aw/go-resize
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Merge branch 'charlievieth-master'

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This commit is contained in:
jst 2015-03-18 19:57:50 +01:00
commit 4b952c4b95
4 changed files with 120 additions and 68 deletions
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45
converter.go
View File

@ -20,24 +20,27 @@ import "image"
// Keep value in [0,255] range.
func clampUint8(in int32) uint8 {
if in < 0 {
return 0
// casting a negative int to an uint will result in an overflown large int.
// this behavior will be exploited here and in other functions to archive
// a higher performance.
if uint32(in) < 256 {
return uint8(in)
}
if in > 255 {
return 255
}
return uint8(in)
return 0
}
// Keep value in [0,65535] range.
func clampUint16(in int64) uint16 {
if in < 0 {
return 0
if uint64(in) < 65536 {
return uint16(in)
}
if in > 65535 {
return 65535
}
return uint16(in)
return 0
}
func resizeGeneric(in image.Image, out *image.RGBA64, scale float64, coeffs []int32, offset []int, filterLength int) {
@ -102,12 +105,12 @@ func resizeRGBA(in *image.RGBA, out *image.RGBA, scale float64, coeffs []int16,
if coeff != 0 {
xi := start + i
switch {
case xi < 0:
xi = 0
case uint(xi) < uint(maxX):
xi *= 4
case xi >= maxX:
xi = 4 * maxX
default:
xi *= 4
xi = 0
}
rgba[0] += int32(coeff) * int32(row[xi+0])
rgba[1] += int32(coeff) * int32(row[xi+1])
@ -142,12 +145,12 @@ func resizeRGBA64(in *image.RGBA64, out *image.RGBA64, scale float64, coeffs []i
if coeff != 0 {
xi := start + i
switch {
case xi < 0:
xi = 0
case uint(xi) < uint(maxX):
xi *= 8
case xi >= maxX:
xi = 8 * maxX
default:
xi *= 8
xi = 0
}
rgba[0] += int64(coeff) * int64(uint16(row[xi+0])<<8|uint16(row[xi+1]))
rgba[1] += int64(coeff) * int64(uint16(row[xi+2])<<8|uint16(row[xi+3]))
@ -222,12 +225,12 @@ func resizeGray16(in *image.Gray16, out *image.Gray16, scale float64, coeffs []i
if coeff != 0 {
xi := start + i
switch {
case xi < 0:
xi = 0
case uint(xi) < uint(maxX):
xi *= 2
case xi >= maxX:
xi = 2 * maxX
default:
xi *= 2
xi = 0
}
gray += int64(coeff) * int64(uint16(row[xi+0])<<8|uint16(row[xi+1]))
sum += int64(coeff)
@ -258,12 +261,12 @@ func resizeYCbCr(in *ycc, out *ycc, scale float64, coeffs []int16, offset []int,
if coeff != 0 {
xi := start + i
switch {
case xi < 0:
xi = 0
case uint(xi) < uint(maxX):
xi *= 3
case xi >= maxX:
xi = 3 * maxX
default:
xi *= 3
xi = 0
}
p[0] += int32(coeff) * int32(row[xi+0])
p[1] += int32(coeff) * int32(row[xi+1])
@ -295,12 +298,12 @@ func nearestYCbCr(in *ycc, out *ycc, scale float64, coeffs []bool, offset []int,
if coeffs[ci+i] {
xi := start + i
switch {
case xi < 0:
xi = 0
case uint(xi) < uint(maxX):
xi *= 3
case xi >= maxX:
xi = 3 * maxX
default:
xi *= 3
xi = 0
}
p[0] += float32(row[xi+0])
p[1] += float32(row[xi+1])

18
nearest.go
View File

@ -94,12 +94,12 @@ func nearestRGBA(in *image.RGBA, out *image.RGBA, scale float64, coeffs []bool,
if coeffs[ci+i] {
xi := start + i
switch {
case xi < 0:
xi = 0
case uint(xi) < uint(maxX):
xi *= 4
case xi >= maxX:
xi = 4 * maxX
default:
xi *= 4
xi = 0
}
rgba[0] += float32(row[xi+0])
rgba[1] += float32(row[xi+1])
@ -133,12 +133,12 @@ func nearestRGBA64(in *image.RGBA64, out *image.RGBA64, scale float64, coeffs []
if coeffs[ci+i] {
xi := start + i
switch {
case xi < 0:
xi = 0
case uint(xi) < uint(maxX):
xi *= 8
case xi >= maxX:
xi = 8 * maxX
default:
xi *= 8
xi = 0
}
rgba[0] += float32(uint16(row[xi+0])<<8 | uint16(row[xi+1]))
rgba[1] += float32(uint16(row[xi+2])<<8 | uint16(row[xi+3]))
@ -211,12 +211,12 @@ func nearestGray16(in *image.Gray16, out *image.Gray16, scale float64, coeffs []
if coeffs[ci+i] {
xi := start + i
switch {
case xi < 0:
xi = 0
case uint(xi) < uint(maxX):
xi *= 2
case xi >= maxX:
xi = 2 * maxX
default:
xi *= 2
xi = 0
}
gray += float32(uint16(row[xi+0])<<8 | uint16(row[xi+1]))
sum++

