,
+ .use_dither_map = result->use_dither_map,
+ .palette_error = result->palette_error,
+ .gamma = result->gamma,
+ .palette = pam_duplicate_colormap(result->palette),
+ .progress_callback = result->progress_callback,
+ .progress_callback_user_info = result->progress_callback_user_info,
+ .progress_stage1 = result->use_dither_map ? 20 : 0,
+ };
+ return res;
+}
+
+LIQ_EXPORT LIQ_NONNULL double liq_get_output_gamma(const liq_result *result)
+{
+ if (!CHECK_STRUCT_TYPE(result, liq_result)) return -1;
+
+ return result->gamma;
+}
+
+LIQ_NONNULL static void liq_remapping_result_destroy(liq_remapping_result *result)
+{
+ if (!CHECK_STRUCT_TYPE(result, liq_remapping_result)) return;
+
+ if (result->palette) pam_freecolormap(result->palette);
+ if (result->pixels) result->free(result->pixels);
+
+ result->magic_header = liq_freed_magic;
+ result->free(result);
+}
+
+LIQ_EXPORT LIQ_NONNULL void liq_result_destroy(liq_result *res)
+{
+ if (!CHECK_STRUCT_TYPE(res, liq_result)) return;
+
+ memset(&res->int_palette, 0, sizeof(liq_palette));
+
+ if (res->remapping) {
+ memset(&res->remapping->int_palette, 0, sizeof(liq_palette));
+ liq_remapping_result_destroy(res->remapping);
+ }
+
+ pam_freecolormap(res->palette);
+
+ res->magic_header = liq_freed_magic;
+ res->free(res);
+}
+
+
+LIQ_EXPORT LIQ_NONNULL double liq_get_quantization_error(const liq_result *result) {
+ if (!CHECK_STRUCT_TYPE(result, liq_result)) return -1;
+
+ if (result->palette_error >= 0) {
+ return mse_to_standard_mse(result->palette_error);
+ }
+
+ return -1;
+}
+
+LIQ_EXPORT LIQ_NONNULL double liq_get_remapping_error(const liq_result *result) {
+ if (!CHECK_STRUCT_TYPE(result, liq_result)) return -1;
+
+ if (result->remapping && result->remapping->palette_error >= 0) {
+ return mse_to_standard_mse(result->remapping->palette_error);
+ }
+
+ return -1;
+}
+
+LIQ_EXPORT LIQ_NONNULL int liq_get_quantization_quality(const liq_result *result) {
+ if (!CHECK_STRUCT_TYPE(result, liq_result)) return -1;
+
+ if (result->palette_error >= 0) {
+ return mse_to_quality(result->palette_error);
+ }
+
+ return -1;
+}
+
+LIQ_EXPORT LIQ_NONNULL int liq_get_remapping_quality(const liq_result *result) {
+ if (!CHECK_STRUCT_TYPE(result, liq_result)) return -1;
+
+ if (result->remapping && result->remapping->palette_error >= 0) {
+ return mse_to_quality(result->remapping->palette_error);
+ }
+
+ return -1;
+}
+
+LIQ_NONNULL static int compare_popularity(const void *ch1, const void *ch2)
+{
+ const float v1 = ((const colormap_item*)ch1)->popularity;
+ const float v2 = ((const colormap_item*)ch2)->popularity;
+ return v1 > v2 ? -1 : 1;
+}
+
+LIQ_NONNULL static void sort_palette_qsort(colormap *map, int start, int nelem)
+{
+ if (!nelem) return;
+ qsort(map->palette + start, nelem, sizeof(map->palette[0]), compare_popularity);
+}
+
+#define SWAP_PALETTE(map, a,b) { \
+ const colormap_item tmp = (map)->palette[(a)]; \
+ (map)->palette[(a)] = (map)->palette[(b)]; \
+ (map)->palette[(b)] = tmp; }
+
+LIQ_NONNULL static void sort_palette(colormap *map, const liq_attr *options)
+{
+ /*
+ ** Step 3.5 [GRR]: remap the palette colors so that all entries with
+ ** the maximal alpha value (i.e., fully opaque) are at the end and can
+ ** therefore be omitted from the tRNS chunk.
+ */
+ if (options->last_index_transparent) {
+ for(unsigned int i=0; i < map->colors; i++) {
+ if (map->palette[i].acolor.a < 1.0/256.0) {
+ const unsigned int old = i, transparent_dest = map->colors-1;
+
+ SWAP_PALETTE(map, transparent_dest, old);
+
+ /* colors sorted by popularity make pngs slightly more compressible */
+ sort_palette_qsort(map, 0, map->colors-1);
+ return;
+ }
+ }
+ }
+
+ unsigned int non_fixed_colors = 0;
+ for(unsigned int i = 0; i < map->colors; i++) {
+ if (map->palette[i].fixed) {
+ break;
+ }
+ non_fixed_colors++;
+ }
+
+ /* move transparent colors to the beginning to shrink trns chunk */
+ unsigned int num_transparent = 0;
+ for(unsigned int i = 0; i < non_fixed_colors; i++) {
+ if (map->palette[i].acolor.a < 255.0/256.0) {
+ // current transparent color is swapped with earlier opaque one
+ if (i != num_transparent) {
+ SWAP_PALETTE(map, num_transparent, i);
+ i--;
+ }
+ num_transparent++;
+ }
+ }
+
+ liq_verbose_printf(options, " eliminated opaque tRNS-chunk entries...%d entr%s transparent", num_transparent, (num_transparent == 1)? "y" : "ies");
+
+ /* colors sorted by popularity make pngs slightly more compressible
+ * opaque and transparent are sorted separately
+ */
+ sort_palette_qsort(map, 0, num_transparent);
+ sort_palette_qsort(map, num_transparent, non_fixed_colors - num_transparent);
+
+ if (non_fixed_colors > 9 && map->colors > 16) {
+ SWAP_PALETTE(map, 7, 1); // slightly improves compression
+ SWAP_PALETTE(map, 8, 2);
+ SWAP_PALETTE(map, 9, 3);
+ }
+}
+
+inline static unsigned int posterize_channel(unsigned int color, unsigned int bits)
+{
+ return (color & ~((1<> (8-bits));
+}
+
+LIQ_NONNULL static void set_rounded_palette(liq_palette *const dest, colormap *const map, const double gamma, unsigned int posterize)
+{
+ float gamma_lut[256];
+ to_f_set_gamma(gamma_lut, gamma);
+
+ dest->count = map->colors;
+ for(unsigned int x = 0; x < map->colors; ++x) {
+ rgba_pixel px = f_to_rgb(gamma, map->palette[x].acolor);
+
+ px.r = posterize_channel(px.r, posterize);
+ px.g = posterize_channel(px.g, posterize);
+ px.b = posterize_channel(px.b, posterize);
+ px.a = posterize_channel(px.a, posterize);
+
+ map->palette[x].acolor = rgba_to_f(gamma_lut, px); /* saves rounding error introduced by to_rgb, which makes remapping & dithering more accurate */
+
+ if (!px.a && !map->palette[x].fixed) {
+ px.r = 71; px.g = 112; px.b = 76;
+ }
+
+ dest->entries[x] = (liq_color){.r=px.r,.g=px.g,.b=px.b,.a=px.a};
+ }
+}
+
+LIQ_EXPORT LIQ_NONNULL const liq_palette *liq_get_palette(liq_result *result)
+{
+ if (!CHECK_STRUCT_TYPE(result, liq_result)) return NULL;
+
+ if (result->remapping && result->remapping->int_palette.count) {
+ return &result->remapping->int_palette;
+ }
+
+ if (!result->int_palette.count) {
+ set_rounded_palette(&result->int_palette, result->palette, result->gamma, result->min_posterization_output);
+ }
+ return &result->int_palette;
+}
+
+LIQ_NONNULL static float remap_to_palette(liq_image *const input_image, unsigned char *const *const output_pixels, colormap *const map)
+{
+ const int rows = input_image->height;
+ const unsigned int cols = input_image->width;
+ double remapping_error=0;
+
+ if (!liq_image_get_row_f(input_image, 0)) { // trigger lazy conversion
+ return -1;
+ }
+
+ struct nearest_map *const n = nearest_init(map);
+
+ const unsigned int max_threads = omp_get_max_threads();
+ kmeans_state average_color[(KMEANS_CACHE_LINE_GAP+map->colors) * max_threads];
+ kmeans_init(map, max_threads, average_color);
+
+ #pragma omp parallel for if (rows*cols > 3000) \
+ schedule(static) default(none) shared(average_color) reduction(+:remapping_error)
+ for(int row = 0; row < rows; ++row) {
+ const f_pixel *const row_pixels = liq_image_get_row_f(input_image, row);
+ unsigned int last_match=0;
+ for(unsigned int col = 0; col < cols; ++col) {
+ float diff;
+ output_pixels[row][col] = last_match = nearest_search(n, &row_pixels[col], last_match, &diff);
+
+ remapping_error += diff;
+ kmeans_update_color(row_pixels[col], 1.0, map, last_match, omp_get_thread_num(), average_color);
+ }
+ }
+
+ kmeans_finalize(map, max_threads, average_color);
+
+ nearest_free(n);
+
+ return remapping_error / (input_image->width * input_image->height);
+}
+
+inline static f_pixel get_dithered_pixel(const float dither_level, const float max_dither_error, const f_pixel thiserr, const f_pixel px)
+{
+ /* Use Floyd-Steinberg errors to adjust actual color. */
+ const float sr = thiserr.r * dither_level,
+ sg = thiserr.g * dither_level,
+ sb = thiserr.b * dither_level,
+ sa = thiserr.a * dither_level;
+
+ float ratio = 1.0;
+ const float max_overflow = 1.1f;
+ const float max_underflow = -0.1f;
+
+ // allowing some overflow prevents undithered bands caused by clamping of all channels
+ if (px.r + sr > max_overflow) ratio = MIN(ratio, (max_overflow -px.r)/sr);
+ else { if (px.r + sr < max_underflow) ratio = MIN(ratio, (max_underflow-px.r)/sr); }
+ if (px.g + sg > max_overflow) ratio = MIN(ratio, (max_overflow -px.g)/sg);
+ else { if (px.g + sg < max_underflow) ratio = MIN(ratio, (max_underflow-px.g)/sg); }
+ if (px.b + sb > max_overflow) ratio = MIN(ratio, (max_overflow -px.b)/sb);
+ else { if (px.b + sb < max_underflow) ratio = MIN(ratio, (max_underflow-px.b)/sb); }
+
+ float a = px.a + sa;
+ if (a > 1.0) { a = 1.0; }
+ else if (a < 0) { a = 0; }
+
+ // If dithering error is crazy high, don't propagate it that much
+ // This prevents crazy geen pixels popping out of the blue (or red or black! ;)
+ const float dither_error = sr*sr + sg*sg + sb*sb + sa*sa;
+ if (dither_error > max_dither_error) {
+ ratio *= 0.8;
+ } else if (dither_error < 2.f/256.f/256.f) {
+ // don't dither areas that don't have noticeable error — makes file smaller
+ return px;
+ }
+
+ return (f_pixel){
+ .r=px.r + sr * ratio,
+ .g=px.g + sg * ratio,
+ .b=px.b + sb * ratio,
+ .a=a,
+ };
+}
+
+/**
+ Uses edge/noise map to apply dithering only to flat areas. Dithering on edges creates jagged lines, and noisy areas are "naturally" dithered.
+
+ If output_image_is_remapped is true, only pixels noticeably changed by error diffusion will be written to output image.
