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image/internal/imageutil: inline the color.YCbCrToRGB calls.

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The image/draw benchmark:
benchmark          old ns/op     new ns/op     delta
BenchmarkYCbCr     1198605       978647        -18.35%

Change-Id: Iacfc21e6f641ecb05adc00b3aec0048f1f43d265
Reviewed-on: https://go-review.googlesource.com/7952
Reviewed-by: Rob Pike <r@golang.org>
This commit is contained in:
Nigel Tao 2015-03-24 11:45:29 +11:00
parent 713451a097
commit a3a193c018
2 changed files with 131 additions and 22 deletions
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32
src/image/internal/imageutil/gen.go
View File

@ -47,7 +47,6 @@ package imageutil
import (
"image"
"image/color"
)
// DrawYCbCr draws the YCbCr source image on the RGBA destination image with
@ -94,10 +93,33 @@ const sratioCase = `
dpix := dst.Pix[y*dst.Stride:]
yi := (sy-src.Rect.Min.Y)*src.YStride + (sp.X - src.Rect.Min.X)
%s
rr, gg, bb := color.YCbCrToRGB(src.Y[yi], src.Cb[ci], src.Cr[ci])
dpix[x+0] = rr
dpix[x+1] = gg
dpix[x+2] = bb
// This is an inline version of image/color/ycbcr.go's func YCbCrToRGB.
yy1 := int(src.Y[yi])<<16 + 1<<15
cb1 := int(src.Cb[ci]) - 128
cr1 := int(src.Cr[ci]) - 128
r := (yy1 + 91881*cr1) >> 16
g := (yy1 - 22554*cb1 - 46802*cr1) >> 16
b := (yy1 + 116130*cb1) >> 16
if r < 0 {
r = 0
} else if r > 255 {
r = 255
}
if g < 0 {
g = 0
} else if g > 255 {
g = 255
}
if b < 0 {
b = 0
} else if b > 255 {
b = 255
}
dpix[x+0] = uint8(r)
dpix[x+1] = uint8(g)
dpix[x+2] = uint8(b)
dpix[x+3] = 255
}
}

