mirror of
https://github.com/golang/go
synced 2024-11-12 09:30:25 -07:00
image/draw: optimize out some bounds checks.
We could undoubtedly squeeze even more out of these loops, and in the long term, a better compiler would be smarter with bounds checks, but in the short term, this small change is an easy win. benchmark old ns/op new ns/op delta BenchmarkFillOver-8 1619470 1323192 -18.29% BenchmarkCopyOver-8 1129369 1062787 -5.90% BenchmarkGlyphOver-8 420070 378608 -9.87% On github.com/golang/freetype/truetype's BenchmarkDrawString: benchmark old ns/op new ns/op delta BenchmarkDrawString-8 9561435 8807019 -7.89% Change-Id: Ib1c6271ac18bced85e0fb5ebf250dd57d7747e75 Reviewed-on: https://go-review.googlesource.com/14093 Reviewed-by: Rob Pike <r@golang.org>
This commit is contained in:
parent
754d4c052a
commit
e424d59680
@ -240,15 +240,15 @@ func drawFillOver(dst *image.RGBA, r image.Rectangle, src *image.Uniform) {
|
||||
i1 := i0 + r.Dx()*4
|
||||
for y := r.Min.Y; y != r.Max.Y; y++ {
|
||||
for i := i0; i < i1; i += 4 {
|
||||
dr := uint32(dst.Pix[i+0])
|
||||
dg := uint32(dst.Pix[i+1])
|
||||
db := uint32(dst.Pix[i+2])
|
||||
da := uint32(dst.Pix[i+3])
|
||||
dr := &dst.Pix[i+0]
|
||||
dg := &dst.Pix[i+1]
|
||||
db := &dst.Pix[i+2]
|
||||
da := &dst.Pix[i+3]
|
||||
|
||||
dst.Pix[i+0] = uint8((dr*a/m + sr) >> 8)
|
||||
dst.Pix[i+1] = uint8((dg*a/m + sg) >> 8)
|
||||
dst.Pix[i+2] = uint8((db*a/m + sb) >> 8)
|
||||
dst.Pix[i+3] = uint8((da*a/m + sa) >> 8)
|
||||
*dr = uint8((uint32(*dr)*a/m + sr) >> 8)
|
||||
*dg = uint8((uint32(*dg)*a/m + sg) >> 8)
|
||||
*db = uint8((uint32(*db)*a/m + sb) >> 8)
|
||||
*da = uint8((uint32(*da)*a/m + sa) >> 8)
|
||||
}
|
||||
i0 += dst.Stride
|
||||
i1 += dst.Stride
|
||||
@ -310,18 +310,18 @@ func drawCopyOver(dst *image.RGBA, r image.Rectangle, src *image.RGBA, sp image.
|
||||
sb := uint32(spix[i+2]) * 0x101
|
||||
sa := uint32(spix[i+3]) * 0x101
|
||||
|
||||
dr := uint32(dpix[i+0])
|
||||
dg := uint32(dpix[i+1])
|
||||
db := uint32(dpix[i+2])
|
||||
da := uint32(dpix[i+3])
|
||||
dr := &dpix[i+0]
|
||||
dg := &dpix[i+1]
|
||||
db := &dpix[i+2]
|
||||
da := &dpix[i+3]
|
||||
|
||||
// The 0x101 is here for the same reason as in drawRGBA.
|
||||
a := (m - sa) * 0x101
|
||||
|
||||
dpix[i+0] = uint8((dr*a/m + sr) >> 8)
|
||||
dpix[i+1] = uint8((dg*a/m + sg) >> 8)
|
||||
dpix[i+2] = uint8((db*a/m + sb) >> 8)
|
||||
dpix[i+3] = uint8((da*a/m + sa) >> 8)
|
||||
*dr = uint8((uint32(*dr)*a/m + sr) >> 8)
|
||||
*dg = uint8((uint32(*dg)*a/m + sg) >> 8)
|
||||
*db = uint8((uint32(*db)*a/m + sb) >> 8)
|
||||
*da = uint8((uint32(*da)*a/m + sa) >> 8)
|
||||
}
|
||||
d0 += ddelta
|
||||
s0 += sdelta
|
||||
@ -471,18 +471,18 @@ func drawGlyphOver(dst *image.RGBA, r image.Rectangle, src *image.Uniform, mask
|
||||
}
|
||||
ma |= ma << 8
|
||||
|
||||
dr := uint32(dst.Pix[i+0])
|
||||
dg := uint32(dst.Pix[i+1])
|
||||
db := uint32(dst.Pix[i+2])
|
||||
da := uint32(dst.Pix[i+3])
|
||||
dr := &dst.Pix[i+0]
|
||||
dg := &dst.Pix[i+1]
|
||||
db := &dst.Pix[i+2]
|
||||
da := &dst.Pix[i+3]
|
||||
|
||||
// The 0x101 is here for the same reason as in drawRGBA.
|
||||
a := (m - (sa * ma / m)) * 0x101
|
||||
|
||||
dst.Pix[i+0] = uint8((dr*a + sr*ma) / m >> 8)
|
||||
dst.Pix[i+1] = uint8((dg*a + sg*ma) / m >> 8)
|
||||
dst.Pix[i+2] = uint8((db*a + sb*ma) / m >> 8)
|
||||
dst.Pix[i+3] = uint8((da*a + sa*ma) / m >> 8)
|
||||
*dr = uint8((uint32(*dr)*a + sr*ma) / m >> 8)
|
||||
*dg = uint8((uint32(*dg)*a + sg*ma) / m >> 8)
|
||||
*db = uint8((uint32(*db)*a + sb*ma) / m >> 8)
|
||||
*da = uint8((uint32(*da)*a + sa*ma) / m >> 8)
|
||||
}
|
||||
i0 += dst.Stride
|
||||
i1 += dst.Stride
|
||||
|
Loading…
Reference in New Issue
Block a user