+ */
+LIQ_NONNULL static bool remap_to_palette_floyd(liq_image *input_image, unsigned char *const output_pixels[], liq_remapping_result *quant, const float max_dither_error, const bool output_image_is_remapped)
+{
+ const int rows = input_image->height, cols = input_image->width;
+ const unsigned char *dither_map = quant->use_dither_map ? (input_image->dither_map ? input_image->dither_map : input_image->edges) : NULL;
+
+ const colormap *map = quant->palette;
+ const colormap_item *acolormap = map->palette;
+
+ /* Initialize Floyd-Steinberg error vectors. */
+ f_pixel *restrict thiserr, *restrict nexterr;
+ const size_t errsize = (cols + 2) * sizeof(*thiserr) * 2;
+ thiserr = input_image->malloc(errsize); // +2 saves from checking out of bounds access
+ if (!thiserr) return false;
+ memset(thiserr, 0, errsize);
+ nexterr = thiserr + (cols + 2);
+
+ bool ok = true;
+ struct nearest_map *const n = nearest_init(map);
+
+ // response to this value is non-linear and without it any value < 0.8 would give almost no dithering
+ float base_dithering_level = quant->dither_level;
+ base_dithering_level = 1.0 - (1.0-base_dithering_level)*(1.0-base_dithering_level);
+
+ if (dither_map) {
+ base_dithering_level *= 1.0/255.0; // convert byte to float
+ }
+ base_dithering_level *= 15.0/16.0; // prevent small errors from accumulating
+
+ int fs_direction = 1;
+ unsigned int last_match=0;
+ for (int row = 0; row < rows; ++row) {
+ if (liq_remap_progress(quant, quant->progress_stage1 + row * (100.f - quant->progress_stage1) / rows)) {
+ ok = false;
+ break;
+ }
+
+ memset(nexterr, 0, (cols + 2) * sizeof(*nexterr));
+
+ int col = (fs_direction > 0) ? 0 : (cols - 1);
+ const f_pixel *const row_pixels = liq_image_get_row_f(input_image, row);
+
+ do {
+ float dither_level = base_dithering_level;
+ if (dither_map) {
+ dither_level *= dither_map[row*cols + col];
+ }
+
+ const f_pixel spx = get_dithered_pixel(dither_level, max_dither_error, thiserr[col + 1], row_pixels[col]);
+
+ const unsigned int guessed_match = output_image_is_remapped ? output_pixels[row][col] : last_match;
+ output_pixels[row][col] = last_match = nearest_search(n, &spx, guessed_match, NULL);
+
+ const f_pixel output_px = acolormap[last_match].acolor;
+ f_pixel err = {
+ .r = (spx.r - output_px.r),
+ .g = (spx.g - output_px.g),
+ .b = (spx.b - output_px.b),
+ .a = (spx.a - output_px.a),
+ };
+
+ // If dithering error is crazy high, don't propagate it that much
+ // This prevents crazy geen pixels popping out of the blue (or red or black! ;)
+ if (err.r*err.r + err.g*err.g + err.b*err.b + err.a*err.a > max_dither_error) {
+ err.r *= 0.75;
+ err.g *= 0.75;
+ err.b *= 0.75;
+ err.a *= 0.75;
+ }
+
+ /* Propagate Floyd-Steinberg error terms. */
+ if (fs_direction > 0) {
+ thiserr[col + 2].a += err.a * (7.f/16.f);
+ thiserr[col + 2].r += err.r * (7.f/16.f);
+ thiserr[col + 2].g += err.g * (7.f/16.f);
+ thiserr[col + 2].b += err.b * (7.f/16.f);
+
+ nexterr[col + 2].a = err.a * (1.f/16.f);
+ nexterr[col + 2].r = err.r * (1.f/16.f);
+ nexterr[col + 2].g = err.g * (1.f/16.f);
+ nexterr[col + 2].b = err.b * (1.f/16.f);
+
+ nexterr[col + 1].a += err.a * (5.f/16.f);
+ nexterr[col + 1].r += err.r * (5.f/16.f);
+ nexterr[col + 1].g += err.g * (5.f/16.f);
+ nexterr[col + 1].b += err.b * (5.f/16.f);
+
+ nexterr[col ].a += err.a * (3.f/16.f);
+ nexterr[col ].r += err.r * (3.f/16.f);
+ nexterr[col ].g += err.g * (3.f/16.f);
+ nexterr[col ].b += err.b * (3.f/16.f);
+
+ } else {
+ thiserr[col ].a += err.a * (7.f/16.f);
+ thiserr[col ].r += err.r * (7.f/16.f);
+ thiserr[col ].g += err.g * (7.f/16.f);
+ thiserr[col ].b += err.b * (7.f/16.f);
+
+ nexterr[col ].a = err.a * (1.f/16.f);
+ nexterr[col ].r = err.r * (1.f/16.f);
+ nexterr[col ].g = err.g * (1.f/16.f);
+ nexterr[col ].b = err.b * (1.f/16.f);
+
+ nexterr[col + 1].a += err.a * (5.f/16.f);
+ nexterr[col + 1].r += err.r * (5.f/16.f);
+ nexterr[col + 1].g += err.g * (5.f/16.f);
+ nexterr[col + 1].b += err.b * (5.f/16.f);
+
+ nexterr[col + 2].a += err.a * (3.f/16.f);
+ nexterr[col + 2].r += err.r * (3.f/16.f);
+ nexterr[col + 2].g += err.g * (3.f/16.f);
+ nexterr[col + 2].b += err.b * (3.f/16.f);
+ }
+
+ // remapping is done in zig-zag
+ col += fs_direction;
+ if (fs_direction > 0) {
+ if (col >= cols) break;
+ } else {
+ if (col <= 0) break;
+ }
+ } while(1);
+
+ f_pixel *const temperr = thiserr;
+ thiserr = nexterr;
+ nexterr = temperr;
+ fs_direction = -fs_direction;
+ }
+
+ input_image->free(MIN(thiserr, nexterr)); // MIN because pointers were swapped
+ nearest_free(n);
+
+ return ok;
+}
+
+/* fixed colors are always included in the palette, so it would be wasteful to duplicate them in palette from histogram */
+LIQ_NONNULL static void remove_fixed_colors_from_histogram(histogram *hist, const int fixed_colors_count, const f_pixel fixed_colors[], const float target_mse)
+{
+ const float max_difference = MAX(target_mse/2.0, 2.0/256.0/256.0);
+ if (fixed_colors_count) {
+ for(int j=0; j < hist->size; j++) {
+ for(unsigned int i=0; i < fixed_colors_count; i++) {
+ if (colordifference(hist->achv[j].acolor, fixed_colors[i]) < max_difference) {
+ hist->achv[j] = hist->achv[--hist->size]; // remove color from histogram by overwriting with the last entry
+ j--; break; // continue searching histogram
+ }
+ }
+ }
+ }
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_error liq_histogram_add_colors(liq_histogram *input_hist, const liq_attr *options, const liq_histogram_entry entries[], int num_entries, double gamma)
+{
+ if (!CHECK_STRUCT_TYPE(options, liq_attr)) return LIQ_INVALID_POINTER;
+ if (!CHECK_STRUCT_TYPE(input_hist, liq_histogram)) return LIQ_INVALID_POINTER;
+ if (!CHECK_USER_POINTER(entries)) return LIQ_INVALID_POINTER;
+ if (gamma < 0 || gamma >= 1.0) return LIQ_VALUE_OUT_OF_RANGE;
+ if (num_entries <= 0 || num_entries > 1<<30) return LIQ_VALUE_OUT_OF_RANGE;
+
+ if (input_hist->ignorebits > 0 && input_hist->had_image_added) {
+ return LIQ_UNSUPPORTED;
+ }
+ input_hist->ignorebits = 0;
+
+ input_hist->had_image_added = true;
+ input_hist->gamma = gamma ? gamma : 0.45455;
+
+ if (!input_hist->acht) {
+ input_hist->acht = pam_allocacolorhash(~0, num_entries*num_entries, 0, options->malloc, options->free);
+ if (!input_hist->acht) {
+ return LIQ_OUT_OF_MEMORY;
+ }
+ }
+ // Fake image size. It's only for hash size estimates.
+ if (!input_hist->acht->cols) {
+ input_hist->acht->cols = num_entries;
+ }
+ input_hist->acht->rows += num_entries;
+
+ const unsigned int hash_size = input_hist->acht->hash_size;
+ for(int i=0; i < num_entries; i++) {
+ const rgba_pixel rgba = {
+ .r = entries[i].color.r,
+ .g = entries[i].color.g,
+ .b = entries[i].color.b,
+ .a = entries[i].color.a,
+ };
+ union rgba_as_int px = {rgba};
+ unsigned int hash;
+ if (px.rgba.a) {
+ hash = px.l % hash_size;
+ } else {
+ hash=0; px.l=0;
+ }
+ if (!pam_add_to_hash(input_hist->acht, hash, entries[i].count, px, i, num_entries)) {
+ return LIQ_OUT_OF_MEMORY;
+ }
+ }
+
+ return LIQ_OK;
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_error liq_histogram_add_image(liq_histogram *input_hist, const liq_attr *options, liq_image *input_image)
+{
+ if (!CHECK_STRUCT_TYPE(options, liq_attr)) return LIQ_INVALID_POINTER;
+ if (!CHECK_STRUCT_TYPE(input_hist, liq_histogram)) return LIQ_INVALID_POINTER;
+ if (!CHECK_STRUCT_TYPE(input_image, liq_image)) return LIQ_INVALID_POINTER;
+
+ const unsigned int cols = input_image->width, rows = input_image->height;
+
+ if (!input_image->noise && options->use_contrast_maps) {
+ contrast_maps(input_image);
+ }
+
+ input_hist->gamma = input_image->gamma;
+
+ for(int i = 0; i < input_image->fixed_colors_count; i++) {
+ liq_error res = liq_histogram_add_fixed_color_internal(input_hist, input_image->fixed_colors[i]);
+ if (res != LIQ_OK) {
+ return res;
+ }
+ }
+
+ /*
+ ** Step 2: attempt to make a histogram of the colors, unclustered.
+ ** If at first we don't succeed, increase ignorebits to increase color
+ ** coherence and try again.
+ */
+
+ if (liq_progress(options, options->progress_stage1 * 0.4f)) return LIQ_ABORTED;
+
+ const bool all_rows_at_once = liq_image_can_use_rgba_rows(input_image);
+
+ // Usual solution is to start from scratch when limit is exceeded, but that's not possible if it's not
+ // the first image added
+ const unsigned int max_histogram_entries = input_hist->had_image_added ? ~0 : options->max_histogram_entries;
+ do {
+ if (!input_hist->acht) {
+ input_hist->acht = pam_allocacolorhash(max_histogram_entries, rows*cols, input_hist->ignorebits, options->malloc, options->free);
+ }
+ if (!input_hist->acht) return LIQ_OUT_OF_MEMORY;
+
+ // histogram uses noise contrast map for importance. Color accuracy in noisy areas is not very important.
+ // noise map does not include edges to avoid ruining anti-aliasing
+ for(unsigned int row=0; row < rows; row++) {
+ bool added_ok;
+ if (all_rows_at_once) {
+ added_ok = pam_computeacolorhash(input_hist->acht, (const rgba_pixel *const *)input_image->rows, cols, rows, input_image->noise);
+ if (added_ok) break;
+ } else {
+ const rgba_pixel* rows_p[1] = { liq_image_get_row_rgba(input_image, row) };
+ added_ok = pam_computeacolorhash(input_hist->acht, rows_p, cols, 1, input_image->noise ? &input_image->noise[row * cols] : NULL);
+ }
+ if (!added_ok) {
+ input_hist->ignorebits++;
+ liq_verbose_printf(options, " too many colors! Scaling colors to improve clustering... %d", input_hist->ignorebits);
+ pam_freeacolorhash(input_hist->acht);
+ input_hist->acht = NULL;
+ if (liq_progress(options, options->progress_stage1 * 0.6f)) return LIQ_ABORTED;
+ break;
+ }
+ }
+ } while(!input_hist->acht);
+
+ input_hist->had_image_added = true;
+
+ if (input_image->noise) {
+ input_image->free(input_image->noise);
+ input_image->noise = NULL;
+ }
+
+ if (input_image->free_pixels && input_image->f_pixels) {
+ liq_image_free_rgba_source(input_image); // bow can free the RGBA source if copy has been made in f_pixels
+ }
+
+ return LIQ_OK;
+}
+
+LIQ_NONNULL static liq_error finalize_histogram(liq_histogram *input_hist, liq_attr *options, histogram **hist_output)
+{
+ if (liq_progress(options, options->progress_stage1 * 0.9f)) {
+ return LIQ_ABORTED;
+ }
+
+ if (!input_hist->acht) {
+ return LIQ_BITMAP_NOT_AVAILABLE;
+ }
+
+ histogram *hist = pam_acolorhashtoacolorhist(input_hist->acht, input_hist->gamma, options->malloc, options->free);
+ pam_freeacolorhash(input_hist->acht);
+ input_hist->acht = NULL;
+
+ if (!hist) {
+ return LIQ_OUT_OF_MEMORY;
+ }
+ liq_verbose_printf(options, " made histogram...%d colors found", hist->size);
+ remove_fixed_colors_from_histogram(hist, input_hist->fixed_colors_count, input_hist->fixed_colors, options->target_mse);
+
+ *hist_output = hist;
+ return LIQ_OK;
+}
+
+LIQ_NONNULL static void modify_alpha(liq_image *input_image, rgba_pixel *const row_pixels)
+{
+ /* IE6 makes colors with even slightest transparency completely transparent,
+ thus to improve situation in IE, make colors that are less than ~10% transparent
+ completely opaque */
+
+ const float min_opaque_val = input_image->min_opaque_val;
+ const float almost_opaque_val = min_opaque_val * 169.f/256.f;
+ const unsigned int almost_opaque_val_int = (min_opaque_val * 169.f/256.f)*255.f;
+
+ for(unsigned int col = 0; col < input_image->width; col++) {
+ const rgba_pixel px = row_pixels[col];
+
+ /* ie bug: to avoid visible step caused by forced opaqueness, linearily raise opaqueness of almost-opaque colors */
+ if (px.a >= almost_opaque_val_int) {
+ float al = px.a / 255.f;
+ al = almost_opaque_val + (al-almost_opaque_val) * (1.f-almost_opaque_val) / (min_opaque_val-almost_opaque_val);
+ al *= 256.f;
+ row_pixels[col].a = al >= 255.f ? 255 : al;
+ }
+ }
+}
+
+/**
+ Builds two maps:
+ noise - approximation of areas with high-frequency noise, except straight edges. 1=flat, 0=noisy.
