draw: autogenerate impl.go.
Adding fast paths for concrete dst and src image types will be follow-up
changes.
Change-Id: Ib23e3cc46d9c7a52ebd5eddfbad09177b0b421af
Reviewed-on: https://go-review.googlesource.com/5417
Reviewed-by: Rob Pike <r@golang.org>
diff --git a/draw/gen.go b/draw/gen.go
new file mode 100644
index 0000000..4ba769a
--- /dev/null
+++ b/draw/gen.go
@@ -0,0 +1,410 @@
+// 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.
+
+// +build ignore
+
+package main
+
+import (
+ "bytes"
+ "flag"
+ "fmt"
+ "go/format"
+ "io/ioutil"
+ "log"
+ "os"
+ "strings"
+)
+
+var debug = flag.Bool("debug", false, "")
+
+func main() {
+ flag.Parse()
+
+ w := new(bytes.Buffer)
+ 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)
+ genKernel(w)
+
+ if *debug {
+ os.Stdout.Write(w.Bytes())
+ return
+ }
+ out, err := format.Source(w.Bytes())
+ if err != nil {
+ log.Fatal(err)
+ }
+ if err := ioutil.WriteFile("impl.go", out, 0660); err != nil {
+ log.Fatal(err)
+ }
+}
+
+// dsTypes are the space-separated (dst image type, src image type) pairs to
+// generate scale_DType_SType implementations for. The last element in the
+// slice should be the fallback pair "Image image.Image".
+//
+// TODO: add more concrete types: *image.RGBA, *image.YCbCr, etc.
+var dsTypes = []string{
+ "Image image.Image",
+}
+
+type data struct {
+ dType string
+ sType string
+ receiver string
+}
+
+func gen(w *bytes.Buffer, receiver string, code string) {
+ expn(w, codeRoot, &data{receiver: receiver})
+
+ for _, dsType := range dsTypes {
+ dType, sType := split(dsType, " ")
+ expn(w, code, &data{
+ dType: dType,
+ sType: sType,
+ receiver: receiver,
+ })
+ }
+}
+
+func genKernel(w *bytes.Buffer) {
+ expn(w, codeKernelRoot, &data{})
+
+ dTypesSeen := map[string]bool{}
+ sTypesSeen := map[string]bool{}
+ for _, dsType := range dsTypes {
+ dType, sType := split(dsType, " ")
+ if !sTypesSeen[sType] {
+ sTypesSeen[sType] = true
+ expn(w, codeKernelLeafX, &data{
+ sType: sType,
+ })
+ }
+ if !dTypesSeen[dType] {
+ dTypesSeen[dType] = true
+ expn(w, codeKernelLeafY, &data{
+ dType: dType,
+ })
+ }
+ }
+}
+
+func expn(w *bytes.Buffer, code string, d *data) {
+ for _, line := range strings.Split(code, "\n") {
+ for {
+ i := strings.IndexByte(line, '$')
+ if i < 0 {
+ break
+ }
+ prefix, s := line[:i], line[i+1:]
+
+ i = len(s)
+ for j, c := range s {
+ if !('A' <= c && c <= 'Z' || 'a' <= c && c <= 'z') {
+ i = j
+ break
+ }
+ }
+ dollar, suffix := s[:i], s[i:]
+
+ e := expnLine(prefix, dollar, suffix, d)
+ if e == "" {
+ log.Fatalf("couldn't expand %q", line)
+ }
+ line = e
+ }
+ fmt.Fprintln(w, line)
+ }
+}
+
+func expnLine(prefix, dollar, suffix string, d *data) string {
+ switch dollar {
+ case "dType":
+ return prefix + d.dType + suffix
+ case "dTypeRN":
+ return prefix + relName(d.dType) + suffix
+ case "sType":
+ return prefix + d.sType + suffix
+ case "sTypeRN":
+ return prefix + relName(d.sType) + suffix
+ case "receiver":
+ return prefix + d.receiver + suffix
+
+ case "dstColorDecl":
+ if d.dType == "Image" {
+ return "dstColorRGBA64 := &color.RGBA64{}\n" +
+ "dstColor := color.Color(dstColorRGBA64)"
+ }
+ return ";"
+
+ case "blend":
+ args, _ := splitArgs(suffix)
+ if len(args) != 4 {
+ return ""
+ }
+ return fmt.Sprintf(""+
+ "%sr = %s*%sr + %s*%sr\n"+
+ "%sg = %s*%sg + %s*%sg\n"+
+ "%sb = %s*%sb + %s*%sb\n"+
+ "%sa = %s*%sa + %s*%sa",
+ args[3], args[0], args[1], args[2], args[3],
+ args[3], args[0], args[1], args[2], args[3],
+ args[3], args[0], args[1], args[2], args[3],
+ args[3], args[0], args[1], args[2], args[3],
+ )
+
+ case "outputu":
+ args, _ := splitArgs(suffix)
+ if len(args) != 3 {
+ return ""
