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-rw-r--r--src/image/draw/draw_test.go810
1 files changed, 810 insertions, 0 deletions
diff --git a/src/image/draw/draw_test.go b/src/image/draw/draw_test.go
new file mode 100644
index 0000000..a34d1c3
--- /dev/null
+++ b/src/image/draw/draw_test.go
@@ -0,0 +1,810 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package draw
+
+import (
+ "image"
+ "image/color"
+ "image/png"
+ "os"
+ "testing"
+ "testing/quick"
+)
+
+// slowestRGBA is a draw.Image like image.RGBA but it is a different type and
+// therefore does not trigger the draw.go fastest code paths.
+//
+// Unlike slowerRGBA, it does not implement the draw.RGBA64Image interface.
+type slowestRGBA struct {
+ Pix []uint8
+ Stride int
+ Rect image.Rectangle
+}
+
+func (p *slowestRGBA) ColorModel() color.Model { return color.RGBAModel }
+
+func (p *slowestRGBA) Bounds() image.Rectangle { return p.Rect }
+
+func (p *slowestRGBA) At(x, y int) color.Color {
+ return p.RGBA64At(x, y)
+}
+
+func (p *slowestRGBA) RGBA64At(x, y int) color.RGBA64 {
+ if !(image.Point{x, y}.In(p.Rect)) {
+ return color.RGBA64{}
+ }
+ i := p.PixOffset(x, y)
+ s := p.Pix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857
+ r := uint16(s[0])
+ g := uint16(s[1])
+ b := uint16(s[2])
+ a := uint16(s[3])
+ return color.RGBA64{
+ (r << 8) | r,
+ (g << 8) | g,
+ (b << 8) | b,
+ (a << 8) | a,
+ }
+}
+
+func (p *slowestRGBA) Set(x, y int, c color.Color) {
+ if !(image.Point{x, y}.In(p.Rect)) {
+ return
+ }
+ i := p.PixOffset(x, y)
+ c1 := color.RGBAModel.Convert(c).(color.RGBA)
+ s := p.Pix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857
+ s[0] = c1.R
+ s[1] = c1.G
+ s[2] = c1.B
+ s[3] = c1.A
+}
+
+func (p *slowestRGBA) PixOffset(x, y int) int {
+ return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4
+}
+
+func convertToSlowestRGBA(m image.Image) *slowestRGBA {
+ if rgba, ok := m.(*image.RGBA); ok {
+ return &slowestRGBA{
+ Pix: append([]byte(nil), rgba.Pix...),
+ Stride: rgba.Stride,
+ Rect: rgba.Rect,
+ }
+ }
+ rgba := image.NewRGBA(m.Bounds())
+ Draw(rgba, rgba.Bounds(), m, m.Bounds().Min, Src)
+ return &slowestRGBA{
+ Pix: rgba.Pix,
+ Stride: rgba.Stride,
+ Rect: rgba.Rect,
+ }
+}
+
+func init() {
+ var p any = (*slowestRGBA)(nil)
+ if _, ok := p.(RGBA64Image); ok {
+ panic("slowestRGBA should not be an RGBA64Image")
+ }
+}
+
+// slowerRGBA is a draw.Image like image.RGBA but it is a different type and
+// therefore does not trigger the draw.go fastest code paths.
+//
+// Unlike slowestRGBA, it still implements the draw.RGBA64Image interface.
+type slowerRGBA struct {
+ Pix []uint8
+ Stride int
+ Rect image.Rectangle
+}
+
+func (p *slowerRGBA) ColorModel() color.Model { return color.RGBAModel }
+
+func (p *slowerRGBA) Bounds() image.Rectangle { return p.Rect }
+
+func (p *slowerRGBA) At(x, y int) color.Color {
+ return p.RGBA64At(x, y)
+}
+
+func (p *slowerRGBA) RGBA64At(x, y int) color.RGBA64 {
+ if !(image.Point{x, y}.In(p.Rect)) {
+ return color.RGBA64{}
+ }
+ i := p.PixOffset(x, y)
+ s := p.Pix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857
+ r := uint16(s[0])
+ g := uint16(s[1])
+ b := uint16(s[2])
+ a := uint16(s[3])
+ return color.RGBA64{
+ (r << 8) | r,
+ (g << 8) | g,
+ (b << 8) | b,
+ (a << 8) | a,
+ }
+}
+
+func (p *slowerRGBA) Set(x, y int, c color.Color) {
+ if !(image.Point{x, y}.In(p.Rect)) {
+ return
+ }
+ i := p.PixOffset(x, y)
+ c1 := color.RGBAModel.Convert(c).(color.RGBA)
+ s := p.Pix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857
