// 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" + "\"math\"\n" + "\n" + "\"golang.org/x/image/math/f64\"\n" + ")\n") gen(w, "nnInterpolator", codeNNScaleLeaf, codeNNTransformLeaf) gen(w, "ablInterpolator", codeABLScaleLeaf, codeABLTransformLeaf) 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) } } var ( // dsTypes are the (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 *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"}, {"*image.RGBA", "*image.YCbCr"}, {"*image.RGBA", "image.Image"}, {"Image", "image.Image"}, } dTypes, sTypes []string sTypesForDType = map[string][]string{} subsampleRatios = []string{ "444", "422", "420", "440", } ) func init() { dTypesSeen := map[string]bool{} sTypesSeen := map[string]bool{} for _, t := range dsTypes { if !sTypesSeen[t.sType] { sTypesSeen[t.sType] = true sTypes = append(sTypes, t.sType) } if !dTypesSeen[t.dType] { dTypesSeen[t.dType] = true dTypes = append(dTypes, t.dType) } sTypesForDType[t.dType] = append(sTypesForDType[t.dType], t.sType) } sTypesForDType["anyDType"] = sTypes } type data struct { dType string sType string sratio string receiver string } func gen(w *bytes.Buffer, receiver string, codes ...string) { expn(w, codeRoot, &data{receiver: receiver}) for _, code := range codes { for _, t := range dsTypes { expn(w, code, &data{ dType: t.dType, sType: t.sType, receiver: receiver, }) } } } func genKernel(w *bytes.Buffer) { expn(w, codeKernelRoot, &data{}) for _, sType := range sTypes { expn(w, codeKernelScaleLeafX, &data{ sType: sType, }) } for _, dType := range dTypes { expn(w, codeKernelScaleLeafY, &data{ dType: dType, }) } for _, t := range dsTypes { expn(w, codeKernelTransformLeaf, &data{ dType: t.dType, sType: t.sType, }) } } func expn(w *bytes.Buffer, code string, d *data) { if d.sType == "*image.YCbCr" && d.sratio == "" { for _, sratio := range subsampleRatios { e := *d e.sratio = sratio expn(w, code, &e) } return } for _, line := range strings.Split(code, "\n") { line = expnLine(line, d) if line == ";" { continue } fmt.Fprintln(w, line) } } func expnLine(line string, d *data) string { for { i := strings.IndexByte(line, '$') if i < 0 { break } prefix, s := line[:i], line[i+1:] i = len(s) for j, c := range s { if !('A' <= c && c <= 'Z' || 'a' <= c && c <= 'z') { i = j break } } dollar, suffix := s[:i], s[i:] e := expnDollar(prefix, dollar, suffix, d) if e == "" { log.Fatalf("couldn't expand %q", line) } line = e } return line } // expnDollar expands a "$foo" fragment in a line of generated code. It returns // the empty string if there was a problem. It returns ";" if the generated // code is a no-op. func expnDollar(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 "sratio": return prefix + d.sratio + suffix case "sType": return prefix + d.sType + suffix case "sTypeRN": return prefix + relName(d.sType) + suffix case "receiver": return prefix + d.receiver + suffix case "switch": return expnSwitch("", true, suffix) case "switchD": return expnSwitch("", false, suffix) case "switchS": return expnSwitch("anyDType", false, suffix) case "preOuter": switch d.dType { default: return ";" case "Image": return "" + "dstColorRGBA64 := &color.RGBA64{}\n" + "dstColor := color.Color(dstColorRGBA64)" } case "preInner": switch d.dType { default: return ";" case "*image.RGBA": return "d := dst.PixOffset(dr.Min.X+adr.Min.X, dr.Min.Y+int(dy))" } case "preKernelInner": switch d.dType { default: return ";" case "*image.RGBA": return "d := dst.PixOffset(dr.Min.X+int(dx), dr.Min.Y+adr.Min.Y)" } case "blend": args, _ := splitArgs(suffix) if len(args) != 4 { return "" } switch d.sType { default: 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 "*image.Gray": return fmt.Sprintf(""+ "%sr = %s*%sr + %s*%sr", 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": switch d.sType { default: 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(%s, %s, dstColor)", args[2], args[2], args[2], args[2], args[0], args[1], ) case "*image.Gray": return fmt.Sprintf(""+ "out := uint16(%sr)\n"+ "dstColorRGBA64.R = out\n"+ "dstColorRGBA64.G = out\n"+ "dstColorRGBA64.B = out\n"+ "dstColorRGBA64.A = 0xffff\n"+ "dst.Set(%s, %s, dstColor)", args[2], args[0], args[1], ) } case "*image.RGBA": switch d.sType { default: return fmt.Sprintf(""+ "dst.Pix[d+0] = uint8(uint32(%sr) >> 8)\n"+ "dst.Pix[d+1] = uint8(uint32(%sg) >> 8)\n"+ "dst.Pix[d+2] = uint8(uint32(%sb) >> 8)\n"+ "dst.Pix[d+3] = uint8(uint32(%sa) >> 8)", args[2], args[2], args[2], args[2], ) case "*image.Gray": return fmt.Sprintf(""+ "out := uint8(uint32(%sr) >> 8)\n"+ "dst.Pix[d+0] = out\n"+ "dst.Pix[d+1] = out\n"+ "dst.Pix[d+2] = out\n"+ "dst.Pix[d+3] = 0xff", args[2], ) } } case "outputf": args, _ := splitArgs(suffix) if len(args) != 5 { return "" } ret := "" switch d.dType { default: log.Fatalf("bad dType %q", d.dType) case "Image": switch d.sType { default: ret = fmt.Sprintf(""+ "dstColorRGBA64.R = %s(%sr * %s)\n"+ "dstColorRGBA64.G = %s(%sg * %s)\n"+ "dstColorRGBA64.B = %s(%sb * %s)\n"+ "dstColorRGBA64.A = %s(%sa * %s)\n"+ "dst.Set(%s, %s, dstColor)", args[2], args[3], args[4], args[2], args[3], args[4], args[2], args[3], args[4], args[2], args[3], args[4], args[0], args[1], ) case "*image.Gray": ret = fmt.Sprintf(""+ "out := %s(%sr * %s)\n"+ "dstColorRGBA64.R = out\n"+ "dstColorRGBA64.G = out\n"+ "dstColorRGBA64.B = out\n"+ "dstColorRGBA64.A = 0xffff\n"+ "dst.Set(%s, %s, dstColor)", args[2], args[3], args[4], args[0], args[1], ) } case "*image.RGBA": switch d.sType { default: ret = fmt.Sprintf(""+ "dst.Pix[d+0] = uint8(%s(%sr * %s) >> 8)\n"+ "dst.Pix[d+1] = uint8(%s(%sg * %s) >> 8)\n"+ "dst.Pix[d+2] = uint8(%s(%sb * %s) >> 8)\n"+ "dst.Pix[d+3] = uint8(%s(%sa * %s) >> 8)", args[2], args[3], args[4], args[2], args[3], args[4], args[2], args[3], args[4], args[2], args[3], args[4], ) case "*image.Gray": ret = fmt.Sprintf(""+ "out := uint8(%s(%sr * %s) >> 8)\n"+ "dst.Pix[d+0] = out\n"+ "dst.Pix[d+1] = out\n"+ "dst.Pix[d+2] = out\n"+ "dst.Pix[d+3] = 0xff", args[2], args[3], args[4], ) } } return strings.Replace(ret, " * 1)", ")", -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", "*image.Uniform", "*image.YCbCr": // TODO: separate code for concrete types. fmt.Fprintf(buf, "%sr%s, %sg%s, %sb%s, %sa%s := "+ "src.At(%s, %s).RGBA()\n", lhs, tmp, lhs, tmp, lhs, tmp, lhs, tmp, args[0], args[1], ) case "*image.Gray": // 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(%s, %s)\n"+ "%sr%s := uint32(src.Pix[%si]) * 0x101\n", lhs, args[0], args[1], lhs, tmp, lhs, ) case "*image.NRGBA": // 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(%s, %s)\n"+ "%sa%s := uint32(src.Pix[%si+3]) * 0x101\n"+ "%sr%s := uint32(src.Pix[%si+0]) * %sa%s / 0xff\n"+ "%sg%s := uint32(src.Pix[%si+1]) * %sa%s / 0xff\n"+ "%sb%s := uint32(src.Pix[%si+2]) * %sa%s / 0xff\n", lhs, args[0], args[1], lhs, tmp, lhs, lhs, tmp, lhs, lhs, tmp, lhs, tmp, lhs, lhs, tmp, lhs, tmp, lhs, lhs, tmp, ) 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(%s, %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"+ "%sa%s := uint32(src.Pix[%si+3]) * 0x101\n", lhs, args[0], args[1], lhs, tmp, lhs, lhs, tmp, lhs, lhs, tmp, lhs, lhs, tmp, lhs, ) } if dollar == "srcf" { switch d.sType { default: 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, ) case "*image.Gray": fmt.Fprintf(buf, ""+ "%sr %s