exp/draw: small draw.drawGlyphOver optimization.

Make dpix variable names consistent.

R=rsc
CC=golang-dev
https://golang.org/cl/1563041

diff --git a/src/pkg/exp/draw/draw.go b/src/pkg/exp/draw/draw.go
index 6c50faa84cb032bcb36712b681e6714e6d8c7772..415dd99acd865eb62ae860fe268fe576f30e6def 100644 (file)
--- a/src/pkg/exp/draw/draw.go
+++ b/src/pkg/exp/draw/draw.go
@@ -165,14 +165,14 @@ func drawFillOver(dst *image.RGBA, r Rectangle, src image.ColorImage) {
        x0, x1 := r.Min.X, r.Max.X
        y0, y1 := r.Min.Y, r.Max.Y
        for y := y0; y != y1; y++ {
-               p := dst.Pixel[y]
+               dpix := dst.Pixel[y]
                for x := x0; x != x1; x++ {
-                       rgba := p[x]
+                       rgba := dpix[x]
                        dr := (uint32(rgba.R)*a)/m + cr
                        dg := (uint32(rgba.G)*a)/m + cg
                        db := (uint32(rgba.B)*a)/m + cb
                        da := (uint32(rgba.A)*a)/m + ca
-                       p[x] = image.RGBAColor{uint8(dr >> 8), uint8(dg >> 8), uint8(db >> 8), uint8(da >> 8)}
+                       dpix[x] = image.RGBAColor{uint8(dr >> 8), uint8(dg >> 8), uint8(db >> 8), uint8(da >> 8)}
                }
        }
 }
@@ -209,14 +209,15 @@ func drawGlyphOver(dst *image.RGBA, r Rectangle, src image.ColorImage, mask *ima
        y0, y1 := r.Min.Y, r.Max.Y
        cr, cg, cb, ca := src.RGBA()
        for y, my := y0, mp.Y; y != y1; y, my = y+1, my+1 {
-               p := dst.Pixel[y]
+               dpix := dst.Pixel[y]
+               mpix := mask.Pixel[my]
                for x, mx := x0, mp.X; x != x1; x, mx = x+1, mx+1 {
-                       ma := uint32(mask.Pixel[my][mx].A)
+                       ma := uint32(mpix[mx].A)
                        if ma == 0 {
                                continue
                        }
                        ma |= ma << 8
-                       rgba := p[x]
+                       rgba := dpix[x]
                        dr := uint32(rgba.R)
                        dg := uint32(rgba.G)
                        db := uint32(rgba.B)
@@ -227,7 +228,7 @@ func drawGlyphOver(dst *image.RGBA, r Rectangle, src image.ColorImage, mask *ima
                        dg = (dg*a + cg*ma) / m
                        db = (db*a + cb*ma) / m
                        da = (da*a + ca*ma) / m
-                       p[x] = image.RGBAColor{uint8(dr >> 8), uint8(dg >> 8), uint8(db >> 8), uint8(da >> 8)}
+                       dpix[x] = image.RGBAColor{uint8(dr >> 8), uint8(dg >> 8), uint8(db >> 8), uint8(da >> 8)}
                }
        }
 }
@@ -277,7 +278,7 @@ func drawRGBA(dst *image.RGBA, r Rectangle, src image.Image, sp Point, mask imag
        for y := y0; y != y1; y, sy, my = y+dy, sy+dy, my+dy {
                sx := sp.X + x0 - r.Min.X
                mx := mp.X + x0 - r.Min.X
-               p := dst.Pixel[y]
+               dpix := dst.Pixel[y]
                for x := x0; x != x1; x, sx, mx = x+dx, sx+dx, mx+dx {
                        ma := uint32(m)
                        if mask != nil {
@@ -286,7 +287,7 @@ func drawRGBA(dst *image.RGBA, r Rectangle, src image.Image, sp Point, mask imag
                        sr, sg, sb, sa := src.At(sx, sy).RGBA()
                        var dr, dg, db, da uint32
                        if op == Over {
-                               rgba := p[x]
+                               rgba := dpix[x]
                                dr = uint32(rgba.R)
                                dg = uint32(rgba.G)
                                db = uint32(rgba.B)
@@ -308,7 +309,7 @@ func drawRGBA(dst *image.RGBA, r Rectangle, src image.Image, sp Point, mask imag
                                db = sb * ma / m
                                da = sa * ma / m
                        }
-                       p[x] = image.RGBAColor{uint8(dr >> 8), uint8(dg >> 8), uint8(db >> 8), uint8(da >> 8)}
+                       dpix[x] = image.RGBAColor{uint8(dr >> 8), uint8(dg >> 8), uint8(db >> 8), uint8(da >> 8)}
                }
        }
 }