+ s[0] = c1.R
+ s[1] = c1.G
+ s[2] = c1.B
+ s[3] = c1.A
+}
+
+func (p *slowerRGBA) SetRGBA64(x, y int, c color.RGBA64) {
+ if !(image.Point{x, y}.In(p.Rect)) {
+ return
+ }
+ i := p.PixOffset(x, y)
+ s := p.Pix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857
+ s[0] = uint8(c.R >> 8)
+ s[1] = uint8(c.G >> 8)
+ s[2] = uint8(c.B >> 8)
+ s[3] = uint8(c.A >> 8)
+}
+
+func (p *slowerRGBA) PixOffset(x, y int) int {
+ return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4
+}
+
+func convertToSlowerRGBA(m image.Image) *slowerRGBA {
+ if rgba, ok := m.(*image.RGBA); ok {
+ return &slowerRGBA{
+ Pix: append([]byte(nil), rgba.Pix...),
+ Stride: rgba.Stride,
+ Rect: rgba.Rect,
+ }
+ }
+ rgba := image.NewRGBA(m.Bounds())
+ Draw(rgba, rgba.Bounds(), m, m.Bounds().Min, Src)
+ return &slowerRGBA{
+ Pix: rgba.Pix,
+ Stride: rgba.Stride,
+ Rect: rgba.Rect,
+ }
+}
+
+func init() {
+ var p any = (*slowerRGBA)(nil)
+ if _, ok := p.(RGBA64Image); !ok {
+ panic("slowerRGBA should be an RGBA64Image")
+ }
+}
+
+func eq(c0, c1 color.Color) bool {
+ r0, g0, b0, a0 := c0.RGBA()
+ r1, g1, b1, a1 := c1.RGBA()
+ return r0 == r1 && g0 == g1 && b0 == b1 && a0 == a1
+}
+
+func fillBlue(alpha int) image.Image {
+ return image.NewUniform(color.RGBA{0, 0, uint8(alpha), uint8(alpha)})
+}
+
+func fillAlpha(alpha int) image.Image {
+ return image.NewUniform(color.Alpha{uint8(alpha)})
+}
+
+func vgradGreen(alpha int) image.Image {
+ m := image.NewRGBA(image.Rect(0, 0, 16, 16))
+ for y := 0; y < 16; y++ {
+ for x := 0; x < 16; x++ {
+ m.Set(x, y, color.RGBA{0, uint8(y * alpha / 15), 0, uint8(alpha)})
+ }
+ }
+ return m
+}
+
+func vgradAlpha(alpha int) image.Image {
+ m := image.NewAlpha(image.Rect(0, 0, 16, 16))
+ for y := 0; y < 16; y++ {
+ for x := 0; x < 16; x++ {
+ m.Set(x, y, color.Alpha{uint8(y * alpha / 15)})
+ }
+ }
+ return m
+}
+
+func vgradGreenNRGBA(alpha int) image.Image {
+ m := image.NewNRGBA(image.Rect(0, 0, 16, 16))
+ for y := 0; y < 16; y++ {
+ for x := 0; x < 16; x++ {
+ m.Set(x, y, color.RGBA{0, uint8(y * 0x11), 0, uint8(alpha)})
+ }
+ }
+ return m
+}
+
+func vgradCr() image.Image {
+ m := &image.YCbCr{
+ Y: make([]byte, 16*16),
+ Cb: make([]byte, 16*16),
+ Cr: make([]byte, 16*16),
+ YStride: 16,
+ CStride: 16,
+ SubsampleRatio: image.YCbCrSubsampleRatio444,
+ Rect: image.Rect(0, 0, 16, 16),
+ }
+ for y := 0; y < 16; y++ {
+ for x := 0; x < 16; x++ {
+ m.Cr[y*m.CStride+x] = uint8(y * 0x11)
+ }
+ }
+ return m
+}
+
+func vgradGray() image.Image {
+ m := image.NewGray(image.Rect(0, 0, 16, 16))
+ for y := 0; y < 16; y++ {
+ for x := 0; x < 16; x++ {
+ m.Set(x, y, color.Gray{uint8(y * 0x11)})
+ }
+ }
+ return m
+}
+
+func vgradMagenta() image.Image {
+ m := image.NewCMYK(image.Rect(0, 0, 16, 16))
+ for y := 0; y < 16; y++ {
+ for x := 0; x < 16; x++ {
+ m.Set(x, y, color.CMYK{0, uint8(y * 0x11), 0, 0x3f})
+ }
+ }
+ return m
+}
+
+func hgradRed(alpha int) Image {
+ m := image.NewRGBA(image.Rect(0, 0, 16, 16))
+ for y := 0; y < 16; y++ {
+ for x := 0; x < 16; x++ {
+ m.Set(x, y, color.RGBA{uint8(x * alpha / 15), 0, 0, uint8(alpha)})
+ }
+ }
+ return m
+}
+
+func gradYellow(alpha int) Image {
+ m := image.NewRGBA(image.Rect(0, 0, 16, 16))
+ for y := 0; y < 16; y++ {
+ for x := 0; x < 16; x++ {
+ m.Set(x, y, color.RGBA{uint8(x * alpha / 15), uint8(y * alpha / 15), 0, uint8(alpha)})
+ }
+ }
+ return m
+}
+
+type drawTest struct {
+ desc string
+ src image.Image
+ mask image.Image
+ op Op
+ expected color.Color
+}
+
+var drawTests = []drawTest{
+ // Uniform mask (0% opaque).
