draw: make Scale an Interpolator method instead of a function.

This means that only Kernel values have a NewScaler method, which
re-uses computation when scaling multiple images of the same dst and src
dimensions. The NearestNeighbor and ApproxBiLinear scalers don't get any
pre-computation to re-use, so don't need a NewScaler method just to
satisfy the previous Interpolator interface. As a small bonus, NN.Scale
and ABL.Scale should no longer allocate on the fast paths.

This change is consistent the upcoming Transformer method, so that the
Interpolator interface will be

type Interpolator interface {
	Scale(etc)
	Transform(etc)
}

instead of

type Interpolator interface {
	NewScaler(etc) Scaler
	Transform(etc)
}

I don't have a good theory for why the "func (ablInterpolator)
scale_RGBA_RGBA" benchmark is such a dramatic improvement, but at least
it's in the right direction. I'm calling the other benchmark changes as
noise.

benchmark                     old ns/op      new ns/op      delta
BenchmarkScaleLargeDownNN     3233406        3169060        -1.99%
BenchmarkScaleLargeDownAB     12018178       12011348       -0.06%
BenchmarkScaleLargeDownBL     1420827834     1409335695     -0.81%
BenchmarkScaleLargeDownCR     2820669690     2795534035     -0.89%
BenchmarkScaleDownNN          866628         869241         +0.30%
BenchmarkScaleDownAB          3175963        3216041        +1.26%
BenchmarkScaleDownBL          26639767       26677003       +0.14%
BenchmarkScaleDownCR          51720996       51621628       -0.19%
BenchmarkScaleUpNN            42758485       43258611       +1.17%
BenchmarkScaleUpAB            156693813      156943367      +0.16%
BenchmarkScaleUpBL            69511444       69621698       +0.16%
BenchmarkScaleUpCR            124530191      124885601      +0.29%
BenchmarkScaleSrcGray         8992205        9129321        +1.52%
BenchmarkScaleSrcNRGBA        9807837        9894466        +0.88%
BenchmarkScaleSrcRGBA         1333188        1104282        -17.17%
BenchmarkScaleSrcUniform      1147788        1162488        +1.28%
BenchmarkScaleSrcYCbCr        12164542       12305373       +1.16%

Change-Id: I2aee6c392eb7437e843260775aed97ce145b4d47
Reviewed-on: https://go-review.googlesource.com/6556
Reviewed-by: Rob Pike <r@golang.org>
This commit is contained in:
Nigel Tao 2015-03-03 16:54:53 +11:00
parent 7c413c859c
commit 2c27a34d37
4 changed files with 287 additions and 250 deletions

View File

@ -26,8 +26,8 @@ func main() {
w.WriteString("// generated by \"go run gen.go\". DO NOT EDIT.\n\n" +
"package draw\n\nimport (\n\"image\"\n\"image/color\"\n)\n")
gen(w, "nnScaler", codeNNLeaf)
gen(w, "ablScaler", codeABLLeaf)
gen(w, "nnInterpolator", codeNNLeaf)
gen(w, "ablInterpolator", codeABLLeaf)
genKernel(w)
if *debug {
@ -181,7 +181,7 @@ func expnDollar(prefix, dollar, suffix string, d *data) string {
default:
return ";"
case "*image.RGBA":
return "d := dst.PixOffset(dp.X+adr.Min.X, dp.Y+int(dy))"
return "d := dst.PixOffset(dr.Min.X+adr.Min.X, dr.Min.Y+int(dy))"
}
case "preKernelInner":
@ -189,7 +189,7 @@ func expnDollar(prefix, dollar, suffix string, d *data) string {
default:
return ";"
case "*image.RGBA":
return "d := dst.PixOffset(dp.X+int(dx), dp.Y+adr.Min.Y)"
return "d := dst.PixOffset(dr.Min.X+int(dx), dr.Min.Y+adr.Min.Y)"
}
case "blend":
@ -222,7 +222,7 @@ func expnDollar(prefix, dollar, suffix string, d *data) string {
"dstColorRGBA64.G = uint16(%sg)\n"+
"dstColorRGBA64.B = uint16(%sb)\n"+
"dstColorRGBA64.A = uint16(%sa)\n"+
"dst.Set(dp.X+int(%s), dp.Y+int(%s), dstColor)",
"dst.Set(dr.Min.X+int(%s), dr.Min.Y+int(%s), dstColor)",
args[2], args[2], args[2], args[2],
args[0], args[1],
)
@ -251,7 +251,7 @@ func expnDollar(prefix, dollar, suffix string, d *data) string {
"dstColorRGBA64.G = ftou(%sg * %s)\n"+
"dstColorRGBA64.B = ftou(%sb * %s)\n"+
"dstColorRGBA64.A = ftou(%sa * %s)\n"+
"dst.Set(dp.X+int(%s), dp.Y+int(%s), dstColor)",
"dst.Set(dr.Min.X+int(%s), dr.Min.Y+int(%s), dstColor)",
args[2], args[3], args[2], args[3], args[2], args[3], args[2], args[3],
args[0], args[1],
)
@ -287,14 +287,14 @@ func expnDollar(prefix, dollar, suffix string, d *data) string {
log.Fatalf("bad sType %q", d.sType)
case "image.Image", "*image.Gray", "*image.NRGBA", "*image.Uniform", "*image.YCbCr": // TODO: separate code for concrete types.
fmt.Fprintf(buf, "%sr%s, %sg%s, %sb%s, %sa%s := "+
"src.At(sp.X + int(%s), sp.Y+int(%s)).RGBA()\n",
"src.At(sr.Min.X + int(%s), sr.Min.Y+int(%s)).RGBA()\n",
lhs, tmp, lhs, tmp, lhs, tmp, lhs, tmp,
args[0], args[1],
)
case "*image.RGBA":
// TODO: there's no need to multiply by 0x101 if the next thing
// we're going to do is shift right by 8.
fmt.Fprintf(buf, "%si := src.PixOffset(sp.X + int(%s), sp.Y+int(%s))\n"+
fmt.Fprintf(buf, "%si := src.PixOffset(sr.Min.X + int(%s), sr.Min.Y+int(%s))\n"+
"%sr%s := uint32(src.Pix[%si+0]) * 0x101\n"+
"%sg%s := uint32(src.Pix[%si+1]) * 0x101\n"+
"%sb%s := uint32(src.Pix[%si+2]) * 0x101\n"+
@ -407,34 +407,35 @@ func relName(s string) string {
const (
codeRoot = `
func (z *$receiver) Scale(dst Image, dp image.Point, src image.Image, sp image.Point) {
if z.dw <= 0 || z.dh <= 0 || z.sw <= 0 || z.sh <= 0 {
return
}
// adr is the affected destination pixels, relative to dp.
adr := dst.Bounds().Sub(dp).Intersect(image.Rectangle{Max: image.Point{int(z.dw), int(z.dh)}})
if adr.Empty() {
func (z $receiver) Scale(dst Image, dr image.Rectangle, src image.Image, sr image.Rectangle) {
// adr is the affected destination pixels, relative to dr.Min.
adr := dst.Bounds().Intersect(dr).Sub(dr.Min)
if adr.Empty() || sr.Empty() {
return
}
// sr is the source pixels. If it extends beyond the src bounds,
// we cannot use the type-specific fast paths, as they access
// the Pix fields directly without bounds checking.
if sr := (image.Rectangle{sp, sp.Add(image.Point{int(z.sw), int(z.sh)})}); !sr.In(src.Bounds()) {
z.scale_Image_Image(dst, dp, adr, src, sp)
if !sr.In(src.Bounds()) {
z.scale_Image_Image(dst, dr, adr, src, sr)
} else {
$switch z.scale_$dTypeRN_$sTypeRN(dst, dp, adr, src, sp)
$switch z.scale_$dTypeRN_$sTypeRN(dst, dr, adr, src, sr)
}
}
`
codeNNLeaf = `
func (z *nnScaler) scale_$dTypeRN_$sTypeRN(dst $dType, dp image.Point, adr image.Rectangle, src $sType, sp image.Point) {
func (nnInterpolator) scale_$dTypeRN_$sTypeRN(dst $dType, dr, adr image.Rectangle, src $sType, sr image.Rectangle) {
dw2 := uint64(dr.Dx()) * 2
dh2 := uint64(dr.Dy()) * 2
sw := uint64(sr.Dx())
sh := uint64(sr.Dy())
$preOuter
for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
sy := (2*uint64(dy) + 1) * uint64(z.sh) / (2 * uint64(z.dh))
sy := (2*uint64(dy) + 1) * sh / dh2
$preInner
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
sx := (2*uint64(dx) + 1) * uint64(z.sw) / (2 * uint64(z.dw))
sx := (2*uint64(dx) + 1) * sw / dw2
p := $srcu[sx, sy]
$outputu[dx, dy, p]
}
@ -443,9 +444,11 @@ const (
`
codeABLLeaf = `
func (z *ablScaler) scale_$dTypeRN_$sTypeRN(dst $dType, dp image.Point, adr image.Rectangle, src $sType, sp image.Point) {
yscale := float64(z.sh) / float64(z.dh)
xscale := float64(z.sw) / float64(z.dw)
func (ablInterpolator) scale_$dTypeRN_$sTypeRN(dst $dType, dr, adr image.Rectangle, src $sType, sr image.Rectangle) {
sw := int32(sr.Dx())
sh := int32(sr.Dy())
yscale := float64(sh) / float64(dr.Dy())
xscale := float64(sw) / float64(dr.Dx())
$preOuter
for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
sy := (float64(dy)+0.5)*yscale - 0.5
@ -456,7 +459,7 @@ const (
if sy < 0 {
sy0, sy1 = 0, 0
yFrac0, yFrac1 = 0, 1
} else if sy1 >= z.sh {
} else if sy1 >= sh {
sy1 = sy0
yFrac0, yFrac1 = 1, 0
}
@ -470,7 +473,7 @@ const (
if sx < 0 {
sx0, sx1 = 0, 0
xFrac0, xFrac1 = 0, 1
} else if sx1 >= z.sw {
} else if sx1 >= sw {
sx1 = sx0
xFrac0, xFrac1 = 1, 0
}
@ -488,13 +491,14 @@ const (
`
codeKernelRoot = `
func (z *kernelScaler) Scale(dst Image, dp image.Point, src image.Image, sp image.Point) {
if z.dw <= 0 || z.dh <= 0 || z.sw <= 0 || z.sh <= 0 {
func (z *kernelScaler) Scale(dst Image, dr image.Rectangle, src image.Image, sr image.Rectangle) {
if z.dw != int32(dr.Dx()) || z.dh != int32(dr.Dy()) || z.sw != int32(sr.Dx()) || z.sh != int32(sr.Dy()) {
z.kernel.Scale(dst, dr, src, sr)
return
}
// adr is the affected destination pixels, relative to dp.
adr := dst.Bounds().Sub(dp).Intersect(image.Rectangle{Max: image.Point{int(z.dw), int(z.dh)}})
if adr.Empty() {
// adr is the affected destination pixels, relative to dr.Min.
adr := dst.Bounds().Intersect(dr).Sub(dr.Min)
if adr.Empty() || sr.Empty() {
return
}
// Create a temporary buffer:
@ -506,18 +510,18 @@ const (
// sr is the source pixels. If it extends beyond the src bounds,
// we cannot use the type-specific fast paths, as they access
// the Pix fields directly without bounds checking.
if sr := (image.Rectangle{sp, sp.Add(image.Point{int(z.sw), int(z.sh)})}); !sr.In(src.Bounds()) {
z.scaleX_Image(tmp, src, sp)
if !sr.In(src.Bounds()) {
z.scaleX_Image(tmp, src, sr)
} else {
$switchS z.scaleX_$sTypeRN(tmp, src, sp)
$switchS z.scaleX_$sTypeRN(tmp, src, sr)
}
$switchD z.scaleY_$dTypeRN(dst, dp, adr, tmp)
$switchD z.scaleY_$dTypeRN(dst, dr, adr, tmp)
}
`
codeKernelLeafX = `
func (z *kernelScaler) scaleX_$sTypeRN(tmp [][4]float64, src $sType, sp image.Point) {
func (z *kernelScaler) scaleX_$sTypeRN(tmp [][4]float64, src $sType, sr image.Rectangle) {
t := 0
for y := int32(0); y < z.sh; y++ {
for _, s := range z.horizontal.sources {
@ -538,7 +542,7 @@ const (
`
codeKernelLeafY = `
func (z *kernelScaler) scaleY_$dTypeRN(dst $dType, dp image.Point, adr image.Rectangle, tmp [][4]float64) {
func (z *kernelScaler) scaleY_$dTypeRN(dst $dType, dr, adr image.Rectangle, tmp [][4]float64) {
$preOuter
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
$preKernelInner