4
resize.go
View File

@ -97,7 +97,7 @@ func Resize(width, height uint, img image.Image, interp InterpolationFunction) i
}
taps, kernel := interp.kernel()
cpus := runtime.NumCPU()
cpus := runtime.GOMAXPROCS(0)
wg := sync.WaitGroup{}
// Generic access to image.Image is slow in tight loops.
@ -283,7 +283,7 @@ func Resize(width, height uint, img image.Image, interp InterpolationFunction) i
func resizeNearest(width, height uint, scaleX, scaleY float64, img image.Image, interp InterpolationFunction) image.Image {
taps, _ := interp.kernel()
cpus := runtime.NumCPU()
cpus := runtime.GOMAXPROCS(0)
wg := sync.WaitGroup{}
switch input := img.(type) {

115
resize_test.go
View File

@ -85,56 +85,105 @@ func Test_SameSizeReturnsOriginal(t *testing.T) {
}
}
func Benchmark_BigResizeLanczos3(b *testing.B) {
var m image.Image
const (
// Use a small image size for benchmarks. We don't want memory performance
// to affect the benchmark results.
benchMaxX = 250
benchMaxY = 250
// Resize values near the original size require increase the amount of time
// resize spends converting the image.
benchWidth = 200
benchHeight = 200
)
func benchRGBA(b *testing.B, interp InterpolationFunction) {
m := image.NewRGBA(image.Rect(0, 0, benchMaxX, benchMaxY))
// Initialize m's pixels to create a non-uniform image.
for y := m.Rect.Min.Y; y < m.Rect.Max.Y; y++ {
for x := m.Rect.Min.X; x < m.Rect.Max.X; x++ {
i := m.PixOffset(x, y)
m.Pix[i+0] = uint8(y + 4*x)
m.Pix[i+1] = uint8(y + 4*x)
m.Pix[i+2] = uint8(y + 4*x)
m.Pix[i+3] = uint8(4*y + x)
}
}
var out image.Image
b.ResetTimer()
for i := 0; i < b.N; i++ {
m = Resize(1000, 1000, img, Lanczos3)
out = Resize(benchWidth, benchHeight, m, interp)
}
m.At(0, 0)
out.At(0, 0)
}
func Benchmark_Reduction(b *testing.B) {
largeImg := image.NewRGBA(image.Rect(0, 0, 1000, 1000))
// The names of some interpolation functions are truncated so that the columns
// of 'go test -bench' line up.
func Benchmark_Nearest_RGBA(b *testing.B) {
benchRGBA(b, NearestNeighbor)
}
var m image.Image
func Benchmark_Bilinear_RGBA(b *testing.B) {
benchRGBA(b, Bilinear)
}
func Benchmark_Bicubic_RGBA(b *testing.B) {
benchRGBA(b, Bicubic)
}
func Benchmark_Mitchell_RGBA(b *testing.B) {
benchRGBA(b, MitchellNetravali)
}
func Benchmark_Lanczos2_RGBA(b *testing.B) {
benchRGBA(b, Lanczos2)
}
func Benchmark_Lanczos3_RGBA(b *testing.B) {
benchRGBA(b, Lanczos3)
}
func benchYCbCr(b *testing.B, interp InterpolationFunction) {
m := image.NewYCbCr(image.Rect(0, 0, benchMaxX, benchMaxY), image.YCbCrSubsampleRatio422)
// Initialize m's pixels to create a non-uniform image.
for y := m.Rect.Min.Y; y < m.Rect.Max.Y; y++ {
for x := m.Rect.Min.X; x < m.Rect.Max.X; x++ {
yi := m.YOffset(x, y)
ci := m.COffset(x, y)
m.Y[yi] = uint8(16*y + x)
m.Cb[ci] = uint8(y + 16*x)
m.Cr[ci] = uint8(y + 16*x)
}
}
var out image.Image
b.ResetTimer()
for i := 0; i < b.N; i++ {
m = Resize(300, 300, largeImg, Bicubic)
out = Resize(benchWidth, benchHeight, m, interp)
}
m.At(0, 0)
out.At(0, 0)
}
// Benchmark resize of 16 MPix jpeg image to 800px width.
func jpegThumb(b *testing.B, interp InterpolationFunction) {
input := image.NewYCbCr(image.Rect(0, 0, 4896, 3264), image.YCbCrSubsampleRatio422)
var output image.Image
for i := 0; i < b.N; i++ {
output = Resize(800, 0, input, interp)
func Benchmark_Nearest_YCC(b *testing.B) {
benchYCbCr(b, NearestNeighbor)
}
output.At(0, 0)
func Benchmark_Bilinear_YCC(b *testing.B) {
benchYCbCr(b, Bilinear)
}
func Benchmark_LargeJpegThumbNearestNeighbor(b *testing.B) {
jpegThumb(b, NearestNeighbor)
func Benchmark_Bicubic_YCC(b *testing.B) {
benchYCbCr(b, Bicubic)
}
func Benchmark_LargeJpegThumbBilinear(b *testing.B) {
jpegThumb(b, Bilinear)
func Benchmark_Mitchell_YCC(b *testing.B) {
benchYCbCr(b, MitchellNetravali)
}
func Benchmark_LargeJpegThumbBicubic(b *testing.B) {
jpegThumb(b, Bicubic)
func Benchmark_Lanczos2_YCC(b *testing.B) {
benchYCbCr(b, Lanczos2)
}
func Benchmark_LargeJpegThumbMitchellNetravali(b *testing.B) {
jpegThumb(b, MitchellNetravali)
}
func Benchmark_LargeJpegThumbLanczos2(b *testing.B) {
jpegThumb(b, Lanczos2)
}
func Benchmark_LargeJpegThumbLanczos3(b *testing.B) {
jpegThumb(b, Lanczos3)
func Benchmark_Lanczos3_YCC(b *testing.B) {
benchYCbCr(b, Lanczos3)
}