float64(%sru)%s\n", lhs, eqOp, lhs, extra, ) } } return strings.TrimSpace(buf.String()) case "tweakD": if d.dType == "*image.RGBA" { return "d += dst.Stride" } return ";" case "tweakDx": if d.dType == "*image.RGBA" { return strings.Replace(prefix, "dx++", "dx, d = dx+1, d+4", 1) } return prefix case "tweakDy": if d.dType == "*image.RGBA" { return strings.Replace(prefix, "for dy, s", "for _, s", 1) } return prefix case "tweakP": if d.sType == "*image.Gray" { if strings.HasPrefix(strings.TrimSpace(prefix), "pa * ") { return "1," } return "pr," } return prefix case "tweakPr": if d.sType == "*image.Gray" { return "pr *= s.invTotalWeightFFFF" } return ";" case "tweakVarP": if d.sType == "*image.Gray" { return strings.Replace(prefix, "var pr, pg, pb, pa", "var pr", 1) } return prefix } return "" } func expnSwitch(dType string, expandBoth bool, template string) string { switchVar := "dst" if dType != "" { switchVar = "src" } lines := []string{fmt.Sprintf("switch %s := %s.(type) {", switchVar, switchVar)} fallback, values := "Image", dTypes if dType != "" { fallback, values = "image.Image", sTypesForDType[dType] } for _, v := range values { if v == fallback { lines = append(lines, "default:") } else { lines = append(lines, fmt.Sprintf("case %s:", v)) } if dType != "" { if v == "*image.YCbCr" { lines = append(lines, expnSwitchYCbCr(dType, template)) } else { lines = append(lines, expnLine(template, &data{dType: dType, sType: v})) } } else if !expandBoth { lines = append(lines, expnLine(template, &data{dType: v})) } else { lines = append(lines, expnSwitch(v, false, template)) } } lines = append(lines, "}") return strings.Join(lines, "\n") } func expnSwitchYCbCr(dType, template string) string { lines := []string{ "switch src.SubsampleRatio {", "default:", expnLine(template, &data{dType: dType, sType: "image.Image"}), } for _, sratio := range subsampleRatios { lines = append(lines, fmt.Sprintf("case image.YCbCrSubsampleRatio%s:", sratio), expnLine(template, &data{dType: dType, sType: "*image.YCbCr", sratio: sratio}), ) } lines = append(lines, "}") return strings.Join(lines, "\n") } 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, dr image.Rectangle, src image.Image, sr image.Rectangle, opts *Options) { // 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.In(src.Bounds()) { z.scale_Image_Image(dst, dr, adr, src, sr) } else { $switch z.scale_$dTypeRN_$sTypeRN$sratio(dst, dr, adr, src, sr) } } func (z $receiver) Transform(dst Image, s2d *f64.Aff3, src image.Image, sr image.Rectangle, opts *Options) { dr := transformRect(s2d, &sr) // adr is the affected destination pixels, relative to dr.Min. adr := dst.Bounds().Intersect(dr).Sub(dr.Min) if adr.Empty() || sr.Empty() { return } d2s := invert(s2d) // 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.In(src.Bounds()) { z.transform_Image_Image(dst, dr, adr, &d2s, src, sr) } else { $switch z.transform_$dTypeRN_$sTypeRN$sratio(dst, dr, adr, &d2s, src, sr) } } ` codeNNScaleLeaf = ` func (nnInterpolator) scale_$dTypeRN_$sTypeRN$sratio(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) * sh / dh2 $preInner for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ { $tweakDx sx := (2*uint64(dx) + 1) * sw / dw2 p := $srcu[sr.Min.X + int(sx), sr.Min.Y + int(sy)] $outputu[dr.Min.X + int(dx), dr.Min.Y + int(dy), p] } } } ` codeNNTransformLeaf = ` func (nnInterpolator) transform_$dTypeRN_$sTypeRN$sratio(dst $dType, dr, adr image.Rectangle, d2s *f64.Aff3, src $sType, sr image.Rectangle) { $preOuter for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ { dyf := float64(dr.Min.Y + int(dy)) + 0.5 $preInner for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ { $tweakDx dxf := float64(dr.Min.X + int(dx)) + 0.5 // TODO: change the src origin so that we can say int(f) instead of int(math.Floor(f)). sx0 := int(math.Floor(d2s[0]*dxf + d2s[1]*dyf + d2s[2])) sy0 := int(math.Floor(d2s[3]*dxf + d2s[4]*dyf + d2s[5])) if !