draw: factor out the Scale implementations.
This is just a copy/paste/rename in anticipation of automatically
generating fast-path code for specific dst-image types and src-image
types, a la the standard library's image/draw package.
Change-Id: If6385b347cb5e1d134b0ce841ef38ed4450a6fef
Reviewed-on: https://go-review.googlesource.com/5252
Reviewed-by: David Symonds <dsymonds@golang.org>
diff --git a/draw/impl.go b/draw/impl.go
new file mode 100644
index 0000000..c59ba87
--- /dev/null
+++ b/draw/impl.go
@@ -0,0 +1,165 @@
+// Copyright 2015 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
+
+// TODO: autogenerate this file.
+
+import (
+ "image"
+ "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
+ }
+ dstColorRGBA64 := &color.RGBA64{}
+ dstColor := color.Color(dstColorRGBA64)
+ for dy := int32(0); dy < z.dh; dy++ {
+ sy := (2*uint64(dy) + 1) * uint64(z.sh) / (2 * uint64(z.dh))
+ for dx := int32(0); dx < z.dw; 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()
+ 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)
+ }
+ }
+}
+
+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
+ }
+ yscale := float64(z.sh) / float64(z.dh)
+ xscale := float64(z.sw) / float64(z.dw)
+ dstColorRGBA64 := &color.RGBA64{}
+ dstColor := color.Color(dstColorRGBA64)
+ for dy := int32(0); dy < z.dh; dy++ {
+ sy := (float64(dy)+0.5)*yscale - 0.5
+ sy0 := int32(sy)
+ yFrac0 := sy - float64(sy0)
+ yFrac1 := 1 - yFrac0
+ sy1 := sy0 + 1
+ if sy < 0 {
+ sy0, sy1 = 0, 0
+ yFrac0, yFrac1 = 0, 1
+ } else if sy1 >= z.sh {
+ sy1 = sy0
+ yFrac0, yFrac1 = 1, 0
+ }
+ for dx := int32(0); dx < z.dw; dx++ {
+ sx := (float64(dx)+0.5)*xscale - 0.5
+ sx0 := int32(sx)
+ xFrac0 := sx - float64(sx0)
+ xFrac1 := 1 - xFrac0
+ sx1 := sx0 + 1
+ if sx < 0 {
+ sx0, sx1 = 0, 0
+ xFrac0, xFrac1 = 0, 1
+ } else if sx1 >= z.sw {
+ sx1 = sx0
+ xFrac0, xFrac1 = 1, 0
+ }
+ s00ru, s00gu, s00bu, s00au := src.At(sp.X+int(sx0), sp.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()
+ s10r := float64(s10ru)
+ s10g := float64(s10gu)
+ s10b := float64(s10bu)
+ s10a := float64(s10au)
+ s10r = xFrac1*s00r + xFrac0*s10r
+ 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()
+ 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()
+ s11r := float64(s11ru)
+ s11g := float64(s11gu)
+ s11b := float64(s11bu)
+ s11a := float64(s11au)
+ s11r = xFrac1*s01r + xFrac0*s11r
+ s11g = xFrac1*s01g + xFrac0*s11g
+ s11b = xFrac1*s01b + xFrac0*s11b
+ s11a = xFrac1*s01a + xFrac0*s11a
+ s11r = yFrac1*s10r + yFrac0*s11r
+ s11g = yFrac1*s10g + yFrac0*s11g
+ s11b = yFrac1*s10b + yFrac0*s11b
+ s11a = yFrac1*s10a + yFrac0*s11a
+ dstColorRGBA64.R = uint16(s11r)
+ dstColorRGBA64.G = uint16(s11g)
+ dstColorRGBA64.B = uint16(s11b)
+ dstColorRGBA64.A = uint16(s11a)
+ dst.Set(dp.X+int(dx), dp.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 {
+ return
+ }
+ // Create a temporary buffer:
+ // scaleX distributes the source image's columns over the temporary image.
+ // scaleY distributes the temporary image's rows over the destination image.
+ // TODO: is it worth having a sync.Pool for this temporary buffer?