View File

@ -7,53 +7,54 @@ import (
"image/color"
)
func (z *nnScaler) Scale(dst Image, dp image.Point, src image.Image, sp image.Point) {
if z.dw <= 0 || z.dh <= 0 || z.sw <= 0 || z.sh <= 0 {
return
}
// adr is the affected destination pixels, relative to dp.
adr := dst.Bounds().Sub(dp).Intersect(image.Rectangle{Max: image.Point{int(z.dw), int(z.dh)}})
if adr.Empty() {
func (z nnInterpolator) Scale(dst Image, dr image.Rectangle, src image.Image, sr image.Rectangle) {
// adr is the affected destination pixels, relative to dr.Min.
adr := dst.Bounds().Intersect(dr).Sub(dr.Min)
if adr.Empty() || sr.Empty() {
return
}
// sr is the source pixels. If it extends beyond the src bounds,
// we cannot use the type-specific fast paths, as they access
// the Pix fields directly without bounds checking.
if sr := (image.Rectangle{sp, sp.Add(image.Point{int(z.sw), int(z.sh)})}); !sr.In(src.Bounds()) {
z.scale_Image_Image(dst, dp, adr, src, sp)
if !sr.In(src.Bounds()) {
z.scale_Image_Image(dst, dr, adr, src, sr)
} else {
switch dst := dst.(type) {
case *image.RGBA:
switch src := src.(type) {
case *image.Gray:
z.scale_RGBA_Gray(dst, dp, adr, src, sp)
z.scale_RGBA_Gray(dst, dr, adr, src, sr)
case *image.NRGBA:
z.scale_RGBA_NRGBA(dst, dp, adr, src, sp)
z.scale_RGBA_NRGBA(dst, dr, adr, src, sr)
case *image.RGBA:
z.scale_RGBA_RGBA(dst, dp, adr, src, sp)
z.scale_RGBA_RGBA(dst, dr, adr, src, sr)
case *image.Uniform:
z.scale_RGBA_Uniform(dst, dp, adr, src, sp)
z.scale_RGBA_Uniform(dst, dr, adr, src, sr)
case *image.YCbCr:
z.scale_RGBA_YCbCr(dst, dp, adr, src, sp)
z.scale_RGBA_YCbCr(dst, dr, adr, src, sr)
default:
z.scale_RGBA_Image(dst, dp, adr, src, sp)
z.scale_RGBA_Image(dst, dr, adr, src, sr)
}
default:
switch src := src.(type) {
default:
z.scale_Image_Image(dst, dp, adr, src, sp)
z.scale_Image_Image(dst, dr, adr, src, sr)
}
}
}
}
func (z *nnScaler) scale_RGBA_Gray(dst *image.RGBA, dp image.Point, adr image.Rectangle, src *image.Gray, sp image.Point) {
func (nnInterpolator) scale_RGBA_Gray(dst *image.RGBA, dr, adr image.Rectangle, src *image.Gray, sr image.Rectangle) {
dw2 := uint64(dr.Dx()) * 2
dh2 := uint64(dr.Dy()) * 2
sw := uint64(sr.Dx())
sh := uint64(sr.Dy())
for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
sy := (2*uint64(dy) + 1) * uint64(z.sh) / (2 * uint64(z.dh))
d := dst.PixOffset(dp.X+adr.Min.X, dp.Y+int(dy))
sy := (2*uint64(dy) + 1) * sh / dh2
d := dst.PixOffset(dr.Min.X+adr.Min.X, dr.Min.Y+int(dy))
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
sx := (2*uint64(dx) + 1) * uint64(z.sw) / (2 * uint64(z.dw))
pr, pg, pb, pa := src.At(sp.X+int(sx), sp.Y+int(sy)).RGBA()
sx := (2*uint64(dx) + 1) * sw / dw2
pr, pg, pb, pa := src.At(sr.Min.X+int(sx), sr.Min.Y+int(sy)).RGBA()
dst.Pix[d+0] = uint8(uint32(pr) >> 8)
dst.Pix[d+1] = uint8(uint32(pg) >> 8)
dst.Pix[d+2] = uint8(uint32(pb) >> 8)
@ -63,13 +64,17 @@ func (z *nnScaler) scale_RGBA_Gray(dst *image.RGBA, dp image.Point, adr image.Re
}
}
func (z *nnScaler) scale_RGBA_NRGBA(dst *image.RGBA, dp image.Point, adr image.Rectangle, src *image.NRGBA, sp image.Point) {
func (nnInterpolator) scale_RGBA_NRGBA(dst *image.RGBA, dr, adr image.Rectangle, src *image.NRGBA, sr image.Rectangle) {
dw2 := uint64(dr.Dx()) * 2
dh2 := uint64(dr.Dy()) * 2
sw := uint64(sr.Dx())
sh := uint64(sr.Dy())
for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
sy := (2*uint64(dy) + 1) * uint64(z.sh) / (2 * uint64(z.dh))
d := dst.PixOffset(dp.X+adr.Min.X, dp.Y+int(dy))
sy := (2*uint64(dy) + 1) * sh / dh2
d := dst.PixOffset(dr.Min.X+adr.Min.X, dr.Min.Y+int(dy))
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
sx := (2*uint64(dx) + 1) * uint64(z.sw) / (2 * uint64(z.dw))
pr, pg, pb, pa := src.At(sp.X+int(sx), sp.Y+int(sy)).RGBA()
sx := (2*uint64(dx) + 1) * sw / dw2
pr, pg, pb, pa := src.At(sr.Min.X+int(sx), sr.Min.Y+int(sy)).RGBA()
dst.Pix[d+0] = uint8(uint32(pr) >> 8)
dst.Pix[d+1] = uint8(uint32(pg) >> 8)
dst.Pix[d+2] = uint8(uint32(pb) >> 8)
@ -79,13 +84,17 @@ func (z *nnScaler) scale_RGBA_NRGBA(dst *image.RGBA, dp image.Point, adr image.R
}
}
func (z *nnScaler) scale_RGBA_RGBA(dst *image.RGBA, dp image.Point, adr image.Rectangle, src *image.RGBA, sp image.Point) {
func (nnInterpolator) scale_RGBA_RGBA(dst *image.RGBA, dr, adr image.Rectangle, src *image.RGBA, sr image.Rectangle) {
dw2 := uint64(dr.Dx()) * 2
dh2 := uint64(dr.Dy()) * 2
sw := uint64(sr.Dx())
sh := uint64(sr.Dy())
for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
sy := (2*uint64(dy) + 1) * uint64(z.sh) / (2 * uint64(z.dh))
d := dst.PixOffset(dp.X+adr.Min.X, dp.Y+int(dy))
sy := (2*uint64(dy) + 1) * sh / dh2
d := dst.PixOffset(dr.Min.X+adr.Min.X, dr.Min.Y+int(dy))
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
sx := (2*uint64(dx) + 1) * uint64(z.sw) / (2 * uint64(z.dw))
pi := src.PixOffset(sp.X+int(sx), sp.Y+int(sy))
sx := (2*uint64(dx) + 1) * sw / dw2
pi := src.PixOffset(sr.Min.X+int(sx), sr.Min.Y+int(sy))
pr := uint32(src.Pix[pi+0]) * 0x101
pg := uint32(src.Pix[pi+1]) * 0x101
pb := uint32(src.Pix[pi+2]) * 0x101
@ -99,13 +108,17 @@ func (z *nnScaler) scale_RGBA_RGBA(dst *image.RGBA, dp image.Point, adr image.Re
}
}
func (z *nnScaler) scale_RGBA_Uniform(dst *image.RGBA, dp image.Point, adr image.Rectangle, src *image.Uniform, sp image.Point) {
func (nnInterpolator) scale_RGBA_Uniform(dst *image.RGBA, dr, adr image.Rectangle, src *image.Uniform, sr image.Rectangle) {
dw2 := uint64(dr.Dx()) * 2
dh2 := uint64(dr.Dy()) * 2
sw := uint64(sr.Dx())
sh := uint64(sr.Dy())
for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
sy := (2*uint64(dy) + 1) * uint64(z.sh) / (2 * uint64(z.dh))
d := dst.PixOffset(dp.X+adr.Min.X, dp.Y+int(dy))
sy := (2*uint64(dy) + 1) * sh / dh2
d := dst.PixOffset(dr.Min.X+adr.Min.X, dr.Min.Y+int(dy))
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
sx := (2*uint64(dx) + 1) * uint64(z.sw) / (2 * uint64(z.dw))
pr, pg, pb, pa := src.At(sp.X+int(sx), sp.Y+int(sy)).RGBA()
sx := (2*uint64(dx) + 1) * sw / dw2
pr, pg, pb, pa := src.At(sr.Min.X+int(sx), sr.Min.Y+int(sy)).RGBA()
dst.Pix[d+0] = uint8(uint32(pr) >> 8)
