image: add type-specific Set methods and use them when decoding PNG.
This speeds up PNG decode about 20% by avoiding per-pixel interface conversions.
R=nigeltao, rsc
CC=golang-dev
https://golang.org/cl/4428080
diff --git a/src/pkg/image/image.go b/src/pkg/image/image.go
index 5f398a3..9f205c1 100644
--- a/src/pkg/image/image.go
+++ b/src/pkg/image/image.go
@@ -51,6 +51,13 @@
p.Pix[y*p.Stride+x] = toRGBAColor(c).(RGBAColor)
}
+func (p *RGBA) SetRGBA(x, y int, c RGBAColor) {
+ if !p.Rect.Contains(Point{x, y}) {
+ return
+ }
+ p.Pix[y*p.Stride+x] = c
+}
+
// Opaque scans the entire image and returns whether or not it is fully opaque.
func (p *RGBA) Opaque() bool {
if p.Rect.Empty() {
@@ -103,6 +110,13 @@
p.Pix[y*p.Stride+x] = toRGBA64Color(c).(RGBA64Color)
}
+func (p *RGBA64) SetRGBA64(x, y int, c RGBA64Color) {
+ if !p.Rect.Contains(Point{x, y}) {
+ return
+ }
+ p.Pix[y*p.Stride+x] = c
+}
+
// Opaque scans the entire image and returns whether or not it is fully opaque.
func (p *RGBA64) Opaque() bool {
if p.Rect.Empty() {
@@ -155,6 +169,13 @@
p.Pix[y*p.Stride+x] = toNRGBAColor(c).(NRGBAColor)
}
+func (p *NRGBA) SetNRGBA(x, y int, c NRGBAColor) {
+ if !p.Rect.Contains(Point{x, y}) {
+ return
+ }
+ p.Pix[y*p.Stride+x] = c
+}
+
// Opaque scans the entire image and returns whether or not it is fully opaque.
func (p *NRGBA) Opaque() bool {
if p.Rect.Empty() {
@@ -207,6 +228,13 @@
p.Pix[y*p.Stride+x] = toNRGBA64Color(c).(NRGBA64Color)
}
+func (p *NRGBA64) SetNRGBA64(x, y int, c NRGBA64Color) {
+ if !p.Rect.Contains(Point{x, y}) {
+ return
+ }
+ p.Pix[y*p.Stride+x] = c
+}
+
// Opaque scans the entire image and returns whether or not it is fully opaque.
func (p *NRGBA64) Opaque() bool {
if p.Rect.Empty() {
@@ -252,11 +280,11 @@
return p.Pix[y*p.Stride+x]
}
-func (p *Alpha) Set(x, y int, c Color) {
+func (p *Alpha) SetAlpha(x, y int, c AlphaColor) {
if !p.Rect.Contains(Point{x, y}) {
return
}
- p.Pix[y*p.Stride+x] = toAlphaColor(c).(AlphaColor)
+ p.Pix[y*p.Stride+x] = c
}
// Opaque scans the entire image and returns whether or not it is fully opaque.
@@ -311,6 +339,13 @@
p.Pix[y*p.Stride+x] = toAlpha16Color(c).(Alpha16Color)
}
+func (p *Alpha16) SetAlpha16(x, y int, c Alpha16Color) {
+ if !p.Rect.Contains(Point{x, y}) {
+ return
+ }
+ p.Pix[y*p.Stride+x] = c
+}
+
// Opaque scans the entire image and returns whether or not it is fully opaque.
func (p *Alpha16) Opaque() bool {
if p.Rect.Empty() {
@@ -363,6 +398,13 @@
p.Pix[y*p.Stride+x] = toGrayColor(c).(GrayColor)
}
+func (p *Gray) SetGray(x, y int, c GrayColor) {
+ if !p.Rect.Contains(Point{x, y}) {
+ return
+ }
+ p.Pix[y*p.Stride+x] = c
+}
+
// Opaque scans the entire image and returns whether or not it is fully opaque.
func (p *Gray) Opaque() bool {
return true
@@ -401,6 +443,13 @@
p.Pix[y*p.Stride+x] = toGray16Color(c).(Gray16Color)
}
+func (p *Gray16) SetGray16(x, y int, c Gray16Color) {
+ if !p.Rect.Contains(Point{x, y}) {
+ return
+ }
+ p.Pix[y*p.Stride+x] = c
+}
+
// Opaque scans the entire image and returns whether or not it is fully opaque.