+ tmp := make([][4]float64, z.dw*z.sh)
+ z.scaleX(tmp, src, sp)
+ z.scaleY(dst, dp, tmp)
+}
+
+func (z *kernelScaler) scaleX(tmp [][4]float64, src image.Image, sp image.Point) {
+ t := 0
+ for y := int32(0); y < z.sh; y++ {
+ for _, s := range z.horizontal.sources {
+ var r, g, b, a float64
+ for _, c := range z.horizontal.contribs[s.i:s.j] {
+ rr, gg, bb, aa := src.At(sp.X+int(c.coord), sp.Y+int(y)).RGBA()
+ r += float64(rr) * c.weight
+ g += float64(gg) * c.weight
+ b += float64(bb) * c.weight
+ a += float64(aa) * c.weight
+ }
+ tmp[t] = [4]float64{
+ r * s.invTotalWeightFFFF,
+ g * s.invTotalWeightFFFF,
+ b * s.invTotalWeightFFFF,
+ a * s.invTotalWeightFFFF,
+ }
+ t++
+ }
+ }
+}
+
+func (z *kernelScaler) scaleY(dst Image, dp image.Point, tmp [][4]float64) {
+ dstColorRGBA64 := &color.RGBA64{}
+ dstColor := color.Color(dstColorRGBA64)
+ for x := int32(0); x < z.dw; x++ {
+ for y, s := range z.vertical.sources {
+ var r, g, b, a float64
+ for _, c := range z.vertical.contribs[s.i:s.j] {
+ p := &tmp[c.coord*z.dw+x]
+ r += p[0] * c.weight
+ g += p[1] * c.weight
+ b += p[2] * c.weight
+ a += p[3] * c.weight
+ }
+ dstColorRGBA64.R = ftou(r * s.invTotalWeight)
+ dstColorRGBA64.G = ftou(g * s.invTotalWeight)
+ dstColorRGBA64.B = ftou(b * s.invTotalWeight)
+ dstColorRGBA64.A = ftou(a * s.invTotalWeight)
+ dst.Set(dp.X+int(x), dp.Y+y, dstColor)
+ }
+ }
+}
diff --git a/draw/scale.go b/draw/scale.go
index 96b3a0c..b3aaf7e 100644
--- a/draw/scale.go
+++ b/draw/scale.go
@@ -8,7 +8,6 @@
import (
"image"
- "image/color"
"math"
)
@@ -112,26 +111,6 @@
dw, dh, sw, sh int32
}
-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
- }
- dstColorRGBA64 := &color.RGBA64{}
- dstColor := color.Color(dstColorRGBA64)
- for dy := int32(0); dy < z.dh; dy++ {
- sy := (2*uint64(dy) + 1) * uint64(z.sh) / (2 * uint64(z.dh))
- for dx := int32(0); dx < z.dw; 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()
- 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)
- }
- }
-}
-
type ablInterpolator struct{}
func (ablInterpolator) NewScaler(dw, dh, sw, sh int32) Scaler { return &ablScaler{dw, dh, sw, sh} }
@@ -140,96 +119,11 @@
dw, dh, sw, sh int32
}
-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
- }
- yscale := float64(z.sh) / float64(z.dh)
- xscale := float64(z.sw) / float64(z.dw)
- dstColorRGBA64 := &color.RGBA64{}
- dstColor := color.Color(dstColorRGBA64)
- for dy := int32(0); dy < z.dh; dy++ {
- sy := (float64(dy)+0.5)*yscale - 0.5
- sy0 := int32(sy)
- yFrac0 := sy - float64(sy0)
- yFrac1 := 1 - yFrac0
- sy1 := sy0 + 1
- if sy < 0 {
- sy0, sy1 = 0, 0
- yFrac0, yFrac1 = 0, 1
- } else if sy1 >= z.sh {
- sy1 = sy0
- yFrac0, yFrac1 = 1, 0
- }
- for dx := int32(0); dx < z.dw; dx++ {
- sx := (float64(dx)+0.5)*xscale - 0.5
- sx0 := int32(sx)
- xFrac0 := sx - float64(sx0)
- xFrac1 := 1 - xFrac0
- sx1 := sx0 + 1
- if sx < 0 {
- sx0, sx1 = 0, 0
- xFrac0, xFrac1 = 0, 1
- } else if sx1 >= z.sw {
- sx1 = sx0
- xFrac0, xFrac1 = 1, 0