dst.Pix[d+1] = uint8(uint32(pg) >> 8)
dst.Pix[d+2] = uint8(uint32(pb) >> 8)
@ -115,13 +128,17 @@ func (z *nnScaler) scale_RGBA_Uniform(dst *image.RGBA, dp image.Point, adr image
}
}
func (z *nnScaler) scale_RGBA_YCbCr(dst *image.RGBA, dp image.Point, adr image.Rectangle, src *image.YCbCr, sp image.Point) {
func (nnInterpolator) scale_RGBA_YCbCr(dst *image.RGBA, dr, adr image.Rectangle, src *image.YCbCr, sr image.Rectangle) {
dw2 := uint64(dr.Dx()) * 2
dh2 := uint64(dr.Dy()) * 2
sw := uint64(sr.Dx())
sh := uint64(sr.Dy())
for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
sy := (2*uint64(dy) + 1) * uint64(z.sh) / (2 * uint64(z.dh))
d := dst.PixOffset(dp.X+adr.Min.X, dp.Y+int(dy))
sy := (2*uint64(dy) + 1) * sh / dh2
d := dst.PixOffset(dr.Min.X+adr.Min.X, dr.Min.Y+int(dy))
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
sx := (2*uint64(dx) + 1) * uint64(z.sw) / (2 * uint64(z.dw))
pr, pg, pb, pa := src.At(sp.X+int(sx), sp.Y+int(sy)).RGBA()
sx := (2*uint64(dx) + 1) * sw / dw2
pr, pg, pb, pa := src.At(sr.Min.X+int(sx), sr.Min.Y+int(sy)).RGBA()
dst.Pix[d+0] = uint8(uint32(pr) >> 8)
dst.Pix[d+1] = uint8(uint32(pg) >> 8)
dst.Pix[d+2] = uint8(uint32(pb) >> 8)
@ -131,13 +148,17 @@ func (z *nnScaler) scale_RGBA_YCbCr(dst *image.RGBA, dp image.Point, adr image.R
}
}
func (z *nnScaler) scale_RGBA_Image(dst *image.RGBA, dp image.Point, adr image.Rectangle, src image.Image, sp image.Point) {
func (nnInterpolator) scale_RGBA_Image(dst *image.RGBA, dr, adr image.Rectangle, src image.Image, sr image.Rectangle) {
dw2 := uint64(dr.Dx()) * 2
dh2 := uint64(dr.Dy()) * 2
sw := uint64(sr.Dx())
sh := uint64(sr.Dy())
for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
sy := (2*uint64(dy) + 1) * uint64(z.sh) / (2 * uint64(z.dh))
d := dst.PixOffset(dp.X+adr.Min.X, dp.Y+int(dy))
sy := (2*uint64(dy) + 1) * sh / dh2
d := dst.PixOffset(dr.Min.X+adr.Min.X, dr.Min.Y+int(dy))
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
sx := (2*uint64(dx) + 1) * uint64(z.sw) / (2 * uint64(z.dw))
pr, pg, pb, pa := src.At(sp.X+int(sx), sp.Y+int(sy)).RGBA()
sx := (2*uint64(dx) + 1) * sw / dw2
pr, pg, pb, pa := src.At(sr.Min.X+int(sx), sr.Min.Y+int(sy)).RGBA()
dst.Pix[d+0] = uint8(uint32(pr) >> 8)
dst.Pix[d+1] = uint8(uint32(pg) >> 8)
dst.Pix[d+2] = uint8(uint32(pb) >> 8)
@ -147,66 +168,69 @@ func (z *nnScaler) scale_RGBA_Image(dst *image.RGBA, dp image.Point, adr image.R
}
}
func (z *nnScaler) scale_Image_Image(dst Image, dp image.Point, adr image.Rectangle, src image.Image, sp image.Point) {
func (nnInterpolator) scale_Image_Image(dst Image, dr, adr image.Rectangle, src image.Image, sr image.Rectangle) {
dw2 := uint64(dr.Dx()) * 2
dh2 := uint64(dr.Dy()) * 2
sw := uint64(sr.Dx())
sh := uint64(sr.Dy())
dstColorRGBA64 := &color.RGBA64{}
dstColor := color.Color(dstColorRGBA64)
for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
sy := (2*uint64(dy) + 1) * uint64(z.sh) / (2 * uint64(z.dh))
sy := (2*uint64(dy) + 1) * sh / dh2
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
sx := (2*uint64(dx) + 1) * uint64(z.sw) / (2 * uint64(z.dw))
pr, pg, pb, pa := src.At(sp.X+int(sx), sp.Y+int(sy)).RGBA()
sx := (2*uint64(dx) + 1) * sw / dw2
pr, pg, pb, pa := src.At(sr.Min.X+int(sx), sr.Min.Y+int(sy)).RGBA()
dstColorRGBA64.R = uint16(pr)
dstColorRGBA64.G = uint16(pg)
dstColorRGBA64.B = uint16(pb)
dstColorRGBA64.A = uint16(pa)
dst.Set(dp.X+int(dx), dp.Y+int(dy), dstColor)
dst.Set(dr.Min.X+int(dx), dr.Min.Y+int(dy), dstColor)
}
}
}
func (z *ablScaler) Scale(dst Image, dp image.Point, src image.Image, sp image.Point) {
if z.dw <= 0 || z.dh <= 0 || z.sw <= 0 || z.sh <= 0 {
return
}
// adr is the affected destination pixels, relative to dp.
adr := dst.Bounds().Sub(dp).Intersect(image.Rectangle{Max: image.Point{int(z.dw), int(z.dh)}})
if adr.Empty() {
func (z ablInterpolator) Scale(dst Image, dr image.Rectangle, src image.Image, sr image.Rectangle) {
// adr is the affected destination pixels, relative to dr.Min.
adr := dst.Bounds().Intersect(dr).Sub(dr.Min)
if adr.Empty() || sr.Empty() {
return
}
// sr is the source pixels. If it extends beyond the src bounds,
// we cannot use the type-specific fast paths, as they access
// the Pix fields directly without bounds checking.
if sr := (image.Rectangle{sp, sp.Add(image.Point{int(z.sw), int(z.sh)})}); !sr.In(src.Bounds()) {
z.scale_Image_Image(dst, dp, adr, src, sp)
if !sr.In(src.Bounds()) {
z.scale_Image_Image(dst, dr, adr, src, sr)
} else {
switch dst := dst.(type) {
case *image.RGBA:
switch src := src.(type) {
case *image.Gray:
z.scale_RGBA_Gray(dst, dp, adr, src, sp)
z.scale_RGBA_Gray(dst, dr, adr, src, sr)
case *image.NRGBA:
z.scale_RGBA_NRGBA(dst, dp, adr, src, sp)
z.scale_RGBA_NRGBA(dst, dr, adr, src, sr)
case *image.RGBA:
z.scale_RGBA_RGBA(dst, dp, adr, src, sp)
z.scale_RGBA_RGBA(dst, dr, adr, src, sr)
case *image.Uniform:
z.scale_RGBA_Uniform(dst, dp, adr, src, sp)
z.scale_RGBA_Uniform(dst, dr, adr, src, sr)
case *image.YCbCr:
z.scale_RGBA_YCbCr(dst, dp, adr, src, sp)
z.scale_RGBA_YCbCr(dst, dr, adr, src, sr)
default:
z.scale_RGBA_Image(dst, dp, adr, src, sp)
z.scale_RGBA_Image(dst, dr, adr, src, sr)
}
default:
switch src := src.(type) {
default:
z.scale_Image_Image(dst, dp, adr, src, sp)
z.scale_Image_Image(dst, dr, adr, src, sr)
}
}
}
}
func (z *ablScaler) scale_RGBA_Gray(dst *image.RGBA, dp image.Point, adr image.Rectangle, src *image.Gray, sp image.Point) {
yscale := float64(z.sh) / float64(z.dh)
xscale := float64(z.sw) / float64(z.dw)
func (ablInterpolator) scale_RGBA_Gray(dst *image.RGBA, dr, adr image.Rectangle, src *image.Gray, sr image.Rectangle) {
sw := int32(sr.Dx())
sh := int32(sr.Dy())
yscale := float64(sh) / float64(dr.Dy())
xscale := float64(sw) / float64(dr.Dx())
for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
sy := (float64(dy)+0.5)*yscale - 0.5
sy0 := int32(sy)
@ -216,11 +240,11 @@ func (z *ablScaler) scale_RGBA_Gray(dst *image.RGBA, dp image.Point, adr image.R
if sy < 0 {
sy0, sy1 = 0, 0
yFrac0, yFrac1 = 0, 1
} else if sy1 >= z.sh {
} else if sy1 >= sh {
sy1 = sy0
yFrac0, yFrac1 = 1, 0
}
d := dst.PixOffset(dp.X+adr.Min.X, dp.Y+int(dy))