func (p *Gray16) Opaque() bool {
return true
diff --git a/src/pkg/image/png/reader.go b/src/pkg/image/png/reader.go
index b30a951..8c76afa 100644
--- a/src/pkg/image/png/reader.go
+++ b/src/pkg/image/png/reader.go
@@ -378,7 +378,7 @@
for x := 0; x < d.width; x += 8 {
b := cdat[x/8]
for x2 := 0; x2 < 8 && x+x2 < d.width; x2++ {
- gray.Set(x+x2, y, image.GrayColor{(b >> 7) * 0xff})
+ gray.SetGray(x+x2, y, image.GrayColor{(b >> 7) * 0xff})
b <<= 1
}
}
@@ -386,7 +386,7 @@
for x := 0; x < d.width; x += 4 {
b := cdat[x/4]
for x2 := 0; x2 < 4 && x+x2 < d.width; x2++ {
- gray.Set(x+x2, y, image.GrayColor{(b >> 6) * 0x55})
+ gray.SetGray(x+x2, y, image.GrayColor{(b >> 6) * 0x55})
b <<= 2
}
}
@@ -394,22 +394,22 @@
for x := 0; x < d.width; x += 2 {
b := cdat[x/2]
for x2 := 0; x2 < 2 && x+x2 < d.width; x2++ {
- gray.Set(x+x2, y, image.GrayColor{(b >> 4) * 0x11})
+ gray.SetGray(x+x2, y, image.GrayColor{(b >> 4) * 0x11})
b <<= 4
}
}
case cbG8:
for x := 0; x < d.width; x++ {
- gray.Set(x, y, image.GrayColor{cdat[x]})
+ gray.SetGray(x, y, image.GrayColor{cdat[x]})
}
case cbGA8:
for x := 0; x < d.width; x++ {
ycol := cdat[2*x+0]
- nrgba.Set(x, y, image.NRGBAColor{ycol, ycol, ycol, cdat[2*x+1]})
+ nrgba.SetNRGBA(x, y, image.NRGBAColor{ycol, ycol, ycol, cdat[2*x+1]})
}
case cbTC8:
for x := 0; x < d.width; x++ {
- rgba.Set(x, y, image.RGBAColor{cdat[3*x+0], cdat[3*x+1], cdat[3*x+2], 0xff})
+ rgba.SetRGBA(x, y, image.RGBAColor{cdat[3*x+0], cdat[3*x+1], cdat[3*x+2], 0xff})
}
case cbP1:
for x := 0; x < d.width; x += 8 {
@@ -456,25 +456,25 @@
}
case cbTCA8:
for x := 0; x < d.width; x++ {
- nrgba.Set(x, y, image.NRGBAColor{cdat[4*x+0], cdat[4*x+1], cdat[4*x+2], cdat[4*x+3]})
+ nrgba.SetNRGBA(x, y, image.NRGBAColor{cdat[4*x+0], cdat[4*x+1], cdat[4*x+2], cdat[4*x+3]})
}
case cbG16:
for x := 0; x < d.width; x++ {
ycol := uint16(cdat[2*x+0])<<8 | uint16(cdat[2*x+1])
- gray16.Set(x, y, image.Gray16Color{ycol})
+ gray16.SetGray16(x, y, image.Gray16Color{ycol})
}
case cbGA16:
for x := 0; x < d.width; x++ {
ycol := uint16(cdat[4*x+0])<<8 | uint16(cdat[4*x+1])
acol := uint16(cdat[4*x+2])<<8 | uint16(cdat[4*x+3])
- nrgba64.Set(x, y, image.NRGBA64Color{ycol, ycol, ycol, acol})
+ nrgba64.SetNRGBA64(x, y, image.NRGBA64Color{ycol, ycol, ycol, acol})
}
case cbTC16:
for x := 0; x < d.width; x++ {
rcol := uint16(cdat[6*x+0])<<8 | uint16(cdat[6*x+1])
gcol := uint16(cdat[6*x+2])<<8 | uint16(cdat[6*x+3])
bcol := uint16(cdat[6*x+4])<<8 | uint16(cdat[6*x+5])
- rgba64.Set(x, y, image.RGBA64Color{rcol, gcol, bcol, 0xffff})
+ rgba64.SetRGBA64(x, y, image.RGBA64Color{rcol, gcol, bcol, 0xffff})
}
case cbTCA16:
for x := 0; x < d.width; x++ {
@@ -482,7 +482,7 @@
gcol := uint16(cdat[8*x+2])<<8 | uint16(cdat[8*x+3])
bcol := uint16(cdat[8*x+4])<<8 | uint16(cdat[8*x+5])
acol := uint16(cdat[8*x+6])<<8 | uint16(cdat[8*x+7])
- nrgba64.Set(x, y, image.NRGBA64Color{rcol, gcol, bcol, acol})
+ nrgba64.SetNRGBA64(x, y, image.NRGBA64Color{rcol, gcol, bcol, acol})
}
}
