1 files changed, 27 insertions(+), 16 deletions(-)

M srgb.go

@@ 16,36 16,47 @@ import (
 
 // SRGBA wraps an Image encoded in the sRGB color space.
 type SRGBA struct {
-	image.Image
+	image.RGBA64Image
 }
 
+// NewSRGBA returns an SRGBA that wraps img. It panics if ima
+// doesn't implement image.RGBA64Image.
 func NewSRGBA(img image.Image) *SRGBA {
-	return &SRGBA{img}
+	return &SRGBA{img.(image.RGBA64Image)}
 }
 
-// At converts an sRGB color from the underlying image to linear RGB.
-func (p *SRGBA) At(x, y int) color.Color {
-	c := p.Image.At(x, y)
-	r, g, b, a := c.RGBA()
+// RGBA64At converts an sRGB color from the underlying image to linear RGB.
+func (p *SRGBA) RGBA64At(x, y int) color.RGBA64 {
+	c := p.RGBA64Image.RGBA64At(x, y)
 	ret := color.RGBA64{
-		uint16(sRGBToLinear(float32(r)/0xffff)*0xffff + .5),
-		uint16(sRGBToLinear(float32(g)/0xffff)*0xffff + .5),
-		uint16(sRGBToLinear(float32(b)/0xffff)*0xffff + .5),
-		uint16(a),
+		uint16(sRGBToLinear(float32(c.R)/0xffff)*0xffff + .5),
+		uint16(sRGBToLinear(float32(c.G)/0xffff)*0xffff + .5),
+		uint16(sRGBToLinear(float32(c.B)/0xffff)*0xffff + .5),
+		c.A,
 	}
 	return ret
 }
 
+// At converts an sRGB color from the underlying image to linear RGB.
+func (p *SRGBA) At(x, y int) color.Color {
+	return p.RGBA64At(x, y)
+}
+
 // Set converts a linear RGB color to sRGB and stores it in the underlying image.
 func (p *SRGBA) Set(x, y int, c color.Color) {
 	r, g, b, a := c.RGBA()
-	srgb := color.RGBA{
-		uint8(linearTosRGB(float32(r)/0xffff)*0xff + .5),
-		uint8(linearTosRGB(float32(g)/0xffff)*0xff + .5),
-		uint8(linearTosRGB(float32(b)/0xffff)*0xff + .5),
-		uint8(a >> 8),
+	p.SetRGBA64(x, y, color.RGBA64{uint16(r), uint16(g), uint16(b), uint16(a)})
+}
+
+// SetRGBA64 converts a linear RGB color to sRGB and stores it in the underlying image.
+func (p *SRGBA) SetRGBA64(x, y int, c color.RGBA64) {
+	srgb := color.RGBA64{
+		uint16(linearTosRGB(float32(c.R)/0xffff)*0xffff + .5),
+		uint16(linearTosRGB(float32(c.G)/0xffff)*0xffff + .5),
+		uint16(linearTosRGB(float32(c.B)/0xffff)*0xffff + .5),
+		c.A,
 	}
-	p.Image.(draw.Image).Set(x, y, srgb)
+	p.RGBA64Image.(draw.RGBA64Image).SetRGBA64(x, y, srgb)
 }
 
 func linearTosRGB(c float32) float32 {