+ {"nop", vgradGreen(255), fillAlpha(0), Over, color.RGBA{136, 0, 0, 255}},
+ {"clear", vgradGreen(255), fillAlpha(0), Src, color.RGBA{0, 0, 0, 0}},
+ // Uniform mask (100%, 75%, nil) and uniform source.
+ // At (x, y) == (8, 8):
+ // The destination pixel is {136, 0, 0, 255}.
+ // The source pixel is {0, 0, 90, 90}.
+ {"fill", fillBlue(90), fillAlpha(255), Over, color.RGBA{88, 0, 90, 255}},
+ {"fillSrc", fillBlue(90), fillAlpha(255), Src, color.RGBA{0, 0, 90, 90}},
+ {"fillAlpha", fillBlue(90), fillAlpha(192), Over, color.RGBA{100, 0, 68, 255}},
+ {"fillAlphaSrc", fillBlue(90), fillAlpha(192), Src, color.RGBA{0, 0, 68, 68}},
+ {"fillNil", fillBlue(90), nil, Over, color.RGBA{88, 0, 90, 255}},
+ {"fillNilSrc", fillBlue(90), nil, Src, color.RGBA{0, 0, 90, 90}},
+ // Uniform mask (100%, 75%, nil) and variable source.
+ // At (x, y) == (8, 8):
+ // The destination pixel is {136, 0, 0, 255}.
+ // The source pixel is {0, 48, 0, 90}.
+ {"copy", vgradGreen(90), fillAlpha(255), Over, color.RGBA{88, 48, 0, 255}},
+ {"copySrc", vgradGreen(90), fillAlpha(255), Src, color.RGBA{0, 48, 0, 90}},
+ {"copyAlpha", vgradGreen(90), fillAlpha(192), Over, color.RGBA{100, 36, 0, 255}},
+ {"copyAlphaSrc", vgradGreen(90), fillAlpha(192), Src, color.RGBA{0, 36, 0, 68}},
+ {"copyNil", vgradGreen(90), nil, Over, color.RGBA{88, 48, 0, 255}},
+ {"copyNilSrc", vgradGreen(90), nil, Src, color.RGBA{0, 48, 0, 90}},
+ // Uniform mask (100%, 75%, nil) and variable NRGBA source.
+ // At (x, y) == (8, 8):
+ // The destination pixel is {136, 0, 0, 255}.
+ // The source pixel is {0, 136, 0, 90} in NRGBA-space, which is {0, 48, 0, 90} in RGBA-space.
+ // The result pixel is different than in the "copy*" test cases because of rounding errors.
+ {"nrgba", vgradGreenNRGBA(90), fillAlpha(255), Over, color.RGBA{88, 46, 0, 255}},
+ {"nrgbaSrc", vgradGreenNRGBA(90), fillAlpha(255), Src, color.RGBA{0, 46, 0, 90}},
+ {"nrgbaAlpha", vgradGreenNRGBA(90), fillAlpha(192), Over, color.RGBA{100, 34, 0, 255}},
+ {"nrgbaAlphaSrc", vgradGreenNRGBA(90), fillAlpha(192), Src, color.RGBA{0, 34, 0, 68}},
+ {"nrgbaNil", vgradGreenNRGBA(90), nil, Over, color.RGBA{88, 46, 0, 255}},
+ {"nrgbaNilSrc", vgradGreenNRGBA(90), nil, Src, color.RGBA{0, 46, 0, 90}},
+ // Uniform mask (100%, 75%, nil) and variable YCbCr source.
+ // At (x, y) == (8, 8):
+ // The destination pixel is {136, 0, 0, 255}.
+ // The source pixel is {0, 0, 136} in YCbCr-space, which is {11, 38, 0, 255} in RGB-space.
+ {"ycbcr", vgradCr(), fillAlpha(255), Over, color.RGBA{11, 38, 0, 255}},
+ {"ycbcrSrc", vgradCr(), fillAlpha(255), Src, color.RGBA{11, 38, 0, 255}},
+ {"ycbcrAlpha", vgradCr(), fillAlpha(192), Over, color.RGBA{42, 28, 0, 255}},
+ {"ycbcrAlphaSrc", vgradCr(), fillAlpha(192), Src, color.RGBA{8, 28, 0, 192}},
+ {"ycbcrNil", vgradCr(), nil, Over, color.RGBA{11, 38, 0, 255}},
+ {"ycbcrNilSrc", vgradCr(), nil, Src, color.RGBA{11, 38, 0, 255}},
+ // Uniform mask (100%, 75%, nil) and variable Gray source.
