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Diffstat (limited to 'src/pkg/image/draw/draw.go')
-rw-r--r--src/pkg/image/draw/draw.go96
1 files changed, 44 insertions, 52 deletions
diff --git a/src/pkg/image/draw/draw.go b/src/pkg/image/draw/draw.go
index a748ff8c7..3b6679f7c 100644
--- a/src/pkg/image/draw/draw.go
+++ b/src/pkg/image/draw/draw.go
@@ -2,15 +2,15 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
-// Package draw provides image composition functions
-// in the style of the Plan 9 graphics library
-// (see http://plan9.bell-labs.com/magic/man2html/2/draw)
-// and the X Render extension.
+// Package draw provides image composition functions.
+//
+// See "The Go image/draw package" for an introduction to this package:
+// http://blog.golang.org/2011/09/go-imagedraw-package.html
package draw
import (
"image"
- "image/ycbcr"
+ "image/color"
)
// m is the maximum color value returned by image.Color.RGBA.
@@ -26,12 +26,10 @@ const (
Src
)
-var zeroColor image.Color = image.AlphaColor{0}
-
// A draw.Image is an image.Image with a Set method to change a single pixel.
type Image interface {
image.Image
- Set(x, y int, c image.Color)
+ Set(x, y int, c color.Color)
}
// Draw calls DrawMask with a nil mask.
@@ -73,7 +71,7 @@ func DrawMask(dst Image, r image.Rectangle, src image.Image, sp image.Point, mas
if op == Over {
if mask == nil {
switch src0 := src.(type) {
- case *image.ColorImage:
+ case *image.Uniform:
drawFillOver(dst0, r, src0)
return
case *image.RGBA:
@@ -82,13 +80,13 @@ func DrawMask(dst Image, r image.Rectangle, src image.Image, sp image.Point, mas
case *image.NRGBA:
drawNRGBAOver(dst0, r, src0, sp)
return
- case *ycbcr.YCbCr:
+ case *image.YCbCr:
drawYCbCr(dst0, r, src0, sp)
return
}
} else if mask0, ok := mask.(*image.Alpha); ok {
switch src0 := src.(type) {
- case *image.ColorImage:
+ case *image.Uniform:
drawGlyphOver(dst0, r, src0, mask0, mp)
return
}
@@ -96,7 +94,7 @@ func DrawMask(dst Image, r image.Rectangle, src image.Image, sp image.Point, mas
} else {
if mask == nil {
switch src0 := src.(type) {
- case *image.ColorImage:
+ case *image.Uniform:
drawFillSrc(dst0, r, src0)
return
case *image.RGBA:
@@ -105,7 +103,7 @@ func DrawMask(dst Image, r image.Rectangle, src image.Image, sp image.Point, mas
case *image.NRGBA:
drawNRGBASrc(dst0, r, src0, sp)
return
- case *ycbcr.YCbCr:
+ case *image.YCbCr:
drawYCbCr(dst0, r, src0, sp)
return
}
@@ -125,7 +123,7 @@ func DrawMask(dst Image, r image.Rectangle, src image.Image, sp image.Point, mas
}
}
- var out *image.RGBA64Color
+ var out *color.RGBA64
sy := sp.Y + y0 - r.Min.Y
my := mp.Y + y0 - r.Min.Y
for y := y0; y != y1; y, sy, my = y+dy, sy+dy, my+dy {
@@ -141,14 +139,14 @@ func DrawMask(dst Image, r image.Rectangle, src image.Image, sp image.Point, mas
if op == Over {
// No-op.
} else {
- dst.Set(x, y, zeroColor)
+ dst.Set(x, y, color.Transparent)
}
case ma == m && op == Src:
dst.Set(x, y, src.At(sx, sy))
default:
sr, sg, sb, sa := src.At(sx, sy).RGBA()
if out == nil {
- out = new(image.RGBA64Color)
+ out = new(color.RGBA64)
}
if op == Over {
dr, dg, db, da := dst.At(x, y).RGBA()
@@ -169,11 +167,11 @@ func DrawMask(dst Image, r image.Rectangle, src image.Image, sp image.Point, mas
}
}
-func drawFillOver(dst *image.RGBA, r image.Rectangle, src *image.ColorImage) {
+func drawFillOver(dst *image.RGBA, r image.Rectangle, src *image.Uniform) {
sr, sg, sb, sa := src.RGBA()
// The 0x101 is here for the same reason as in drawRGBA.