- }
- s00ru, s00gu, s00bu, s00au := src.At(sp.X+int(sx0), sp.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()
- s10r := float64(s10ru)
- s10g := float64(s10gu)
- s10b := float64(s10bu)
- s10a := float64(s10au)
- s10r = xFrac1*s00r + xFrac0*s10r
- 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()
- 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()
- s11r := float64(s11ru)
- s11g := float64(s11gu)
- s11b := float64(s11bu)
- s11a := float64(s11au)
- s11r = xFrac1*s01r + xFrac0*s11r
- s11g = xFrac1*s01g + xFrac0*s11g
- s11b = xFrac1*s01b + xFrac0*s11b
- s11a = xFrac1*s01a + xFrac0*s11a
- s11r = yFrac1*s10r + yFrac0*s11r
- s11g = yFrac1*s10g + yFrac0*s11g
- s11b = yFrac1*s10b + yFrac0*s11b
- s11a = yFrac1*s10a + yFrac0*s11a
- dstColorRGBA64.R = uint16(s11r)
- dstColorRGBA64.G = uint16(s11g)
- dstColorRGBA64.B = uint16(s11b)
- dstColorRGBA64.A = uint16(s11a)
- dst.Set(dp.X+int(dx), dp.Y+int(dy), dstColor)
- }
- }
-}
-
type kernelScaler struct {
dw, dh, sw, sh int32
horizontal, vertical distrib
}
-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 {
- return
- }
- // TODO: is it worth having a sync.Pool for this temporary buffer?
- tmp := make([][4]float64, z.dw*z.sh)
- z.scaleX(tmp, src, sp)
- z.scaleY(dst, dp, tmp)
-}
-
// source is a range of contribs, their inverse total weight, and that ITW
// divided by 0xffff.
type source struct {
@@ -317,53 +211,6 @@
return distrib{sources, contribs}
}
-// scaleX distributes the source image's columns over the temporary image.
-func (z *kernelScaler) scaleX(tmp [][4]float64, src image.Image, sp image.Point) {
- t := 0
- for y := int32(0); y < z.sh; y++ {
- for _, s := range z.horizontal.sources {
- var r, g, b, a float64
- for _, c := range z.horizontal.contribs[s.i:s.j] {
- rr, gg, bb, aa := src.At(sp.X+int(c.coord), sp.Y+int(y)).RGBA()
- r += float64(rr) * c.weight
- g += float64(gg) * c.weight
- b += float64(bb) * c.weight
- a += float64(aa) * c.weight
- }
- tmp[t] = [4]float64{
- r * s.invTotalWeightFFFF,
- g * s.invTotalWeightFFFF,
- b * s.invTotalWeightFFFF,
- a * s.invTotalWeightFFFF,
- }
- t++
- }
- }
-}
-
-// scaleY distributes the temporary image's rows over the destination image.
-func (z *kernelScaler) scaleY(dst Image, dp image.Point, tmp [][4]float64) {
- dstColorRGBA64 := &color.RGBA64{}
- dstColor := color.Color(dstColorRGBA64)
- for x := int32(0); x < z.dw; x++ {
- for y, s := range z.vertical.sources {
- var r, g, b, a float64
- for _, c := range z.vertical.contribs[s.i:s.j] {
- p := &tmp[c.coord*z.dw+x]
- r += p[0] * c.weight
- g += p[1] * c.weight
- b += p[2] * c.weight
- a += p[3] * c.weight
- }
- dstColorRGBA64.R = ftou(r * s.invTotalWeight)
- dstColorRGBA64.G = ftou(g * s.invTotalWeight)
- dstColorRGBA64.B = ftou(b * s.invTotalWeight)
- dstColorRGBA64.A = ftou(a * s.invTotalWeight)
- dst.Set(dp.X+int(x), dp.Y+y, dstColor)
- }
- }
-}
-
func ftou(f float64) uint16 {
i := int32(0xffff*f + 0.5)
if i > 0xffff {