d := dst.PixOffset(dr.Min.X+adr.Min.X, dr.Min.Y+int(dy))
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
sx := (float64(dx)+0.5)*xscale - 0.5
sx0 := int32(sx)
@ -230,16 +254,16 @@ func (z *ablScaler) scale_RGBA_Gray(dst *image.RGBA, dp image.Point, adr image.R
if sx < 0 {
sx0, sx1 = 0, 0
xFrac0, xFrac1 = 0, 1
} else if sx1 >= z.sw {
} else if sx1 >= sw {
sx1 = sx0
xFrac0, xFrac1 = 1, 0
}
s00ru, s00gu, s00bu, s00au := src.At(sp.X+int(sx0), sp.Y+int(sy0)).RGBA()
s00ru, s00gu, s00bu, s00au := src.At(sr.Min.X+int(sx0), sr.Min.Y+int(sy0)).RGBA()
s00r := float64(s00ru)
s00g := float64(s00gu)
s00b := float64(s00bu)
s00a := float64(s00au)
s10ru, s10gu, s10bu, s10au := src.At(sp.X+int(sx1), sp.Y+int(sy0)).RGBA()
s10ru, s10gu, s10bu, s10au := src.At(sr.Min.X+int(sx1), sr.Min.Y+int(sy0)).RGBA()
s10r := float64(s10ru)
s10g := float64(s10gu)
s10b := float64(s10bu)
@ -248,12 +272,12 @@ func (z *ablScaler) scale_RGBA_Gray(dst *image.RGBA, dp image.Point, adr image.R
s10g = xFrac1*s00g + xFrac0*s10g
s10b = xFrac1*s00b + xFrac0*s10b
s10a = xFrac1*s00a + xFrac0*s10a
s01ru, s01gu, s01bu, s01au := src.At(sp.X+int(sx0), sp.Y+int(sy1)).RGBA()
s01ru, s01gu, s01bu, s01au := src.At(sr.Min.X+int(sx0), sr.Min.Y+int(sy1)).RGBA()
s01r := float64(s01ru)
s01g := float64(s01gu)
s01b := float64(s01bu)
s01a := float64(s01au)
s11ru, s11gu, s11bu, s11au := src.At(sp.X+int(sx1), sp.Y+int(sy1)).RGBA()
s11ru, s11gu, s11bu, s11au := src.At(sr.Min.X+int(sx1), sr.Min.Y+int(sy1)).RGBA()
s11r := float64(s11ru)
s11g := float64(s11gu)
s11b := float64(s11bu)
@ -275,9 +299,11 @@ func (z *ablScaler) scale_RGBA_Gray(dst *image.RGBA, dp image.Point, adr image.R
}
}
func (z *ablScaler) scale_RGBA_NRGBA(dst *image.RGBA, dp image.Point, adr image.Rectangle, src *image.NRGBA, sp image.Point) {
yscale := float64(z.sh) / float64(z.dh)
xscale := float64(z.sw) / float64(z.dw)
func (ablInterpolator) scale_RGBA_NRGBA(dst *image.RGBA, dr, adr image.Rectangle, src *image.NRGBA, sr image.Rectangle) {
sw := int32(sr.Dx())
sh := int32(sr.Dy())
yscale := float64(sh) / float64(dr.Dy())
xscale := float64(sw) / float64(dr.Dx())
for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
sy := (float64(dy)+0.5)*yscale - 0.5
sy0 := int32(sy)
@ -287,11 +313,11 @@ func (z *ablScaler) scale_RGBA_NRGBA(dst *image.RGBA, dp image.Point, adr image.
if sy < 0 {
sy0, sy1 = 0, 0
yFrac0, yFrac1 = 0, 1
} else if sy1 >= z.sh {
} else if sy1 >= sh {
sy1 = sy0
yFrac0, yFrac1 = 1, 0
}
d := dst.PixOffset(dp.X+adr.Min.X, dp.Y+int(dy))
d := dst.PixOffset(dr.Min.X+adr.Min.X, dr.Min.Y+int(dy))
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
sx := (float64(dx)+0.5)*xscale - 0.5
sx0 := int32(sx)
@ -301,16 +327,16 @@ func (z *ablScaler) scale_RGBA_NRGBA(dst *image.RGBA, dp image.Point, adr image.
if sx < 0 {
sx0, sx1 = 0, 0
xFrac0, xFrac1 = 0, 1
} else if sx1 >= z.sw {
} else if sx1 >= sw {
sx1 = sx0
xFrac0, xFrac1 = 1, 0
}
s00ru, s00gu, s00bu, s00au := src.At(sp.X+int(sx0), sp.Y+int(sy0)).RGBA()
s00ru, s00gu, s00bu, s00au := src.At(sr.Min.X+int(sx0), sr.Min.Y+int(sy0)).RGBA()
s00r := float64(s00ru)
s00g := float64(s00gu)
s00b := float64(s00bu)
s00a := float64(s00au)
s10ru, s10gu, s10bu, s10au := src.At(sp.X+int(sx1), sp.Y+int(sy0)).RGBA()
s10ru, s10gu, s10bu, s10au := src.At(sr.Min.X+int(sx1), sr.Min.Y+int(sy0)).RGBA()
s10r := float64(s10ru)
s10g := float64(s10gu)
s10b := float64(s10bu)
@ -319,12 +345,12 @@ func (z *ablScaler) scale_RGBA_NRGBA(dst *image.RGBA, dp image.Point, adr image.
s10g = xFrac1*s00g + xFrac0*s10g
s10b = xFrac1*s00b + xFrac0*s10b
s10a = xFrac1*s00a + xFrac0*s10a
s01ru, s01gu, s01bu, s01au := src.At(sp.X+int(sx0), sp.Y+int(sy1)).RGBA()
s01ru, s01gu, s01bu, s01au := src.At(sr.Min.X+int(sx0), sr.Min.Y+int(sy1)).RGBA()
s01r := float64(s01ru)
s01g := float64(s01gu)
s01b := float64(s01bu)
s01a := float64(s01au)
s11ru, s11gu, s11bu, s11au := src.At(sp.X+int(sx1), sp.Y+int(sy1)).RGBA()
s11ru, s11gu, s11bu, s11au := src.At(sr.Min.X+int(sx1), sr.Min.Y+int(sy1)).RGBA()
s11r := float64(s11ru)
s11g := float64(s11gu)
s11b := float64(s11bu)
@ -346,9 +372,11 @@ func (z *ablScaler) scale_RGBA_NRGBA(dst *image.RGBA, dp image.Point, adr image.
}
}
func (z *ablScaler) scale_RGBA_RGBA(dst *image.RGBA, dp image.Point, adr image.Rectangle, src *image.RGBA, sp image.Point) {
yscale := float64(z.sh) / float64(z.dh)
xscale := float64(z.sw) / float64(z.dw)
func (ablInterpolator) scale_RGBA_RGBA(dst *image.RGBA, dr, adr image.Rectangle, src *image.RGBA, sr image.Rectangle) {
sw := int32(sr.Dx())
sh := int32(sr.Dy())
yscale := float64(sh) / float64(dr.Dy())
xscale := float64(sw) / float64(dr.Dx())
for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
sy := (float64(dy)+0.5)*yscale - 0.5
sy0 := int32(sy)
@ -358,11 +386,11 @@ func (z *ablScaler) scale_RGBA_RGBA(dst *image.RGBA, dp image.Point, adr image.R
if sy < 0 {
sy0, sy1 = 0, 0
yFrac0, yFrac1 = 0, 1
} else if sy1 >= z.sh {
} else if sy1 >= sh {
sy1 = sy0
yFrac0, yFrac1 = 1, 0
}
d := dst.PixOffset(dp.X+adr.Min.X, dp.Y+int(dy))
d := dst.PixOffset(dr.Min.X+adr.Min.X, dr.Min.Y+int(dy))
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
sx := (float64(dx)+0.5)*xscale - 0.5
sx0 := int32(sx)
@ -372,11 +400,11 @@ func (z *ablScaler) scale_RGBA_RGBA(dst *image.RGBA, dp image.Point, adr image.R
if sx < 0 {
sx0, sx1 = 0, 0
xFrac0, xFrac1 = 0, 1
} else if sx1 >= z.sw {
} else if sx1 >= sw {
sx1 = sx0
xFrac0, xFrac1 = 1, 0
}
s00i := src.PixOffset(sp.X+int(sx0), sp.Y+int(sy0))
s00i := src.PixOffset(sr.Min.X+int(sx0), sr.Min.Y+int(sy0))
s00ru := uint32(src.Pix[s00i+0]) * 0x101
s00gu := uint32(src.Pix[s00i+1]) * 0x101
s00bu := uint32(src.Pix[s00i+2]) * 0x101
@ -385,7 +413,7 @@ func (z *ablScaler) scale_RGBA_RGBA(dst *image.RGBA, dp image.Point, adr image.R
s00g := float64(s00gu)
s00b := float64(s00bu)
s00a := float64(s00au)
s10i := src.PixOffset(sp.X+int(sx1), sp.Y+int(sy0))
s10i := src.PixOffset(sr.Min.X+int(sx1), sr.Min.Y+int(sy0))
s10ru := uint32(src.Pix[s10i+0]) * 0x101
s10gu := uint32(src.Pix[s10i+1]) * 0x101
s10bu := uint32(src.Pix[s10i+2]) * 0x101
