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
parent
5869597f23
commit
2a1231edb8
165
draw/impl.go
Normal file
165
draw/impl.go
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@ -0,0 +1,165 @@
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// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package draw
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// TODO: autogenerate this file.
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import (
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"image"
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"image/color"
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)
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func (z *nnScaler) Scale(dst Image, dp image.Point, src image.Image, sp image.Point) {
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if z.dw <= 0 || z.dh <= 0 || z.sw <= 0 || z.sh <= 0 {
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return
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}
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dstColorRGBA64 := &color.RGBA64{}
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dstColor := color.Color(dstColorRGBA64)
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for dy := int32(0); dy < z.dh; dy++ {
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sy := (2*uint64(dy) + 1) * uint64(z.sh) / (2 * uint64(z.dh))
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for dx := int32(0); dx < z.dw; dx++ {
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sx := (2*uint64(dx) + 1) * uint64(z.sw) / (2 * uint64(z.dw))
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pr, pg, pb, pa := src.At(sp.X+int(sx), sp.Y+int(sy)).RGBA()
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dstColorRGBA64.R = uint16(pr)
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dstColorRGBA64.G = uint16(pg)
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dstColorRGBA64.B = uint16(pb)
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dstColorRGBA64.A = uint16(pa)
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dst.Set(dp.X+int(dx), dp.Y+int(dy), dstColor)
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}
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}
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}
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func (z *ablScaler) Scale(dst Image, dp image.Point, src image.Image, sp image.Point) {
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if z.dw <= 0 || z.dh <= 0 || z.sw <= 0 || z.sh <= 0 {
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return
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}
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yscale := float64(z.sh) / float64(z.dh)
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xscale := float64(z.sw) / float64(z.dw)
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dstColorRGBA64 := &color.RGBA64{}
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dstColor := color.Color(dstColorRGBA64)
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for dy := int32(0); dy < z.dh; dy++ {
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sy := (float64(dy)+0.5)*yscale - 0.5
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sy0 := int32(sy)
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yFrac0 := sy - float64(sy0)
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yFrac1 := 1 - yFrac0
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sy1 := sy0 + 1
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if sy < 0 {
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sy0, sy1 = 0, 0
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yFrac0, yFrac1 = 0, 1
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} else if sy1 >= z.sh {
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sy1 = sy0
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yFrac0, yFrac1 = 1, 0
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}
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for dx := int32(0); dx < z.dw; dx++ {
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sx := (float64(dx)+0.5)*xscale - 0.5
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sx0 := int32(sx)
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xFrac0 := sx - float64(sx0)
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xFrac1 := 1 - xFrac0
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sx1 := sx0 + 1
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if sx < 0 {
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sx0, sx1 = 0, 0
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xFrac0, xFrac1 = 0, 1
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} else if sx1 >= z.sw {
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sx1 = sx0
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xFrac0, xFrac1 = 1, 0
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}
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s00ru, s00gu, s00bu, s00au := src.At(sp.X+int(sx0), sp.Y+int(sy0)).RGBA()
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s00r := float64(s00ru)
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s00g := float64(s00gu)
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s00b := float64(s00bu)
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s00a := float64(s00au)
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s10ru, s10gu, s10bu, s10au := src.At(sp.X+int(sx1), sp.Y+int(sy0)).RGBA()
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s10r := float64(s10ru)
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s10g := float64(s10gu)
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s10b := float64(s10bu)
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s10a := float64(s10au)
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s10r = xFrac1*s00r + xFrac0*s10r
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s10g = xFrac1*s00g + xFrac0*s10g
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s10b = xFrac1*s00b + xFrac0*s10b
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s10a = xFrac1*s00a + xFrac0*s10a
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s01ru, s01gu, s01bu, s01au := src.At(sp.X+int(sx0), sp.Y+int(sy1)).RGBA()
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s01r := float64(s01ru)
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s01g := float64(s01gu)
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s01b := float64(s01bu)
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s01a := float64(s01au)
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s11ru, s11gu, s11bu, s11au := src.At(sp.X+int(sx1), sp.Y+int(sy1)).RGBA()
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s11r := float64(s11ru)
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s11g := float64(s11gu)
