aw/go-resize
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Merge pull request #34 from minodisk/master

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Fix wrong color with RGBA input
This commit is contained in:
Jan Schlicht 2015-05-27 10:09:16 +02:00
commit a3789c3aed
2 changed files with 96 additions and 6 deletions
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6
converter.go
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@ -131,11 +131,11 @@ func resizeRGBA(in *image.RGBA, out *image.NRGBA, scale float64, coeffs []int16,
// reverse alpha-premultiplication.
if a != 0 {
r *= 0xffff
r *= 0xff
r /= a
g *= 0xffff
g *= 0xff
g /= a
b *= 0xffff
b *= 0xff
b /= a
}

96
resize_test.go
View File

@ -46,7 +46,7 @@ func Test_CorrectResize(t *testing.T) {
}
}
func Test_SameColor(t *testing.T) {
func Test_SameColorWithRGBA(t *testing.T) {
img := image.NewRGBA(image.Rect(0, 0, 20, 20))
for y := img.Bounds().Min.Y; y < img.Bounds().Max.Y; y++ {
for x := img.Bounds().Min.X; x < img.Bounds().Max.X; x++ {
@ -56,9 +56,99 @@ func Test_SameColor(t *testing.T) {
out := Resize(10, 10, img, Lanczos3)
for y := out.Bounds().Min.Y; y < out.Bounds().Max.Y; y++ {
for x := out.Bounds().Min.X; x < out.Bounds().Max.X; x++ {
color := img.At(x, y).(color.RGBA)
color := out.At(x, y).(color.NRGBA)
if color.R != 0x80 || color.G != 0x80 || color.B != 0x80 || color.A != 0xFF {
t.Fail()
t.Errorf("%+v", color)
}
}
}
}
func Test_SameColorWithNRGBA(t *testing.T) {
img := image.NewNRGBA(image.Rect(0, 0, 20, 20))
for y := img.Bounds().Min.Y; y < img.Bounds().Max.Y; y++ {
for x := img.Bounds().Min.X; x < img.Bounds().Max.X; x++ {
img.SetNRGBA(x, y, color.NRGBA{0x80, 0x80, 0x80, 0xFF})
}
}
out := Resize(10, 10, img, Lanczos3)
for y := out.Bounds().Min.Y; y < out.Bounds().Max.Y; y++ {
for x := out.Bounds().Min.X; x < out.Bounds().Max.X; x++ {
color := out.At(x, y).(color.NRGBA)
if color.R != 0x80 || color.G != 0x80 || color.B != 0x80 || color.A != 0xFF {
t.Errorf("%+v", color)
}
}
}
}
func Test_SameColorWithRGBA64(t *testing.T) {
img := image.NewRGBA64(image.Rect(0, 0, 20, 20))
for y := img.Bounds().Min.Y; y < img.Bounds().Max.Y; y++ {
for x := img.Bounds().Min.X; x < img.Bounds().Max.X; x++ {
img.SetRGBA64(x, y, color.RGBA64{0x8000, 0x8000, 0x8000, 0xFFFF})
}
}
out := Resize(10, 10, img, Lanczos3)
for y := out.Bounds().Min.Y; y < out.Bounds().Max.Y; y++ {
for x := out.Bounds().Min.X; x < out.Bounds().Max.X; x++ {
color := out.At(x, y).(color.NRGBA64)
if color.R != 0x8000 || color.G != 0x8000 || color.B != 0x8000 || color.A != 0xFFFF {
t.Errorf("%+v", color)
}
}
}
}
func Test_SameColorWithNRGBA64(t *testing.T) {
img := image.NewNRGBA64(image.Rect(0, 0, 20, 20))
for y := img.Bounds().Min.Y; y < img.Bounds().Max.Y; y++ {
for x := img.Bounds().Min.X; x < img.Bounds().Max.X; x++ {
img.SetNRGBA64(x, y, color.NRGBA64{0x8000, 0x8000, 0x8000, 0xFFFF})
}
}
out := Resize(10, 10, img, Lanczos3)
for y := out.Bounds().Min.Y; y < out.Bounds().Max.Y; y++ {
for x := out.Bounds().Min.X; x < out.Bounds().Max.X; x++ {
color := out.At(x, y).(color.NRGBA64)
if color.R != 0x8000 || color.G != 0x8000 || color.B != 0x8000 || color.A != 0xFFFF {
t.Errorf("%+v", color)
}
}
}
}
func Test_SameColorWithGray(t *testing.T) {
img := image.NewGray(image.Rect(0, 0, 20, 20))
for y := img.Bounds().Min.Y; y < img.Bounds().Max.Y; y++ {
for x := img.Bounds().Min.X; x < img.Bounds().Max.X; x++ {
img.SetGray(x, y, color.Gray{0x80})
}
}
out := Resize(10, 10, img, Lanczos3)
for y := out.Bounds().Min.Y; y < out.Bounds().Max.Y; y++ {
for x := out.Bounds().Min.X; x < out.Bounds().Max.X; x++ {
color := out.At(x, y).(color.Gray)
if color.Y != 0x80 {
t.Errorf("%+v", color)
}
}
}
}
func Test_SameColorWithGray16(t *testing.T) {
img := image.NewGray16(image.Rect(0, 0, 20, 20))
for y := img.Bounds().Min.Y; y < img.Bounds().Max.Y; y++ {
for x := img.Bounds().Min.X; x < img.Bounds().Max.X; x++ {
img.SetGray16(x, y, color.Gray16{0x8000})
}
}
out := Resize(10, 10, img, Lanczos3)
for y := out.Bounds().Min.Y; y < out.Bounds().Max.Y; y++ {
for x := out.Bounds().Min.X; x < out.Bounds().Max.X; x++ {
color := out.At(x, y).(color.Gray16)
if color.Y != 0x8000 {
t.Errorf("%+v", color)
}
}
}