golang-image/draw/gen.go
Nigel Tao b293696c81 draw: switch on the Op compositing operator.
This change only *prepares* the codegen to handle multiple Ops. The
actual generated code still only supports one Op (Src) and not the other
(Over). A follow-up change will add Over.

This Op switch (an eventual x2 multiplier in the amount of code
generated) should be the last of the codegen LoC multipliers. The dst
and src mask options will be implemented in the slow path fallback.

Change-Id: Iecbcc6fad063e2aac36d78d5380c0a0947c709df
Reviewed-on: https://go-review.googlesource.com/8488
Reviewed-by: Rob Pike <r@golang.org>
2015-04-07 06:16:14 +00:00

1184 lines
32 KiB
Go

// 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.YCbCr"},
{"*image.RGBA", "image.Image"},
{"Image", "image.Image"},
}
dTypes, sTypes []string
sTypesForDType = map[string][]string{}
subsampleRatios = []string{
"444",
"422",
"420",
"440",
}
ops = []string{"Src"} // TODO: add "Over".
)
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
op string
}
func gen(w *bytes.Buffer, receiver string, codes ...string) {
expn(w, codeRoot, &data{receiver: receiver})
for _, code := range codes {
for _, t := range dsTypes {
for _, op := range ops {
expn(w, code, &data{
dType: t.dType,
sType: t.sType,
receiver: receiver,
op: op,
})
}
}
}
}
func genKernel(w *bytes.Buffer) {
expn(w, codeKernelRoot, &data{})
for _, sType := range sTypes {
expn(w, codeKernelScaleLeafX, &data{
sType: sType,
})
}
for _, dType := range dTypes {
for _, op := range ops {
expn(w, codeKernelScaleLeafY, &data{
dType: dType,
op: op,
})
}
}
for _, t := range dsTypes {
for _, op := range ops {
expn(w, codeKernelTransformLeaf, &data{
dType: t.dType,
sType: t.sType,
op: op,
})
}
}
}
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 "op":
return prefix + d.op + 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 := " + pixOffset("dst", "dr.Min.X+adr.Min.X", "dr.Min.Y+int(dy)", "*4", "*dst.Stride")
}
case "preKernelInner":
switch d.dType {
default:
return ";"
case "*image.RGBA":
return "d := " + pixOffset("dst", "dr.Min.X+int(dx)", "dr.Min.Y+adr.Min.Y", "*4", "*dst.Stride")
}
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 "*image.YCbCr":
return fmt.Sprintf(""+
"%sr = %s*%sr + %s*%sr\n"+
"%sg = %s*%sg + %s*%sg\n"+
"%sb = %s*%sb + %s*%sb",
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":
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.YCbCr":
return fmt.Sprintf(""+
"dstColorRGBA64.R = uint16(%sr)\n"+
"dstColorRGBA64.G = uint16(%sg)\n"+
"dstColorRGBA64.B = uint16(%sb)\n"+
"dstColorRGBA64.A = 0xffff\n"+
"dst.Set(%s, %s, dstColor)",
args[2], args[2], 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 "*image.YCbCr":
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] = 0xff",
args[2], args[2], 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.YCbCr":
ret = fmt.Sprintf(""+
"dstColorRGBA64.R = %s(%sr * %s)\n"+
"dstColorRGBA64.G = %s(%sg * %s)\n"+
"dstColorRGBA64.B = %s(%sb * %s)\n"+
"dstColorRGBA64.A = 0xffff\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[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],
)
case "*image.YCbCr":
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] = 0xff",
args[2], args[3], args[4],
args[2], args[3], args[4],
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"
}
// TODO: there's no need to multiply by 0x101 in the switch below if
// the next thing we're going to do is shift right by 8.