@ -398,7 +426,7 @@ func (z *ablScaler) scale_RGBA_RGBA(dst *image.RGBA, dp image.Point, adr image.R
s10g = xFrac1*s00g + xFrac0*s10g
s10b = xFrac1*s00b + xFrac0*s10b
s10a = xFrac1*s00a + xFrac0*s10a
s01i := src.PixOffset(sp.X+int(sx0), sp.Y+int(sy1))
s01i := src.PixOffset(sr.Min.X+int(sx0), sr.Min.Y+int(sy1))
s01ru := uint32(src.Pix[s01i+0]) * 0x101
s01gu := uint32(src.Pix[s01i+1]) * 0x101
s01bu := uint32(src.Pix[s01i+2]) * 0x101
@ -407,7 +435,7 @@ func (z *ablScaler) scale_RGBA_RGBA(dst *image.RGBA, dp image.Point, adr image.R
s01g := float64(s01gu)
s01b := float64(s01bu)
s01a := float64(s01au)
s11i := src.PixOffset(sp.X+int(sx1), sp.Y+int(sy1))
s11i := src.PixOffset(sr.Min.X+int(sx1), sr.Min.Y+int(sy1))
s11ru := uint32(src.Pix[s11i+0]) * 0x101
s11gu := uint32(src.Pix[s11i+1]) * 0x101
s11bu := uint32(src.Pix[s11i+2]) * 0x101
@ -433,9 +461,11 @@ func (z *ablScaler) scale_RGBA_RGBA(dst *image.RGBA, dp image.Point, adr image.R
}
}
func (z *ablScaler) scale_RGBA_Uniform(dst *image.RGBA, dp image.Point, adr image.Rectangle, src *image.Uniform, sp image.Point) {
yscale := float64(z.sh) / float64(z.dh)
xscale := float64(z.sw) / float64(z.dw)
func (ablInterpolator) scale_RGBA_Uniform(dst *image.RGBA, dr, adr image.Rectangle, src *image.Uniform, sr image.Rectangle) {
sw := int32(sr.Dx())
sh := int32(sr.Dy())
yscale := float64(sh) / float64(dr.Dy())
xscale := float64(sw) / float64(dr.Dx())
for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
sy := (float64(dy)+0.5)*yscale - 0.5
sy0 := int32(sy)
@ -445,11 +475,11 @@ func (z *ablScaler) scale_RGBA_Uniform(dst *image.RGBA, dp image.Point, adr imag
if sy < 0 {
sy0, sy1 = 0, 0
yFrac0, yFrac1 = 0, 1
} else if sy1 >= z.sh {
} else if sy1 >= sh {
sy1 = sy0
yFrac0, yFrac1 = 1, 0
}
d := dst.PixOffset(dp.X+adr.Min.X, dp.Y+int(dy))
d := dst.PixOffset(dr.Min.X+adr.Min.X, dr.Min.Y+int(dy))
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
sx := (float64(dx)+0.5)*xscale - 0.5
sx0 := int32(sx)
@ -459,16 +489,16 @@ func (z *ablScaler) scale_RGBA_Uniform(dst *image.RGBA, dp image.Point, adr imag
if sx < 0 {
sx0, sx1 = 0, 0
xFrac0, xFrac1 = 0, 1
} else if sx1 >= z.sw {
} else if sx1 >= sw {
sx1 = sx0
xFrac0, xFrac1 = 1, 0
}
s00ru, s00gu, s00bu, s00au := src.At(sp.X+int(sx0), sp.Y+int(sy0)).RGBA()
s00ru, s00gu, s00bu, s00au := src.At(sr.Min.X+int(sx0), sr.Min.Y+int(sy0)).RGBA()
s00r := float64(s00ru)
s00g := float64(s00gu)
s00b := float64(s00bu)
s00a := float64(s00au)
s10ru, s10gu, s10bu, s10au := src.At(sp.X+int(sx1), sp.Y+int(sy0)).RGBA()
s10ru, s10gu, s10bu, s10au := src.At(sr.Min.X+int(sx1), sr.Min.Y+int(sy0)).RGBA()
s10r := float64(s10ru)
s10g := float64(s10gu)
s10b := float64(s10bu)
@ -477,12 +507,12 @@ func (z *ablScaler) scale_RGBA_Uniform(dst *image.RGBA, dp image.Point, adr imag
s10g = xFrac1*s00g + xFrac0*s10g
s10b = xFrac1*s00b + xFrac0*s10b
s10a = xFrac1*s00a + xFrac0*s10a
s01ru, s01gu, s01bu, s01au := src.At(sp.X+int(sx0), sp.Y+int(sy1)).RGBA()
s01ru, s01gu, s01bu, s01au := src.At(sr.Min.X+int(sx0), sr.Min.Y+int(sy1)).RGBA()
s01r := float64(s01ru)
s01g := float64(s01gu)
s01b := float64(s01bu)
s01a := float64(s01au)
s11ru, s11gu, s11bu, s11au := src.At(sp.X+int(sx1), sp.Y+int(sy1)).RGBA()
s11ru, s11gu, s11bu, s11au := src.At(sr.Min.X+int(sx1), sr.Min.Y+int(sy1)).RGBA()
s11r := float64(s11ru)
s11g := float64(s11gu)
s11b := float64(s11bu)
@ -504,9 +534,11 @@ func (z *ablScaler) scale_RGBA_Uniform(dst *image.RGBA, dp image.Point, adr imag
}
}
func (z *ablScaler) scale_RGBA_YCbCr(dst *image.RGBA, dp image.Point, adr image.Rectangle, src *image.YCbCr, sp image.Point) {
yscale := float64(z.sh) / float64(z.dh)
xscale := float64(z.sw) / float64(z.dw)
func (ablInterpolator) scale_RGBA_YCbCr(dst *image.RGBA, dr, adr image.Rectangle, src *image.YCbCr, sr image.Rectangle) {
sw := int32(sr.Dx())
sh := int32(sr.Dy())
yscale := float64(sh) / float64(dr.Dy())
xscale := float64(sw) / float64(dr.Dx())
for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
sy := (float64(dy)+0.5)*yscale - 0.5
sy0 := int32(sy)
@ -516,11 +548,11 @@ func (z *ablScaler) scale_RGBA_YCbCr(dst *image.RGBA, dp image.Point, adr image.
if sy < 0 {
sy0, sy1 = 0, 0
yFrac0, yFrac1 = 0, 1
} else if sy1 >= z.sh {
} else if sy1 >= sh {
sy1 = sy0
yFrac0, yFrac1 = 1, 0
}
d := dst.PixOffset(dp.X+adr.Min.X, dp.Y+int(dy))
d := dst.PixOffset(dr.Min.X+adr.Min.X, dr.Min.Y+int(dy))
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
sx := (float64(dx)+0.5)*xscale - 0.5
sx0 := int32(sx)
@ -530,16 +562,16 @@ func (z *ablScaler) scale_RGBA_YCbCr(dst *image.RGBA, dp image.Point, adr image.
if sx < 0 {
sx0, sx1 = 0, 0
xFrac0, xFrac1 = 0, 1
} else if sx1 >= z.sw {
} else if sx1 >= sw {
sx1 = sx0
xFrac0, xFrac1 = 1, 0
}
s00ru, s00gu, s00bu, s00au := src.At(sp.X+int(sx0), sp.Y+int(sy0)).RGBA()
s00ru, s00gu, s00bu, s00au := src.At(sr.Min.X+int(sx0), sr.Min.Y+int(sy0)).RGBA()
s00r := float64(s00ru)
s00g := float64(s00gu)
s00b := float64(s00bu)
s00a := float64(s00au)
s10ru, s10gu, s10bu, s10au := src.At(sp.X+int(sx1), sp.Y+int(sy0)).RGBA()
s10ru, s10gu, s10bu, s10au := src.At(sr.Min.X+int(sx1), sr.Min.Y+int(sy0)).RGBA()
s10r := float64(s10ru)
s10g := float64(s10gu)
s10b := float64(s10bu)
@ -548,12 +580,12 @@ func (z *ablScaler) scale_RGBA_YCbCr(dst *image.RGBA, dp image.Point, adr image.
s10g = xFrac1*s00g + xFrac0*s10g
s10b = xFrac1*s00b + xFrac0*s10b
s10a = xFrac1*s00a + xFrac0*s10a
s01ru, s01gu, s01bu, s01au := src.At(sp.X+int(sx0), sp.Y+int(sy1)).RGBA()
s01ru, s01gu, s01bu, s01au := src.At(sr.Min.X+int(sx0), sr.Min.Y+int(sy1)).RGBA()
s01r := float64(s01ru)
s01g := float64(s01gu)
s01b := float64(s01bu)
s01a := float64(s01au)
s11ru, s11gu, s11bu, s11au := src.At(sp.X+int(sx1), sp.Y+int(sy1)).RGBA()
s11ru, s11gu, s11bu, s11au := src.At(sr.Min.X+int(sx1), sr.Min.Y+int(sy1)).RGBA()
s11r := float64(s11ru)
s11g := float64(s11gu)
s11b := float64(s11bu)
@ -575,9 +607,11 @@ func (z *ablScaler) scale_RGBA_YCbCr(dst *image.RGBA, dp image.Point, adr image.
}
}
func (z *ablScaler) scale_RGBA_Image(dst *image.RGBA, dp image.Point, adr image.Rectangle, src image.Image, sp image.Point) {
