| // Copyright 2009 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Package image implements a basic 2-D image library. |
| // |
| // See "The Go image package" for an introduction to this package: |
| // http://blog.golang.org/2011/09/go-image-package.html |
| package image |
| |
| // Config holds an image's color model and dimensions. |
| type Config struct { |
| ColorModel ColorModel |
| Width, Height int |
| } |
| |
| // Image is a finite rectangular grid of Colors drawn from a ColorModel. |
| type Image interface { |
| // ColorModel returns the Image's ColorModel. |
| ColorModel() ColorModel |
| // Bounds returns the domain for which At can return non-zero color. |
| // The bounds do not necessarily contain the point (0, 0). |
| Bounds() Rectangle |
| // At returns the color of the pixel at (x, y). |
| // At(Bounds().Min.X, Bounds().Min.Y) returns the upper-left pixel of the grid. |
| // At(Bounds().Max.X-1, Bounds().Max.Y-1) returns the lower-right one. |
| At(x, y int) Color |
| } |
| |
| // RGBA is an in-memory image of RGBAColor values. |
| type RGBA struct { |
| // Pix holds the image's pixels, in R, G, B, A order. The pixel at |
| // (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*4]. |
| Pix []uint8 |
| // Stride is the Pix stride (in bytes) between vertically adjacent pixels. |
| Stride int |
| // Rect is the image's bounds. |
| Rect Rectangle |
| } |
| |
| func (p *RGBA) ColorModel() ColorModel { return RGBAColorModel } |
| |
| func (p *RGBA) Bounds() Rectangle { return p.Rect } |
| |
| func (p *RGBA) At(x, y int) Color { |
| if !(Point{x, y}.In(p.Rect)) { |
| return RGBAColor{} |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4 |
| return RGBAColor{p.Pix[i+0], p.Pix[i+1], p.Pix[i+2], p.Pix[i+3]} |
| } |
| |
| func (p *RGBA) Set(x, y int, c Color) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4 |
| c1 := toRGBAColor(c).(RGBAColor) |
| p.Pix[i+0] = c1.R |
| p.Pix[i+1] = c1.G |
| p.Pix[i+2] = c1.B |
| p.Pix[i+3] = c1.A |
| } |
| |
| func (p *RGBA) SetRGBA(x, y int, c RGBAColor) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4 |
| p.Pix[i+0] = c.R |
| p.Pix[i+1] = c.G |
| p.Pix[i+2] = c.B |
| p.Pix[i+3] = c.A |
| } |
| |
| // 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 { |
| r = r.Intersect(p.Rect) |
| // If r1 and r2 are Rectangles, r1.Intersect(r2) is not guaranteed to be inside |
| // either r1 or r2 if the intersection is empty. Without explicitly checking for |
| // this, the Pix[i:] expression below can panic. |
| if r.Empty() { |
| return &RGBA{} |
| } |
| i := (r.Min.Y-p.Rect.Min.Y)*p.Stride + (r.Min.X-p.Rect.Min.X)*4 |
| return &RGBA{ |
| Pix: p.Pix[i:], |
| Stride: p.Stride, |
| Rect: r, |
| } |
| } |
| |
| // Opaque scans the entire image and returns whether or not it is fully opaque. |
| func (p *RGBA) Opaque() bool { |
| if p.Rect.Empty() { |
| return true |
| } |
| i0, i1 := 3, p.Rect.Dx()*4 |
| for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ { |
| for i := i0; i < i1; i += 4 { |
| if p.Pix[i] != 0xff { |
| return false |
| } |
| } |
| i0 += p.Stride |
| i1 += p.Stride |
| } |
| return true |
| } |
| |
| // NewRGBA returns a new RGBA with the given width and height. |
| func NewRGBA(w, h int) *RGBA { |
| buf := make([]uint8, 4*w*h) |
| return &RGBA{buf, 4 * w, Rectangle{ZP, Point{w, h}}} |
| } |
| |
| // RGBA64 is an in-memory image of RGBA64Color values. |
| type RGBA64 struct { |