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(%s, %s).RGBA()\n",
lhs, tmp, lhs, tmp, lhs, tmp, lhs, tmp, args[0], args[1],
)
case "*image.Gray":
fmt.Fprintf(buf, ""+
"%si := %s\n"+
"%sr%s := uint32(src.Pix[%si]) * 0x101\n",
lhs, pixOffset("src", args[0], args[1], "", "*src.Stride"),
lhs, tmp, lhs,
)
case "*image.NRGBA":
fmt.Fprintf(buf, ""+
"%si := %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, pixOffset("src", args[0], args[1], "*4", "*src.Stride"),
lhs, tmp, lhs,
lhs, tmp, lhs, lhs, tmp,
lhs, tmp, lhs, lhs, tmp,
lhs, tmp, lhs, lhs, tmp,
)
case "*image.RGBA":
fmt.Fprintf(buf, ""+
"%si := %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, pixOffset("src", args[0], args[1], "*4", "*src.Stride"),
lhs, tmp, lhs,
lhs, tmp, lhs,
lhs, tmp, lhs,
lhs, tmp, lhs,
)
case "*image.YCbCr":
fmt.Fprintf(buf, ""+
"%si := %s\n"+
"%sj := %s\n"+
"%s\n",
lhs, pixOffset("src", args[0], args[1], "", "*src.YStride"),
lhs, cOffset(args[0], args[1], d.sratio),
ycbcrToRGB(lhs, tmp),
)
}
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,
)
case "*image.YCbCr":
fmt.Fprintf(buf, ""+
"%sr %s float64(%sru)%s\n"+
"%sg %s float64(%sgu)%s\n"+
"%sb %s float64(%sbu)%s\n",
lhs, eqOp, lhs, extra,
lhs, eqOp, lhs, extra,
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":
switch d.sType {
case "*image.Gray":
if strings.HasPrefix(strings.TrimSpace(prefix), "pa * ") {
return "1,"
}
return "pr,"
case "*image.YCbCr":
if strings.HasPrefix(strings.TrimSpace(prefix), "pa * ") {
return "1,"
}
}
return prefix
case "tweakPr":
if d.sType == "*image.Gray" {
return "pr *= s.invTotalWeightFFFF"
}
return ";"
case "tweakVarP":
switch d.sType {
case "*image.Gray":
return strings.Replace(prefix, "var pr, pg, pb, pa", "var pr", 1)
case "*image.YCbCr":
return strings.Replace(prefix, "var pr, pg, pb, pa", "var pr, pg, pb", 1)
}
return prefix
}
return ""
}
func expnSwitch(op, dType string, expandBoth bool, template string) string {
if op == "" && dType != "anyDType" {
lines := []string{"switch opts.op() {"}
for _, op = range ops {
lines = append(lines,
fmt.Sprintf("case %s:", op),
expnSwitch(op, dType, expandBoth, template),
)
}
lines = append(lines, "}")
return strings.Join(lines, "\n")
}
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(op, dType, template))
} else {
lines = append(lines, expnLine(template, &data{dType: dType, sType: v, op: op}))
}
} else if !expandBoth {
lines = append(lines, expnLine(template, &data{dType: v, op: op}))
} else {
lines = append(lines, expnSwitch(op, v, false, template))
}
}
lines = append(lines, "}")
return strings.Join(lines, "\n")
}
func expnSwitchYCbCr(op, dType, template string) string {
lines := []string{
"switch src.SubsampleRatio {",
"default:",
expnLine(template, &data{dType: dType, sType: "image.Image", op: op}),
}
for _, sratio := range subsampleRatios {
lines = append(lines,
fmt.Sprintf("case image.YCbCrSubsampleRatio%s:", sratio),
expnLine(template, &data{dType: dType, sType: "*image.YCbCr", sratio: sratio, op: op}),
)
}
lines = append(lines, "}")
return strings.Join(lines, "\n")
}
func pixOffset(m, x, y, xstride, ystride string) string {
return fmt.Sprintf("(%s-%s.Rect.Min.Y)%s + (%s-%s.Rect.Min.X)%s", y, m, ystride, x, m, xstride)
}
func cOffset(x, y, sratio string) string {
switch sratio {
case "444":
return fmt.Sprintf("( %s - src.Rect.Min.Y )*src.CStride + ( %s - src.Rect.Min.X )", y, x)
case "422":
return fmt.Sprintf("( %s - src.Rect.Min.Y )*src.CStride + ((%s)/2 - src.Rect.Min.X/2)", y, x)
case "420":
return fmt.Sprintf("((%s)/2 - src.Rect.Min.Y/2)*src.CStride + ((%s)/2 - src.Rect.Min.X/2)", y, x)
case "440":
return fmt.Sprintf("((%s)/2 - src.Rect.Min.Y/2)*src.CStride + ( %s - src.Rect.Min.X )", y, x)
}
return fmt.Sprintf("unsupported sratio %q", sratio)
}
func ycbcrToRGB(lhs, tmp string) string {
s := `
// This is an inline version of image/color/ycbcr.go's YCbCr.RGBA method.