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s11b := float64(s11bu)
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s11a := float64(s11au)
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s11r = xFrac1*s01r + xFrac0*s11r
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s11g = xFrac1*s01g + xFrac0*s11g
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s11b = xFrac1*s01b + xFrac0*s11b
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s11a = xFrac1*s01a + xFrac0*s11a
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s11r = yFrac1*s10r + yFrac0*s11r
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s11g = yFrac1*s10g + yFrac0*s11g
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s11b = yFrac1*s10b + yFrac0*s11b
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s11a = yFrac1*s10a + yFrac0*s11a
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dstColorRGBA64.R = uint16(s11r)
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dstColorRGBA64.G = uint16(s11g)
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dstColorRGBA64.B = uint16(s11b)
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dstColorRGBA64.A = uint16(s11a)
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dst.Set(dp.X+int(dx), dp.Y+int(dy), dstColor)
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}
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}
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}
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func (z *kernelScaler) Scale(dst Image, dp image.Point, src image.Image, sp image.Point) {
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if z.dw <= 0 || z.dh <= 0 || z.sw <= 0 || z.sh <= 0 {
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return
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}
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// Create a temporary buffer:
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// scaleX distributes the source image's columns over the temporary image.
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// scaleY distributes the temporary image's rows over the destination image.
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// TODO: is it worth having a sync.Pool for this temporary buffer?
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tmp := make([][4]float64, z.dw*z.sh)
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z.scaleX(tmp, src, sp)
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z.scaleY(dst, dp, tmp)
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}
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func (z *kernelScaler) scaleX(tmp [][4]float64, src image.Image, sp image.Point) {
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t := 0
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for y := int32(0); y < z.sh; y++ {
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for _, s := range z.horizontal.sources {
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var r, g, b, a float64
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for _, c := range z.horizontal.contribs[s.i:s.j] {
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rr, gg, bb, aa := src.At(sp.X+int(c.coord), sp.Y+int(y)).RGBA()
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r += float64(rr) * c.weight
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g += float64(gg) * c.weight
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b += float64(bb) * c.weight
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a += float64(aa) * c.weight
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}
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tmp[t] = [4]float64{
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r * s.invTotalWeightFFFF,
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g * s.invTotalWeightFFFF,
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b * s.invTotalWeightFFFF,
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a * s.invTotalWeightFFFF,
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}
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t++
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}
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}
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}
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func (z *kernelScaler) scaleY(dst Image, dp image.Point, tmp [][4]float64) {
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dstColorRGBA64 := &color.RGBA64{}
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dstColor := color.Color(dstColorRGBA64)
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for x := int32(0); x < z.dw; x++ {
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for y, s := range z.vertical.sources {
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var r, g, b, a float64
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for _, c := range z.vertical.contribs[s.i:s.j] {
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p := &tmp[c.coord*z.dw+x]
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r += p[0] * c.weight
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g += p[1] * c.weight
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b += p[2] * c.weight
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a += p[3] * c.weight
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}
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dstColorRGBA64.R = ftou(r * s.invTotalWeight)
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dstColorRGBA64.G = ftou(g * s.invTotalWeight)
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dstColorRGBA64.B = ftou(b * s.invTotalWeight)
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dstColorRGBA64.A = ftou(a * s.invTotalWeight)
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dst.Set(dp.X+int(x), dp.Y+y, dstColor)
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}
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}
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}
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153
draw/scale.go
153
draw/scale.go
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@ -8,7 +8,6 @@ package draw
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import (
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"image"
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"image/color"
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"math"
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)
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@ -112,26 +111,6 @@ type nnScaler struct {
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dw, dh, sw, sh int32
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}
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func (z *nnScaler) Scale(dst Image, dp image.Point, src image.Image, sp image.Point) {