+ // At (x, y) == (8, 8):
+ // The destination pixel is {136, 0, 0, 255}.
+ // The source pixel is {136} in Gray-space, which is {136, 136, 136, 255} in RGBA-space.
+ {"gray", vgradGray(), fillAlpha(255), Over, color.RGBA{136, 136, 136, 255}},
+ {"graySrc", vgradGray(), fillAlpha(255), Src, color.RGBA{136, 136, 136, 255}},
+ {"grayAlpha", vgradGray(), fillAlpha(192), Over, color.RGBA{136, 102, 102, 255}},
+ {"grayAlphaSrc", vgradGray(), fillAlpha(192), Src, color.RGBA{102, 102, 102, 192}},
+ {"grayNil", vgradGray(), nil, Over, color.RGBA{136, 136, 136, 255}},
+ {"grayNilSrc", vgradGray(), nil, Src, color.RGBA{136, 136, 136, 255}},
+ // Same again, but with a slowerRGBA source.
+ {"graySlower", convertToSlowerRGBA(vgradGray()), fillAlpha(255),
+ Over, color.RGBA{136, 136, 136, 255}},
+ {"graySrcSlower", convertToSlowerRGBA(vgradGray()), fillAlpha(255),
+ Src, color.RGBA{136, 136, 136, 255}},
+ {"grayAlphaSlower", convertToSlowerRGBA(vgradGray()), fillAlpha(192),
+ Over, color.RGBA{136, 102, 102, 255}},
+ {"grayAlphaSrcSlower", convertToSlowerRGBA(vgradGray()), fillAlpha(192),
+ Src, color.RGBA{102, 102, 102, 192}},
+ {"grayNilSlower", convertToSlowerRGBA(vgradGray()), nil,
+ Over, color.RGBA{136, 136, 136, 255}},
+ {"grayNilSrcSlower", convertToSlowerRGBA(vgradGray()), nil,
+ Src, color.RGBA{136, 136, 136, 255}},
+ // Same again, but with a slowestRGBA source.
+ {"graySlowest", convertToSlowestRGBA(vgradGray()), fillAlpha(255),
+ Over, color.RGBA{136, 136, 136, 255}},
+ {"graySrcSlowest", convertToSlowestRGBA(vgradGray()), fillAlpha(255),
+ Src, color.RGBA{136, 136, 136, 255}},
+ {"grayAlphaSlowest", convertToSlowestRGBA(vgradGray()), fillAlpha(192),
+ Over, color.RGBA{136, 102, 102, 255}},
+ {"grayAlphaSrcSlowest", convertToSlowestRGBA(vgradGray()), fillAlpha(192),
+ Src, color.RGBA{102, 102, 102, 192}},
+ {"grayNilSlowest", convertToSlowestRGBA(vgradGray()), nil,
+ Over, color.RGBA{136, 136, 136, 255}},
+ {"grayNilSrcSlowest", convertToSlowestRGBA(vgradGray()), nil,
+ Src, color.RGBA{136, 136, 136, 255}},
+ // Uniform mask (100%, 75%, nil) and variable CMYK source.
+ // At (x, y) == (8, 8):
+ // The destination pixel is {136, 0, 0, 255}.
+ // The source pixel is {0, 136, 0, 63} in CMYK-space, which is {192, 89, 192} in RGB-space.
+ {"cmyk", vgradMagenta(), fillAlpha(255), Over, color.RGBA{192, 89, 192, 255}},
+ {"cmykSrc", vgradMagenta(), fillAlpha(255), Src, color.RGBA{192, 89, 192, 255}},
+ {"cmykAlpha", vgradMagenta(), fillAlpha(192), Over, color.RGBA{178, 67, 145, 255}},
+ {"cmykAlphaSrc", vgradMagenta(), fillAlpha(192), Src, color.RGBA{145, 67, 145, 192}},
+ {"cmykNil", vgradMagenta(), nil, Over, color.RGBA{192, 89, 192, 255}},
+ {"cmykNilSrc", vgradMagenta(), nil, Src, color.RGBA{192, 89, 192, 255}},
+ // Variable mask and uniform source.
+ // At (x, y) == (8, 8):
+ // The destination pixel is {136, 0, 0, 255}.
+ // The source pixel is {0, 0, 255, 255}.
+ // The mask pixel's alpha is 102, or 40%.
+ {"generic", fillBlue(255), vgradAlpha(192), Over, color.RGBA{81, 0, 102, 255}},
+ {"genericSrc", fillBlue(255), vgradAlpha(192), Src, color.RGBA{0, 0, 102, 102}},
+ // Same again, but with a slowerRGBA mask.