$yy1 := int(src.Y[$i])<<16 + 1<<15
$cb1 := int(src.Cb[$j]) - 128
$cr1 := int(src.Cr[$j]) - 128
$r@ := ($yy1 + 91881*$cr1) >> 8
$g@ := ($yy1 - 22554*$cb1 - 46802*$cr1) >> 8
$b@ := ($yy1 + 116130*$cb1) >> 8
if $r@ < 0 {
$r@ = 0
} else if $r@ > 0xffff {
$r@ = 0xffff
}
if $g@ < 0 {
$g@ = 0
} else if $g@ > 0xffff {
$g@ = 0xffff
}
if $b@ < 0 {
$b@ = 0
} else if $b@ > 0xffff {
$b@ = 0xffff
}
`
s = strings.Replace(s, "$", lhs, -1)
s = strings.Replace(s, "@", tmp, -1)
return s
}
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()) {
switch opts.op() {
case Over:
// TODO: z.scale_Image_Image_Over(dst, dr, adr, src, sr)
case Src:
z.scale_Image_Image_Src(dst, dr, adr, src, sr)
}
} else if _, ok := src.(*image.Uniform); ok {
Draw(dst, dr, src, src.Bounds().Min, opts.op())
} else {
$switch z.scale_$dTypeRN_$sTypeRN$sratio_$op(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.
adr := dst.Bounds().Intersect(dr)
if adr.Empty() || sr.Empty() {
return
}
d2s := invert(s2d)
// bias is a translation of the mapping from dst co-ordinates to
// src co-ordinates such that the latter temporarily have
// non-negative X and Y co-ordinates. This allows us to write
// int(f) instead of int(math.Floor(f)), since "round to zero" and
// "round down" are equivalent when f >= 0, but the former is much
// cheaper. The X-- and Y-- are because the TransformLeaf methods
// have a "sx -= 0.5" adjustment.
bias := transformRect(&d2s, &adr).Min
bias.X--
bias.Y--
d2s[2] -= float64(bias.X)
d2s[5] -= float64(bias.Y)
// Make adr relative to dr.Min.
