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>
This commit is contained in:
Nigel Tao 2015-02-19 15:53:02 +11:00
parent 5869597f23
commit 2a1231edb8
2 changed files with 165 additions and 153 deletions

165
draw/impl.go Normal file
View File

@ -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)
}
}
}

View File

@ -8,7 +8,6 @@ package draw
import (
"image"
"image/color"
"math"
)
@ -112,26 +111,6 @@ type nnScaler struct {
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 @@ type ablScaler struct {
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 @@ func newDistrib(q *Kernel, dw, sw int32) distrib {
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 {