+ {"genericSlower", fillBlue(255), convertToSlowerRGBA(vgradAlpha(192)),
+ Over, color.RGBA{81, 0, 102, 255}},
+ {"genericSrcSlower", fillBlue(255), convertToSlowerRGBA(vgradAlpha(192)),
+ Src, color.RGBA{0, 0, 102, 102}},
+ // Same again, but with a slowestRGBA mask.
+ {"genericSlowest", fillBlue(255), convertToSlowestRGBA(vgradAlpha(192)),
+ Over, color.RGBA{81, 0, 102, 255}},
+ {"genericSrcSlowest", fillBlue(255), convertToSlowestRGBA(vgradAlpha(192)),
+ Src, color.RGBA{0, 0, 102, 102}},
+ // Variable mask and variable source.
+ // At (x, y) == (8, 8):
+ // The destination pixel is {136, 0, 0, 255}.
+ // The source pixel is:
+ // - {0, 48, 0, 90}.
+ // - {136} in Gray-space, which is {136, 136, 136, 255} in RGBA-space.
+ // The mask pixel's alpha is 102, or 40%.
+ {"rgbaVariableMaskOver", vgradGreen(90), vgradAlpha(192), Over, color.RGBA{117, 19, 0, 255}},
+ {"grayVariableMaskOver", vgradGray(), vgradAlpha(192), Over, color.RGBA{136, 54, 54, 255}},
+}
+
+func makeGolden(dst image.Image, r image.Rectangle, src image.Image, sp image.Point, mask image.Image, mp image.Point, op Op) image.Image {
+ // Since golden is a newly allocated image, we don't have to check if the
+ // input source and mask images and the output golden image overlap.
+ b := dst.Bounds()
+ sb := src.Bounds()
+ mb := image.Rect(-1e9, -1e9, 1e9, 1e9)
+ if mask != nil {
+ mb = mask.Bounds()
+ }
+ golden := image.NewRGBA(image.Rect(0, 0, b.Max.X, b.Max.Y))
+ for y := r.Min.Y; y < r.Max.Y; y++ {
+ sy := y + sp.Y - r.Min.Y
+ my := y + mp.Y - r.Min.Y
+ for x := r.Min.X; x < r.Max.X; x++ {
+ if !(image.Pt(x, y).In(b)) {
+ continue
+ }
+ sx := x + sp.X - r.Min.X
+ if !(image.Pt(sx, sy).In(sb)) {
+ continue
+ }
+ mx := x + mp.X - r.Min.X
+ if !(image.Pt(mx, my).In(mb)) {
+ continue
+ }
+
+ const M = 1<<16 - 1
+ var dr, dg, db, da uint32
+ if op == Over {
+ dr, dg, db, da = dst.At(x, y).RGBA()
+ }
+ sr, sg, sb, sa := src.At(sx, sy).RGBA()
+ ma := uint32(M)
+ if mask != nil {
+ _, _, _, ma = mask.At(mx, my).RGBA()
+ }
+ a := M - (sa * ma / M)
+ golden.Set(x, y, color.RGBA64{
+ uint16((dr*a + sr*ma) / M),
+ uint16((dg*a + sg*ma) / M),
+ uint16((db*a + sb*ma) / M),
+ uint16((da*a + sa*ma) / M),
+ })
+ }
+ }
+ return golden.SubImage(b)
+}
+
+func TestDraw(t *testing.T) {
+ rr := []image.Rectangle{
+ image.Rect(0, 0, 0, 0),
+ image.Rect(0, 0, 16, 16),
+ image.Rect(3, 5, 12, 10),
+ image.Rect(0, 0, 9, 9),
+ image.Rect(8, 8, 16, 16),
+ image.Rect(8, 0, 9, 16),
+ image.Rect(0, 8, 16, 9),
+ image.Rect(8, 8, 9, 9),
+ image.Rect(8, 8, 8, 8),
+ }
+ for _, r := range rr {
+ loop:
+ for _, test := range drawTests {
+ for i := 0; i < 3; i++ {
+ dst := hgradRed(255).(*image.RGBA).SubImage(r).(Image)
+ // For i != 0, substitute a different-typed dst that will take
+ // us off the fastest code paths. We should still get the same
+ // result, in terms of final pixel RGBA values.
+ switch i {
+ case 1:
+ dst = convertToSlowerRGBA(dst)
+ case 2:
+ dst = convertToSlowestRGBA(dst)
+ }
+
+ // Draw the (src, mask, op) onto a copy of dst using a slow but obviously correct implementation.
+ golden := makeGolden(dst, image.Rect(0, 0, 16, 16), test.src, image.ZP, test.mask, image.ZP, test.op)
+ b := dst.Bounds()
+ if !b.Eq(golden.Bounds()) {
+ t.Errorf("draw %v %s on %T: bounds %v versus %v",
+ r, test.desc, dst, dst.Bounds(), golden.Bounds())
+ continue
+ }
+ // Draw the same combination onto the actual dst using the optimized DrawMask implementation.