+ edges - noise map including all edges
+ */
+LIQ_NONNULL static void contrast_maps(liq_image *image)
+{
+ const unsigned int cols = image->width, rows = image->height;
+ if (cols < 4 || rows < 4 || (3*cols*rows) > LIQ_HIGH_MEMORY_LIMIT) {
+ return;
+ }
+
+ unsigned char *restrict noise = image->noise ? image->noise : image->malloc(cols*rows);
+ image->noise = NULL;
+ unsigned char *restrict edges = image->edges ? image->edges : image->malloc(cols*rows);
+ image->edges = NULL;
+
+ unsigned char *restrict tmp = image->malloc(cols*rows);
+
+ if (!noise || !edges || !tmp) {
+ image->free(noise);
+ image->free(edges);
+ image->free(tmp);
+ return;
+ }
+
+ const f_pixel *curr_row, *prev_row, *next_row;
+ curr_row = prev_row = next_row = liq_image_get_row_f(image, 0);
+
+ for (unsigned int j=0; j < rows; j++) {
+ prev_row = curr_row;
+ curr_row = next_row;
+ next_row = liq_image_get_row_f(image, MIN(rows-1,j+1));
+
+ f_pixel prev, curr = curr_row[0], next=curr;
+ for (unsigned int i=0; i < cols; i++) {
+ prev=curr;
+ curr=next;
+ next = curr_row[MIN(cols-1,i+1)];
+
+ // contrast is difference between pixels neighbouring horizontally and vertically
+ const float a = fabsf(prev.a+next.a - curr.a*2.f),
+ r = fabsf(prev.r+next.r - curr.r*2.f),
+ g = fabsf(prev.g+next.g - curr.g*2.f),
+ b = fabsf(prev.b+next.b - curr.b*2.f);
+
+ const f_pixel prevl = prev_row[i];
+ const f_pixel nextl = next_row[i];
+
+ const float a1 = fabsf(prevl.a+nextl.a - curr.a*2.f),
+ r1 = fabsf(prevl.r+nextl.r - curr.r*2.f),
+ g1 = fabsf(prevl.g+nextl.g - curr.g*2.f),
+ b1 = fabsf(prevl.b+nextl.b - curr.b*2.f);
+
+ const float horiz = MAX(MAX(a,r),MAX(g,b));
+ const float vert = MAX(MAX(a1,r1),MAX(g1,b1));
+ const float edge = MAX(horiz,vert);
+ float z = edge - fabsf(horiz-vert)*.5f;
+ z = 1.f - MAX(z,MIN(horiz,vert));
+ z *= z; // noise is amplified
+ z *= z;
+
+ z *= 256.f;
+ noise[j*cols+i] = z < 256 ? z : 255;
+ z = (1.f-edge)*256.f;
+ edges[j*cols+i] = z > 0 ? (z < 256 ? z : 255) : 0;
+ }
+ }
+
+ // noise areas are shrunk and then expanded to remove thin edges from the map
+ liq_max3(noise, tmp, cols, rows);
+ liq_max3(tmp, noise, cols, rows);
+
+ liq_blur(noise, tmp, noise, cols, rows, 3);
+
+ liq_max3(noise, tmp, cols, rows);
+
+ liq_min3(tmp, noise, cols, rows);
+ liq_min3(noise, tmp, cols, rows);
+ liq_min3(tmp, noise, cols, rows);
+
+ liq_min3(edges, tmp, cols, rows);
+ liq_max3(tmp, edges, cols, rows);
+ for(unsigned int i=0; i < cols*rows; i++) edges[i] = MIN(noise[i], edges[i]);
+
+ image->free(tmp);
+
+ image->noise = noise;
+ image->edges = edges;
+}
+
+/**
+ * Builds map of neighbor pixels mapped to the same palette entry
+ *
+ * For efficiency/simplicity it mainly looks for same consecutive pixels horizontally
+ * and peeks 1 pixel above/below. Full 2d algorithm doesn't improve it significantly.
+ * Correct flood fill doesn't have visually good properties.
+ */
+LIQ_NONNULL static void update_dither_map(unsigned char *const *const row_pointers, liq_image *input_image)
+{
+ const unsigned int width = input_image->width;
+ const unsigned int height = input_image->height;
+ unsigned char *const edges = input_image->edges;
+
+ for(unsigned int row=0; row < height; row++) {
+ unsigned char lastpixel = row_pointers[row][0];
+ unsigned int lastcol=0;
+
+ for(unsigned int col=1; col < width; col++) {
+ const unsigned char px = row_pointers[row][col];
+
+ if (px != lastpixel || col == width-1) {
+ int neighbor_count = 10 * (col-lastcol);
+
+ unsigned int i=lastcol;
+ while(i < col) {
+ if (row > 0) {
+ unsigned char pixelabove = row_pointers[row-1][i];
+ if (pixelabove == lastpixel) neighbor_count += 15;
+ }
+ if (row < height-1) {
+ unsigned char pixelbelow = row_pointers[row+1][i];
+ if (pixelbelow == lastpixel) neighbor_count += 15;
+ }
+ i++;
+ }
+
+ while(lastcol <= col) {
+ int e = edges[row*width + lastcol];
+ edges[row*width + lastcol++] = (e+128) * (255.f/(255+128)) * (1.f - 20.f / (20 + neighbor_count));
+ }
+ lastpixel = px;
+ }
+ }
+ }
+ input_image->dither_map = input_image->edges;
+ input_image->edges = NULL;
+}
+
+/**
+ * Palette can be NULL, in which case it creates a new palette from scratch.
+ */
+static colormap *add_fixed_colors_to_palette(colormap *palette, const int max_colors, const f_pixel fixed_colors[], const int fixed_colors_count, void* (*malloc)(size_t), void (*free)(void*))
+{
+ if (!fixed_colors_count) return palette;
+
+ colormap *newpal = pam_colormap(MIN(max_colors, (palette ? palette->colors : 0) + fixed_colors_count), malloc, free);
+ unsigned int i=0;
+ if (palette && fixed_colors_count < max_colors) {
+ unsigned int palette_max = MIN(palette->colors, max_colors - fixed_colors_count);
+ for(; i < palette_max; i++) {
+ newpal->palette[i] = palette->palette[i];
+ }
+ }
+ for(int j=0; j < MIN(max_colors, fixed_colors_count); j++) {
+ newpal->palette[i++] = (colormap_item){
+ .acolor = fixed_colors[j],
+ .fixed = true,
+ };
+ }
+ if (palette) pam_freecolormap(palette);
+ return newpal;
+}
+
+LIQ_NONNULL static void adjust_histogram_callback(hist_item *item, float diff)
+{
+ item->adjusted_weight = (item->perceptual_weight+item->adjusted_weight) * (sqrtf(1.f+diff));
+}
+
+/**
+ Repeats mediancut with different histogram weights to find palette with minimum error.
+
+ feedback_loop_trials controls how long the search will take. < 0 skips the iteration.
+ */
+static colormap *find_best_palette(histogram *hist, const liq_attr *options, const double max_mse, const f_pixel fixed_colors[], const unsigned int fixed_colors_count, double *palette_error_p)
+{
+ unsigned int max_colors = options->max_colors;
+
+ // if output is posterized it doesn't make sense to aim for perfrect colors, so increase target_mse
+ // at this point actual gamma is not set, so very conservative posterization estimate is used
+ const double target_mse = MIN(max_mse, MAX(options->target_mse, pow((1<min_posterization_output)/1024.0, 2)));
+ int feedback_loop_trials = options->feedback_loop_trials;
+ colormap *acolormap = NULL;
+ double least_error = MAX_DIFF;
+ double target_mse_overshoot = feedback_loop_trials>0 ? 1.05 : 1.0;
+ const float total_trials = (float)(feedback_loop_trials>0?feedback_loop_trials:1);
+
+ do {
+ colormap *newmap;
+ if (hist->size && fixed_colors_count < max_colors) {
+ newmap = mediancut(hist, max_colors-fixed_colors_count, target_mse * target_mse_overshoot, MAX(MAX(45.0/65536.0, target_mse), least_error)*1.2,
+ options->malloc, options->free);
+ } else {
+ feedback_loop_trials = 0;
+ newmap = NULL;
+ }
+ newmap = add_fixed_colors_to_palette(newmap, max_colors, fixed_colors, fixed_colors_count, options->malloc, options->free);
+ if (!newmap) {
+ return NULL;
+ }
+
+ if (feedback_loop_trials <= 0) {
+ return newmap;
+ }
+
+ // after palette has been created, total error (MSE) is calculated to keep the best palette
+ // at the same time K-Means iteration is done to improve the palette
+ // and histogram weights are adjusted based on remapping error to give more weight to poorly matched colors
+
+ const bool first_run_of_target_mse = !acolormap && target_mse > 0;
+ double total_error = kmeans_do_iteration(hist, newmap, first_run_of_target_mse ? NULL : adjust_histogram_callback);
+
+ // goal is to increase quality or to reduce number of colors used if quality is good enough
+ if (!acolormap || total_error < least_error || (total_error <= target_mse && newmap->colors < max_colors)) {
+ if (acolormap) pam_freecolormap(acolormap);
+ acolormap = newmap;
+
+ if (total_error < target_mse && total_error > 0) {
+ // K-Means iteration improves quality above what mediancut aims for
+ // this compensates for it, making mediancut aim for worse
+ target_mse_overshoot = MIN(target_mse_overshoot*1.25, target_mse/total_error);
+ }
+
+ least_error = total_error;
+
+ // if number of colors could be reduced, try to keep it that way
+ // but allow extra color as a bit of wiggle room in case quality can be improved too
+ max_colors = MIN(newmap->colors+1, max_colors);
+
+ feedback_loop_trials -= 1; // asymptotic improvement could make it go on forever
+ } else {
+ for(unsigned int j=0; j < hist->size; j++) {
+ hist->achv[j].adjusted_weight = (hist->achv[j].perceptual_weight + hist->achv[j].adjusted_weight)/2.0;
+ }
+
+ target_mse_overshoot = 1.0;
+ feedback_loop_trials -= 6;
+ // if error is really bad, it's unlikely to improve, so end sooner
+ if (total_error > least_error*4) feedback_loop_trials -= 3;
+ pam_freecolormap(newmap);
+ }
+
+ float fraction_done = 1.f-MAX(0.f, feedback_loop_trials/total_trials);
+ if (liq_progress(options, options->progress_stage1 + fraction_done * options->progress_stage2)) break;
+ liq_verbose_printf(options, " selecting colors...%d%%", (int)(100.f * fraction_done));
+ }
+ while(feedback_loop_trials > 0);
+
+ *palette_error_p = least_error;
+ return acolormap;
+}
+
+static colormap *histogram_to_palette(const histogram *hist, const liq_attr *options) {
+ if (!hist->size) {
+ return NULL;
+ }
+ colormap *acolormap = pam_colormap(hist->size, options->malloc, options->free);
+ for(unsigned int i=0; i < hist->size; i++) {
+ acolormap->palette[i].acolor = hist->achv[i].acolor;
+ acolormap->palette[i].popularity = hist->achv[i].perceptual_weight;
+ }
+ return acolormap;
+}
+
+LIQ_NONNULL static liq_error pngquant_quantize(histogram *hist, const liq_attr *options, const int fixed_colors_count, const f_pixel fixed_colors[], const double gamma, bool fixed_result_colors, liq_result **result_output)
+{
+ colormap *acolormap;
+ double palette_error = -1;
+
+ assert((verbose_print(options, "SLOW debug checks enabled. Recompile with NDEBUG for normal operation."),1));
+
+ const bool few_input_colors = hist->size+fixed_colors_count <= options->max_colors;
+
+ if (liq_progress(options, options->progress_stage1)) return LIQ_ABORTED;
+
+ // If image has few colors to begin with (and no quality degradation is required)
+ // then it's possible to skip quantization entirely
+ if (few_input_colors && options->target_mse == 0) {
+ acolormap = add_fixed_colors_to_palette(histogram_to_palette(hist, options), options->max_colors, fixed_colors, fixed_colors_count, options->malloc, options->free);
+ palette_error = 0;
+ } else {
+ const double max_mse = options->max_mse * (few_input_colors ? 0.33 : 1.0); // when degrading image that's already paletted, require much higher improvement, since pal2pal often looks bad and there's little gain
