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image: add a SubImage method.

R=r
CC=golang-dev
https://golang.org/cl/4515179
This commit is contained in:
Nigel Tao 2011-06-02 18:51:41 +10:00
parent b873701dbd
commit 422abf3b8e
2 changed files with 100 additions and 0 deletions

View File

@ -58,6 +58,16 @@ func (p *RGBA) SetRGBA(x, y int, c RGBAColor) {
p.Pix[y*p.Stride+x] = c
}
// SubImage returns an image representing the portion of the image p visible
// through r. The returned value shares pixels with the original image.
func (p *RGBA) SubImage(r Rectangle) Image {
return &RGBA{
Pix: p.Pix,
Stride: p.Stride,
Rect: p.Rect.Intersect(r),
}
}
// Opaque scans the entire image and returns whether or not it is fully opaque.
func (p *RGBA) Opaque() bool {
if p.Rect.Empty() {
@ -117,6 +127,16 @@ func (p *RGBA64) SetRGBA64(x, y int, c RGBA64Color) {
p.Pix[y*p.Stride+x] = c
}
// SubImage returns an image representing the portion of the image p visible
// through r. The returned value shares pixels with the original image.
func (p *RGBA64) SubImage(r Rectangle) Image {
return &RGBA64{
Pix: p.Pix,
Stride: p.Stride,
Rect: p.Rect.Intersect(r),
}
}
// Opaque scans the entire image and returns whether or not it is fully opaque.
func (p *RGBA64) Opaque() bool {
if p.Rect.Empty() {
@ -176,6 +196,16 @@ func (p *NRGBA) SetNRGBA(x, y int, c NRGBAColor) {
p.Pix[y*p.Stride+x] = c
}
// SubImage returns an image representing the portion of the image p visible
// through r. The returned value shares pixels with the original image.
func (p *NRGBA) SubImage(r Rectangle) Image {
return &NRGBA{
Pix: p.Pix,
Stride: p.Stride,
Rect: p.Rect.Intersect(r),
}
}
// Opaque scans the entire image and returns whether or not it is fully opaque.
func (p *NRGBA) Opaque() bool {
if p.Rect.Empty() {
@ -235,6 +265,16 @@ func (p *NRGBA64) SetNRGBA64(x, y int, c NRGBA64Color) {
p.Pix[y*p.Stride+x] = c
}
// SubImage returns an image representing the portion of the image p visible
// through r. The returned value shares pixels with the original image.
func (p *NRGBA64) SubImage(r Rectangle) Image {
return &NRGBA64{
Pix: p.Pix,
Stride: p.Stride,
Rect: p.Rect.Intersect(r),
}
}
// Opaque scans the entire image and returns whether or not it is fully opaque.
func (p *NRGBA64) Opaque() bool {
if p.Rect.Empty() {
@ -294,6 +334,16 @@ func (p *Alpha) SetAlpha(x, y int, c AlphaColor) {
p.Pix[y*p.Stride+x] = c
}
// SubImage returns an image representing the portion of the image p visible
// through r. The returned value shares pixels with the original image.
func (p *Alpha) SubImage(r Rectangle) Image {
return &Alpha{
Pix: p.Pix,
Stride: p.Stride,
Rect: p.Rect.Intersect(r),
}
}
// Opaque scans the entire image and returns whether or not it is fully opaque.
func (p *Alpha) Opaque() bool {
if p.Rect.Empty() {
@ -353,6 +403,16 @@ func (p *Alpha16) SetAlpha16(x, y int, c Alpha16Color) {
p.Pix[y*p.Stride+x] = c
}
// SubImage returns an image representing the portion of the image p visible
// through r. The returned value shares pixels with the original image.
func (p *Alpha16) SubImage(r Rectangle) Image {
return &Alpha16{
Pix: p.Pix,
Stride: p.Stride,
Rect: p.Rect.Intersect(r),
}
}
// Opaque scans the entire image and returns whether or not it is fully opaque.
func (p *Alpha16) Opaque() bool {
if p.Rect.Empty() {
@ -412,6 +472,16 @@ func (p *Gray) SetGray(x, y int, c GrayColor) {
p.Pix[y*p.Stride+x] = c
}
// SubImage returns an image representing the portion of the image p visible
// through r. The returned value shares pixels with the original image.
func (p *Gray) SubImage(r Rectangle) Image {
return &Gray{
Pix: p.Pix,
Stride: p.Stride,
Rect: p.Rect.Intersect(r),
}
}
// Opaque scans the entire image and returns whether or not it is fully opaque.
func (p *Gray) Opaque() bool {
return true
@ -457,6 +527,16 @@ func (p *Gray16) SetGray16(x, y int, c Gray16Color) {
p.Pix[y*p.Stride+x] = c
}
// SubImage returns an image representing the portion of the image p visible
// through r. The returned value shares pixels with the original image.
func (p *Gray16) SubImage(r Rectangle) Image {
return &Gray16{
Pix: p.Pix,
Stride: p.Stride,
Rect: p.Rect.Intersect(r),
}
}
// Opaque scans the entire image and returns whether or not it is fully opaque.
func (p *Gray16) Opaque() bool {
return true
@ -544,6 +624,17 @@ func (p *Paletted) SetColorIndex(x, y int, index uint8) {
p.Pix[y*p.Stride+x] = index
}
// SubImage returns an image representing the portion of the image p visible
// through r. The returned value shares pixels with the original image.
func (p *Paletted) SubImage(r Rectangle) Image {
return &Paletted{
Pix: p.Pix,
Stride: p.Stride,
Rect: p.Rect.Intersect(r),
Palette: p.Palette,
}
}
// Opaque scans the entire image and returns whether or not it is fully opaque.
func (p *Paletted) Opaque() bool {
for _, c := range p.Palette {

View File

@ -169,6 +169,15 @@ func (p *YCbCr) At(x, y int) image.Color {
}
}
// SubImage returns an image representing the portion of the image p visible
// through r. The returned value shares pixels with the original image.
func (p *YCbCr) SubImage(r image.Rectangle) image.Image {
q := new(YCbCr)
*q = *p
q.Rect = q.Rect.Intersect(r)
return q
}
func (p *YCbCr) Opaque() bool {
return true
}