adr = adr.Sub(dr.Min)
// 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()) {
switch opts.op() {
case Over:
// TODO: z.transform_Image_Image_Over(dst, dr, adr, &d2s, src, sr, bias)
case Src:
z.transform_Image_Image_Src(dst, dr, adr, &d2s, src, sr, bias)
}
} else if u, ok := src.(*image.Uniform); ok {
transform_Uniform(dst, dr, adr, &d2s, u, sr, bias, opts.op())
} else {
$switch z.transform_$dTypeRN_$sTypeRN$sratio_$op(dst, dr, adr, &d2s, src, sr, bias)
}
}
`
codeNNScaleLeaf = `
func (nnInterpolator) scale_$dTypeRN_$sTypeRN$sratio_$op(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_$op(dst $dType, dr, adr image.Rectangle, d2s *f64.Aff3, src $sType, sr image.Rectangle, bias image.Point) {
$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
sx0 := int(d2s[0]*dxf + d2s[1]*dyf + d2s[2]) + bias.X
sy0 := int(d2s[3]*dxf + d2s[4]*dyf + d2s[5]) + bias.Y
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_$op(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_$op(dst $dType, dr, adr image.Rectangle, d2s *f64.Aff3, src $sType, sr image.Rectangle, bias image.Point) {
$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
sx := d2s[0]*dxf + d2s[1]*dyf + d2s[2]
sy := d2s[3]*dxf + d2s[4]*dyf + d2s[5]
if !(image.Point{int(sx) + bias.X, int(sy) + bias.Y}).In(sr) {
continue
}
sx -= 0.5
sx0 := int(sx)
xFrac0 := sx - float64(sx0)
xFrac1 := 1 - xFrac0
sx0 += bias.X
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
sy0 := int(sy)
yFrac0 := sy - float64(sy0)
yFrac1 := 1 - yFrac0
sy0 += bias.Y
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
}
if _, ok := src.(*image.Uniform); ok && sr.In(src.Bounds()) {
Draw(dst, dr, src, src.Bounds().Min, opts.op())
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.
var tmp [][4]float64
if z.pool.New != nil {
tmpp := z.pool.Get().(*[][4]float64)
defer z.pool.Put(tmpp)
tmp = *tmpp
} else {
tmp = z.makeTmpBuf()
}
// 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_$op(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.
adr := dst.Bounds().Intersect(dr)
if adr.Empty() || sr.Empty() {
return
}
d2s := invert(s2d)
// bias is a translation of the mapping from dst co-ordinates to
// src co-ordinates such that the latter temporarily have
// non-negative X and Y co-ordinates. This allows us to write
// int(f) instead of int(math.Floor(f)), since "round to zero" and
// "round down" are equivalent when f >= 0, but the former is much
// cheaper. The X-- and Y-- are because the TransformLeaf methods
// have a "sx -= 0.5" adjustment.
bias := transformRect(&d2s, &adr).Min
bias.X--
bias.Y--
d2s[2] -= float64(bias.X)
d2s[5] -= float64(bias.Y)
// Make adr relative to dr.Min.
adr = adr.Sub(dr.Min)
if u, ok := src.(*image.Uniform); ok && sr.In(src.Bounds()) {
transform_Uniform(dst, dr, adr, &d2s, u, sr, bias, opts.op())
return
}
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()) {
switch opts.op() {
case Over:
// TODO: q.transform_Image_Image_Over(dst, dr, adr, &d2s, src, sr, bias, xscale, yscale)
case Src:
q.transform_Image_Image_Src(dst, dr, adr, &d2s, src, sr, bias, xscale, yscale)
}
} else {
$switch q.transform_$dTypeRN_$sTypeRN$sratio_$op(dst, dr, adr, &d2s, src, sr, bias, xscale, yscale)
}
}
`
codeKernelScaleLeafX = `
func (z *kernelScaler) scaleX_$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_$op(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_$op(dst $dType, dr, adr image.Rectangle, d2s *f64.Aff3, src $sType, sr image.Rectangle, bias image.Point, 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
sx := d2s[0]*dxf + d2s[1]*dyf + d2s[2]
sy := d2s[3]*dxf + d2s[4]*dyf + d2s[5]
if !(image.Point{int(sx) + bias.X, int(sy) + bias.Y}).In(sr) {
continue
}
// TODO: adjust the bias so that we can use int(f) instead
// of math.Floor(f) and math.Ceil(f).
sx += float64(bias.X)
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 += float64(bias.Y)
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++ {
if yWeight := yWeights[ky - iy]; yWeight != 0 {
for kx := ix; kx < jx; kx++ {
if w := xWeights[kx - ix] * yWeight; w != 0 {
p += $srcf[kx, ky] * w
}
}
}
}
$outputf[dr.Min.X + int(dx), dr.Min.Y + int(dy), fffftou, p, 1]
}
}
}
`
)