+ acolormap = find_best_palette(hist, options, max_mse, fixed_colors, fixed_colors_count, &palette_error);
+ if (!acolormap) {
+ return LIQ_VALUE_OUT_OF_RANGE;
+ }
+
+ // K-Means iteration approaches local minimum for the palette
+ const double iteration_limit = options->kmeans_iteration_limit;
+ unsigned int iterations = options->kmeans_iterations;
+
+ if (!iterations && palette_error < 0 && max_mse < MAX_DIFF) iterations = 1; // otherwise total error is never calculated and MSE limit won't work
+
+ if (iterations) {
+ // likely_colormap_index (used and set in kmeans_do_iteration) can't point to index outside colormap
+ if (acolormap->colors < 256) for(unsigned int j=0; j < hist->size; j++) {
+ if (hist->achv[j].tmp.likely_colormap_index >= acolormap->colors) {
+ hist->achv[j].tmp.likely_colormap_index = 0; // actual value doesn't matter, as the guess is out of date anyway
+ }
+ }
+
+ verbose_print(options, " moving colormap towards local minimum");
+
+ double previous_palette_error = MAX_DIFF;
+
+ for(unsigned int i=0; i < iterations; i++) {
+ palette_error = kmeans_do_iteration(hist, acolormap, NULL);
+
+ if (liq_progress(options, options->progress_stage1 + options->progress_stage2 + (i * options->progress_stage3 * 0.9f) / iterations)) {
+ break;
+ }
+
+ if (fabs(previous_palette_error-palette_error) < iteration_limit) {
+ break;
+ }
+
+ if (palette_error > max_mse*1.5) { // probably hopeless
+ if (palette_error > max_mse*3.0) break; // definitely hopeless
+ i++;
+ }
+
+ previous_palette_error = palette_error;
+ }
+ }
+
+ if (palette_error > max_mse) {
+ liq_verbose_printf(options, " image degradation MSE=%.3f (Q=%d) exceeded limit of %.3f (%d)",
+ mse_to_standard_mse(palette_error), mse_to_quality(palette_error),
+ mse_to_standard_mse(max_mse), mse_to_quality(max_mse));
+ pam_freecolormap(acolormap);
+ return LIQ_QUALITY_TOO_LOW;
+ }
+ }
+
+ if (liq_progress(options, options->progress_stage1 + options->progress_stage2 + options->progress_stage3 * 0.95f)) {
+ pam_freecolormap(acolormap);
+ return LIQ_ABORTED;
+ }
+
+ sort_palette(acolormap, options);
+
+ // If palette was created from a multi-image histogram,
+ // then it shouldn't be optimized for one image during remapping
+ if (fixed_result_colors) {
+ for(unsigned int i=0; i < acolormap->colors; i++) {
+ acolormap->palette[i].fixed = true;
+ }
+ }
+
+ liq_result *result = options->malloc(sizeof(liq_result));
+ if (!result) return LIQ_OUT_OF_MEMORY;
+ *result = (liq_result){
+ .magic_header = liq_result_magic,
+ .malloc = options->malloc,
+ .free = options->free,
+ .palette = acolormap,
+ .palette_error = palette_error,
+ .use_dither_map = options->use_dither_map,
+ .gamma = gamma,
+ .min_posterization_output = options->min_posterization_output,
+ };
+ *result_output = result;
+ return LIQ_OK;
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_error liq_write_remapped_image(liq_result *result, liq_image *input_image, void *buffer, size_t buffer_size)
+{
+ if (!CHECK_STRUCT_TYPE(result, liq_result)) {
+ return LIQ_INVALID_POINTER;
+ }
+ if (!CHECK_STRUCT_TYPE(input_image, liq_image)) {
+ return LIQ_INVALID_POINTER;
+ }
+ if (!CHECK_USER_POINTER(buffer)) {
+ return LIQ_INVALID_POINTER;
+ }
+
+ const size_t required_size = input_image->width * input_image->height;
+ if (buffer_size < required_size) {
+ return LIQ_BUFFER_TOO_SMALL;
+ }
+
+ unsigned char *rows[input_image->height];
+ unsigned char *buffer_bytes = buffer;
+ for(unsigned int i=0; i < input_image->height; i++) {
+ rows[i] = &buffer_bytes[input_image->width * i];
+ }
+ return liq_write_remapped_image_rows(result, input_image, rows);
+}
+
+LIQ_EXPORT LIQ_NONNULL liq_error liq_write_remapped_image_rows(liq_result *quant, liq_image *input_image, unsigned char **row_pointers)
+{
+ if (!CHECK_STRUCT_TYPE(quant, liq_result)) return LIQ_INVALID_POINTER;
+ if (!CHECK_STRUCT_TYPE(input_image, liq_image)) return LIQ_INVALID_POINTER;
+ for(unsigned int i=0; i < input_image->height; i++) {
+ if (!CHECK_USER_POINTER(row_pointers+i) || !CHECK_USER_POINTER(row_pointers[i])) return LIQ_INVALID_POINTER;
+ }
+
+ if (quant->remapping) {
+ liq_remapping_result_destroy(quant->remapping);
+ }
+ liq_remapping_result *const result = quant->remapping = liq_remapping_result_create(quant);
+ if (!result) return LIQ_OUT_OF_MEMORY;
+
+ if (!input_image->edges && !input_image->dither_map && quant->use_dither_map) {
+ contrast_maps(input_image);
+ }
+
+ if (liq_remap_progress(result, result->progress_stage1 * 0.25f)) {
+ return LIQ_ABORTED;
+ }
+
+ /*
+ ** Step 4: map the colors in the image to their closest match in the
+ ** new colormap, and write 'em out.
+ */
+
+ float remapping_error = result->palette_error;
+ if (result->dither_level == 0) {
+ set_rounded_palette(&result->int_palette, result->palette, result->gamma, quant->min_posterization_output);
+ remapping_error = remap_to_palette(input_image, row_pointers, result->palette);
+ } else {
+ const bool generate_dither_map = result->use_dither_map && (input_image->edges && !input_image->dither_map);
+ if (generate_dither_map) {
+ // If dithering (with dither map) is required, this image is used to find areas that require dithering
+ remapping_error = remap_to_palette(input_image, row_pointers, result->palette);
+ update_dither_map(row_pointers, input_image);
+ }
+
+ if (liq_remap_progress(result, result->progress_stage1 * 0.5f)) {
+ return LIQ_ABORTED;
+ }
+
+ // remapping above was the last chance to do K-Means iteration, hence the final palette is set after remapping
+ set_rounded_palette(&result->int_palette, result->palette, result->gamma, quant->min_posterization_output);
+
+ if (!remap_to_palette_floyd(input_image, row_pointers, result, MAX(remapping_error*2.4, 16.f/256.f), generate_dither_map)) {
+ return LIQ_ABORTED;
+ }
+ }
+
+ // remapping error from dithered image is absurd, so always non-dithered value is used
+ // palette_error includes some perceptual weighting from histogram which is closer correlated with dssim
+ // so that should be used when possible.
+ if (result->palette_error < 0) {
+ result->palette_error = remapping_error;
+ }
+
+ return LIQ_OK;
+}
+
+LIQ_EXPORT int liq_version() {
+ return LIQ_VERSION;
+}
diff --git a/vendor/code.ivysaur.me/imagequant/libimagequant.h b/vendor/code.ivysaur.me/imagequant/libimagequant.h
new file mode 100644
index 0000000..c86f5a5
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/libimagequant.h
@@ -0,0 +1,144 @@
+/*
+ * https://pngquant.org
+ */
+
+#ifndef LIBIMAGEQUANT_H
+#define LIBIMAGEQUANT_H
+
+#ifdef IMAGEQUANT_EXPORTS
+#define LIQ_EXPORT __declspec(dllexport)
+#endif
+
+#ifndef LIQ_EXPORT
+#define LIQ_EXPORT extern
+#endif
+
+#define LIQ_VERSION 20900
+#define LIQ_VERSION_STRING "2.9.0"
+
+#ifndef LIQ_PRIVATE
+#if defined(__GNUC__) || defined (__llvm__)
+#define LIQ_PRIVATE __attribute__((visibility("hidden")))
+#define LIQ_NONNULL __attribute__((nonnull))
+#define LIQ_USERESULT __attribute__((warn_unused_result))
+#else
+#define LIQ_PRIVATE
+#define LIQ_NONNULL
+#define LIQ_USERESULT
+#endif
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include
+
+typedef struct liq_attr liq_attr;
+typedef struct liq_image liq_image;
+typedef struct liq_result liq_result;
+typedef struct liq_histogram liq_histogram;
+
+typedef struct liq_color {
+ unsigned char r, g, b, a;
+} liq_color;
+
+typedef struct liq_palette {
+ unsigned int count;
+ liq_color entries[256];
+} liq_palette;
+
+typedef enum liq_error {
+ LIQ_OK = 0,
+ LIQ_QUALITY_TOO_LOW = 99,
+ LIQ_VALUE_OUT_OF_RANGE = 100,
+ LIQ_OUT_OF_MEMORY,
+ LIQ_ABORTED,
+ LIQ_BITMAP_NOT_AVAILABLE,
+ LIQ_BUFFER_TOO_SMALL,
+ LIQ_INVALID_POINTER,
+ LIQ_UNSUPPORTED,
+} liq_error;
+
+enum liq_ownership {LIQ_OWN_ROWS=4, LIQ_OWN_PIXELS=8};
+
+typedef struct liq_histogram_entry {
+ liq_color color;
+ unsigned int count;
+} liq_histogram_entry;
+
+LIQ_EXPORT LIQ_USERESULT liq_attr* liq_attr_create(void);
+LIQ_EXPORT LIQ_USERESULT liq_attr* liq_attr_create_with_allocator(void* (*malloc)(size_t), void (*free)(void*));
+LIQ_EXPORT LIQ_USERESULT liq_attr* liq_attr_copy(const liq_attr *orig) LIQ_NONNULL;
+LIQ_EXPORT void liq_attr_destroy(liq_attr *attr) LIQ_NONNULL;
+
+LIQ_EXPORT LIQ_USERESULT liq_histogram* liq_histogram_create(const liq_attr* attr);
+LIQ_EXPORT liq_error liq_histogram_add_image(liq_histogram *hist, const liq_attr *attr, liq_image* image) LIQ_NONNULL;
+LIQ_EXPORT liq_error liq_histogram_add_colors(liq_histogram *hist, const liq_attr *attr, const liq_histogram_entry entries[], int num_entries, double gamma) LIQ_NONNULL;
+LIQ_EXPORT void liq_histogram_destroy(liq_histogram *hist) LIQ_NONNULL;
+
+LIQ_EXPORT liq_error liq_set_max_colors(liq_attr* attr, int colors) LIQ_NONNULL;
+LIQ_EXPORT LIQ_USERESULT int liq_get_max_colors(const liq_attr* attr) LIQ_NONNULL;
+LIQ_EXPORT liq_error liq_set_speed(liq_attr* attr, int speed) LIQ_NONNULL;
+LIQ_EXPORT LIQ_USERESULT int liq_get_speed(const liq_attr* attr) LIQ_NONNULL;
+LIQ_EXPORT liq_error liq_set_min_opacity(liq_attr* attr, int min) LIQ_NONNULL;
+LIQ_EXPORT LIQ_USERESULT int liq_get_min_opacity(const liq_attr* attr) LIQ_NONNULL;
+LIQ_EXPORT liq_error liq_set_min_posterization(liq_attr* attr, int bits) LIQ_NONNULL;
+LIQ_EXPORT LIQ_USERESULT int liq_get_min_posterization(const liq_attr* attr) LIQ_NONNULL;
+LIQ_EXPORT liq_error liq_set_quality(liq_attr* attr, int minimum, int maximum) LIQ_NONNULL;
+LIQ_EXPORT LIQ_USERESULT int liq_get_min_quality(const liq_attr* attr) LIQ_NONNULL;
+LIQ_EXPORT LIQ_USERESULT int liq_get_max_quality(const liq_attr* attr) LIQ_NONNULL;
+LIQ_EXPORT void liq_set_last_index_transparent(liq_attr* attr, int is_last) LIQ_NONNULL;
+
+typedef void liq_log_callback_function(const liq_attr*, const char *message, void* user_info);
+typedef void liq_log_flush_callback_function(const liq_attr*, void* user_info);
+LIQ_EXPORT void liq_set_log_callback(liq_attr*, liq_log_callback_function*, void* user_info);
+LIQ_EXPORT void liq_set_log_flush_callback(liq_attr*, liq_log_flush_callback_function*, void* user_info);
+
+typedef int liq_progress_callback_function(float progress_percent, void* user_info);
+LIQ_EXPORT void liq_attr_set_progress_callback(liq_attr*, liq_progress_callback_function*, void* user_info);
+LIQ_EXPORT void liq_result_set_progress_callback(liq_result*, liq_progress_callback_function*, void* user_info);
+
+// The rows and their data are not modified. The type of `rows` is non-const only due to a bug in C's typesystem design.