(image.Point{sx0, sy0}).In(sr) { continue } p := $srcu[sx0, sy0] $outputu[dr.Min.X + int(dx), dr.Min.Y + int(dy), p] } } } ` codeABLScaleLeaf = ` func (ablInterpolator) scale_$dTypeRN_$sTypeRN$sratio(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()) swMinus1, shMinus1 := sw - 1, sh - 1 $preOuter for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ { sy := (float64(dy)+0.5)*yscale - 0.5 // If sy < 0, we will clamp sy0 to 0 anyway, so it doesn't matter if // we say int32(sy) instead of int32(math.Floor(sy)). Similarly for // sx, below. 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 > shMinus1 { sy0, sy1 = shMinus1, shMinus1 yFrac0, yFrac1 = 1, 0 } $preInner for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ { $tweakDx 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 > swMinus1 { sx0, sx1 = swMinus1, swMinus1 xFrac0, xFrac1 = 1, 0 } s00 := $srcf[sr.Min.X + int(sx0), sr.Min.Y + int(sy0)] s10 := $srcf[sr.Min.X + int(sx1), sr.Min.Y + int(sy0)] $blend[xFrac1, s00, xFrac0, s10] s01 := $srcf[sr.Min.X + int(sx0), sr.Min.Y + int(sy1)] s11 := $srcf[sr.Min.X + int(sx1), sr.Min.Y + int(sy1)] $blend[xFrac1, s01, xFrac0, s11] $blend[yFrac1, s10, yFrac0, s11] $outputu[dr.Min.X + int(dx), dr.Min.Y + int(dy), s11] } } } ` codeABLTransformLeaf = ` func (ablInterpolator) transform_$dTypeRN_$sTypeRN$sratio(dst $dType, dr, adr image.Rectangle, d2s *f64.Aff3, src $sType, sr image.Rectangle) { $preOuter for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ { dyf := float64(dr.Min.Y + int(dy)) + 0.5 $preInner for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ { $tweakDx dxf := float64(dr.Min.X + int(dx)) + 0.5 // TODO: change the src origin so that we can say int(f) instead of int(math.Floor(f)). sx := d2s[0]*dxf + d2s[1]*dyf + d2s[2] sy := d2s[3]*dxf + d2s[4]*dyf + d2s[5] if !(image.Point{int(math.Floor(sx)), int(math.Floor(sy))}).In(sr) { continue } sx -= 0.5 sxf := math.Floor(sx) xFrac0 := sx - sxf xFrac1 := 1 - xFrac0 sx0 := int(sxf) sx1 := sx0 + 1 if sx0 < sr.Min.X { sx0, sx1 = sr.Min.X, sr.Min.X xFrac0, xFrac1 = 0, 1 } else if sx1 >= sr.Max.X { sx0, sx1 = sr.Max.X-1, sr.Max.X-1 xFrac0, xFrac1 = 1, 0 } sy -= 0.5 syf := math.Floor(sy) yFrac0 := sy - syf yFrac1 := 1 - yFrac0 sy0 := int(syf) sy1 := sy0 + 1 if sy0 < sr.Min.Y { sy0, sy1 = sr.Min.Y, sr.Min.Y yFrac0, yFrac1 = 0, 1 } else if sy1 >= sr.Max.Y { sy0, sy1 = sr.Max.Y-1, sr.Max.Y-1 yFrac0, yFrac1 = 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[dr.Min.X + int(dx), dr.Min.Y + int(dy), s11] } } } ` codeKernelRoot = ` func (z *kernelScaler) Scale(dst Image, dr image.Rectangle, src image.Image, sr image.Rectangle, opts *Options) { 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, opts) return } // 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: // 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) // 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.In(src.Bounds()) { z.scaleX_Image(tmp, src, sr) } else { $switchS z.scaleX_$sTypeRN$sratio(tmp, src, sr) } $switchD z.scaleY_$dTypeRN(dst, dr, adr, tmp) } func (q *Kernel) Transform(dst Image, s2d *f64.Aff3, src image.Image, sr image.Rectangle, opts *Options) { dr := transformRect(s2d, &sr) // adr is the affected destination pixels, relative to dr.Min. adr := dst.Bounds().Intersect(dr).Sub(dr.Min) if adr.Empty() || sr.Empty() { return } d2s := invert(s2d) xscale := abs(d2s[0]) if