+ DrawMask(dst, image.Rect(0, 0, 16, 16), test.src, image.ZP, test.mask, image.ZP, test.op)
+ if image.Pt(8, 8).In(r) {
+ // Check that the resultant pixel at (8, 8) matches what we expect
+ // (the expected value can be verified by hand).
+ if !eq(dst.At(8, 8), test.expected) {
+ t.Errorf("draw %v %s on %T: at (8, 8) %v versus %v",
+ r, test.desc, dst, dst.At(8, 8), test.expected)
+ continue
+ }
+ }
+ // Check that the resultant dst image matches the golden output.
+ for y := b.Min.Y; y < b.Max.Y; y++ {
+ for x := b.Min.X; x < b.Max.X; x++ {
+ if !eq(dst.At(x, y), golden.At(x, y)) {
+ t.Errorf("draw %v %s on %T: at (%d, %d), %v versus golden %v",
+ r, test.desc, dst, x, y, dst.At(x, y), golden.At(x, y))
+ continue loop
+ }
+ }
+ }
+ }
+ }
+ }
+}
+
+func TestDrawOverlap(t *testing.T) {
+ for _, op := range []Op{Over, Src} {
+ for yoff := -2; yoff <= 2; yoff++ {
+ loop:
+ for xoff := -2; xoff <= 2; xoff++ {
+ m := gradYellow(127).(*image.RGBA)
+ dst := m.SubImage(image.Rect(5, 5, 10, 10)).(*image.RGBA)
+ src := m.SubImage(image.Rect(5+xoff, 5+yoff, 10+xoff, 10+yoff)).(*image.RGBA)
+ b := dst.Bounds()
+ // Draw the (src, mask, op) onto a copy of dst using a slow but obviously correct implementation.
+ golden := makeGolden(dst, b, src, src.Bounds().Min, nil, image.ZP, op)
+ if !b.Eq(golden.Bounds()) {
+ t.Errorf("drawOverlap xoff=%d,yoff=%d: bounds %v versus %v", xoff, yoff, dst.Bounds(), golden.Bounds())
+ continue
+ }
+ // Draw the same combination onto the actual dst using the optimized DrawMask implementation.
+ DrawMask(dst, b, src, src.Bounds().Min, nil, image.ZP, op)
+ // Check that the resultant dst image matches the golden output.
+ for y := b.Min.Y; y < b.Max.Y; y++ {
+ for x := b.Min.X; x < b.Max.X; x++ {
+ if !eq(dst.At(x, y), golden.At(x, y)) {
+ t.Errorf("drawOverlap xoff=%d,yoff=%d: at (%d, %d), %v versus golden %v", xoff, yoff, x, y, dst.At(x, y), golden.At(x, y))
+ continue loop
+ }
+ }
+ }
+ }
+ }
+ }
+}
+
+// TestNonZeroSrcPt checks drawing with a non-zero src point parameter.
+func TestNonZeroSrcPt(t *testing.T) {
+ a := image.NewRGBA(image.Rect(0, 0, 1, 1))
+ b := image.NewRGBA(image.Rect(0, 0, 2, 2))
+ b.Set(0, 0, color.RGBA{0, 0, 0, 5})
+ b.Set(1, 0, color.RGBA{0, 0, 5, 5})
+ b.Set(0, 1, color.RGBA{0, 5, 0, 5})
+ b.Set(1, 1, color.RGBA{5, 0, 0, 5})
+ Draw(a, image.Rect(0, 0, 1, 1), b, image.Pt(1, 1), Over)
+ if !eq(color.RGBA{5, 0, 0, 5}, a.At(0, 0)) {
+ t.Errorf("non-zero src pt: want %v got %v", color.RGBA{5, 0, 0, 5}, a.At(0, 0))
+ }
+}
+
+func TestFill(t *testing.T) {
+ rr := []image.Rectangle{
+ image.Rect(0, 0, 0, 0),
+ image.Rect(0, 0, 40, 30),
+ image.Rect(10, 0, 40, 30),
+ image.Rect(0, 20, 40, 30),
+ image.Rect(10, 20, 40, 30),
+ image.Rect(10, 20, 15, 25),
+ image.Rect(10, 0, 35, 30),
+ image.Rect(0, 15, 40, 16),
+ image.Rect(24, 24, 25, 25),
+ image.Rect(23, 23, 26, 26),
+ image.Rect(22, 22, 27, 27),
+ image.Rect(21, 21, 28, 28),
+ image.Rect(20, 20, 29, 29),
+ }
+ for _, r := range rr {
+ m := image.NewRGBA(image.Rect(0, 0, 40, 30)).SubImage(r).(*image.RGBA)
+ b := m.Bounds()
+ c := color.RGBA{11, 0, 0, 255}
+ src := &image.Uniform{C: c}
+ check := func(desc string) {
+ for y := b.Min.Y; y < b.Max.Y; y++ {
+ for x := b.Min.X; x < b.Max.X; x++ {
+ if !eq(c, m.At(x, y)) {
+ t.Errorf("%s fill: at (%d, %d), sub-image bounds=%v: want %v got %v", desc, x, y, r, c, m.At(x, y))
+ return
+ }
+ }
+ }
+ }
+ // Draw 1 pixel at a time.