+LIQ_EXPORT LIQ_USERESULT liq_image *liq_image_create_rgba_rows(const liq_attr *attr, void *const rows[], int width, int height, double gamma) LIQ_NONNULL;
+LIQ_EXPORT LIQ_USERESULT liq_image *liq_image_create_rgba(const liq_attr *attr, const void *bitmap, int width, int height, double gamma) LIQ_NONNULL;
+
+typedef void liq_image_get_rgba_row_callback(liq_color row_out[], int row, int width, void* user_info);
+LIQ_EXPORT LIQ_USERESULT liq_image *liq_image_create_custom(const liq_attr *attr, liq_image_get_rgba_row_callback *row_callback, void* user_info, int width, int height, double gamma);
+
+LIQ_EXPORT liq_error liq_image_set_memory_ownership(liq_image *image, int ownership_flags) LIQ_NONNULL;
+LIQ_EXPORT liq_error liq_image_add_fixed_color(liq_image *img, liq_color color) LIQ_NONNULL;
+LIQ_EXPORT LIQ_USERESULT int liq_image_get_width(const liq_image *img) LIQ_NONNULL;
+LIQ_EXPORT LIQ_USERESULT int liq_image_get_height(const liq_image *img) LIQ_NONNULL;
+LIQ_EXPORT void liq_image_destroy(liq_image *img) LIQ_NONNULL;
+
+LIQ_EXPORT LIQ_USERESULT liq_error liq_histogram_quantize(liq_histogram *const input_hist, liq_attr *const options, liq_result **result_output) LIQ_NONNULL;
+LIQ_EXPORT LIQ_USERESULT liq_error liq_image_quantize(liq_image *const input_image, liq_attr *const options, liq_result **result_output) LIQ_NONNULL;
+
+LIQ_EXPORT liq_error liq_set_dithering_level(liq_result *res, float dither_level) LIQ_NONNULL;
+LIQ_EXPORT liq_error liq_set_output_gamma(liq_result* res, double gamma) LIQ_NONNULL;
+LIQ_EXPORT LIQ_USERESULT double liq_get_output_gamma(const liq_result *result) LIQ_NONNULL;
+
+LIQ_EXPORT LIQ_USERESULT const liq_palette *liq_get_palette(liq_result *result) LIQ_NONNULL;
+
+LIQ_EXPORT liq_error liq_write_remapped_image(liq_result *result, liq_image *input_image, void *buffer, size_t buffer_size) LIQ_NONNULL;
+LIQ_EXPORT liq_error liq_write_remapped_image_rows(liq_result *result, liq_image *input_image, unsigned char **row_pointers) LIQ_NONNULL;
+
+LIQ_EXPORT double liq_get_quantization_error(const liq_result *result) LIQ_NONNULL;
+LIQ_EXPORT int liq_get_quantization_quality(const liq_result *result) LIQ_NONNULL;
+LIQ_EXPORT double liq_get_remapping_error(const liq_result *result) LIQ_NONNULL;
+LIQ_EXPORT int liq_get_remapping_quality(const liq_result *result) LIQ_NONNULL;
+
+LIQ_EXPORT void liq_result_destroy(liq_result *) LIQ_NONNULL;
+
+LIQ_EXPORT int liq_version(void);
+
+
+// Deprecated
+LIQ_EXPORT LIQ_USERESULT liq_result *liq_quantize_image(liq_attr *options, liq_image *input_image) LIQ_NONNULL;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/vendor/code.ivysaur.me/imagequant/mediancut.c b/vendor/code.ivysaur.me/imagequant/mediancut.c
new file mode 100644
index 0000000..6e3e590
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/mediancut.c
@@ -0,0 +1,470 @@
+/*
+** © 2009-2015 by Kornel Lesiński.
+**
+** This file is part of libimagequant.
+**
+** libimagequant is free software: you can redistribute it and/or modify
+** it under the terms of the GNU General Public License as published by
+** the Free Software Foundation, either version 3 of the License, or
+** (at your option) any later version.
+**
+** libimagequant is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+** GNU General Public License for more details.
+**
+** You should have received a copy of the GNU General Public License
+** along with libimagequant. If not, see .
+*/
+/*
+** Copyright (C) 1989, 1991 by Jef Poskanzer.
+** Copyright (C) 1997, 2000, 2002 by Greg Roelofs; based on an idea by
+** Stefan Schneider.
+**
+** Permission to use, copy, modify, and distribute this software and its
+** documentation for any purpose and without fee is hereby granted, provided
+** that the above copyright notice appear in all copies and that both that
+** copyright notice and this permission notice appear in supporting
+** documentation. This software is provided "as is" without express or
+** implied warranty.
+*/
+
+#include
+#include
+
+#include "libimagequant.h"
+#include "pam.h"
+#include "mediancut.h"
+
+#define index_of_channel(ch) (offsetof(f_pixel,ch)/sizeof(float))
+
+static f_pixel averagepixels(unsigned int clrs, const hist_item achv[]);
+
+struct box {
+ f_pixel color;
+ f_pixel variance;
+ double sum, total_error, max_error;
+ unsigned int ind;
+ unsigned int colors;
+};
+
+ALWAYS_INLINE static double variance_diff(double val, const double good_enough);
+inline static double variance_diff(double val, const double good_enough)
+{
+ val *= val;
+ if (val < good_enough*good_enough) return val*0.25;
+ return val;
+}
+
+/** Weighted per-channel variance of the box. It's used to decide which channel to split by */
+static f_pixel box_variance(const hist_item achv[], const struct box *box)
+{
+ f_pixel mean = box->color;
+ double variancea=0, variancer=0, varianceg=0, varianceb=0;
+
+ for(unsigned int i = 0; i < box->colors; ++i) {
+ const f_pixel px = achv[box->ind + i].acolor;
+ double weight = achv[box->ind + i].adjusted_weight;
+ variancea += variance_diff(mean.a - px.a, 2.0/256.0)*weight;
+ variancer += variance_diff(mean.r - px.r, 1.0/256.0)*weight;
+ varianceg += variance_diff(mean.g - px.g, 1.0/256.0)*weight;
+ varianceb += variance_diff(mean.b - px.b, 1.0/256.0)*weight;
+ }
+
+ return (f_pixel){
+ .a = variancea*(4.0/16.0),
+ .r = variancer*(7.0/16.0),
+ .g = varianceg*(9.0/16.0),
+ .b = varianceb*(5.0/16.0),
+ };
+}
+
+static double box_max_error(const hist_item achv[], const struct box *box)
+{
+ f_pixel mean = box->color;
+ double max_error = 0;
+
+ for(unsigned int i = 0; i < box->colors; ++i) {
+ const double diff = colordifference(mean, achv[box->ind + i].acolor);
+ if (diff > max_error) {
+ max_error = diff;
+ }
+ }
+ return max_error;
+}
+
+ALWAYS_INLINE static double color_weight(f_pixel median, hist_item h);
+
+static inline void hist_item_swap(hist_item *l, hist_item *r)
+{
+ if (l != r) {
+ hist_item t = *l;
+ *l = *r;
+ *r = t;
+ }
+}
+
+ALWAYS_INLINE static unsigned int qsort_pivot(const hist_item *const base, const unsigned int len);
+inline static unsigned int qsort_pivot(const hist_item *const base, const unsigned int len)
+{
+ if (len < 32) {
+ return len/2;
+ }
+
+ const unsigned int aidx=8, bidx=len/2, cidx=len-1;
+ const unsigned int a=base[aidx].tmp.sort_value, b=base[bidx].tmp.sort_value, c=base[cidx].tmp.sort_value;
+ return (a < b) ? ((b < c) ? bidx : ((a < c) ? cidx : aidx ))
+ : ((b > c) ? bidx : ((a < c) ? aidx : cidx ));
+}
+
+ALWAYS_INLINE static unsigned int qsort_partition(hist_item *const base, const unsigned int len);
+inline static unsigned int qsort_partition(hist_item *const base, const unsigned int len)
+{
+ unsigned int l = 1, r = len;
+ if (len >= 8) {
+ hist_item_swap(&base[0], &base[qsort_pivot(base,len)]);
+ }
+
+ const unsigned int pivot_value = base[0].tmp.sort_value;
+ while (l < r) {
+ if (base[l].tmp.sort_value >= pivot_value) {
+ l++;
+ } else {
+ while(l < --r && base[r].tmp.sort_value <= pivot_value) {}
+ hist_item_swap(&base[l], &base[r]);
+ }
+ }
+ l--;
+ hist_item_swap(&base[0], &base[l]);
+
+ return l;
+}
+
+/** quick select algorithm */
+static void hist_item_sort_range(hist_item *base, unsigned int len, unsigned int sort_start)
+{
+ for(;;) {
+ const unsigned int l = qsort_partition(base, len), r = l+1;
+
+ if (l > 0 && sort_start < l) {
+ len = l;
+ }
+ else if (r < len && sort_start > r) {
+ base += r; len -= r; sort_start -= r;
+ }
+ else break;
+ }
+}
+
+/** sorts array to make sum of weights lower than halfvar one side, returns edge between halfvar parts of the set */
+static hist_item *hist_item_sort_halfvar(hist_item *base, unsigned int len, double *const lowervar, const double halfvar)
+{
+ do {
+ const unsigned int l = qsort_partition(base, len), r = l+1;
+
+ // check if sum of left side is smaller than half,
+ // if it is, then it doesn't need to be sorted
+ unsigned int t = 0; double tmpsum = *lowervar;
+ while (t <= l && tmpsum < halfvar) tmpsum += base[t++].color_weight;
+
+ if (tmpsum < halfvar) {
+ *lowervar = tmpsum;
+ } else {
+ if (l > 0) {
+ hist_item *res = hist_item_sort_halfvar(base, l, lowervar, halfvar);
+ if (res) return res;
+ } else {
+ // End of left recursion. This will be executed in order from the first element.
+ *lowervar += base[0].color_weight;
+ if (*lowervar > halfvar) return &base[0];
+ }
+ }
+
+ if (len > r) {
+ base += r; len -= r; // tail-recursive "call"
+ } else {
+ *lowervar += base[r].color_weight;
+ return (*lowervar > halfvar) ? &base[r] : NULL;
+ }
+ } while(1);
+}
+
+static f_pixel get_median(const struct box *b, hist_item achv[]);
+
+typedef struct {
+ unsigned int chan; float variance;
+} channelvariance;
+
+static int comparevariance(const void *ch1, const void *ch2)
+{
+ return ((const channelvariance*)ch1)->variance > ((const channelvariance*)ch2)->variance ? -1 :
+ (((const channelvariance*)ch1)->variance < ((const channelvariance*)ch2)->variance ? 1 : 0);
+}
+
+/** Finds which channels need to be sorted first and preproceses achv for fast sort */
+static double prepare_sort(struct box *b, hist_item achv[])
+{
+ /*
+ ** Sort dimensions by their variance, and then sort colors first by dimension with highest variance
+ */
+ channelvariance channels[4] = {
+ {index_of_channel(a), b->variance.a},
+ {index_of_channel(r), b->variance.r},
+ {index_of_channel(g), b->variance.g},
+ {index_of_channel(b), b->variance.b},
+ };
+
+ qsort(channels, 4, sizeof(channels[0]), comparevariance);
+
+ for(unsigned int i=0; i < b->colors; i++) {
+ const float *chans = (const float *)&achv[b->ind + i].acolor;
+ // Only the first channel really matters. When trying median cut many times
+ // with different histogram weights, I don't want sort randomness to influence outcome.
+ achv[b->ind + i].tmp.sort_value = ((unsigned int)(chans[channels[0].chan]*65535.0)<<16) |
+ (unsigned int)((chans[channels[2].chan] + chans[channels[1].chan]/2.0 + chans[channels[3].chan]/4.0)*65535.0);
+ }
+
+ const f_pixel median = get_median(b, achv);
+
+ // box will be split to make color_weight of each side even
+ const unsigned int ind = b->ind, end = ind+b->colors;
+ double totalvar = 0;
+ for(unsigned int j=ind; j < end; j++) totalvar += (achv[j].color_weight = color_weight(median, achv[j]));
+ return totalvar / 2.0;
+}
+
+/** finds median in unsorted set by sorting only minimum required */
+static f_pixel get_median(const struct box *b, hist_item achv[])
+{
+ const unsigned int median_start = (b->colors-1)/2;
+
+ hist_item_sort_range(&(achv[b->ind]), b->colors,
+ median_start);
+
+ if (b->colors&1) return achv[b->ind + median_start].acolor;
+
+ // technically the second color is not guaranteed to be sorted correctly
+ // but most of the time it is good enough to be useful
+ return averagepixels(2, &achv[b->ind + median_start]);
+}
+
+/*
+ ** Find the best splittable box. -1 if no boxes are splittable.
+ */
+static int best_splittable_box(struct box* bv, unsigned int boxes, const double max_mse)
+{
+ int bi=-1; double maxsum=0;
+ for(unsigned int i=0; i < boxes; i++) {
+ if (bv[i].colors < 2) {
+ continue;
+ }
+
+ // looks only at max variance, because it's only going to split by it
+ const double cv = MAX(bv[i].variance.r, MAX(bv[i].variance.g,bv[i].variance.b));
+ double thissum = bv[i].sum * MAX(bv[i].variance.a, cv);
+
+ if (bv[i].max_error > max_mse) {
+ thissum = thissum* bv[i].max_error/max_mse;
+ }
+
+ if (thissum > maxsum) {
+ maxsum = thissum;
+ bi = i;
+ }
+ }
+ return bi;
+}
+
+inline static double color_weight(f_pixel median, hist_item h)
+{
+ float diff = colordifference(median, h.acolor);
+ return sqrt(diff) * (sqrt(1.0+h.adjusted_weight)-1.0);
+}
+
+static void set_colormap_from_boxes(colormap *map, struct box* bv, unsigned int boxes, hist_item *achv);
+static void adjust_histogram(hist_item *achv, const struct box* bv, unsigned int boxes);
+
+static double box_error(const struct box *box, const hist_item achv[])
+{
+ f_pixel avg = box->color;
+
+ double total_error=0;
+ for (unsigned int i = 0; i < box->colors; ++i) {
+ total_error += colordifference(avg, achv[box->ind + i].acolor) * achv[box->ind + i].perceptual_weight;
+ }
+
+ return total_error;
+}
+
+
+static bool total_box_error_below_target(double target_mse, struct box bv[], unsigned int boxes, const histogram *hist)
+{
+ target_mse *= hist->total_perceptual_weight;
+ double total_error=0;
+
+ for(unsigned int i=0; i < boxes; i++) {
+ // error is (re)calculated lazily
+ if (bv[i].total_error >= 0) {
+ total_error += bv[i].total_error;
+ }
+ if (total_error > target_mse) return false;
+ }
+
+ for(unsigned int i=0; i < boxes; i++) {
+ if (bv[i].total_error < 0) {
+ bv[i].total_error = box_error(&bv[i], hist->achv);
+ total_error += bv[i].total_error;
+ }
+ if (total_error > target_mse) return false;
+ }
+
+ return true;
+}
+
+static void box_init(struct box *box, const hist_item *achv, const unsigned int ind, const unsigned int colors, const double sum) {
+ box->ind = ind;
+ box->colors = colors;
+ box->sum = sum;
+ box->total_error = -1;
+ box->color = averagepixels(colors, &achv[ind]);
+ box->variance = box_variance(achv, box);
+ box->max_error = box_max_error(achv, box);
+}
+
+/*
+ ** Here is the fun part, the median-cut colormap generator. This is based
+ ** on Paul Heckbert's paper, "Color Image Quantization for Frame Buffer
+ ** Display," SIGGRAPH 1982 Proceedings, page 297.