s := abs(d2s[1]); xscale < s { xscale = s } yscale := abs(d2s[3]) if s := abs(d2s[4]); yscale < s { yscale = s } // 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.In(src.Bounds()) { q.transform_Image_Image(dst, dr, adr, &d2s, src, sr, xscale, yscale) } else { $switch q.transform_$dTypeRN_$sTypeRN$sratio(dst, dr, adr, &d2s, src, sr, xscale, yscale) } } ` codeKernelScaleLeafX = ` func (z *kernelScaler) scaleX_$sTypeRN$sratio(tmp [][4]float64, src $sType, 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 $tweakVarP for _, c := range z.horizontal.contribs[s.i:s.j] { p += $srcf[sr.Min.X + int(c.coord), sr.Min.Y + int(y)] * c.weight } $tweakPr tmp[t] = [4]float64{ pr * s.invTotalWeightFFFF, $tweakP pg * s.invTotalWeightFFFF, $tweakP pb * s.invTotalWeightFFFF, $tweakP pa * s.invTotalWeightFFFF, $tweakP } t++ } } } ` codeKernelScaleLeafY = ` func (z *kernelScaler) scaleY_$dTypeRN(dst $dType, dr, adr image.Rectangle, tmp [][4]float64) { $preOuter for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ { $preKernelInner for dy, s := range z.vertical.sources[adr.Min.Y:adr.Max.Y] { $tweakDy var pr, pg, pb, pa float64 for _, c := range z.vertical.contribs[s.i:s.j] { p := &tmp[c.coord*z.dw+dx] pr += p[0] * c.weight pg += p[1] * c.weight pb += p[2] * c.weight pa += p[3] * c.weight } $outputf[dr.Min.X + int(dx), dr.Min.Y + int(adr.Min.Y + dy), ftou, p, s.invTotalWeight] $tweakD } } } ` codeKernelTransformLeaf = ` func (q *Kernel) transform_$dTypeRN_$sTypeRN$sratio(dst $dType, dr, adr image.Rectangle, d2s *f64.Aff3, src $sType, sr image.Rectangle, xscale, yscale float64) { // When shrinking, broaden the effective kernel support so that we still // visit every source pixel. xHalfWidth, xKernelArgScale := q.Support, 1.0 if xscale > 1 { xHalfWidth *= xscale xKernelArgScale = 1 / xscale } yHalfWidth, yKernelArgScale := q.Support, 1.0 if yscale > 1 { yHalfWidth *= yscale yKernelArgScale = 1 / yscale } xWeights := make([]float64, 1 + 2*int(math.Ceil(xHalfWidth))) yWeights := make([]float64, 1 + 2*int(math.Ceil(yHalfWidth))) $preOuter for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ { dyf := float64(dr.Min.Y + int(dy)) + 0.5 $preInner for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ { $tweakDx dxf := float64(dr.Min.X + int(dx)) + 0.5 // TODO: change the src origin so that we can say int(f) instead of int(math.Floor(f)). sx := d2s[0]*dxf + d2s[1]*dyf + d2s[2] sy := d2s[3]*dxf + d2s[4]*dyf + d2s[5] if !(image.Point{int(math.Floor(sx)), int(math.Floor(sy))}).In(sr) { continue } sx -= 0.5 ix := int(math.Floor(sx - xHalfWidth)) if ix < sr.Min.X { ix = sr.Min.X } jx := int(math.Ceil(sx + xHalfWidth)) if jx > sr.Max.X { jx = sr.Max.X } totalXWeight := 0.0 for kx := ix; kx < jx; kx++ { xWeight := 0.0 if t := abs((sx - float64(kx)) * xKernelArgScale); t < q.Support { xWeight = q.At(t) } xWeights[kx - ix] = xWeight totalXWeight += xWeight } for x := range xWeights[:jx-ix] { xWeights[x] /= totalXWeight } sy -= 0.5 iy := int(math.Floor(sy - yHalfWidth)) if iy < sr.Min.Y { iy = sr.Min.Y } jy := int(math.Ceil(sy + yHalfWidth)) if jy > sr.Max.Y { jy = sr.Max.Y } totalYWeight := 0.0 for ky := iy; ky < jy; ky++ { yWeight := 0.0 if t := abs((sy - float64(ky)) * yKernelArgScale); t < q.Support { yWeight = q.At(t) } yWeights[ky - iy] = yWeight totalYWeight += yWeight } for y := range yWeights[:jy-iy] { yWeights[y] /= totalYWeight } var pr, pg, pb, pa float64 $tweakVarP for ky := iy; ky < jy; ky++ { yWeight := yWeights[ky - iy] for kx := ix; kx < jx; kx++ { w := xWeights[kx - ix] * yWeight p += $srcf[kx, ky] * w } } $outputf[dr.Min.X + int(dx), dr.Min.Y + int(dy), fffftou, p, 1] } } } ` )