+ }
+ switch d.dType {
+ default:
+ log.Fatalf("bad dType %q", d.dType)
+ case "Image":
+ return fmt.Sprintf(""+
+ "dstColorRGBA64.R = uint16(%sr)\n"+
+ "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)",
+ args[2], args[2], args[2], args[2],
+ args[0], args[1],
+ )
+ }
+
+ case "outputf":
+ args, _ := splitArgs(suffix)
+ if len(args) != 4 {
+ return ""
+ }
+ switch d.dType {
+ default:
+ log.Fatalf("bad dType %q", d.dType)
+ case "Image":
+ return fmt.Sprintf(""+
+ "dstColorRGBA64.R = ftou(%sr * %s)\n"+
+ "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)",
+ args[2], args[3], args[2], args[3], args[2], args[3], args[2], args[3],
+ args[0], args[1],
+ )
+ }
+
+ case "srcf", "srcu":
+ lhs, eqOp := splitEq(prefix)
+ if lhs == "" {
+ return ""
+ }
+ args, extra := splitArgs(suffix)
+ if len(args) != 2 {
+ return ""
+ }
+
+ tmp := ""
+ if dollar == "srcf" {
+ tmp = "u"
+ }
+
+ buf := new(bytes.Buffer)
+ switch d.sType {
+ default:
+ log.Fatalf("bad sType %q", d.sType)
+ case "image.Image":
+ 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, args[0], args[1])
+ }
+
+ if dollar == "srcf" {
+ fmt.Fprintf(buf, ""+
+ "%sr %s float64(%sru)%s\n"+
+ "%sg %s float64(%sgu)%s\n"+
+ "%sb %s float64(%sbu)%s\n"+
+ "%sa %s float64(%sau)%s\n",
+ lhs, eqOp, lhs, extra,
+ lhs, eqOp, lhs, extra,
+ lhs, eqOp, lhs, extra,
+ lhs, eqOp, lhs, extra,
+ )
+ }
+
+ return strings.TrimSpace(buf.String())
+ }
+ return ""
+}
+
+func split(s, sep string) (string, string) {
+ if i := strings.Index(s, sep); i >= 0 {
+ return strings.TrimSpace(s[:i]), strings.TrimSpace(s[i+len(sep):])
+ }
+ return "", ""
+}
+
+func splitEq(s string) (lhs, eqOp string) {
+ s = strings.TrimSpace(s)
+ if lhs, _ = split(s, ":="); lhs != "" {
+ return lhs, ":="
+ }
+ if lhs, _ = split(s, "+="); lhs != "" {
+ return lhs, "+="
+ }
+ return "", ""
+}
+
+func splitArgs(s string) (args []string, extra string) {
+ s = strings.TrimSpace(s)
+ if s == "" || s[0] != '[' {
+ return nil, ""
+ }
+ s = s[1:]
+
+ i := strings.IndexByte(s, ']')
+ if i < 0 {
+ return nil, ""
+ }
+ args, extra = strings.Split(s[:i], ","), s[i+1:]
+ for i := range args {
+ args[i] = strings.TrimSpace(args[i])
+ }
+ return args, extra
+}
+
+func relName(s string) string {
+ if i := strings.LastIndex(s, "."); i >= 0 {
+ return s[i+1:]
+ }
+ return s
+}
+
+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
+ }
+ // TODO: generate type switches for the different dsTypes.
+ z.scale_Image_Image(dst, dp, src, sp)
+ }
+ `
+
+ codeNNLeaf = `
+ func (z *nnScaler) scale_$dTypeRN_$sTypeRN(dst $dType, dp image.Point, src $sType, sp image.Point) {
+ $dstColorDecl
+ 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))
+ p := $srcu[sx, sy]
+ $outputu[dx, dy, p]
+ }
+ }
+ }
+ `
+
+ codeABLLeaf = `
+ func (z *ablScaler) scale_$dTypeRN_$sTypeRN(dst $dType, dp image.Point, src $sType, sp image.Point) {
+ yscale := float64(z.sh) / float64(z.dh)
+ xscale := float64(z.sw) / float64(z.dw)
+ $dstColorDecl
+ 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
+ }
+ s00 := $srcf[sx0, sy0]
+ s10 := $srcf[sx1, sy0]
+ $blend[xFrac1, s00, xFrac0, s10]
+ s01 := $srcf[sx0, sy1]
+ s11 := $srcf[sx1, sy1]
+ $blend[xFrac1, s01, xFrac0, s11]
+ $blend[yFrac1, s10, yFrac0, s11]
+ $outputu[dx, dy, s11]
+ }
+ }
+ }
+ `
+
+ codeKernelRoot = `
+ func (z *kernelScaler) Scale(dst Image, dp image.Point, src image.Image, sp image.Point) {
+ if z.dw <= 0 || z.dh <= 0 || z.sw <= 0 || z.sh <= 0 {
+ return
+ }
+ // Create a temporary buffer:
+ // scaleX distributes the source image's columns over the temporary image.
+ // scaleY distributes the temporary image's rows over the destination image.