| // Pix holds the image's pixels, in R, G, B, A order and big-endian format. The pixel at |
| // (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*8]. |
| Pix []uint8 |
| // Stride is the Pix stride (in bytes) between vertically adjacent pixels. |
| Stride int |
| // Rect is the image's bounds. |
| Rect Rectangle |
| } |
| |
| func (p *RGBA64) ColorModel() ColorModel { return RGBA64ColorModel } |
| |
| func (p *RGBA64) Bounds() Rectangle { return p.Rect } |
| |
| func (p *RGBA64) At(x, y int) Color { |
| if !(Point{x, y}.In(p.Rect)) { |
| return RGBA64Color{} |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*8 |
| return RGBA64Color{ |
| uint16(p.Pix[i+0])<<8 | uint16(p.Pix[i+1]), |
| uint16(p.Pix[i+2])<<8 | uint16(p.Pix[i+3]), |
| uint16(p.Pix[i+4])<<8 | uint16(p.Pix[i+5]), |
| uint16(p.Pix[i+6])<<8 | uint16(p.Pix[i+7]), |
| } |
| } |
| |
| func (p *RGBA64) Set(x, y int, c Color) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*8 |
| c1 := toRGBA64Color(c).(RGBA64Color) |
| p.Pix[i+0] = uint8(c1.R >> 8) |
| p.Pix[i+1] = uint8(c1.R) |
| p.Pix[i+2] = uint8(c1.G >> 8) |
| p.Pix[i+3] = uint8(c1.G) |
| p.Pix[i+4] = uint8(c1.B >> 8) |
| p.Pix[i+5] = uint8(c1.B) |
| p.Pix[i+6] = uint8(c1.A >> 8) |
| p.Pix[i+7] = uint8(c1.A) |
| } |
| |
| func (p *RGBA64) SetRGBA64(x, y int, c RGBA64Color) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*8 |
| p.Pix[i+0] = uint8(c.R >> 8) |
| p.Pix[i+1] = uint8(c.R) |
| p.Pix[i+2] = uint8(c.G >> 8) |
| p.Pix[i+3] = uint8(c.G) |
| p.Pix[i+4] = uint8(c.B >> 8) |
| p.Pix[i+5] = uint8(c.B) |
| p.Pix[i+6] = uint8(c.A >> 8) |
| p.Pix[i+7] = uint8(c.A) |
| } |
| |
| // 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 { |
| r = r.Intersect(p.Rect) |
| // If r1 and r2 are Rectangles, r1.Intersect(r2) is not guaranteed to be inside |
| // either r1 or r2 if the intersection is empty. Without explicitly checking for |
| // this, the Pix[i:] expression below can panic. |
| if r.Empty() { |
| return &RGBA64{} |
| } |
| i := (r.Min.Y-p.Rect.Min.Y)*p.Stride + (r.Min.X-p.Rect.Min.X)*8 |
| return &RGBA64{ |
| Pix: p.Pix[i:], |
| Stride: p.Stride, |
| Rect: r, |
| } |
| } |
| |
| // Opaque scans the entire image and returns whether or not it is fully opaque. |
| func (p *RGBA64) Opaque() bool { |
| if p.Rect.Empty() { |
| return true |
| } |
| i0, i1 := 6, p.Rect.Dx()*8 |
| for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ { |
| for i := i0; i < i1; i += 8 { |
| if p.Pix[i+0] != 0xff || p.Pix[i+1] != 0xff { |
| return false |
| } |
| } |
| i0 += p.Stride |
| i1 += p.Stride |
| } |
| return true |
| } |
| |
| // NewRGBA64 returns a new RGBA64 with the given width and height. |
| func NewRGBA64(w, h int) *RGBA64 { |
| pix := make([]uint8, 8*w*h) |
| return &RGBA64{pix, 8 * w, Rectangle{ZP, Point{w, h}}} |
| } |
| |
| // NRGBA is an in-memory image of NRGBAColor values. |
| type NRGBA struct { |
| // Pix holds the image's pixels, in R, G, B, A order. The pixel at |
| // (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*4]. |
| Pix []uint8 |
| // Stride is the Pix stride (in bytes) between vertically adjacent pixels. |
| Stride int |
| // Rect is the image's bounds. |
| Rect Rectangle |
| } |
| |
| func (p *NRGBA) ColorModel() ColorModel { return NRGBAColorModel } |
| |
| func (p *NRGBA) Bounds() Rectangle { return p.Rect } |
| |
| func (p *NRGBA) At(x, y int) Color { |
| if !(Point{x, y}.In(p.Rect)) { |
| return NRGBAColor{} |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4 |