+ for y := b.Min.Y; y < b.Max.Y; y++ {
+ for x := b.Min.X; x < b.Max.X; x++ {
+ DrawMask(m, image.Rect(x, y, x+1, y+1), src, image.ZP, nil, image.ZP, Src)
+ }
+ }
+ check("pixel")
+ // Draw 1 row at a time.
+ c = color.RGBA{0, 22, 0, 255}
+ src = &image.Uniform{C: c}
+ for y := b.Min.Y; y < b.Max.Y; y++ {
+ DrawMask(m, image.Rect(b.Min.X, y, b.Max.X, y+1), src, image.ZP, nil, image.ZP, Src)
+ }
+ check("row")
+ // Draw 1 column at a time.
+ c = color.RGBA{0, 0, 33, 255}
+ src = &image.Uniform{C: c}
+ for x := b.Min.X; x < b.Max.X; x++ {
+ DrawMask(m, image.Rect(x, b.Min.Y, x+1, b.Max.Y), src, image.ZP, nil, image.ZP, Src)
+ }
+ check("column")
+ // Draw the whole image at once.
+ c = color.RGBA{44, 55, 66, 77}
+ src = &image.Uniform{C: c}
+ DrawMask(m, b, src, image.ZP, nil, image.ZP, Src)
+ check("whole")
+ }
+}
+
+func TestDrawSrcNonpremultiplied(t *testing.T) {
+ var (
+ opaqueGray = color.NRGBA{0x99, 0x99, 0x99, 0xff}
+ transparentBlue = color.NRGBA{0x00, 0x00, 0xff, 0x00}
+ transparentGreen = color.NRGBA{0x00, 0xff, 0x00, 0x00}
+ transparentRed = color.NRGBA{0xff, 0x00, 0x00, 0x00}
+
+ opaqueGray64 = color.NRGBA64{0x9999, 0x9999, 0x9999, 0xffff}
+ transparentPurple64 = color.NRGBA64{0xfedc, 0x0000, 0x7654, 0x0000}
+ )
+
+ // dst and src are 1x3 images but the dr rectangle (and hence the overlap)
+ // is only 1x2. The Draw call should affect dst's pixels at (1, 10) and (2,
+ // 10) but the pixel at (0, 10) should be untouched.
+ //
+ // The src image is entirely transparent (and the Draw operator is Src) so
+ // the two touched pixels should be set to transparent colors.
+ //
+ // In general, Go's color.Color type (and specifically the Color.RGBA
+ // method) works in premultiplied alpha, where there's no difference
+ // between "transparent blue" and "transparent red". It's all "just
+ // transparent" and canonically "transparent black" (all zeroes).
+ //
+ // However, since the operator is Src (so the pixels are 'copied', not
+ // 'blended') and both dst and src images are *image.NRGBA (N stands for
+ // Non-premultiplied alpha which *does* distinguish "transparent blue" and
+ // "transparent red"), we prefer that this distinction carries through and
+ // dst's touched pixels should be transparent blue and transparent green,
+ // not just transparent black.
+ {
+ dst := image.NewNRGBA(image.Rect(0, 10, 3, 11))
+ dst.SetNRGBA(0, 10, opaqueGray)
+ src := image.NewNRGBA(image.Rect(1, 20, 4, 21))
+ src.SetNRGBA(1, 20, transparentBlue)
+ src.SetNRGBA(2, 20, transparentGreen)
+ src.SetNRGBA(3, 20, transparentRed)
+
+ dr := image.Rect(1, 10, 3, 11)
+ Draw(dst, dr, src, image.Point{1, 20}, Src)
+
+ if got, want := dst.At(0, 10), opaqueGray; got != want {
+ t.Errorf("At(0, 10):\ngot %#v\nwant %#v", got, want)
+ }
+ if got, want := dst.At(1, 10), transparentBlue; got != want {
+ t.Errorf("At(1, 10):\ngot %#v\nwant %#v", got, want)
+ }
+ if got, want := dst.At(2, 10), transparentGreen; got != want {
+ t.Errorf("At(2, 10):\ngot %#v\nwant %#v", got, want)
+ }
+ }
+
+ // Check image.NRGBA64 (not image.NRGBA) similarly.