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if z.dw <= 0 || z.dh <= 0 || z.sw <= 0 || z.sh <= 0 {
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return
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}
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dstColorRGBA64 := &color.RGBA64{}
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dstColor := color.Color(dstColorRGBA64)
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for dy := int32(0); dy < z.dh; dy++ {
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sy := (2*uint64(dy) + 1) * uint64(z.sh) / (2 * uint64(z.dh))
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for dx := int32(0); dx < z.dw; dx++ {
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sx := (2*uint64(dx) + 1) * uint64(z.sw) / (2 * uint64(z.dw))
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pr, pg, pb, pa := src.At(sp.X+int(sx), sp.Y+int(sy)).RGBA()
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dstColorRGBA64.R = uint16(pr)
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dstColorRGBA64.G = uint16(pg)
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dstColorRGBA64.B = uint16(pb)
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dstColorRGBA64.A = uint16(pa)
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dst.Set(dp.X+int(dx), dp.Y+int(dy), dstColor)
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}
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}
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}
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type ablInterpolator struct{}
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func (ablInterpolator) NewScaler(dw, dh, sw, sh int32) Scaler { return &ablScaler{dw, dh, sw, sh} }
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@ -140,96 +119,11 @@ type ablScaler struct {
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dw, dh, sw, sh int32
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}
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func (z *ablScaler) Scale(dst Image, dp image.Point, src image.Image, sp image.Point) {
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if z.dw <= 0 || z.dh <= 0 || z.sw <= 0 || z.sh <= 0 {
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return
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}
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yscale := float64(z.sh) / float64(z.dh)
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xscale := float64(z.sw) / float64(z.dw)
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dstColorRGBA64 := &color.RGBA64{}
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dstColor := color.Color(dstColorRGBA64)
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for dy := int32(0); dy < z.dh; dy++ {
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sy := (float64(dy)+0.5)*yscale - 0.5
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sy0 := int32(sy)
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yFrac0 := sy - float64(sy0)
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yFrac1 := 1 - yFrac0
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sy1 := sy0 + 1
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if sy < 0 {
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sy0, sy1 = 0, 0
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yFrac0, yFrac1 = 0, 1
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} else if sy1 >= z.sh {
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sy1 = sy0
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yFrac0, yFrac1 = 1, 0
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}
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for dx := int32(0); dx < z.dw; dx++ {
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sx := (float64(dx)+0.5)*xscale - 0.5
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sx0 := int32(sx)
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xFrac0 := sx - float64(sx0)
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xFrac1 := 1 - xFrac0
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sx1 := sx0 + 1
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if sx < 0 {
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sx0, sx1 = 0, 0
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xFrac0, xFrac1 = 0, 1
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} else if sx1 >= z.sw {
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sx1 = sx0
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xFrac0, xFrac1 = 1, 0
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}
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s00ru, s00gu, s00bu, s00au := src.At(sp.X+int(sx0), sp.Y+int(sy0)).RGBA()
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s00r := float64(s00ru)
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s00g := float64(s00gu)
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s00b := float64(s00bu)
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s00a := float64(s00au)
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s10ru, s10gu, s10bu, s10au := src.At(sp.X+int(sx1), sp.Y+int(sy0)).RGBA()
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s10r := float64(s10ru)
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s10g := float64(s10gu)
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s10b := float64(s10bu)
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s10a := float64(s10au)
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s10r = xFrac1*s00r + xFrac0*s10r
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s10g = xFrac1*s00g + xFrac0*s10g
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s10b = xFrac1*s00b + xFrac0*s10b
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s10a = xFrac1*s00a + xFrac0*s10a
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s01ru, s01gu, s01bu, s01au := src.At(sp.X+int(sx0), sp.Y+int(sy1)).RGBA()
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s01r := float64(s01ru)
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s01g := float64(s01gu)
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s01b := float64(s01bu)
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s01a := float64(s01au)
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s11ru, s11gu, s11bu, s11au := src.At(sp.X+int(sx1), sp.Y+int(sy1)).RGBA()
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s11r := float64(s11ru)
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s11g := float64(s11gu)
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s11b := float64(s11bu)
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s11a := float64(s11au)
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s11r = xFrac1*s01r + xFrac0*s11r