+ */
+LIQ_PRIVATE colormap *mediancut(histogram *hist, unsigned int newcolors, const double target_mse, const double max_mse, void* (*malloc)(size_t), void (*free)(void*))
+{
+ hist_item *achv = hist->achv;
+ struct box bv[newcolors];
+
+ /*
+ ** Set up the initial box.
+ */
+ double sum = 0;
+ for(unsigned int i=0; i < hist->size; i++) {
+ sum += achv[i].adjusted_weight;
+ }
+ box_init(&bv[0], achv, 0, hist->size, sum);
+
+ unsigned int boxes = 1;
+
+ /*
+ ** Main loop: split boxes until we have enough.
+ */
+ while (boxes < newcolors) {
+
+ // first splits boxes that exceed quality limit (to have colors for things like odd green pixel),
+ // later raises the limit to allow large smooth areas/gradients get colors.
+ const double current_max_mse = max_mse + (boxes/(double)newcolors)*16.0*max_mse;
+ const int bi = best_splittable_box(bv, boxes, current_max_mse);
+ if (bi < 0)
+ break; /* ran out of colors! */
+
+ unsigned int indx = bv[bi].ind;
+ unsigned int clrs = bv[bi].colors;
+
+ /*
+ Classic implementation tries to get even number of colors or pixels in each subdivision.
+
+ Here, instead of popularity I use (sqrt(popularity)*variance) metric.
+ Each subdivision balances number of pixels (popular colors) and low variance -
+ boxes can be large if they have similar colors. Later boxes with high variance
+ will be more likely to be split.
+
+ Median used as expected value gives much better results than mean.
+ */
+
+ const double halfvar = prepare_sort(&bv[bi], achv);
+ double lowervar=0;
+
+ // hist_item_sort_halfvar sorts and sums lowervar at the same time
+ // returns item to break at …minus one, which does smell like an off-by-one error.
+ hist_item *break_p = hist_item_sort_halfvar(&achv[indx], clrs, &lowervar, halfvar);
+ unsigned int break_at = MIN(clrs-1, break_p - &achv[indx] + 1);
+
+ /*
+ ** Split the box.
+ */
+ double sm = bv[bi].sum;
+ double lowersum = 0;
+ for(unsigned int i=0; i < break_at; i++) lowersum += achv[indx + i].adjusted_weight;
+
+ box_init(&bv[bi], achv, bv[bi].ind, break_at, lowersum);
+ box_init(&bv[boxes], achv, indx + break_at, clrs - break_at, sm - lowersum);
+
+ ++boxes;
+
+ if (total_box_error_below_target(target_mse, bv, boxes, hist)) {
+ break;
+ }
+ }
+
+ colormap *map = pam_colormap(boxes, malloc, free);
+ set_colormap_from_boxes(map, bv, boxes, achv);
+
+ adjust_histogram(achv, bv, boxes);
+
+ return map;
+}
+
+static void set_colormap_from_boxes(colormap *map, struct box* bv, unsigned int boxes, hist_item *achv)
+{
+ /*
+ ** Ok, we've got enough boxes. Now choose a representative color for
+ ** each box. There are a number of possible ways to make this choice.
+ ** One would be to choose the center of the box; this ignores any structure
+ ** within the boxes. Another method would be to average all the colors in
+ ** the box - this is the method specified in Heckbert's paper.
+ */
+
+ for(unsigned int bi = 0; bi < boxes; ++bi) {
+ map->palette[bi].acolor = bv[bi].color;
+
+ /* store total color popularity (perceptual_weight is approximation of it) */
+ map->palette[bi].popularity = 0;
+ for(unsigned int i=bv[bi].ind; i < bv[bi].ind+bv[bi].colors; i++) {
+ map->palette[bi].popularity += achv[i].perceptual_weight;
+ }
+ }
+}
+
+/* increase histogram popularity by difference from the final color (this is used as part of feedback loop) */
+static void adjust_histogram(hist_item *achv, const struct box* bv, unsigned int boxes)
+{
+ for(unsigned int bi = 0; bi < boxes; ++bi) {
+ for(unsigned int i=bv[bi].ind; i < bv[bi].ind+bv[bi].colors; i++) {
+ achv[i].tmp.likely_colormap_index = bi;
+ }
+ }
+}
+
+static f_pixel averagepixels(unsigned int clrs, const hist_item achv[])
+{
+ double r = 0, g = 0, b = 0, a = 0, sum = 0;
+
+ for(unsigned int i = 0; i < clrs; i++) {
+ const f_pixel px = achv[i].acolor;
+ const double weight = achv[i].adjusted_weight;
+
+ sum += weight;
+ a += px.a * weight;
+ r += px.r * weight;
+ g += px.g * weight;
+ b += px.b * weight;
+ }
+
+ if (sum) {
+ a /= sum;
+ r /= sum;
+ g /= sum;
+ b /= sum;
+ }
+
+ assert(!isnan(r) && !isnan(g) && !isnan(b) && !isnan(a));
+
+ return (f_pixel){.r=r, .g=g, .b=b, .a=a};
+}
diff --git a/vendor/code.ivysaur.me/imagequant/mediancut.h b/vendor/code.ivysaur.me/imagequant/mediancut.h
new file mode 100644
index 0000000..d97696c
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/mediancut.h
@@ -0,0 +1,2 @@
+
+LIQ_PRIVATE colormap *mediancut(histogram *hist, unsigned int newcolors, const double target_mse, const double max_mse, void* (*malloc)(size_t), void (*free)(void*));
diff --git a/vendor/code.ivysaur.me/imagequant/mempool.c b/vendor/code.ivysaur.me/imagequant/mempool.c
new file mode 100644
index 0000000..cd345a7
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/mempool.c
@@ -0,0 +1,81 @@
+/*
+© 2011-2016 by Kornel Lesiński.
+
+This file is part of libimagequant.
+
+libimagequant is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+libimagequant is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with libimagequant. If not, see .
+*/
+
+#include "libimagequant.h"
+#include "mempool.h"
+#include
+#include
+#include
+
+#define ALIGN_MASK 15UL
+#define MEMPOOL_RESERVED ((sizeof(struct mempool)+ALIGN_MASK) & ~ALIGN_MASK)
+
+struct mempool {
+ unsigned int used, size;
+ void* (*malloc)(size_t);
+ void (*free)(void*);
+ struct mempool *next;
+};
+LIQ_PRIVATE void* mempool_create(mempool *mptr, const unsigned int size, unsigned int max_size, void* (*malloc)(size_t), void (*free)(void*))
+{
+ if (*mptr && ((*mptr)->used+size) <= (*mptr)->size) {
+ unsigned int prevused = (*mptr)->used;
+ (*mptr)->used += (size+15UL) & ~0xFUL;
+ return ((char*)(*mptr)) + prevused;
+ }
+
+ mempool old = *mptr;
+ if (!max_size) max_size = (1<<17);
+ max_size = size+ALIGN_MASK > max_size ? size+ALIGN_MASK : max_size;
+
+ *mptr = malloc(MEMPOOL_RESERVED + max_size);
+ if (!*mptr) return NULL;
+ **mptr = (struct mempool){
+ .malloc = malloc,
+ .free = free,
+ .size = MEMPOOL_RESERVED + max_size,
+ .used = sizeof(struct mempool),
+ .next = old,
+ };
+ uintptr_t mptr_used_start = (uintptr_t)(*mptr) + (*mptr)->used;
+ (*mptr)->used += (ALIGN_MASK + 1 - (mptr_used_start & ALIGN_MASK)) & ALIGN_MASK; // reserve bytes required to make subsequent allocations aligned
+ assert(!(((uintptr_t)(*mptr) + (*mptr)->used) & ALIGN_MASK));
+
+ return mempool_alloc(mptr, size, size);
+}
+
+LIQ_PRIVATE void* mempool_alloc(mempool *mptr, const unsigned int size, const unsigned int max_size)
+{
+ if (((*mptr)->used+size) <= (*mptr)->size) {
+ unsigned int prevused = (*mptr)->used;
+ (*mptr)->used += (size + ALIGN_MASK) & ~ALIGN_MASK;
+ return ((char*)(*mptr)) + prevused;
+ }
+
+ return mempool_create(mptr, size, max_size, (*mptr)->malloc, (*mptr)->free);
+}
+
+LIQ_PRIVATE void mempool_destroy(mempool m)
+{
+ while (m) {
+ mempool next = m->next;
+ m->free(m);
+ m = next;
+ }
+}
diff --git a/vendor/code.ivysaur.me/imagequant/mempool.h b/vendor/code.ivysaur.me/imagequant/mempool.h
new file mode 100644
index 0000000..0797e7c
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/mempool.h
@@ -0,0 +1,13 @@
+#ifndef MEMPOOL_H
+#define MEMPOOL_H
+
+#include
+
+struct mempool;
+typedef struct mempool *mempool;
+
+LIQ_PRIVATE void* mempool_create(mempool *mptr, const unsigned int size, unsigned int capacity, void* (*malloc)(size_t), void (*free)(void*));
+LIQ_PRIVATE void* mempool_alloc(mempool *mptr, const unsigned int size, const unsigned int capacity);
+LIQ_PRIVATE void mempool_destroy(mempool m);
+
+#endif
diff --git a/vendor/code.ivysaur.me/imagequant/nearest.c b/vendor/code.ivysaur.me/imagequant/nearest.c
new file mode 100644
index 0000000..2f1e926
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/nearest.c
@@ -0,0 +1,206 @@
+/*
+© 2011-2015 by Kornel Lesiński.
+
+This file is part of libimagequant.
+
+libimagequant is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+libimagequant is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with libimagequant. If not, see .
+*/
+
+#include "libimagequant.h"
+#include "pam.h"
+#include "nearest.h"
+#include "mempool.h"
+#include
+
+typedef struct vp_sort_tmp {
+ float distance_squared;
+ unsigned int idx;
+} vp_sort_tmp;
+
+typedef struct vp_search_tmp {
+ float distance;
+ unsigned int idx;
+ int exclude;
+} vp_search_tmp;
+
+typedef struct vp_node {
+ struct vp_node *near, *far;
+ f_pixel vantage_point;
+ float radius;
+ unsigned int idx;
+} vp_node;
+
+struct nearest_map {
+ vp_node *root;
+ const colormap_item *palette;
+ float nearest_other_color_dist[256];
+ mempool mempool;
+};
+
+static void vp_search_node(const vp_node *node, const f_pixel *const needle, vp_search_tmp *const best_candidate);
+
+static int vp_compare_distance(const void *ap, const void *bp) {
+ float a = ((const vp_sort_tmp*)ap)->distance_squared;
+ float b = ((const vp_sort_tmp*)bp)->distance_squared;
+ return a > b ? 1 : -1;
+}
+
+static void vp_sort_indexes_by_distance(const f_pixel vantage_point, vp_sort_tmp *indexes, int num_indexes, const colormap_item items[]) {
+ for(int i=0; i < num_indexes; i++) {
+ indexes[i].distance_squared = colordifference(vantage_point, items[indexes[i].idx].acolor);
+ }
+ qsort(indexes, num_indexes, sizeof(indexes[0]), vp_compare_distance);
+}
+
+/*
+ * Usually it should pick farthest point, but picking most popular point seems to make search quicker anyway
+ */
+static int vp_find_best_vantage_point_index(vp_sort_tmp *indexes, int num_indexes, const colormap_item items[]) {
+ int best = 0;
+ float best_popularity = items[indexes[0].idx].popularity;
+ for(int i = 1; i < num_indexes; i++) {
+ if (items[indexes[i].idx].popularity > best_popularity) {
+ best_popularity = items[indexes[i].idx].popularity;
+ best = i;
+ }
+ }
+ return best;
+}
+
+static vp_node *vp_create_node(mempool *m, vp_sort_tmp *indexes, int num_indexes, const colormap_item items[]) {
+ if (num_indexes <= 0) {
+ return NULL;
+ }
+
+ vp_node *node = mempool_alloc(m, sizeof(node[0]), 0);
+
+ if (num_indexes == 1) {
+ *node = (vp_node){
+ .vantage_point = items[indexes[0].idx].acolor,
+ .idx = indexes[0].idx,
+ .radius = MAX_DIFF,
+ };
+ return node;
+ }
+
+ const int ref = vp_find_best_vantage_point_index(indexes, num_indexes, items);
+ const int ref_idx = indexes[ref].idx;
+
+ // Removes the `ref_idx` item from remaining items, because it's included in the current node
+ num_indexes -= 1;
+ indexes[ref] = indexes[num_indexes];
+
+ vp_sort_indexes_by_distance(items[ref_idx].acolor, indexes, num_indexes, items);
+
+ // Remaining items are split by the median distance
+ const int half_idx = num_indexes/2;
+
+ *node = (vp_node){
+ .vantage_point = items[ref_idx].acolor,
+ .idx = ref_idx,
+ .radius = sqrtf(indexes[half_idx].distance_squared),
+ };
+ node->near = vp_create_node(m, indexes, half_idx, items);
+ node->far = vp_create_node(m, &indexes[half_idx], num_indexes - half_idx, items);
+
+ return node;
+}
+
+LIQ_PRIVATE struct nearest_map *nearest_init(const colormap *map) {
+ mempool m = NULL;
+ struct nearest_map *handle = mempool_create(&m, sizeof(handle[0]), sizeof(handle[0]) + sizeof(vp_node)*map->colors+16, map->malloc, map->free);
+
+ vp_sort_tmp indexes[map->colors];
+
+ for(unsigned int i=0; i < map->colors; i++) {
+ indexes[i].idx = i;
+ }
+
+ vp_node *root = vp_create_node(&m, indexes, map->colors, map->palette);
+ *handle = (struct nearest_map){
+ .root = root,
+ .palette = map->palette,
+ .mempool = m,
+ };
+
+ for(unsigned int i=0; i < map->colors; i++) {
+ vp_search_tmp best = {
+ .distance = MAX_DIFF,
+ .exclude = i,
+ };
+ vp_search_node(root, &map->palette[i].acolor, &best);
+ handle->nearest_other_color_dist[i] = best.distance * best.distance / 4.0; // half of squared distance
+ }
+
+ return handle;
+}
+
+static void vp_search_node(const vp_node *node, const f_pixel *const needle, vp_search_tmp *const best_candidate) {
+ do {
+ const float distance = sqrtf(colordifference(node->vantage_point, *needle));
+
+ if (distance < best_candidate->distance && best_candidate->exclude != node->idx) {
+ best_candidate->distance = distance;
+ best_candidate->idx = node->idx;
+ }
+
+ // Recurse towards most likely candidate first to narrow best candidate's distance as soon as possible
+ if (distance < node->radius) {
+ if (node->near) {
+ vp_search_node(node->near, needle, best_candidate);
+ }
+ // The best node (final answer) may be just ouside the radius, but not farther than
+ // the best distance we know so far. The vp_search_node above should have narrowed
+ // best_candidate->distance, so this path is rarely taken.