a := (m - sa) * 0x101
- i0 := (r.Min.Y-dst.Rect.Min.Y)*dst.Stride + (r.Min.X-dst.Rect.Min.X)*4
+ i0 := dst.PixOffset(r.Min.X, r.Min.Y)
i1 := i0 + r.Dx()*4
for y := r.Min.Y; y != r.Max.Y; y++ {
for i := i0; i < i1; i += 4 {
@@ -192,12 +190,12 @@ func drawFillOver(dst *image.RGBA, r image.Rectangle, src *image.ColorImage) {
}
}
-func drawFillSrc(dst *image.RGBA, r image.Rectangle, src *image.ColorImage) {
+func drawFillSrc(dst *image.RGBA, r image.Rectangle, src *image.Uniform) {
sr, sg, sb, sa := src.RGBA()
// The built-in copy function is faster than a straightforward for loop to fill the destination with
// the color, but copy requires a slice source. We therefore use a for loop to fill the first row, and
// then use the first row as the slice source for the remaining rows.
- i0 := (r.Min.Y-dst.Rect.Min.Y)*dst.Stride + (r.Min.X-dst.Rect.Min.X)*4
+ i0 := dst.PixOffset(r.Min.X, r.Min.Y)
i1 := i0 + r.Dx()*4
for i := i0; i < i1; i += 4 {
dst.Pix[i+0] = uint8(sr >> 8)
@@ -215,8 +213,8 @@ func drawFillSrc(dst *image.RGBA, r image.Rectangle, src *image.ColorImage) {
func drawCopyOver(dst *image.RGBA, r image.Rectangle, src *image.RGBA, sp image.Point) {
dx, dy := r.Dx(), r.Dy()
- d0 := (r.Min.Y-dst.Rect.Min.Y)*dst.Stride + (r.Min.X-dst.Rect.Min.X)*4
- s0 := (sp.Y-src.Rect.Min.Y)*src.Stride + (sp.X-src.Rect.Min.X)*4
+ d0 := dst.PixOffset(r.Min.X, r.Min.Y)
+ s0 := src.PixOffset(sp.X, sp.Y)
var (
ddelta, sdelta int
i0, i1, idelta int
@@ -263,8 +261,8 @@ func drawCopyOver(dst *image.RGBA, r image.Rectangle, src *image.RGBA, sp image.
func drawCopySrc(dst *image.RGBA, r image.Rectangle, src *image.RGBA, sp image.Point) {
n, dy := 4*r.Dx(), r.Dy()
- d0 := (r.Min.Y-dst.Rect.Min.Y)*dst.Stride + (r.Min.X-dst.Rect.Min.X)*4
- s0 := (sp.Y-src.Rect.Min.Y)*src.Stride + (sp.X-src.Rect.Min.X)*4
+ d0 := dst.PixOffset(r.Min.X, r.Min.Y)
+ s0 := src.PixOffset(sp.X, sp.Y)
var ddelta, sdelta int
if r.Min.Y <= sp.Y {
ddelta = dst.Stride
@@ -347,41 +345,36 @@ func drawNRGBASrc(dst *image.RGBA, r image.Rectangle, src *image.NRGBA, sp image
}
}
-func drawYCbCr(dst *image.RGBA, r image.Rectangle, src *ycbcr.YCbCr, sp image.Point) {
- // A YCbCr image is always fully opaque, and so if the mask is implicitly nil
+func drawYCbCr(dst *image.RGBA, r image.Rectangle, src *image.YCbCr, sp image.Point) {
+ // An image.YCbCr is always fully opaque, and so if the mask is implicitly nil
// (i.e. fully opaque) then the op is effectively always Src.
