119 lines
2.9 KiB
Go
119 lines
2.9 KiB
Go
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// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package draw_test
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import (
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"fmt"
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"image"
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"image/color"
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"image/png"
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"log"
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"math"
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"os"
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"golang.org/x/image/draw"
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"golang.org/x/image/math/f64"
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)
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func ExampleDraw() {
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fSrc, err := os.Open("../testdata/blue-purple-pink.png")
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if err != nil {
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log.Fatal(err)
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}
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defer fSrc.Close()
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src, err := png.Decode(fSrc)
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if err != nil {
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log.Fatal(err)
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}
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dst := image.NewRGBA(image.Rect(0, 0, 400, 300))
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green := image.NewUniform(color.RGBA{0x00, 0x1f, 0x00, 0xff})
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draw.Copy(dst, image.Point{}, green, dst.Bounds(), draw.Src, nil)
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qs := []draw.Interpolator{
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draw.NearestNeighbor,
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draw.ApproxBiLinear,
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draw.CatmullRom,
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}
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const cos60, sin60 = 0.5, 0.866025404
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t := f64.Aff3{
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+2 * cos60, -2 * sin60, 100,
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+2 * sin60, +2 * cos60, 100,
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}
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draw.Copy(dst, image.Point{20, 30}, src, src.Bounds(), draw.Over, nil)
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for i, q := range qs {
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q.Scale(dst, image.Rect(200+10*i, 100*i, 600+10*i, 150+100*i), src, src.Bounds(), draw.Over, nil)
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}
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draw.NearestNeighbor.Transform(dst, t, src, src.Bounds(), draw.Over, nil)
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red := image.NewNRGBA(image.Rect(0, 0, 16, 16))
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for y := 0; y < 16; y++ {
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for x := 0; x < 16; x++ {
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red.SetNRGBA(x, y, color.NRGBA{
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R: uint8(x * 0x11),
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A: uint8(y * 0x11),
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})
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}
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}
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red.SetNRGBA(0, 0, color.NRGBA{0xff, 0xff, 0x00, 0xff})
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red.SetNRGBA(15, 15, color.NRGBA{0xff, 0xff, 0x00, 0xff})
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ops := []draw.Op{
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draw.Over,
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draw.Src,
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}
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for i, op := range ops {
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dr := image.Rect(120+10*i, 150+60*i, 170+10*i, 200+60*i)
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draw.NearestNeighbor.Scale(dst, dr, red, red.Bounds(), op, nil)
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t := f64.Aff3{
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+cos60, -sin60, float64(190 + 10*i),
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+sin60, +cos60, float64(140 + 50*i),
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}
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draw.NearestNeighbor.Transform(dst, t, red, red.Bounds(), op, nil)
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}
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dr := image.Rect(0, 0, 128, 128)
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checkerboard := image.NewAlpha(dr)
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for y := dr.Min.Y; y < dr.Max.Y; y++ {
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for x := dr.Min.X; x < dr.Max.X; x++ {
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if (x/20)%2 == (y/20)%2 {
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checkerboard.SetAlpha(x, y, color.Alpha{0xff})
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}
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}
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}
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sr := image.Rect(0, 0, 16, 16)
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circle := image.NewAlpha(sr)
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for y := sr.Min.Y; y < sr.Max.Y; y++ {
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for x := sr.Min.X; x < sr.Max.X; x++ {
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dx, dy := x-10, y-8
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if d := 32 * math.Sqrt(float64(dx*dx)+float64(dy*dy)); d < 0xff {
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circle.SetAlpha(x, y, color.Alpha{0xff - uint8(d)})
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}
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}
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}
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cyan := image.NewUniform(color.RGBA{0x00, 0xff, 0xff, 0xff})
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draw.NearestNeighbor.Scale(dst, dr, cyan, sr, draw.Over, &draw.Options{
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DstMask: checkerboard,
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SrcMask: circle,
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})
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// Change false to true to write the resultant image to disk.
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if false {
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fDst, err := os.Create("out.png")
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if err != nil {
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log.Fatal(err)
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}
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defer fDst.Close()
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err = png.Encode(fDst, dst)
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if err != nil {
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log.Fatal(err)
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}
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}
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fmt.Printf("dst has bounds %v.\n", dst.Bounds())
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// Output:
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// dst has bounds (0,0)-(400,300).
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}
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