yscale := float64(z.sh) / float64(z.dh)
xscale := float64(z.sw) / float64(z.dw)
func (ablInterpolator) scale_RGBA_Image(dst *image.RGBA, dr, adr image.Rectangle, src image.Image, sr image.Rectangle) {
sw := int32(sr.Dx())
sh := int32(sr.Dy())
yscale := float64(sh) / float64(dr.Dy())
xscale := float64(sw) / float64(dr.Dx())
for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
sy := (float64(dy)+0.5)*yscale - 0.5
sy0 := int32(sy)
@ -587,11 +621,11 @@ func (z *ablScaler) scale_RGBA_Image(dst *image.RGBA, dp image.Point, adr image.
if sy < 0 {
sy0, sy1 = 0, 0
yFrac0, yFrac1 = 0, 1
} else if sy1 >= z.sh {
} else if sy1 >= sh {
sy1 = sy0
yFrac0, yFrac1 = 1, 0
}
d := dst.PixOffset(dp.X+adr.Min.X, dp.Y+int(dy))
d := dst.PixOffset(dr.Min.X+adr.Min.X, dr.Min.Y+int(dy))
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
sx := (float64(dx)+0.5)*xscale - 0.5
sx0 := int32(sx)
@ -601,16 +635,16 @@ func (z *ablScaler) scale_RGBA_Image(dst *image.RGBA, dp image.Point, adr image.
if sx < 0 {
sx0, sx1 = 0, 0
xFrac0, xFrac1 = 0, 1
} else if sx1 >= z.sw {
} else if sx1 >= sw {
sx1 = sx0
xFrac0, xFrac1 = 1, 0
}
s00ru, s00gu, s00bu, s00au := src.At(sp.X+int(sx0), sp.Y+int(sy0)).RGBA()
s00ru, s00gu, s00bu, s00au := src.At(sr.Min.X+int(sx0), sr.Min.Y+int(sy0)).RGBA()
s00r := float64(s00ru)
s00g := float64(s00gu)
s00b := float64(s00bu)
s00a := float64(s00au)
s10ru, s10gu, s10bu, s10au := src.At(sp.X+int(sx1), sp.Y+int(sy0)).RGBA()
s10ru, s10gu, s10bu, s10au := src.At(sr.Min.X+int(sx1), sr.Min.Y+int(sy0)).RGBA()
s10r := float64(s10ru)
s10g := float64(s10gu)
s10b := float64(s10bu)
@ -619,12 +653,12 @@ func (z *ablScaler) scale_RGBA_Image(dst *image.RGBA, dp image.Point, adr image.
s10g = xFrac1*s00g + xFrac0*s10g
s10b = xFrac1*s00b + xFrac0*s10b
s10a = xFrac1*s00a + xFrac0*s10a
s01ru, s01gu, s01bu, s01au := src.At(sp.X+int(sx0), sp.Y+int(sy1)).RGBA()
s01ru, s01gu, s01bu, s01au := src.At(sr.Min.X+int(sx0), sr.Min.Y+int(sy1)).RGBA()
s01r := float64(s01ru)
s01g := float64(s01gu)
s01b := float64(s01bu)
s01a := float64(s01au)
s11ru, s11gu, s11bu, s11au := src.At(sp.X+int(sx1), sp.Y+int(sy1)).RGBA()
s11ru, s11gu, s11bu, s11au := src.At(sr.Min.X+int(sx1), sr.Min.Y+int(sy1)).RGBA()
s11r := float64(s11ru)
s11g := float64(s11gu)
s11b := float64(s11bu)
@ -646,9 +680,11 @@ func (z *ablScaler) scale_RGBA_Image(dst *image.RGBA, dp image.Point, adr image.
}
}
func (z *ablScaler) scale_Image_Image(dst Image, dp image.Point, adr image.Rectangle, src image.Image, sp image.Point) {
yscale := float64(z.sh) / float64(z.dh)
xscale := float64(z.sw) / float64(z.dw)
func (ablInterpolator) scale_Image_Image(dst Image, dr, adr image.Rectangle, src image.Image, sr image.Rectangle) {
sw := int32(sr.Dx())
sh := int32(sr.Dy())
yscale := float64(sh) / float64(dr.Dy())
xscale := float64(sw) / float64(dr.Dx())
dstColorRGBA64 := &color.RGBA64{}
dstColor := color.Color(dstColorRGBA64)
for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
@ -660,7 +696,7 @@ func (z *ablScaler) scale_Image_Image(dst Image, dp image.Point, adr image.Recta
if sy < 0 {
sy0, sy1 = 0, 0
yFrac0, yFrac1 = 0, 1
} else if sy1 >= z.sh {
} else if sy1 >= sh {
sy1 = sy0
yFrac0, yFrac1 = 1, 0
}
@ -673,16 +709,16 @@ func (z *ablScaler) scale_Image_Image(dst Image, dp image.Point, adr image.Recta
if sx < 0 {
sx0, sx1 = 0, 0
xFrac0, xFrac1 = 0, 1
} else if sx1 >= z.sw {
} else if sx1 >= sw {
sx1 = sx0
xFrac0, xFrac1 = 1, 0
}
s00ru, s00gu, s00bu, s00au := src.At(sp.X+int(sx0), sp.Y+int(sy0)).RGBA()
s00ru, s00gu, s00bu, s00au := src.At(sr.Min.X+int(sx0), sr.Min.Y+int(sy0)).RGBA()
s00r := float64(s00ru)
s00g := float64(s00gu)
s00b := float64(s00bu)
s00a := float64(s00au)
s10ru, s10gu, s10bu, s10au := src.At(sp.X+int(sx1), sp.Y+int(sy0)).RGBA()
s10ru, s10gu, s10bu, s10au := src.At(sr.Min.X+int(sx1), sr.Min.Y+int(sy0)).RGBA()
s10r := float64(s10ru)
s10g := float64(s10gu)
s10b := float64(s10bu)
@ -691,12 +727,12 @@ func (z *ablScaler) scale_Image_Image(dst Image, dp image.Point, adr image.Recta
s10g = xFrac1*s00g + xFrac0*s10g
s10b = xFrac1*s00b + xFrac0*s10b
s10a = xFrac1*s00a + xFrac0*s10a
s01ru, s01gu, s01bu, s01au := src.At(sp.X+int(sx0), sp.Y+int(sy1)).RGBA()
s01ru, s01gu, s01bu, s01au := src.At(sr.Min.X+int(sx0), sr.Min.Y+int(sy1)).RGBA()
s01r := float64(s01ru)
s01g := float64(s01gu)
s01b := float64(s01bu)
s01a := float64(s01au)
s11ru, s11gu, s11bu, s11au := src.At(sp.X+int(sx1), sp.Y+int(sy1)).RGBA()
s11ru, s11gu, s11bu, s11au := src.At(sr.Min.X+int(sx1), sr.Min.Y+int(sy1)).RGBA()
s11r := float64(s11ru)
s11g := float64(s11gu)
s11b := float64(s11bu)
@ -713,18 +749,19 @@ func (z *ablScaler) scale_Image_Image(dst Image, dp image.Point, adr image.Recta
dstColorRGBA64.G = uint16(s11g)
dstColorRGBA64.B = uint16(s11b)
dstColorRGBA64.A = uint16(s11a)
dst.Set(dp.X+int(dx), dp.Y+int(dy), dstColor)
dst.Set(dr.Min.X+int(dx), dr.Min.Y+int(dy), dstColor)
}
}
}
func (z *kernelScaler) Scale(dst Image, dp image.Point, src image.Image, sp image.Point) {
if z.dw <= 0 || z.dh <= 0 || z.sw <= 0 || z.sh <= 0 {
func (z *kernelScaler) Scale(dst Image, dr image.Rectangle, src image.Image, sr image.Rectangle) {
if z.dw != int32(dr.Dx()) || z.dh != int32(dr.Dy()) || z.sw != int32(sr.Dx()) || z.sh != int32(sr.Dy()) {
z.kernel.Scale(dst, dr, src, sr)
return
}
// adr is the affected destination pixels, relative to dp.
adr := dst.Bounds().Sub(dp).Intersect(image.Rectangle{Max: image.Point{int(z.dw), int(z.dh)}})
if adr.Empty() {
// adr is the affected destination pixels, relative to dr.Min.
adr := dst.Bounds().Intersect(dr).Sub(dr.Min)
if adr.Empty() || sr.Empty() {
return
}
// Create a temporary buffer:
@ -736,40 +773,40 @@ func (z *kernelScaler) Scale(dst Image, dp image.Point, src image.Image, sp imag
// sr is the source pixels. If it extends beyond the src bounds,
// we cannot use the type-specific fast paths, as they access
// the Pix fields directly without bounds checking.
if sr := (image.Rectangle{sp, sp.Add(image.Point{int(z.sw), int(z.sh)})}); !sr.In(src.Bounds()) {
z.scaleX_Image(tmp, src, sp)
if !sr.In(src.Bounds()) {
z.scaleX_Image(tmp, src, sr)
} else {
