From 5bba5053675f102a3a81242e8f7551791ae5a56e Mon Sep 17 00:00:00 2001 From: Ian Davis Date: Mon, 24 Sep 2018 10:20:46 +0100 Subject: [PATCH] image/draw: optimize bounds checks in loops MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Use subslices with known length and cap to give bounds checking hints to the compiler. Improves over the earlier pointer based optimizations in https://go-review.googlesource.com/c/go/+/14093 for GlyphOver but not for FillOver so the latter is left unchanged. See #27857 for discussion of small caps used in subslices. name old time/op new time/op delta FillOver-8 607µs ± 1% 609µs ± 1% ~ (p=0.447 n=9+10) FillSrc-8 23.0µs ± 1% 22.9µs ± 2% ~ (p=0.412 n=9+10) CopyOver-8 647µs ± 0% 560µs ± 0% -13.43% (p=0.000 n=9+10) CopySrc-8 19.3µs ± 1% 19.1µs ± 2% -0.66% (p=0.029 n=10+10) NRGBAOver-8 697µs ± 1% 651µs ± 1% -6.64% (p=0.000 n=10+10) NRGBASrc-8 405µs ± 1% 347µs ± 0% -14.23% (p=0.000 n=10+10) YCbCr-8 432µs ± 2% 431µs ± 1% ~ (p=0.764 n=10+9) Gray-8 164µs ± 1% 139µs ± 1% -15.44% (p=0.000 n=10+10) CMYK-8 498µs ± 0% 461µs ± 0% -7.49% (p=0.000 n=10+9) GlyphOver-8 220µs ± 0% 199µs ± 0% -9.52% (p=0.000 n=9+10) RGBA-8 3.81ms ± 5% 3.79ms ± 5% ~ (p=0.549 n=9+10) Paletted-8 1.73ms ± 0% 1.73ms ± 1% ~ (p=0.278 n=10+9) GenericOver-8 11.0ms ± 2% 11.0ms ± 1% ~ (p=0.842 n=9+10) GenericMaskOver-8 5.29ms ± 1% 5.30ms ± 0% ~ (p=0.182 n=9+10) GenericSrc-8 4.24ms ± 1% 4.24ms ± 0% ~ (p=0.436 n=9+9) GenericMaskSrc-8 7.89ms ± 1% 7.90ms ± 2% ~ (p=0.631 n=10+10) Change-Id: I6fe1b21bb5e255826cbfdd2e73efd5858cd5557c Reviewed-on: https://go-review.googlesource.com/136935 Reviewed-by: Brad Fitzpatrick Run-TryBot: Brad Fitzpatrick TryBot-Result: Gobot Gobot --- src/image/draw/draw.go | 126 ++++++++++++++++++++--------------------- 1 file changed, 63 insertions(+), 63 deletions(-) diff --git a/src/image/draw/draw.go b/src/image/draw/draw.go index 977d7c522153a..3ff1828dc0c0a 100644 --- a/src/image/draw/draw.go +++ b/src/image/draw/draw.go @@ -309,23 +309,20 @@ func drawCopyOver(dst *image.RGBA, r image.Rectangle, src *image.RGBA, sp image. dpix := dst.Pix[d0:] spix := src.Pix[s0:] for i := i0; i != i1; i += idelta { - sr := uint32(spix[i+0]) * 0x101 - sg := uint32(spix[i+1]) * 0x101 - sb := uint32(spix[i+2]) * 0x101 - sa := uint32(spix[i+3]) * 0x101 - - dr := &dpix[i+0] - dg := &dpix[i+1] - db := &dpix[i+2] - da := &dpix[i+3] + s := spix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857 + sr := uint32(s[0]) * 0x101 + sg := uint32(s[1]) * 0x101 + sb := uint32(s[2]) * 0x101 + sa := uint32(s[3]) * 0x101 // The 0x101 is here for the same reason as in drawRGBA. a := (m - sa) * 0x101 - *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) + d := dpix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857 + d[0] = uint8((uint32(d[0])*a/m + sr) >> 8) + d[1] = uint8((uint32(d[1])*a/m + sg) >> 8) + d[2] = uint8((uint32(d[2])*a/m + sb) >> 8) + d[3] = uint8((uint32(d[3])*a/m + sa) >> 8) } d0 += ddelta s0 += sdelta @@ -372,23 +369,25 @@ func drawNRGBAOver(dst *image.RGBA, r image.Rectangle, src *image.NRGBA, sp imag for i, si := i0, si0; i < i1; i, si = i+4, si+4 { // Convert from non-premultiplied color to pre-multiplied color. - sa := uint32(spix[si+3]) * 0x101 - sr := uint32(spix[si+0]) * sa / 0xff - sg := uint32(spix[si+1]) * sa / 0xff - sb := uint32(spix[si+2]) * sa / 0xff - - dr := uint32(dpix[i+0]) - dg := uint32(dpix[i+1]) - db := uint32(dpix[i+2]) - da := uint32(dpix[i+3]) + s := spix[si : si+4 : si+4] // Small cap improves performance, see https://golang.org/issue/27857 + sa := uint32(s[3]) * 0x101 + sr := uint32(s[0]) * sa / 0xff + sg := uint32(s[1]) * sa / 0xff + sb := uint32(s[2]) * sa / 0xff + + d := dpix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857 + dr := uint32(d[0]) + dg := uint32(d[1]) + db := uint32(d[2]) + da := uint32(d[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) + d[0] = uint8((dr*a/m + sr) >> 8) + d[1] = uint8((dg*a/m + sg) >> 8) + d[2] = uint8((db*a/m + sb) >> 8) + d[3] = uint8((da*a/m + sa) >> 8) } } } @@ -407,15 +406,17 @@ func drawNRGBASrc(dst *image.RGBA, r image.Rectangle, src *image.NRGBA, sp image for i, si := i0, si0; i < i1; i, si = i+4, si+4 { // Convert from non-premultiplied color to pre-multiplied color. - sa := uint32(spix[si+3]) * 0x101 - sr := uint32(spix[si+0]) * sa / 0xff - sg := uint32(spix[si+1]) * sa / 0xff - sb := uint32(spix[si+2]) * sa / 0xff - - dpix[i+0] = uint8(sr >> 8) - dpix[i+1] = uint8(sg >> 8) - dpix[i+2] = uint8(sb >> 8) - dpix[i+3] = uint8(sa >> 8) + s := spix[si : si+4 : si+4] // Small cap improves performance, see https://golang.org/issue/27857 + sa := uint32(s[3]) * 0x101 + sr := uint32(s[0]) * sa / 0xff + sg := uint32(s[1]) * sa / 0xff + sb := uint32(s[2]) * sa / 0xff + + d := dpix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857 + d[0] = uint8(sr >> 8) + d[1] = uint8(sg >> 8) + d[2] = uint8(sb >> 8) + d[3] = uint8(sa >> 8) } } } @@ -434,10 +435,11 @@ func drawGray(dst *image.RGBA, r image.Rectangle, src *image.Gray, sp image.Poin for i, si := i0, si0; i < i1; i, si = i+4, si+1 { p := spix[si] - dpix[i+0] = p - dpix[i+1] = p - dpix[i+2] = p - dpix[i+3] = 255 + d := dpix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857 + d[0] = p + d[1] = p + d[2] = p + d[3] = 255 } } } @@ -455,9 +457,10 @@ func drawCMYK(dst *image.RGBA, r image.Rectangle, src *image.CMYK, sp image.Poin 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 + s := spix[si : si+4 : si+4] // Small cap improves performance, see https://golang.org/issue/27857 + d := dpix[i : i+4 : i+4] + d[0], d[1], d[2] = color.CMYKToRGB(s[0], s[1], s[2], s[3]) + d[3] = 255 } } } @@ -475,18 +478,14 @@ func drawGlyphOver(dst *image.RGBA, r image.Rectangle, src *image.Uniform, mask } ma |= ma << 8 - 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 - *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) + d := dst.Pix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857 + d[0] = uint8((uint32(d[0])*a + sr*ma) / m >> 8) + d[1] = uint8((uint32(d[1])*a + sg*ma) / m >> 8) + d[2] = uint8((uint32(d[2])*a + sb*ma) / m >> 8) + d[3] = uint8((uint32(d[3])*a + sa*ma) / m >> 8) } i0 += dst.Stride i1 += dst.Stride @@ -518,11 +517,12 @@ func drawRGBA(dst *image.RGBA, r image.Rectangle, src image.Image, sp image.Poin _, _, _, ma = mask.At(mx, my).RGBA() } sr, sg, sb, sa := src.At(sx, sy).RGBA() + d := dst.Pix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857 if op == Over { - 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 := uint32(d[0]) + dg := uint32(d[1]) + db := uint32(d[2]) + da := uint32(d[3]) // dr, dg, db and da are all 8-bit color at the moment, ranging in [0,255]. // We work in 16-bit color, and so would normally do: @@ -532,16 +532,16 @@ func drawRGBA(dst *image.RGBA, r image.Rectangle, src image.Image, sp image.Poin // This yields the same result, but is fewer arithmetic operations. 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) + d[0] = uint8((dr*a + sr*ma) / m >> 8) + d[1] = uint8((dg*a + sg*ma) / m >> 8) + d[2] = uint8((db*a + sb*ma) / m >> 8) + d[3] = uint8((da*a + sa*ma) / m >> 8) } else { - dst.Pix[i+0] = uint8(sr * ma / m >> 8) - dst.Pix[i+1] = uint8(sg * ma / m >> 8) - dst.Pix[i+2] = uint8(sb * ma / m >> 8) - dst.Pix[i+3] = uint8(sa * ma / m >> 8) + d[0] = uint8(sr * ma / m >> 8) + d[1] = uint8(sg * ma / m >> 8) + d[2] = uint8(sb * ma / m >> 8) + d[3] = uint8(sa * ma / m >> 8) } } i0 += dy * dst.Stride