+ // TODO: is it worth having a sync.Pool for this temporary buffer?
+ tmp := make([][4]float64, z.dw*z.sh)
+ // TODO: generate type switches for the different dTypes and sTypes.
+ z.scaleX_Image(tmp, src, sp)
+ z.scaleY_Image(dst, dp, tmp)
+ }
+ `
+
+ codeKernelLeafX = `
+ func (z *kernelScaler) scaleX_$sTypeRN(tmp [][4]float64, src $sType, 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] {
+ p += $srcf[c.coord, y] * c.weight
+ }
+ tmp[t] = [4]float64{
+ pr * s.invTotalWeightFFFF,
+ pg * s.invTotalWeightFFFF,
+ pb * s.invTotalWeightFFFF,
+ pa * s.invTotalWeightFFFF,
+ }
+ t++
+ }
+ }
+ }
+ `
+
+ codeKernelLeafY = `
+ func (z *kernelScaler) scaleY_$dTypeRN(dst $dType, dp image.Point, tmp [][4]float64) {
+ $dstColorDecl
+ for x := int32(0); x < z.dw; x++ {
+ for y, s := range z.vertical.sources {
+ var pr, pg, pb, pa float64
+ for _, c := range z.vertical.contribs[s.i:s.j] {
+ p := &tmp[c.coord*z.dw+x]
+ pr += p[0] * c.weight
+ pg += p[1] * c.weight
+ pb += p[2] * c.weight
+ pa += p[3] * c.weight
+ }
+ $outputf[x, y, p, s.invTotalWeight]
+ }
+ }
+ }
+ `
+)
diff --git a/draw/impl.go b/draw/impl.go
index c59ba87..cf164aa 100644
--- a/draw/impl.go
+++ b/draw/impl.go
@@ -1,11 +1,7 @@
-// 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.
+// generated by "go run gen.go". DO NOT EDIT.
package draw
-// TODO: autogenerate this file.
-
import (
"image"
"image/color"
@@ -15,6 +11,11 @@
if z.dw <= 0 || z.dh <= 0 || z.sw <= 0 || z.sh <= 0 {
return
}
+ // TODO: generate type switches for the different dsTypes.
+ z.scale_Image_Image(dst, dp, src, sp)
+}
+
+func (z *nnScaler) scale_Image_Image(dst Image, dp image.Point, src image.Image, sp image.Point) {
dstColorRGBA64 := &color.RGBA64{}
dstColor := color.Color(dstColorRGBA64)
for dy := int32(0); dy < z.dh; dy++ {
@@ -35,6 +36,11 @@
if z.dw <= 0 || z.dh <= 0 || z.sw <= 0 || z.sh <= 0 {
return
}
+ // TODO: generate type switches for the different dsTypes.
+ z.scale_Image_Image(dst, dp, src, sp)
+}
+
+func (z *ablScaler) scale_Image_Image(dst Image, dp image.Point, src image.Image, sp image.Point) {
yscale := float64(z.sh) / float64(z.dh)
xscale := float64(z.sw) / float64(z.dw)
dstColorRGBA64 := &color.RGBA64{}
@@ -115,51 +121,52 @@
// 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)
+ // TODO: generate type switches for the different dTypes and sTypes.
+ z.scaleX_Image(tmp, src, sp)
+ z.scaleY_Image(dst, dp, tmp)
}
-func (z *kernelScaler) scaleX(tmp [][4]float64, src image.Image, sp image.Point) {
+func (z *kernelScaler) scaleX_Image(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
+ var pr, pg, pb, pa 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
+ 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{
- r * s.invTotalWeightFFFF,
- g * s.invTotalWeightFFFF,
- b * s.invTotalWeightFFFF,
- a * s.invTotalWeightFFFF,
+ pr * s.invTotalWeightFFFF,
+ pg * s.invTotalWeightFFFF,
+ pb * s.invTotalWeightFFFF,
+ pa * s.invTotalWeightFFFF,
}
t++
}
}
}
-func (z *kernelScaler) scaleY(dst Image, dp image.Point, tmp [][4]float64) {
+func (z *kernelScaler) scaleY_Image(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
+ var pr, pg, pb, pa 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
+ pr += p[0] * c.weight
+ pg += p[1] * c.weight
+ pb += p[2] * c.weight
+ pa += 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)
+ dstColorRGBA64.R = ftou(pr * s.invTotalWeight)
+ dstColorRGBA64.G = ftou(pg * s.invTotalWeight)
+ dstColorRGBA64.B = ftou(pb * s.invTotalWeight)
+ dstColorRGBA64.A = ftou(pa * s.invTotalWeight)
+ dst.Set(dp.X+int(x), dp.Y+int(y), dstColor)
}
}
}
diff --git a/draw/scale.go b/draw/scale.go
index b3aaf7e..53ec801 100644
--- a/draw/scale.go
+++ b/draw/scale.go
@@ -2,6 +2,8 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
+//go:generate go run gen.go
+
package draw
// TODO: should Scale and NewScaler also take an Op argument?