switch src := src.(type) {
case *image.Gray:
z.scaleX_Gray(tmp, src, sp)
z.scaleX_Gray(tmp, src, sr)
case *image.NRGBA:
z.scaleX_NRGBA(tmp, src, sp)
z.scaleX_NRGBA(tmp, src, sr)
case *image.RGBA:
z.scaleX_RGBA(tmp, src, sp)
z.scaleX_RGBA(tmp, src, sr)
case *image.Uniform:
z.scaleX_Uniform(tmp, src, sp)
z.scaleX_Uniform(tmp, src, sr)
case *image.YCbCr:
z.scaleX_YCbCr(tmp, src, sp)
z.scaleX_YCbCr(tmp, src, sr)
default:
z.scaleX_Image(tmp, src, sp)
z.scaleX_Image(tmp, src, sr)
}
}
switch dst := dst.(type) {
case *image.RGBA:
z.scaleY_RGBA(dst, dp, adr, tmp)
z.scaleY_RGBA(dst, dr, adr, tmp)
default:
z.scaleY_Image(dst, dp, adr, tmp)
z.scaleY_Image(dst, dr, adr, tmp)
}
}
func (z *kernelScaler) scaleX_Gray(tmp [][4]float64, src *image.Gray, sp image.Point) {
func (z *kernelScaler) scaleX_Gray(tmp [][4]float64, src *image.Gray, sr image.Rectangle) {
t := 0
for y := int32(0); y < z.sh; y++ {
for _, s := range z.horizontal.sources {
var pr, pg, pb, pa float64
for _, c := range z.horizontal.contribs[s.i:s.j] {
pru, pgu, pbu, pau := src.At(sp.X+int(c.coord), sp.Y+int(y)).RGBA()
pru, pgu, pbu, pau := src.At(sr.Min.X+int(c.coord), sr.Min.Y+int(y)).RGBA()
pr += float64(pru) * c.weight
pg += float64(pgu) * c.weight
pb += float64(pbu) * c.weight
@ -786,13 +823,13 @@ func (z *kernelScaler) scaleX_Gray(tmp [][4]float64, src *image.Gray, sp image.P
}
}
func (z *kernelScaler) scaleX_NRGBA(tmp [][4]float64, src *image.NRGBA, sp image.Point) {
func (z *kernelScaler) scaleX_NRGBA(tmp [][4]float64, src *image.NRGBA, sr image.Rectangle) {
t := 0
for y := int32(0); y < z.sh; y++ {
for _, s := range z.horizontal.sources {
var pr, pg, pb, pa float64
for _, c := range z.horizontal.contribs[s.i:s.j] {
pru, pgu, pbu, pau := src.At(sp.X+int(c.coord), sp.Y+int(y)).RGBA()
pru, pgu, pbu, pau := src.At(sr.Min.X+int(c.coord), sr.Min.Y+int(y)).RGBA()
pr += float64(pru) * c.weight
pg += float64(pgu) * c.weight
pb += float64(pbu) * c.weight
@ -809,13 +846,13 @@ func (z *kernelScaler) scaleX_NRGBA(tmp [][4]float64, src *image.NRGBA, sp image
}
}
func (z *kernelScaler) scaleX_RGBA(tmp [][4]float64, src *image.RGBA, sp image.Point) {
func (z *kernelScaler) scaleX_RGBA(tmp [][4]float64, src *image.RGBA, sr image.Rectangle) {
t := 0
for y := int32(0); y < z.sh; y++ {
for _, s := range z.horizontal.sources {
var pr, pg, pb, pa float64
for _, c := range z.horizontal.contribs[s.i:s.j] {
pi := src.PixOffset(sp.X+int(c.coord), sp.Y+int(y))
pi := src.PixOffset(sr.Min.X+int(c.coord), sr.Min.Y+int(y))
pru := uint32(src.Pix[pi+0]) * 0x101
pgu := uint32(src.Pix[pi+1]) * 0x101
pbu := uint32(src.Pix[pi+2]) * 0x101
@ -836,13 +873,13 @@ func (z *kernelScaler) scaleX_RGBA(tmp [][4]float64, src *image.RGBA, sp image.P
}
}
func (z *kernelScaler) scaleX_Uniform(tmp [][4]float64, src *image.Uniform, sp image.Point) {
func (z *kernelScaler) scaleX_Uniform(tmp [][4]float64, src *image.Uniform, sr image.Rectangle) {
t := 0
for y := int32(0); y < z.sh; y++ {
for _, s := range z.horizontal.sources {
var pr, pg, pb, pa float64
for _, c := range z.horizontal.contribs[s.i:s.j] {
pru, pgu, pbu, pau := src.At(sp.X+int(c.coord), sp.Y+int(y)).RGBA()
pru, pgu, pbu, pau := src.At(sr.Min.X+int(c.coord), sr.Min.Y+int(y)).RGBA()
pr += float64(pru) * c.weight
pg += float64(pgu) * c.weight
pb += float64(pbu) * c.weight
@ -859,13 +896,13 @@ func (z *kernelScaler) scaleX_Uniform(tmp [][4]float64, src *image.Uniform, sp i
}
}
func (z *kernelScaler) scaleX_YCbCr(tmp [][4]float64, src *image.YCbCr, sp image.Point) {
func (z *kernelScaler) scaleX_YCbCr(tmp [][4]float64, src *image.YCbCr, sr image.Rectangle) {
t := 0
for y := int32(0); y < z.sh; y++ {
for _, s := range z.horizontal.sources {
var pr, pg, pb, pa float64
for _, c := range z.horizontal.contribs[s.i:s.j] {
pru, pgu, pbu, pau := src.At(sp.X+int(c.coord), sp.Y+int(y)).RGBA()
pru, pgu, pbu, pau := src.At(sr.Min.X+int(c.coord), sr.Min.Y+int(y)).RGBA()
pr += float64(pru) * c.weight
pg += float64(pgu) * c.weight
pb += float64(pbu) * c.weight
@ -882,13 +919,13 @@ func (z *kernelScaler) scaleX_YCbCr(tmp [][4]float64, src *image.YCbCr, sp image
}
}
func (z *kernelScaler) scaleX_Image(tmp [][4]float64, src image.Image, sp image.Point) {
func (z *kernelScaler) scaleX_Image(tmp [][4]float64, src image.Image, sr image.Rectangle) {
t := 0
for y := int32(0); y < z.sh; y++ {
for _, s := range z.horizontal.sources {
var pr, pg, pb, pa float64
for _, c := range z.horizontal.contribs[s.i:s.j] {
pru, pgu, pbu, pau := src.At(sp.X+int(c.coord), sp.Y+int(y)).RGBA()
pru, pgu, pbu, pau := src.At(sr.Min.X+int(c.coord), sr.Min.Y+int(y)).RGBA()
pr += float64(pru) * c.weight
pg += float64(pgu) * c.weight
pb += float64(pbu) * c.weight
@ -905,9 +942,9 @@ func (z *kernelScaler) scaleX_Image(tmp [][4]float64, src image.Image, sp image.
}
}
func (z *kernelScaler) scaleY_RGBA(dst *image.RGBA, dp image.Point, adr image.Rectangle, tmp [][4]float64) {
func (z *kernelScaler) scaleY_RGBA(dst *image.RGBA, dr, adr image.Rectangle, tmp [][4]float64) {
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
d := dst.PixOffset(dp.X+int(dx), dp.Y+adr.Min.Y)
d := dst.PixOffset(dr.Min.X+int(dx), dr.Min.Y+adr.Min.Y)
for _, s := range z.vertical.sources[adr.Min.Y:adr.Max.Y] {
var pr, pg, pb, pa float64
for _, c := range z.vertical.contribs[s.i:s.j] {
@ -926,7 +963,7 @@ func (z *kernelScaler) scaleY_RGBA(dst *image.RGBA, dp image.Point, adr image.Re
}
}
func (z *kernelScaler) scaleY_Image(dst Image, dp image.Point, adr image.Rectangle, tmp [][4]float64) {
func (z *kernelScaler) scaleY_Image(dst Image, dr, adr image.Rectangle, tmp [][4]float64) {
dstColorRGBA64 := &color.RGBA64{}
dstColor := color.Color(dstColorRGBA64)
for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
@ -943,7 +980,7 @@ func (z *kernelScaler) scaleY_Image(dst Image, dp image.Point, adr image.Rectang
dstColorRGBA64.G = ftou(pg * s.invTotalWeight)
dstColorRGBA64.B = ftou(pb * s.invTotalWeight)
dstColorRGBA64.A = ftou(pa * s.invTotalWeight)
dst.Set(dp.X+int(dx), dp.Y+int(adr.Min.Y+dy), dstColor)
dst.Set(dr.Min.X+int(dx), dr.Min.Y+int(adr.Min.Y+dy), dstColor)
}
}
}