+ if (node->far && distance >= node->radius - best_candidate->distance) {
+ node = node->far; // Fast tail recursion
+ } else {
+ break;
+ }
+ } else {
+ if (node->far) {
+ vp_search_node(node->far, needle, best_candidate);
+ }
+ if (node->near && distance <= node->radius + best_candidate->distance) {
+ node = node->near; // Fast tail recursion
+ } else {
+ break;
+ }
+ }
+ } while(true);
+}
+
+LIQ_PRIVATE unsigned int nearest_search(const struct nearest_map *handle, const f_pixel *px, const int likely_colormap_index, float *diff) {
+ const float guess_diff = colordifference(handle->palette[likely_colormap_index].acolor, *px);
+ if (guess_diff < handle->nearest_other_color_dist[likely_colormap_index]) {
+ if (diff) *diff = guess_diff;
+ return likely_colormap_index;
+ }
+
+ vp_search_tmp best_candidate = {
+ .distance = sqrtf(guess_diff),
+ .idx = likely_colormap_index,
+ .exclude = -1,
+ };
+ vp_search_node(handle->root, px, &best_candidate);
+ if (diff) {
+ *diff = best_candidate.distance * best_candidate.distance;
+ }
+ return best_candidate.idx;
+}
+
+LIQ_PRIVATE void nearest_free(struct nearest_map *centroids)
+{
+ mempool_destroy(centroids->mempool);
+}
diff --git a/vendor/code.ivysaur.me/imagequant/nearest.h b/vendor/code.ivysaur.me/imagequant/nearest.h
new file mode 100644
index 0000000..e20233b
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/nearest.h
@@ -0,0 +1,8 @@
+//
+// nearest.h
+// pngquant
+//
+struct nearest_map;
+LIQ_PRIVATE struct nearest_map *nearest_init(const colormap *palette);
+LIQ_PRIVATE unsigned int nearest_search(const struct nearest_map *map, const f_pixel *px, const int palette_index_guess, float *diff);
+LIQ_PRIVATE void nearest_free(struct nearest_map *map);
diff --git a/vendor/code.ivysaur.me/imagequant/pam.c b/vendor/code.ivysaur.me/imagequant/pam.c
new file mode 100644
index 0000000..74165e1
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/pam.c
@@ -0,0 +1,276 @@
+/* pam.c - pam (portable alpha map) utility library
+**
+** Copyright (C) 1989, 1991 by Jef Poskanzer.
+** Copyright (C) 1997, 2000, 2002 by Greg Roelofs; based on an idea by
+** Stefan Schneider.
+** © 2009-2016 by Kornel Lesinski.
+**
+** Permission to use, copy, modify, and distribute this software and its
+** documentation for any purpose and without fee is hereby granted, provided
+** that the above copyright notice appear in all copies and that both that
+** copyright notice and this permission notice appear in supporting
+** documentation. This software is provided "as is" without express or
+** implied warranty.
+*/
+
+#include
+#include
+
+#include "libimagequant.h"
+#include "pam.h"
+#include "mempool.h"
+
+LIQ_PRIVATE bool pam_computeacolorhash(struct acolorhash_table *acht, const rgba_pixel *const pixels[], unsigned int cols, unsigned int rows, const unsigned char *importance_map)
+{
+ const unsigned int ignorebits = acht->ignorebits;
+ const unsigned int channel_mask = 255U>>ignorebits<>ignorebits) ^ 0xFFU;
+ const unsigned int posterize_mask = channel_mask << 24 | channel_mask << 16 | channel_mask << 8 | channel_mask;
+ const unsigned int posterize_high_mask = channel_hmask << 24 | channel_hmask << 16 | channel_hmask << 8 | channel_hmask;
+
+ const unsigned int hash_size = acht->hash_size;
+
+ /* Go through the entire image, building a hash table of colors. */
+ for(unsigned int row = 0; row < rows; ++row) {
+
+ float boost=1.0;
+ for(unsigned int col = 0; col < cols; ++col) {
+ if (importance_map) {
+ boost = 0.5f+ (double)*importance_map++/255.f;
+ }
+
+ // RGBA color is casted to long for easier hasing/comparisons
+ union rgba_as_int px = {pixels[row][col]};
+ unsigned int hash;
+ if (!px.rgba.a) {
+ // "dirty alpha" has different RGBA values that end up being the same fully transparent color
+ px.l=0; hash=0;
+ boost = 10;
+ } else {
+ // mask posterizes all 4 channels in one go
+ px.l = (px.l & posterize_mask) | ((px.l & posterize_high_mask) >> (8-ignorebits));
+ // fancier hashing algorithms didn't improve much
+ hash = px.l % hash_size;
+ }
+
+ if (!pam_add_to_hash(acht, hash, boost, px, row, rows)) {
+ return false;
+ }
+ }
+
+ }
+ acht->cols = cols;
+ acht->rows += rows;
+ return true;
+}
+
+LIQ_PRIVATE bool pam_add_to_hash(struct acolorhash_table *acht, unsigned int hash, float boost, union rgba_as_int px, unsigned int row, unsigned int rows)
+{
+ /* head of the hash function stores first 2 colors inline (achl->used = 1..2),
+ to reduce number of allocations of achl->other_items.
+ */
+ struct acolorhist_arr_head *achl = &acht->buckets[hash];
+ if (achl->inline1.color.l == px.l && achl->used) {
+ achl->inline1.perceptual_weight += boost;
+ return true;
+ }
+ if (achl->used) {
+ if (achl->used > 1) {
+ if (achl->inline2.color.l == px.l) {
+ achl->inline2.perceptual_weight += boost;
+ return true;
+ }
+ // other items are stored as an array (which gets reallocated if needed)
+ struct acolorhist_arr_item *other_items = achl->other_items;
+ unsigned int i = 0;
+ for (; i < achl->used-2; i++) {
+ if (other_items[i].color.l == px.l) {
+ other_items[i].perceptual_weight += boost;
+ return true;
+ }
+ }
+
+ // the array was allocated with spare items
+ if (i < achl->capacity) {
+ other_items[i] = (struct acolorhist_arr_item){
+ .color = px,
+ .perceptual_weight = boost,
+ };
+ achl->used++;
+ ++acht->colors;
+ return true;
+ }
+
+ if (++acht->colors > acht->maxcolors) {
+ return false;
+ }
+
+ struct acolorhist_arr_item *new_items;
+ unsigned int capacity;
+ if (!other_items) { // there was no array previously, alloc "small" array
+ capacity = 8;
+ if (acht->freestackp <= 0) {
+ // estimate how many colors are going to be + headroom
+ const size_t mempool_size = ((acht->rows + rows-row) * 2 * acht->colors / (acht->rows + row + 1) + 1024) * sizeof(struct acolorhist_arr_item);
+ new_items = mempool_alloc(&acht->mempool, sizeof(struct acolorhist_arr_item)*capacity, mempool_size);
+ } else {
+ // freestack stores previously freed (reallocated) arrays that can be reused
+ // (all pesimistically assumed to be capacity = 8)
+ new_items = acht->freestack[--acht->freestackp];
+ }
+ } else {
+ const unsigned int stacksize = sizeof(acht->freestack)/sizeof(acht->freestack[0]);
+
+ // simply reallocs and copies array to larger capacity
+ capacity = achl->capacity*2 + 16;
+ if (acht->freestackp < stacksize-1) {
+ acht->freestack[acht->freestackp++] = other_items;
+ }
+ const size_t mempool_size = ((acht->rows + rows-row) * 2 * acht->colors / (acht->rows + row + 1) + 32*capacity) * sizeof(struct acolorhist_arr_item);
+ new_items = mempool_alloc(&acht->mempool, sizeof(struct acolorhist_arr_item)*capacity, mempool_size);
+ if (!new_items) return false;
+ memcpy(new_items, other_items, sizeof(other_items[0])*achl->capacity);
+ }
+
+ achl->other_items = new_items;
+ achl->capacity = capacity;
+ new_items[i] = (struct acolorhist_arr_item){
+ .color = px,
+ .perceptual_weight = boost,
+ };
+ achl->used++;
+ } else {
+ // these are elses for first checks whether first and second inline-stored colors are used
+ achl->inline2.color.l = px.l;
+ achl->inline2.perceptual_weight = boost;
+ achl->used = 2;
+ ++acht->colors;
+ }
+ } else {
+ achl->inline1.color.l = px.l;
+ achl->inline1.perceptual_weight = boost;
+ achl->used = 1;
+ ++acht->colors;
+ }
+ return true;
+}
+
+LIQ_PRIVATE struct acolorhash_table *pam_allocacolorhash(unsigned int maxcolors, unsigned int surface, unsigned int ignorebits, void* (*malloc)(size_t), void (*free)(void*))
+{
+ const size_t estimated_colors = MIN(maxcolors, surface/(ignorebits + (surface > 512*512 ? 6 : 5)));
+ const size_t hash_size = estimated_colors < 66000 ? 6673 : (estimated_colors < 200000 ? 12011 : 24019);
+
+ mempool m = NULL;
+ const size_t buckets_size = hash_size * sizeof(struct acolorhist_arr_head);
+ const size_t mempool_size = sizeof(struct acolorhash_table) + buckets_size + estimated_colors * sizeof(struct acolorhist_arr_item);
+ struct acolorhash_table *t = mempool_create(&m, sizeof(*t) + buckets_size, mempool_size, malloc, free);
+ if (!t) return NULL;
+ *t = (struct acolorhash_table){
+ .mempool = m,
+ .hash_size = hash_size,
+ .maxcolors = maxcolors,
+ .ignorebits = ignorebits,
+ };
+ memset(t->buckets, 0, buckets_size);
+ return t;
+}
+
+ALWAYS_INLINE static float pam_add_to_hist(const float *gamma_lut, hist_item *achv, unsigned int j, const struct acolorhist_arr_item *entry, const float max_perceptual_weight)
+{
+ achv[j].acolor = rgba_to_f(gamma_lut, entry->color.rgba);
+ const float w = MIN(entry->perceptual_weight, max_perceptual_weight);
+ achv[j].adjusted_weight = achv[j].perceptual_weight = w;
+ return w;
+}
+
+LIQ_PRIVATE histogram *pam_acolorhashtoacolorhist(const struct acolorhash_table *acht, const double gamma, void* (*malloc)(size_t), void (*free)(void*))
+{
+ histogram *hist = malloc(sizeof(hist[0]));
+ if (!hist || !acht) return NULL;
+ *hist = (histogram){
+ .achv = malloc(MAX(1,acht->colors) * sizeof(hist->achv[0])),
+ .size = acht->colors,
+ .free = free,
+ .ignorebits = acht->ignorebits,
+ };
+ if (!hist->achv) return NULL;
+
+ float gamma_lut[256];
+ to_f_set_gamma(gamma_lut, gamma);
+
+ /* Limit perceptual weight to 1/10th of the image surface area to prevent
+ a single color from dominating all others. */
+ float max_perceptual_weight = 0.1f * acht->cols * acht->rows;
+ double total_weight = 0;
+
+ for(unsigned int j=0, i=0; i < acht->hash_size; ++i) {
+ const struct acolorhist_arr_head *const achl = &acht->buckets[i];
+ if (achl->used) {
+ total_weight += pam_add_to_hist(gamma_lut, hist->achv, j++, &achl->inline1, max_perceptual_weight);
+
+ if (achl->used > 1) {
+ total_weight += pam_add_to_hist(gamma_lut, hist->achv, j++, &achl->inline2, max_perceptual_weight);
+
+ for(unsigned int k=0; k < achl->used-2; k++) {
+ total_weight += pam_add_to_hist(gamma_lut, hist->achv, j++, &achl->other_items[k], max_perceptual_weight);
+ }
+ }
+ }
+ }
+
+ hist->total_perceptual_weight = total_weight;
+ return hist;
+}
+
+
+LIQ_PRIVATE void pam_freeacolorhash(struct acolorhash_table *acht)
+{
+ if (acht) {
+ mempool_destroy(acht->mempool);
+ }
+}
+
+LIQ_PRIVATE void pam_freeacolorhist(histogram *hist)
+{
+ hist->free(hist->achv);
+ hist->free(hist);
+}
+
+LIQ_PRIVATE colormap *pam_colormap(unsigned int colors, void* (*malloc)(size_t), void (*free)(void*))
+{
+ assert(colors > 0 && colors < 65536);
+
+ colormap *map;
+ const size_t colors_size = colors * sizeof(map->palette[0]);
+ map = malloc(sizeof(colormap) + colors_size);
+ if (!map) return NULL;
+ *map = (colormap){
+ .malloc = malloc,
+ .free = free,
+ .colors = colors,
+ };
+ memset(map->palette, 0, colors_size);
+ return map;
+}
+
+LIQ_PRIVATE colormap *pam_duplicate_colormap(colormap *map)
+{
+ colormap *dupe = pam_colormap(map->colors, map->malloc, map->free);
+ for(unsigned int i=0; i < map->colors; i++) {
+ dupe->palette[i] = map->palette[i];
+ }
+ return dupe;
+}
+
+LIQ_PRIVATE void pam_freecolormap(colormap *c)
+{
+ c->free(c);
+}
+
+LIQ_PRIVATE void to_f_set_gamma(float gamma_lut[], const double gamma)
+{
+ for(int i=0; i < 256; i++) {
+ gamma_lut[i] = pow((double)i/255.0, internal_gamma/gamma);
+ }
+}
+
diff --git a/vendor/code.ivysaur.me/imagequant/pam.h b/vendor/code.ivysaur.me/imagequant/pam.h
new file mode 100644
index 0000000..6657a14
--- /dev/null
+++ b/vendor/code.ivysaur.me/imagequant/pam.h
@@ -0,0 +1,271 @@
+/* pam.h - pam (portable alpha map) utility library
+ **
+ ** Colormap routines.