| return NRGBAColor{p.Pix[i+0], p.Pix[i+1], p.Pix[i+2], p.Pix[i+3]} |
| } |
| |
| func (p *NRGBA) Set(x, y int, c Color) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4 |
| c1 := toNRGBAColor(c).(NRGBAColor) |
| p.Pix[i+0] = c1.R |
| p.Pix[i+1] = c1.G |
| p.Pix[i+2] = c1.B |
| p.Pix[i+3] = c1.A |
| } |
| |
| func (p *NRGBA) SetNRGBA(x, y int, c NRGBAColor) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4 |
| p.Pix[i+0] = c.R |
| p.Pix[i+1] = c.G |
| p.Pix[i+2] = c.B |
| p.Pix[i+3] = c.A |
| } |
| |
| // 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 { |
| r = r.Intersect(p.Rect) |
| // If r1 and r2 are Rectangles, r1.Intersect(r2) is not guaranteed to be inside |
| // either r1 or r2 if the intersection is empty. Without explicitly checking for |
| // this, the Pix[i:] expression below can panic. |
| if r.Empty() { |
| return &NRGBA{} |
| } |
| i := (r.Min.Y-p.Rect.Min.Y)*p.Stride + (r.Min.X-p.Rect.Min.X)*4 |
| return &NRGBA{ |
| Pix: p.Pix[i:], |
| Stride: p.Stride, |
| Rect: r, |
| } |
| } |
| |
| // Opaque scans the entire image and returns whether or not it is fully opaque. |
| func (p *NRGBA) Opaque() bool { |
| if p.Rect.Empty() { |
| return true |
| } |
| i0, i1 := 3, p.Rect.Dx()*4 |
| for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ { |
| for i := i0; i < i1; i += 4 { |
| if p.Pix[i] != 0xff { |
| return false |
| } |
| } |
| i0 += p.Stride |
| i1 += p.Stride |
| } |
| return true |
| } |
| |
| // NewNRGBA returns a new NRGBA with the given width and height. |
| func NewNRGBA(w, h int) *NRGBA { |
| pix := make([]uint8, 4*w*h) |
| return &NRGBA{pix, 4 * w, Rectangle{ZP, Point{w, h}}} |
| } |
| |
| // NRGBA64 is an in-memory image of NRGBA64Color values. |
| type NRGBA64 struct { |
| // Pix holds the image's pixels, in R, G, B, A order and big-endian format. The pixel at |
| // (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*8]. |
| Pix []uint8 |
| // Stride is the Pix stride (in bytes) between vertically adjacent pixels. |
| Stride int |
| // Rect is the image's bounds. |
| Rect Rectangle |
| } |
| |
| func (p *NRGBA64) ColorModel() ColorModel { return NRGBA64ColorModel } |
| |
| func (p *NRGBA64) Bounds() Rectangle { return p.Rect } |
| |
| func (p *NRGBA64) At(x, y int) Color { |
| if !(Point{x, y}.In(p.Rect)) { |
| return NRGBA64Color{} |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*8 |
| return NRGBA64Color{ |
| uint16(p.Pix[i+0])<<8 | uint16(p.Pix[i+1]), |
| uint16(p.Pix[i+2])<<8 | uint16(p.Pix[i+3]), |
| uint16(p.Pix[i+4])<<8 | uint16(p.Pix[i+5]), |
| uint16(p.Pix[i+6])<<8 | uint16(p.Pix[i+7]), |
| } |
| } |
| |
| func (p *NRGBA64) Set(x, y int, c Color) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*8 |
| c1 := toNRGBA64Color(c).(NRGBA64Color) |
| p.Pix[i+0] = uint8(c1.R >> 8) |
| p.Pix[i+1] = uint8(c1.R) |
| p.Pix[i+2] = uint8(c1.G >> 8) |
| p.Pix[i+3] = uint8(c1.G) |
| p.Pix[i+4] = uint8(c1.B >> 8) |
| p.Pix[i+5] = uint8(c1.B) |
| p.Pix[i+6] = uint8(c1.A >> 8) |
| p.Pix[i+7] = uint8(c1.A) |
| } |
| |
| func (p *NRGBA64) SetNRGBA64(x, y int, c NRGBA64Color) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*8 |
| p.Pix[i+0] = uint8(c.R >> 8) |
| p.Pix[i+1] = uint8(c.R) |
| p.Pix[i+2] = uint8(c.G >> 8) |
| p.Pix[i+3] = uint8(c.G) |
| p.Pix[i+4] = uint8(c.B >> 8) |
| p.Pix[i+5] = uint8(c.B) |
| p.Pix[i+6] = uint8(c.A >> 8) |
| p.Pix[i+7] = uint8(c.A) |
| } |
| |
| // 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 { |
| r = r.Intersect(p.Rect) |