+ {
+ dst := image.NewNRGBA64(image.Rect(0, 0, 1, 1))
+ dst.SetNRGBA64(0, 0, opaqueGray64)
+ src := image.NewNRGBA64(image.Rect(0, 0, 1, 1))
+ src.SetNRGBA64(0, 0, transparentPurple64)
+ Draw(dst, dst.Bounds(), src, image.Point{0, 0}, Src)
+ if got, want := dst.At(0, 0), transparentPurple64; got != want {
+ t.Errorf("At(0, 0):\ngot %#v\nwant %#v", got, want)
+ }
+ }
+}
+
+// TestFloydSteinbergCheckerboard tests that the result of Floyd-Steinberg
+// error diffusion of a uniform 50% gray source image with a black-and-white
+// palette is a checkerboard pattern.
+func TestFloydSteinbergCheckerboard(t *testing.T) {
+ b := image.Rect(0, 0, 640, 480)
+ // We can't represent 50% exactly, but 0x7fff / 0xffff is close enough.
+ src := &image.Uniform{color.Gray16{0x7fff}}
+ dst := image.NewPaletted(b, color.Palette{color.Black, color.White})
+ FloydSteinberg.Draw(dst, b, src, image.Point{})
+ nErr := 0
+ for y := b.Min.Y; y < b.Max.Y; y++ {
+ for x := b.Min.X; x < b.Max.X; x++ {
+ got := dst.Pix[dst.PixOffset(x, y)]
+ want := uint8(x+y) % 2
+ if got != want {
+ t.Errorf("at (%d, %d): got %d, want %d", x, y, got, want)
+ if nErr++; nErr == 10 {
+ t.Fatal("there may be more errors")
+ }
+ }
+ }
+ }
+}
+
+// embeddedPaletted is an Image that behaves like an *image.Paletted but whose
+// type is not *image.Paletted.
+type embeddedPaletted struct {
+ *image.Paletted
+}
+
+// TestPaletted tests that the drawPaletted function behaves the same
+// regardless of whether dst is an *image.Paletted.
+func TestPaletted(t *testing.T) {
+ f, err := os.Open("../testdata/video-001.png")
+ if err != nil {
+ t.Fatalf("open: %v", err)
+ }
+ defer f.Close()
+ video001, err := png.Decode(f)
+ if err != nil {
+ t.Fatalf("decode: %v", err)
+ }
+ b := video001.Bounds()
+
+ cgaPalette := color.Palette{
+ color.RGBA{0x00, 0x00, 0x00, 0xff},
+ color.RGBA{0x55, 0xff, 0xff, 0xff},
+ color.RGBA{0xff, 0x55, 0xff, 0xff},
+ color.RGBA{0xff, 0xff, 0xff, 0xff},
+ }
+ drawers := map[string]Drawer{
+ "src": Src,
+ "floyd-steinberg": FloydSteinberg,
+ }
+ sources := map[string]image.Image{
+ "uniform": &image.Uniform{color.RGBA{0xff, 0x7f, 0xff, 0xff}},
+ "video001": video001,
+ }
+
+ for dName, d := range drawers {
+ loop:
+ for sName, src := range sources {
+ dst0 := image.NewPaletted(b, cgaPalette)
+ dst1 := image.NewPaletted(b, cgaPalette)
+ d.Draw(dst0, b, src, image.Point{})
+ d.Draw(embeddedPaletted{dst1}, b, src, image.Point{})
+ for y := b.Min.Y; y < b.Max.Y; y++ {
+ for x := b.Min.X; x < b.Max.X; x++ {
+ if !eq(dst0.At(x, y), dst1.At(x, y)) {
+ t.Errorf("%s / %s: at (%d, %d), %v versus %v",
+ dName, sName, x, y, dst0.At(x, y), dst1.At(x, y))
+ continue loop
+ }
+ }
+ }
+ }
+ }
+}
+
+func TestSqDiff(t *testing.T) {
+ // This test is similar to the one from the image/color package, but
+ // sqDiff in this package accepts int32 instead of uint32, so test it
+ // for appropriate input.
+
+ // canonical sqDiff implementation
+ orig := func(x, y int32) uint32 {
+ var d uint32
+ if x > y {
+ d = uint32(x - y)
+ } else {
+ d = uint32(y - x)
+ }
+ return (d * d) >> 2
+ }
+ testCases := []int32{
+ 0,
+ 1,
+ 2,
+ 0x0fffd,
+ 0x0fffe,
+ 0x0ffff,
+ 0x10000,
+ 0x10001,
+ 0x10002,
+ 0x7ffffffd,
+ 0x7ffffffe,
+ 0x7fffffff,
+ -0x7ffffffd,
+ -0x7ffffffe,
+ -0x80000000,
+ }
+ for _, x := range testCases {
+ for _, y := range testCases {
+ if got, want := sqDiff(x, y), orig(x, y); got != want {
+ t.Fatalf("sqDiff(%#x, %#x): got %d, want %d", x, y, got, want)
+ }
+ }
+ }
+ if err := quick.CheckEqual(orig, sqDiff, &quick.Config{MaxCountScale: 10}); err != nil {
+ t.Fatal(err)
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-10-12 15:26:08 +0000