- var (
- yy, cb, cr uint8
- )
x0 := (r.Min.X - dst.Rect.Min.X) * 4
x1 := (r.Max.X - dst.Rect.Min.X) * 4
y0 := r.Min.Y - dst.Rect.Min.Y
y1 := r.Max.Y - dst.Rect.Min.Y
switch src.SubsampleRatio {
- case ycbcr.SubsampleRatio422:
+ case image.YCbCrSubsampleRatio422:
for y, sy := y0, sp.Y; y != y1; y, sy = y+1, sy+1 {
dpix := dst.Pix[y*dst.Stride:]
- for x, sx := x0, sp.X; x != x1; x, sx = x+4, sx+1 {
- i := sx / 2
- yy = src.Y[sy*src.YStride+sx]
- cb = src.Cb[sy*src.CStride+i]
- cr = src.Cr[sy*src.CStride+i]
- rr, gg, bb := ycbcr.YCbCrToRGB(yy, cb, cr)
+ yi := (sy-src.Rect.Min.Y)*src.YStride + (sp.X - src.Rect.Min.X)
+ ciBase := (sy-src.Rect.Min.Y)*src.CStride - src.Rect.Min.X/2
+ 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
dpix[x+3] = 255
}
}
- case ycbcr.SubsampleRatio420:
+ case image.YCbCrSubsampleRatio420:
for y, sy := y0, sp.Y; y != y1; y, sy = y+1, sy+1 {
dpix := dst.Pix[y*dst.Stride:]
- for x, sx := x0, sp.X; x != x1; x, sx = x+4, sx+1 {
- i, j := sx/2, sy/2
- yy = src.Y[sy*src.YStride+sx]
- cb = src.Cb[j*src.CStride+i]
- cr = src.Cr[j*src.CStride+i]
- rr, gg, bb := ycbcr.YCbCrToRGB(yy, cb, cr)
+ yi := (sy-src.Rect.Min.Y)*src.YStride + (sp.X - src.Rect.Min.X)
+ ciBase := (sy/2-src.Rect.Min.Y/2)*src.CStride - src.Rect.Min.X/2
+ 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
@@ -392,11 +385,10 @@ func drawYCbCr(dst *image.RGBA, r image.Rectangle, src *ycbcr.YCbCr, sp image.Po
// Default to 4:4:4 subsampling.
for y, sy := y0, sp.Y; y != y1; y, sy = y+1, sy+1 {
dpix := dst.Pix[y*dst.Stride:]
- for x, sx := x0, sp.X; x != x1; x, sx = x+4, sx+1 {
- yy = src.Y[sy*src.YStride+sx]
- cb = src.Cb[sy*src.CStride+sx]
- cr = src.Cr[sy*src.CStride+sx]
- rr, gg, bb := ycbcr.YCbCrToRGB(yy, cb, cr)
+ yi := (sy-src.Rect.Min.Y)*src.YStride + (sp.X - src.Rect.Min.X)
+ 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
@@ -406,10 +398,10 @@ func drawYCbCr(dst *image.RGBA, r image.Rectangle, src *ycbcr.YCbCr, sp image.Po
}
}
-func drawGlyphOver(dst *image.RGBA, r image.Rectangle, src *image.ColorImage, mask *image.Alpha, mp image.Point) {
- i0 := (r.Min.Y-dst.Rect.Min.Y)*dst.Stride + (r.Min.X-dst.Rect.Min.X)*4
+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
- mi0 := (mp.Y-mask.Rect.Min.Y)*mask.Stride + mp.X - mask.Rect.Min.X
+ mi0 := mask.PixOffset(mp.X, mp.Y)
sr, sg, sb, sa := src.RGBA()
for y, my := r.Min.Y, mp.Y; y != r.Max.Y; y, my = y+1, my+1 {
for i, mi := i0, mi0; i < i1; i, mi = i+4, mi+1 {
@@ -453,7 +445,7 @@ func drawRGBA(dst *image.RGBA, r image.Rectangle, src image.Image, sp image.Poin
sx0 := sp.X + x0 - r.Min.X
mx0 := mp.X + x0 - r.Min.X
sx1 := sx0 + (x1 - x0)
- i0 := (y0-dst.Rect.Min.Y)*dst.Stride + (x0-dst.Rect.Min.X)*4
+ i0 := dst.PixOffset(x0, y0)
di := dx * 4
for y := y0; y != y1; y, sy, my = y+dy, sy+dy, my+dy {
for i, sx, mx := i0, sx0, mx0; sx != sx1; i, sx, mx = i+di, sx+dx, mx+dx {
generated by cgit v1.2.3 (git 2.46.0) at 2025-10-23 10:59:37 +0000