+ **
+ ** Copyright (C) 1989, 1991 by Jef Poskanzer.
+ ** Copyright (C) 1997 by Greg Roelofs.
+ **
+ ** Permission to use, copy, modify, and distribute this software and its
+ ** documentation for any purpose and without fee is hereby granted, provided
+ ** that the above copyright notice appear in all copies and that both that
+ ** copyright notice and this permission notice appear in supporting
+ ** documentation. This software is provided "as is" without express or
+ ** implied warranty.
+ */
+
+#ifndef PAM_H
+#define PAM_H
+
+#include
+#include
+#include
+#include
+
+#ifndef MAX
+# define MAX(a,b) ((a) > (b)? (a) : (b))
+# define MIN(a,b) ((a) < (b)? (a) : (b))
+#endif
+
+#define MAX_DIFF 1e20
+
+#ifndef USE_SSE
+# if defined(__SSE__) && (defined(__amd64__) || defined(__X86_64__) || defined(_WIN64) || defined(WIN32) || defined(__WIN32__))
+# define USE_SSE 1
+# else
+# define USE_SSE 0
+# endif
+#endif
+
+#if USE_SSE
+# include
+# ifdef _MSC_VER
+# include
+# define SSE_ALIGN
+# else
+# define SSE_ALIGN __attribute__ ((aligned (16)))
+# if defined(__i386__) && defined(__PIC__)
+# define cpuid(func,ax,bx,cx,dx)\
+ __asm__ __volatile__ ( \
+ "push %%ebx\n" \
+ "cpuid\n" \
+ "mov %%ebx, %1\n" \
+ "pop %%ebx\n" \
+ : "=a" (ax), "=r" (bx), "=c" (cx), "=d" (dx) \
+ : "a" (func));
+# else
+# define cpuid(func,ax,bx,cx,dx)\
+ __asm__ __volatile__ ("cpuid":\
+ "=a" (ax), "=b" (bx), "=c" (cx), "=d" (dx) : "a" (func));
+# endif
+#endif
+#else
+# define SSE_ALIGN
+#endif
+
+#if defined(__GNUC__) || defined (__llvm__)
+#define ALWAYS_INLINE __attribute__((always_inline)) inline
+#define NEVER_INLINE __attribute__ ((noinline))
+#elif defined(_MSC_VER)
+#define inline __inline
+#define restrict __restrict
+#define ALWAYS_INLINE __forceinline
+#define NEVER_INLINE __declspec(noinline)
+#else
+#define ALWAYS_INLINE inline
+#define NEVER_INLINE
+#endif
+
+/* from pam.h */
+
+typedef struct {
+ unsigned char r, g, b, a;
+} rgba_pixel;
+
+typedef struct {
+ float a, r, g, b;
+} SSE_ALIGN f_pixel;
+
+static const double internal_gamma = 0.5499;
+
+LIQ_PRIVATE void to_f_set_gamma(float gamma_lut[], const double gamma);
+
+/**
+ Converts 8-bit color to internal gamma and premultiplied alpha.
+ (premultiplied color space is much better for blending of semitransparent colors)
+ */
+ALWAYS_INLINE static f_pixel rgba_to_f(const float gamma_lut[], const rgba_pixel px);
+inline static f_pixel rgba_to_f(const float gamma_lut[], const rgba_pixel px)
+{
+ float a = px.a/255.f;
+
+ return (f_pixel) {
+ .a = a,
+ .r = gamma_lut[px.r]*a,
+ .g = gamma_lut[px.g]*a,
+ .b = gamma_lut[px.b]*a,
+ };
+}
+
+inline static rgba_pixel f_to_rgb(const float gamma, const f_pixel px)
+{
+ if (px.a < 1.f/256.f) {
+ return (rgba_pixel){0,0,0,0};
+ }
+
+ float r = px.r / px.a,
+ g = px.g / px.a,
+ b = px.b / px.a,
+ a = px.a;
+
+ r = powf(r, gamma/internal_gamma);
+ g = powf(g, gamma/internal_gamma);
+ b = powf(b, gamma/internal_gamma);
+
+ // 256, because numbers are in range 1..255.9999… rounded down
+ r *= 256.f;
+ g *= 256.f;
+ b *= 256.f;
+ a *= 256.f;
+
+ return (rgba_pixel){
+ .r = r>=255.f ? 255 : r,
+ .g = g>=255.f ? 255 : g,
+ .b = b>=255.f ? 255 : b,
+ .a = a>=255.f ? 255 : a,
+ };
+}
+
+ALWAYS_INLINE static double colordifference_ch(const double x, const double y, const double alphas);
+inline static double colordifference_ch(const double x, const double y, const double alphas)
+{
+ // maximum of channel blended on white, and blended on black
+ // premultiplied alpha and backgrounds 0/1 shorten the formula
+ const double black = x-y, white = black+alphas;
+ return MAX(black*black, white*white);
+}
+
+ALWAYS_INLINE static float colordifference_stdc(const f_pixel px, const f_pixel py);
+inline static float colordifference_stdc(const f_pixel px, const f_pixel py)
+{
+ // px_b.rgb = px.rgb + 0*(1-px.a) // blend px on black
+ // px_b.a = px.a + 1*(1-px.a)
+ // px_w.rgb = px.rgb + 1*(1-px.a) // blend px on white
+ // px_w.a = px.a + 1*(1-px.a)
+
+ // px_b.rgb = px.rgb // difference same as in opaque RGB
+ // px_b.a = 1
+ // px_w.rgb = px.rgb - px.a // difference simplifies to formula below
+ // px_w.a = 1
+
+ // (px.rgb - px.a) - (py.rgb - py.a)
+ // (px.rgb - py.rgb) + (py.a - px.a)
+
+ const double alphas = py.a-px.a;
+ return colordifference_ch(px.r, py.r, alphas) +
+ colordifference_ch(px.g, py.g, alphas) +
+ colordifference_ch(px.b, py.b, alphas);
+}
+
+ALWAYS_INLINE static float colordifference(f_pixel px, f_pixel py);
+inline static float colordifference(f_pixel px, f_pixel py)
+{
+#if USE_SSE
+ const __m128 vpx = _mm_load_ps((const float*)&px);
+ const __m128 vpy = _mm_load_ps((const float*)&py);
+
+ // y.a - x.a
+ __m128 alphas = _mm_sub_ss(vpy, vpx);
+ alphas = _mm_shuffle_ps(alphas,alphas,0); // copy first to all four
+
+ __m128 onblack = _mm_sub_ps(vpx, vpy); // x - y
+ __m128 onwhite = _mm_add_ps(onblack, alphas); // x - y + (y.a - x.a)
+
+ onblack = _mm_mul_ps(onblack, onblack);
+ onwhite = _mm_mul_ps(onwhite, onwhite);
+ const __m128 max = _mm_max_ps(onwhite, onblack);
+
+ // add rgb, not a
+ const __m128 maxhl = _mm_movehl_ps(max, max);
+ const __m128 tmp = _mm_add_ps(max, maxhl);
+ const __m128 sum = _mm_add_ss(maxhl, _mm_shuffle_ps(tmp, tmp, 1));
+
+ const float res = _mm_cvtss_f32(sum);
+ assert(fabs(res - colordifference_stdc(px,py)) < 0.001);
+ return res;
+#else
+ return colordifference_stdc(px,py);
+#endif
+}
+
+/* from pamcmap.h */
+union rgba_as_int {
+ rgba_pixel rgba;
+ unsigned int l;
+};
+
+typedef struct {
+ f_pixel acolor;
+ float adjusted_weight, // perceptual weight changed to tweak how mediancut selects colors
+ perceptual_weight; // number of pixels weighted by importance of different areas of the picture
+
+ float color_weight; // these two change every time histogram subset is sorted
+ union {
+ unsigned int sort_value;
+ unsigned char likely_colormap_index;
+ } tmp;
+} hist_item;
+
+typedef struct {
+ hist_item *achv;
+ void (*free)(void*);
+ double total_perceptual_weight;
+ unsigned int size;
+ unsigned int ignorebits;
+} histogram;
+
+typedef struct {
+ f_pixel acolor;
+ float popularity;
+ bool fixed; // if true it's user-supplied and must not be changed (e.g in K-Means iteration)
+} colormap_item;
+
+typedef struct colormap {
+ unsigned int colors;
+ void* (*malloc)(size_t);
+ void (*free)(void*);
+ colormap_item palette[];
+} colormap;
+
+struct acolorhist_arr_item {
+ union rgba_as_int color;
+ float perceptual_weight;
+};
+
+struct acolorhist_arr_head {
+ struct acolorhist_arr_item inline1, inline2;
+ unsigned int used, capacity;
+ struct acolorhist_arr_item *other_items;
+};
+
+struct acolorhash_table {
+ struct mempool *mempool;
+ unsigned int ignorebits, maxcolors, colors, cols, rows;
+ unsigned int hash_size;
+ unsigned int freestackp;
+ struct acolorhist_arr_item *freestack[512];
+ struct acolorhist_arr_head buckets[];
+};
+
+LIQ_PRIVATE void pam_freeacolorhash(struct acolorhash_table *acht);
+LIQ_PRIVATE struct acolorhash_table *pam_allocacolorhash(unsigned int maxcolors, unsigned int surface, unsigned int ignorebits, void* (*malloc)(size_t), void (*free)(void*));
+LIQ_PRIVATE histogram *pam_acolorhashtoacolorhist(const struct acolorhash_table *acht, const double gamma, void* (*malloc)(size_t), void (*free)(void*));
+LIQ_PRIVATE bool pam_computeacolorhash(struct acolorhash_table *acht, const rgba_pixel *const pixels[], unsigned int cols, unsigned int rows, const unsigned char *importance_map);
+LIQ_PRIVATE bool pam_add_to_hash(struct acolorhash_table *acht, unsigned int hash, float boost, union rgba_as_int px, unsigned int row, unsigned int rows);
+
+LIQ_PRIVATE void pam_freeacolorhist(histogram *h);
+
+LIQ_PRIVATE colormap *pam_colormap(unsigned int colors, void* (*malloc)(size_t), void (*free)(void*));
+LIQ_PRIVATE colormap *pam_duplicate_colormap(colormap *map);
+LIQ_PRIVATE void pam_freecolormap(colormap *c);
+
+#endif