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s11g = xFrac1*s01g + xFrac0*s11g
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s11b = xFrac1*s01b + xFrac0*s11b
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s11a = xFrac1*s01a + xFrac0*s11a
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s11r = yFrac1*s10r + yFrac0*s11r
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s11g = yFrac1*s10g + yFrac0*s11g
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s11b = yFrac1*s10b + yFrac0*s11b
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s11a = yFrac1*s10a + yFrac0*s11a
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dstColorRGBA64.R = uint16(s11r)
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dstColorRGBA64.G = uint16(s11g)
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dstColorRGBA64.B = uint16(s11b)
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dstColorRGBA64.A = uint16(s11a)
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dst.Set(dp.X+int(dx), dp.Y+int(dy), dstColor)
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}
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}
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}
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type kernelScaler struct {
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dw, dh, sw, sh int32
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horizontal, vertical distrib
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}
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func (z *kernelScaler) Scale(dst Image, dp image.Point, src image.Image, sp image.Point) {
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if z.dw <= 0 || z.dh <= 0 || z.sw <= 0 || z.sh <= 0 {
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return
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}
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// TODO: is it worth having a sync.Pool for this temporary buffer?
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tmp := make([][4]float64, z.dw*z.sh)
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z.scaleX(tmp, src, sp)
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z.scaleY(dst, dp, tmp)
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}
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// source is a range of contribs, their inverse total weight, and that ITW
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// divided by 0xffff.
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type source struct {
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@ -317,53 +211,6 @@ func newDistrib(q *Kernel, dw, sw int32) distrib {
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return distrib{sources, contribs}
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}
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// scaleX distributes the source image's columns over the temporary image.
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func (z *kernelScaler) scaleX(tmp [][4]float64, src image.Image, sp image.Point) {
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t := 0
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for y := int32(0); y < z.sh; y++ {
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for _, s := range z.horizontal.sources {
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var r, g, b, a float64
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for _, c := range z.horizontal.contribs[s.i:s.j] {
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rr, gg, bb, aa := src.At(sp.X+int(c.coord), sp.Y+int(y)).RGBA()
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r += float64(rr) * c.weight
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g += float64(gg) * c.weight
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b += float64(bb) * c.weight
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a += float64(aa) * c.weight
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}
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tmp[t] = [4]float64{
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r * s.invTotalWeightFFFF,
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g * s.invTotalWeightFFFF,
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b * s.invTotalWeightFFFF,
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a * s.invTotalWeightFFFF,
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}
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t++
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}
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}
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}
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// scaleY distributes the temporary image's rows over the destination image.
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func (z *kernelScaler) scaleY(dst Image, dp image.Point, tmp [][4]float64) {
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dstColorRGBA64 := &color.RGBA64{}
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dstColor := color.Color(dstColorRGBA64)
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for x := int32(0); x < z.dw; x++ {
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for y, s := range z.vertical.sources {
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var r, g, b, a float64
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for _, c := range z.vertical.contribs[s.i:s.j] {
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p := &tmp[c.coord*z.dw+x]
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r += p[0] * c.weight
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g += p[1] * c.weight
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b += p[2] * c.weight
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a += p[3] * c.weight
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}
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dstColorRGBA64.R = ftou(r * s.invTotalWeight)
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dstColorRGBA64.G = ftou(g * s.invTotalWeight)
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dstColorRGBA64.B = ftou(b * s.invTotalWeight)
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dstColorRGBA64.A = ftou(a * s.invTotalWeight)
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dst.Set(dp.X+int(x), dp.Y+y, dstColor)
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}
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}
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}
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func ftou(f float64) uint16 {
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i := int32(0xffff*f + 0.5)
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if i > 0xffff {
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