code.ivysaur.me/imagequant
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cmd/gopngquant: working implementation

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This commit is contained in:
mappu 2016-11-24 20:54:21 +13:00
parent e2484b13c9
commit 67b09086b4
1 changed files with 32 additions and 13 deletions
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45
cmd/gopngquant/main.go
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@ -4,6 +4,7 @@ import (
"flag"
"fmt"
"image"
"image/color"
"image/png"
"os"
@ -15,14 +16,36 @@ func GoImageToRgba32(im image.Image) []byte {
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[y*h+x+0] = uint8(r16 >> 8)
ret[y*h+x+1] = uint8(g16 >> 8)
ret[y*h+x+2] = uint8(b16 >> 8)
ret[y*h+x+3] = uint8(a16 >> 8)
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*h+x])
}
}
@ -42,6 +65,9 @@ func Crush(sourcefile, destfile string) error {
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())
@ -50,7 +76,7 @@ func Crush(sourcefile, destfile string) error {
rgba32data := GoImageToRgba32(img)
iqm, err := imagequant.NewImage(attr, string(rgba32data), img.Bounds().Max.X, img.Bounds().Max.Y, 0)
iqm, err := imagequant.NewImage(attr, string(rgba32data), width, height, 0)
if err != nil {
return fmt.Errorf("NewImage: %s", err.Error())
}
@ -67,14 +93,7 @@ func Crush(sourcefile, destfile string) error {
return fmt.Errorf("WriteRemappedImage: %s", err.Error())
}
rect := image.Rectangle{Max: image.Point{X: res.GetImageWidth(), Y: res.GetImageHeight()}}
pal := res.GetPalette()
im2 := image.NewPaletted(rect, pal)
for y := 0; y < rect.Max.Y; y += 1 {
for x := 0; x < rect.Max.X; x += 1 {
im2.Set(x, y, pal[rgb8data[y*rect.Max.Y+x]])
}
}
im2 := Rgb8PaletteToGoImage(res.GetImageWidth(), res.GetImageHeight(), rgb8data, res.GetPalette())
fh2, err := os.OpenFile(destfile, os.O_WRONLY|os.O_CREATE, 0644)
if err != nil {