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// 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"
"testing"
)
func eq(c0, c1 image.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.NewColorImage(image.RGBAColor{0, 0, uint8(alpha), uint8(alpha)})
}
func fillAlpha(alpha int) image.Image {
return image.NewColorImage(image.AlphaColor{uint8(alpha)})
}
func vgradGreen(alpha int) image.Image {
m := image.NewRGBA(16, 16)
for y := 0; y < 16; y++ {
for x := 0; x < 16; x++ {
m.Set(x, y, image.RGBAColor{0, uint8(y * alpha / 15), 0, uint8(alpha)})
}
}
return m
}
func vgradAlpha(alpha int) image.Image {
m := image.NewAlpha(16, 16)
for y := 0; y < 16; y++ {
for x := 0; x < 16; x++ {
m.Set(x, y, image.AlphaColor{uint8(y * alpha / 15)})
}
}
return m
}
func hgradRed(alpha int) Image {
m := image.NewRGBA(16, 16)
for y := 0; y < 16; y++ {
for x := 0; x < 16; x++ {
m.Set(x, y, image.RGBAColor{uint8(x * alpha / 15), 0, 0, uint8(alpha)})
}
}
return m
}
func gradYellow(alpha int) Image {
m := image.NewRGBA(16, 16)
for y := 0; y < 16; y++ {
for x := 0; x < 16; x++ {
m.Set(x, y, image.RGBAColor{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 image.Color
}
var drawTests = []drawTest{
// Uniform mask (0% opaque).
{"nop", vgradGreen(255), fillAlpha(0), Over, image.RGBAColor{136, 0, 0, 255}},
{"clear", vgradGreen(255), fillAlpha(0), Src, image.RGBAColor{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, image.RGBAColor{88, 0, 90, 255}},
{"fillSrc", fillBlue(90), fillAlpha(255), Src, image.RGBAColor{0, 0, 90, 90}},
{"fillAlpha", fillBlue(90), fillAlpha(192), Over, image.RGBAColor{100, 0, 68, 255}},
{"fillAlphaSrc", fillBlue(90), fillAlpha(192), Src, image.RGBAColor{0, 0, 68, 68}},
{"fillNil", fillBlue(90), nil, Over, image.RGBAColor{88, 0, 90, 255}},
{"fillNilSrc", fillBlue(90), nil, Src, image.RGBAColor{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, image.RGBAColor{88, 48, 0, 255}},
{"copySrc", vgradGreen(90), fillAlpha(255), Src, image.RGBAColor{0, 48, 0, 90}},
{"copyAlpha", vgradGreen(90), fillAlpha(192), Over, image.RGBAColor{100, 36, 0, 255}},
{"copyAlphaSrc", vgradGreen(90), fillAlpha(192), Src, image.RGBAColor{0, 36, 0, 68}},
{"copyNil", vgradGreen(90), nil, Over, image.RGBAColor{88, 48, 0, 255}},
{"copyNilSrc", vgradGreen(90), nil, Src, image.RGBAColor{0, 48, 0, 90}},
// 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, image.RGBAColor{81, 0, 102, 255}},
{"genericSrc", fillBlue(255), vgradAlpha(192), Src, image.RGBAColor{0, 0, 102, 102}},
}
func makeGolden(dst, src, mask image.Image, 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()
sx0 := src.Bounds().Min.X - b.Min.X
sy0 := src.Bounds().Min.Y - b.Min.Y
var mx0, my0 int
if mask != nil {
mx0 = mask.Bounds().Min.X - b.Min.X
my0 = mask.Bounds().Min.Y - b.Min.Y
}
golden := image.NewRGBA(b.Max.X, b.Max.Y)
for y := b.Min.Y; y < b.Max.Y; y++ {
my, sy := my0+y, sy0+y
for x := b.Min.X; x < b.Max.X; x++ {
mx, sx := mx0+x, sx0+x
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, image.RGBA64Color{
uint16((dr*a + sr*ma) / M),
uint16((dg*a + sg*ma) / M),
uint16((db*a + sb*ma) / M),
uint16((da*a + sa*ma) / M),
})
}
}
golden.Rect = b
return golden
}
func TestDraw(t *testing.T) {
loop:
for _, test := range drawTests {
dst := hgradRed(255)
// Draw the (src, mask, op) onto a copy of dst using a slow but obviously correct implementation.
golden := makeGolden(dst, test.src, test.mask, test.op)
b := dst.Bounds()
if !b.Eq(golden.Bounds()) {
t.Errorf("draw %s: bounds %v versus %v", test.desc, dst.Bounds(), golden.Bounds())
continue
}
// Draw the same combination onto the actual dst using the optimized DrawMask implementation.
DrawMask(dst, b, test.src, image.ZP, test.mask, image.ZP, test.op)
// 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 %s: at (8, 8) %v versus %v", 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 %s: at (%d, %d), %v versus golden %v", 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 := &image.RGBA{
Pix: m.Pix,
Stride: m.Stride,
Rect: image.Rect(5, 5, 10, 10),
}
src := &image.RGBA{
Pix: m.Pix,
Stride: m.Stride,
Rect: image.Rect(5+xoff, 5+yoff, 10+xoff, 10+yoff),
}
// Draw the (src, mask, op) onto a copy of dst using a slow but obviously correct implementation.
golden := makeGolden(dst, src, nil, op)
b := dst.Bounds()
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
}
}
}
}
}
}
}
// TestIssue836 verifies http://code.google.com/p/go/issues/detail?id=836.
func TestIssue836(t *testing.T) {
a := image.NewRGBA(1, 1)
b := image.NewRGBA(2, 2)
b.Set(0, 0, image.RGBAColor{0, 0, 0, 5})
b.Set(1, 0, image.RGBAColor{0, 0, 5, 5})
b.Set(0, 1, image.RGBAColor{0, 5, 0, 5})
b.Set(1, 1, image.RGBAColor{5, 0, 0, 5})
Draw(a, image.Rect(0, 0, 1, 1), b, image.Pt(1, 1))
if !eq(image.RGBAColor{5, 0, 0, 5}, a.At(0, 0)) {
t.Errorf("Issue 836: want %v got %v", image.RGBAColor{5, 0, 0, 5}, a.At(0, 0))
}
}
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