// 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"
)
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}},
// 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 variable 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}},
}
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 {
dst := hgradRed(255).(*image.RGBA).SubImage(r).(Image)
// 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: bounds %v versus %v", r, test.desc, 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: at (8, 8) %v versus %v", r, test.desc, 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: at (%d, %d), %v versus golden %v", r, test.desc, 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")
}
}
// 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()
src, err := png.Decode(f)
if err != nil {
t.Fatalf("decode: %v", err)
}
b := src.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,
}
loop:
for dName, d := range drawers {
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: at (%d, %d), %v versus %v",
dName, 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)
}
}
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