121
src/image/internal/imageutil/impl.go
View File

@ -4,7 +4,6 @@ package imageutil
import (
"image"
"image/color"
)
// DrawYCbCr draws the YCbCr source image on the RGBA destination image with
@ -44,10 +43,32 @@ func DrawYCbCr(dst *image.RGBA, r image.Rectangle, src *image.YCbCr, sp image.Po
ci := (sy-src.Rect.Min.Y)*src.CStride + (sp.X - src.Rect.Min.X)
for x := x0; x != x1; x, yi, ci = x+4, yi+1, ci+1 {
rr, gg, bb := color.YCbCrToRGB(src.Y[yi], src.Cb[ci], src.Cr[ci])
dpix[x+0] = rr
dpix[x+1] = gg
dpix[x+2] = bb
// This is an inline version of image/color/ycbcr.go's func YCbCrToRGB.
yy1 := int(src.Y[yi])<<16 + 1<<15
cb1 := int(src.Cb[ci]) - 128
cr1 := int(src.Cr[ci]) - 128
r := (yy1 + 91881*cr1) >> 16
g := (yy1 - 22554*cb1 - 46802*cr1) >> 16
b := (yy1 + 116130*cb1) >> 16
if r < 0 {
r = 0
} else if r > 255 {
r = 255
}
if g < 0 {
g = 0
} else if g > 255 {
g = 255
}
if b < 0 {
b = 0
} else if b > 255 {
b = 255
}
dpix[x+0] = uint8(r)
dpix[x+1] = uint8(g)
dpix[x+2] = uint8(b)
dpix[x+3] = 255
}
}
@ -61,10 +82,32 @@ func DrawYCbCr(dst *image.RGBA, r image.Rectangle, src *image.YCbCr, sp image.Po
for x, sx := x0, sp.X; x != x1; x, sx, yi = x+4, sx+1, yi+1 {
ci := ciBase + sx/2
rr, gg, bb := color.YCbCrToRGB(src.Y[yi], src.Cb[ci], src.Cr[ci])
dpix[x+0] = rr
dpix[x+1] = gg
dpix[x+2] = bb
// This is an inline version of image/color/ycbcr.go's func YCbCrToRGB.
yy1 := int(src.Y[yi])<<16 + 1<<15
cb1 := int(src.Cb[ci]) - 128
cr1 := int(src.Cr[ci]) - 128
r := (yy1 + 91881*cr1) >> 16
g := (yy1 - 22554*cb1 - 46802*cr1) >> 16
b := (yy1 + 116130*cb1) >> 16
if r < 0 {
r = 0
} else if r > 255 {
r = 255
}
if g < 0 {
g = 0
} else if g > 255 {
g = 255
}
if b < 0 {
b = 0
} else if b > 255 {
b = 255
}
dpix[x+0] = uint8(r)
dpix[x+1] = uint8(g)
dpix[x+2] = uint8(b)
dpix[x+3] = 255
}
}
@ -78,10 +121,32 @@ func DrawYCbCr(dst *image.RGBA, r image.Rectangle, src *image.YCbCr, sp image.Po
for x, sx := x0, sp.X; x != x1; x, sx, yi = x+4, sx+1, yi+1 {
ci := ciBase + sx/2
rr, gg, bb := color.YCbCrToRGB(src.Y[yi], src.Cb[ci], src.Cr[ci])
dpix[x+0] = rr
dpix[x+1] = gg
dpix[x+2] = bb
// This is an inline version of image/color/ycbcr.go's func YCbCrToRGB.
yy1 := int(src.Y[yi])<<16 + 1<<15
cb1 := int(src.Cb[ci]) - 128
cr1 := int(src.Cr[ci]) - 128
r := (yy1 + 91881*cr1) >> 16
g := (yy1 - 22554*cb1 - 46802*cr1) >> 16
b := (yy1 + 116130*cb1) >> 16
if r < 0 {
r = 0
} else if r > 255 {
r = 255
}
if g < 0 {
g = 0
} else if g > 255 {
g = 255
}
if b < 0 {
b = 0
} else if b > 255 {
b = 255
}
dpix[x+0] = uint8(r)
dpix[x+1] = uint8(g)
dpix[x+2] = uint8(b)
dpix[x+3] = 255
}
}
@ -94,10 +159,32 @@ func DrawYCbCr(dst *image.RGBA, r image.Rectangle, src *image.YCbCr, sp image.Po
ci := (sy/2-src.Rect.Min.Y/2)*src.CStride + (sp.X - src.Rect.Min.X)
for x := x0; x != x1; x, yi, ci = x+4, yi+1, ci+1 {
rr, gg, bb := color.YCbCrToRGB(src.Y[yi], src.Cb[ci], src.Cr[ci])
dpix[x+0] = rr
dpix[x+1] = gg
dpix[x+2] = bb
// This is an inline version of image/color/ycbcr.go's func YCbCrToRGB.
yy1 := int(src.Y[yi])<<16 + 1<<15
cb1 := int(src.Cb[ci]) - 128
cr1 := int(src.Cr[ci]) - 128
r := (yy1 + 91881*cr1) >> 16
g := (yy1 - 22554*cb1 - 46802*cr1) >> 16
b := (yy1 + 116130*cb1) >> 16
if r < 0 {
r = 0
} else if r > 255 {
r = 255
}
if g < 0 {
g = 0
} else if g > 255 {
g = 255
}
if b < 0 {
b = 0
} else if b > 255 {
b = 255
}
dpix[x+0] = uint8(r)
dpix[x+1] = uint8(g)
dpix[x+2] = uint8(b)
dpix[x+3] = 255
}
}