View File

@ -6,16 +6,25 @@
package draw
// TODO: should Scale and NewScaler also take an Op argument?
// TODO: add an Options type a la
// https://groups.google.com/forum/#!topic/golang-dev/fgn_xM0aeq4
import (
"image"
"math"
)
// Scale scales the part of the source image defined by src and sr and writes
// Scaler scales the part of the source image defined by src and sr and writes
// to the part of the destination image defined by dst and dr.
//
// A Scaler is safe to use concurrently.
type Scaler interface {
Scale(dst Image, dr image.Rectangle, src image.Image, sr image.Rectangle)
}
// Interpolator is an interpolation algorithm, when dst and src pixels don't
// have a 1:1 correspondance.
//
// Of the interpolators provided by this package:
// - NearestNeighbor is fast but usually looks worst.
// - CatmullRom is slow but usually looks best.
@ -24,23 +33,9 @@ import (
// The time taken depends on the size of dr. For kernel interpolators, the
// speed also depends on the size of sr, and so are often slower than
// non-kernel interpolators, especially when scaling down.
func Scale(dst Image, dr image.Rectangle, src image.Image, sr image.Rectangle, q Interpolator) {
q.NewScaler(int32(dr.Dx()), int32(dr.Dy()), int32(sr.Dx()), int32(sr.Dy())).Scale(dst, dr.Min, src, sr.Min)
}
// Scaler scales part of a source image, starting from sp, and writes to a
// destination image, starting from dp. The destination and source width and
// heights are pre-determined, as part of the Scaler.
//
// A Scaler is safe to use concurrently.
type Scaler interface {
Scale(dst Image, dp image.Point, src image.Image, sp image.Point)
}
// Interpolator creates scalers for a given destination and source width and
// heights.
type Interpolator interface {
NewScaler(dw, dh, sw, sh int32) Scaler
Scaler
// TODO: Transformer
}
// Kernel is an interpolator that blends source pixels weighted by a symmetric
@ -54,15 +49,22 @@ type Kernel struct {
At func(t float64) float64
}
// NewScaler implements the Interpolator interface.
func (k *Kernel) NewScaler(dw, dh, sw, sh int32) Scaler {
// Scale implements the Scaler interface.
func (k *Kernel) Scale(dst Image, dr image.Rectangle, src image.Image, sr image.Rectangle) {
k.NewScaler(dr.Dx(), dr.Dy(), sr.Dx(), sr.Dy()).Scale(dst, dr, src, sr)
}
// NewScaler returns a Scaler that is optimized for scaling multiple times with
// the same fixed destination and source width and height.
func (k *Kernel) NewScaler(dw, dh, sw, sh int) Scaler {
return &kernelScaler{
dw: dw,
dh: dh,
sw: sw,
sh: sh,
horizontal: newDistrib(k, dw, sw),
vertical: newDistrib(k, dh, sh),
kernel: k,
dw: int32(dw),
dh: int32(dh),
sw: int32(sw),
sh: int32(sh),
horizontal: newDistrib(k, int32(dw), int32(sw)),
vertical: newDistrib(k, int32(dh), int32(sh)),
}
}
@ -107,21 +109,10 @@ var (
type nnInterpolator struct{}
func (nnInterpolator) NewScaler(dw, dh, sw, sh int32) Scaler { return &nnScaler{dw, dh, sw, sh} }
type nnScaler struct {
dw, dh, sw, sh int32
}
type ablInterpolator struct{}
func (ablInterpolator) NewScaler(dw, dh, sw, sh int32) Scaler { return &ablScaler{dw, dh, sw, sh} }
type ablScaler struct {
dw, dh, sw, sh int32
}
type kernelScaler struct {
kernel *Kernel
dw, dh, sw, sh int32
horizontal, vertical distrib
}

View File

@ -47,7 +47,7 @@ func testScale(t *testing.T, w int, h int, direction, srcFilename string) {
gotFilename := fmt.Sprintf("../testdata/go-turns-two-%s-%s.png", direction, name)
got := image.NewRGBA(image.Rect(0, 0, w, h))
Scale(got, got.Bounds(), src, src.Bounds(), q)
q.Scale(got, got.Bounds(), src, src.Bounds())
if *genScaleFiles {
g, err := os.Create(gotFilename)
if err != nil {
@ -112,12 +112,12 @@ func TestScaleClipCommute(t *testing.T) {
}
// Scale then clip.
Scale(dst0, outer, src, src.Bounds(), q)
q.Scale(dst0, outer, src, src.Bounds())
dst0 = dst0.SubImage(inner).(*image.RGBA)
// Clip then scale.
dst1 = dst1.SubImage(inner).(*image.RGBA)
Scale(dst1, outer, src, src.Bounds(), q)
q.Scale(dst1, outer, src, src.Bounds())
loop:
for y := inner.Min.Y; y < inner.Max.Y; y++ {
@ -187,8 +187,8 @@ func TestFastPaths(t *testing.T) {
dst1 := image.NewRGBA(drs[0])
Draw(dst0, dst0.Bounds(), blue, image.Point{}, Src)
Draw(dstWrapper{dst1}, dst1.Bounds(), srcWrapper{blue}, image.Point{}, Src)
Scale(dst0, dr, src, sr, q)
Scale(dstWrapper{dst1}, dr, srcWrapper{src}, sr, q)
q.Scale(dst0, dr, src, sr)
q.Scale(dstWrapper{dst1}, dr, srcWrapper{src}, sr)
if !bytes.Equal(dst0.Pix, dst1.Pix) {
t.Errorf("pix differ for dr=%v, src=%T, sr=%v, q=%T", dr, src, sr, q)
}
@ -260,11 +260,16 @@ func benchScale(b *testing.B, srcf func(image.Rectangle) (image.Image, error), w
b.Fatal(err)
}
dr, sr := dst.Bounds(), src.Bounds()
scaler := q.NewScaler(int32(dr.Dx()), int32(dr.Dy()), int32(sr.Dx()), int32(sr.Dy()))
scaler := Scaler(q)
if n, ok := q.(interface {
NewScaler(int, int, int, int) Scaler
}); ok {
scaler = n.NewScaler(dr.Dx(), dr.Dy(), sr.Dx(), sr.Dy())
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
scaler.Scale(dst, dr.Min, src, sr.Min)
scaler.Scale(dst, dr, src, sr)
}
}