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image/draw: add CMYK fast path.

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Change-Id: I9582aff7ca141a8aead5692af74b9c708b1700cc
Reviewed-on: https://go-review.googlesource.com/5020
Reviewed-by: Rob Pike <r@golang.org>
This commit is contained in:
Nigel Tao 2015-02-17 17:29:54 +11:00
parent 1ab55a3f04
commit 391805b14b
1 changed files with 28 additions and 0 deletions
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28
src/image/draw/draw.go
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@ -127,6 +127,9 @@ func DrawMask(dst Image, r image.Rectangle, src image.Image, sp image.Point, mas
if drawYCbCr(dst0, r, src0, sp) {
return
}
case *image.CMYK:
drawCMYK(dst0, r, src0, sp)
return
}
} else if mask0, ok := mask.(*image.Alpha); ok {
switch src0 := src.(type) {
@ -151,6 +154,9 @@ func DrawMask(dst Image, r image.Rectangle, src image.Image, sp image.Point, mas
if drawYCbCr(dst0, r, src0, sp) {
return
}
case *image.CMYK:
drawCMYK(dst0, r, src0, sp)
return
}
}
}
@ -462,6 +468,28 @@ func drawYCbCr(dst *image.RGBA, r image.Rectangle, src *image.YCbCr, sp image.Po
return true
}
func drawCMYK(dst *image.RGBA, r image.Rectangle, src *image.CMYK, sp image.Point) {
// An image.CMYK is always fully opaque, and so if the mask is implicitly nil
// (i.e. fully opaque) then the op is effectively always Src.
i0 := (r.Min.X - dst.Rect.Min.X) * 4
i1 := (r.Max.X - dst.Rect.Min.X) * 4
si0 := (sp.X - src.Rect.Min.X) * 4
yMax := r.Max.Y - dst.Rect.Min.Y
y := r.Min.Y - dst.Rect.Min.Y
sy := sp.Y - src.Rect.Min.Y
for ; y != yMax; y, sy = y+1, sy+1 {
dpix := dst.Pix[y*dst.Stride:]
spix := src.Pix[sy*src.Stride:]
for i, si := i0, si0; i < i1; i, si = i+4, si+4 {
dpix[i+0], dpix[i+1], dpix[i+2] =
color.CMYKToRGB(spix[si+0], spix[si+1], spix[si+2], spix[si+3])
dpix[i+3] = 255
}
}
}
func drawGlyphOver(dst *image.RGBA, r image.Rectangle, src *image.Uniform, mask *image.Alpha, mp image.Point) {
i0 := dst.PixOffset(r.Min.X, r.Min.Y)
i1 := i0 + r.Dx()*4