draw: generate code paths for image.Gray sources.
Optimizing this code path will be follow-up changes.
Change-Id: Ifece6c7d3685bb8f2d20cf8828a121c9ff346434
Reviewed-on: https://go-review.googlesource.com/6238
Reviewed-by: Rob Pike <r@golang.org>
diff --git a/draw/gen.go b/draw/gen.go
index 8ffea52..0d98f68 100644
--- a/draw/gen.go
+++ b/draw/gen.go
@@ -50,6 +50,7 @@
//
// TODO: add *image.CMYK src type after Go 1.5 is released.
dsTypes = []struct{ dType, sType string }{
+ {"*image.RGBA", "*image.Gray"},
{"*image.RGBA", "*image.NRGBA"},
{"*image.RGBA", "*image.RGBA"},
{"*image.RGBA", "*image.Uniform"},
@@ -284,7 +285,7 @@
switch d.sType {
default:
log.Fatalf("bad sType %q", d.sType)
- case "image.Image", "*image.NRGBA", "*image.Uniform", "*image.YCbCr": // TODO: separate code for concrete types.
+ 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",
lhs, tmp, lhs, tmp, lhs, tmp, lhs, tmp,
diff --git a/draw/impl.go b/draw/impl.go
index 3c07d31..9a2fbf5 100644
--- a/draw/impl.go
+++ b/draw/impl.go
@@ -25,6 +25,8 @@
switch dst := dst.(type) {
case *image.RGBA:
switch src := src.(type) {
+ case *image.Gray:
+ z.scale_RGBA_Gray(dst, dp, dr, src, sp)
case *image.NRGBA:
z.scale_RGBA_NRGBA(dst, dp, dr, src, sp)
case *image.RGBA:
@@ -45,6 +47,22 @@
}
}
+func (z *nnScaler) scale_RGBA_Gray(dst *image.RGBA, dp image.Point, dr image.Rectangle, src *image.Gray, sp image.Point) {
+ for dy := int32(dr.Min.Y); dy < int32(dr.Max.Y); dy++ {
+ sy := (2*uint64(dy) + 1) * uint64(z.sh) / (2 * uint64(z.dh))
+ d := dst.PixOffset(dp.X+dr.Min.X, dp.Y+int(dy))
+ for dx := int32(dr.Min.X); dx < int32(dr.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()
+ dst.Pix[d+0] = uint8(uint32(pr) >> 8)
+ dst.Pix[d+1] = uint8(uint32(pg) >> 8)
+ dst.Pix[d+2] = uint8(uint32(pb) >> 8)
+ dst.Pix[d+3] = uint8(uint32(pa) >> 8)
+ d += 4
+ }
+ }
+}
+
func (z *nnScaler) scale_RGBA_NRGBA(dst *image.RGBA, dp image.Point, dr image.Rectangle, src *image.NRGBA, sp image.Point) {
for dy := int32(dr.Min.Y); dy < int32(dr.Max.Y); dy++ {
sy := (2*uint64(dy) + 1) * uint64(z.sh) / (2 * uint64(z.dh))
@@ -164,6 +182,8 @@
switch dst := dst.(type) {
case *image.RGBA:
switch src := src.(type) {
+ case *image.Gray:
+ z.scale_RGBA_Gray(dst, dp, dr, src, sp)
case *image.NRGBA:
z.scale_RGBA_NRGBA(dst, dp, dr, src, sp)
case *image.RGBA:
@@ -184,6 +204,77 @@
}
}
+func (z *ablScaler) scale_RGBA_Gray(dst *image.RGBA, dp image.Point, dr image.Rectangle, src *image.Gray, sp image.Point) {
+ yscale := float64(z.sh) / float64(z.dh)
+ xscale := float64(z.sw) / float64(z.dw)
+ for dy := int32(dr.Min.Y); dy < int32(dr.Max.Y); 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
+ }
+ d := dst.PixOffset(dp.X+dr.Min.X, dp.Y+int(dy))
+ for dx := int32(dr.Min.X); dx < int32(dr.Max.X); 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
+ dst.Pix[d+0] = uint8(uint32(s11r) >> 8)
+ dst.Pix[d+1] = uint8(uint32(s11g) >> 8)
+ dst.Pix[d+2] = uint8(uint32(s11b) >> 8)
+ dst.Pix[d+3] = uint8(uint32(s11a) >> 8)
+ d += 4
+ }
+ }
+}
+
func (z *ablScaler) scale_RGBA_NRGBA(dst *image.RGBA, dp image.Point, dr image.Rectangle, src *image.NRGBA, sp image.Point) {
yscale := float64(z.sh) / float64(z.dh)
xscale := float64(z.sw) / float64(z.dw)
@@ -649,6 +740,8 @@
z.scaleX_Image(tmp, src, sp)
} else {
switch src := src.(type) {
+ case *image.Gray:
+ z.scaleX_Gray(tmp, src, sp)
case *image.NRGBA:
z.scaleX_NRGBA(tmp, src, sp)
case *image.RGBA:
@@ -670,6 +763,29 @@
}
}
+func (z *kernelScaler) scaleX_Gray(tmp [][4]float64, src *image.Gray, sp image.Point) {
+ 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()
+ pr += float64(pru) * c.weight
+ pg += float64(pgu) * c.weight
+ pb += float64(pbu) * c.weight
+ pa += float64(pau) * c.weight
+ }
+ tmp[t] = [4]float64{
+ pr * s.invTotalWeightFFFF,
+ pg * s.invTotalWeightFFFF,
+ pb * s.invTotalWeightFFFF,
+ pa * s.invTotalWeightFFFF,
+ }
+ t++
+ }
+ }
+}
+
func (z *kernelScaler) scaleX_NRGBA(tmp [][4]float64, src *image.NRGBA, sp image.Point) {
t := 0
for y := int32(0); y < z.sh; y++ {
diff --git a/draw/scale_test.go b/draw/scale_test.go
index cceaad4..c7c6ef2 100644
--- a/draw/scale_test.go
+++ b/draw/scale_test.go
@@ -158,6 +158,7 @@
image.Rect(5, 5, 5, 5), // Empty.
}
srcfs := []func(image.Rectangle) (image.Image, error){
+ srcGray,
srcNRGBA,
srcRGBA,
srcUniform,
@@ -197,6 +198,12 @@
}
}
+func srcGray(boundsHint image.Rectangle) (image.Image, error) {
+ m := image.NewGray(boundsHint)
+ fillPix(rand.New(rand.NewSource(0)), m.Pix)
+ return m, nil
+}
+
func srcNRGBA(boundsHint image.Rectangle) (image.Image, error) {
m := image.NewNRGBA(boundsHint)
fillPix(rand.New(rand.NewSource(1)), m.Pix)
@@ -276,6 +283,7 @@
func BenchmarkScaleUpBL(b *testing.B) { benchScale(b, srcTux, 800, 600, BiLinear) }
func BenchmarkScaleUpCR(b *testing.B) { benchScale(b, srcTux, 800, 600, CatmullRom) }
+func BenchmarkScaleSrcGray(b *testing.B) { benchScale(b, srcGray, 200, 150, ApproxBiLinear) }
func BenchmarkScaleSrcNRGBA(b *testing.B) { benchScale(b, srcNRGBA, 200, 150, ApproxBiLinear) }
func BenchmarkScaleSrcRGBA(b *testing.B) { benchScale(b, srcRGBA, 200, 150, ApproxBiLinear) }
func BenchmarkScaleSrcUniform(b *testing.B) { benchScale(b, srcUniform, 200, 150, ApproxBiLinear) }