| // If r1 and r2 are Rectangles, r1.Intersect(r2) is not guaranteed to be inside |
| // either r1 or r2 if the intersection is empty. Without explicitly checking for |
| // this, the Pix[i:] expression below can panic. |
| if r.Empty() { |
| return &NRGBA64{} |
| } |
| i := (r.Min.Y-p.Rect.Min.Y)*p.Stride + (r.Min.X-p.Rect.Min.X)*8 |
| return &NRGBA64{ |
| Pix: p.Pix[i:], |
| Stride: p.Stride, |
| Rect: r, |
| } |
| } |
| |
| // Opaque scans the entire image and returns whether or not it is fully opaque. |
| func (p *NRGBA64) Opaque() bool { |
| if p.Rect.Empty() { |
| return true |
| } |
| i0, i1 := 6, p.Rect.Dx()*8 |
| for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ { |
| for i := i0; i < i1; i += 8 { |
| if p.Pix[i+0] != 0xff || p.Pix[i+1] != 0xff { |
| return false |
| } |
| } |
| i0 += p.Stride |
| i1 += p.Stride |
| } |
| return true |
| } |
| |
| // NewNRGBA64 returns a new NRGBA64 with the given width and height. |
| func NewNRGBA64(w, h int) *NRGBA64 { |
| pix := make([]uint8, 8*w*h) |
| return &NRGBA64{pix, 8 * w, Rectangle{ZP, Point{w, h}}} |
| } |
| |
| // Alpha is an in-memory image of AlphaColor values. |
| type Alpha struct { |
| // Pix holds the image's pixels, as alpha values. The pixel at |
| // (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*1]. |
| Pix []uint8 |
| // Stride is the Pix stride (in bytes) between vertically adjacent pixels. |
| Stride int |
| // Rect is the image's bounds. |
| Rect Rectangle |
| } |
| |
| func (p *Alpha) ColorModel() ColorModel { return AlphaColorModel } |
| |
| func (p *Alpha) Bounds() Rectangle { return p.Rect } |
| |
| func (p *Alpha) At(x, y int) Color { |
| if !(Point{x, y}.In(p.Rect)) { |
| return AlphaColor{} |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x - p.Rect.Min.X) |
| return AlphaColor{p.Pix[i]} |
| } |
| |
| func (p *Alpha) Set(x, y int, c Color) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x - p.Rect.Min.X) |
| p.Pix[i] = toAlphaColor(c).(AlphaColor).A |
| } |
| |
| func (p *Alpha) SetAlpha(x, y int, c AlphaColor) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x - p.Rect.Min.X) |
| p.Pix[i] = c.A |
| } |
| |
| // 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 { |
| r = r.Intersect(p.Rect) |
| // If r1 and r2 are Rectangles, r1.Intersect(r2) is not guaranteed to be inside |
| // either r1 or r2 if the intersection is empty. Without explicitly checking for |
| // this, the Pix[i:] expression below can panic. |
| if r.Empty() { |
| return &Alpha{} |
| } |
| i := (r.Min.Y-p.Rect.Min.Y)*p.Stride + (r.Min.X-p.Rect.Min.X)*1 |
| return &Alpha{ |
| Pix: p.Pix[i:], |
| Stride: p.Stride, |
| Rect: r, |
| } |
| } |
| |
| // Opaque scans the entire image and returns whether or not it is fully opaque. |
| func (p *Alpha) Opaque() bool { |
| if p.Rect.Empty() { |
| return true |
| } |
| i0, i1 := 0, p.Rect.Dx() |
| for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ { |
| for i := i0; i < i1; i++ { |
| if p.Pix[i] != 0xff { |
| return false |
| } |
| } |
| i0 += p.Stride |
| i1 += p.Stride |
| } |
| return true |
| } |
| |
| // NewAlpha returns a new Alpha with the given width and height. |
| func NewAlpha(w, h int) *Alpha { |
| pix := make([]uint8, 1*w*h) |
| return &Alpha{pix, 1 * w, Rectangle{ZP, Point{w, h}}} |
| } |
| |
| // Alpha16 is an in-memory image of Alpha16Color values. |
| type Alpha16 struct { |
| // Pix holds the image's pixels, as alpha values in big-endian format. The pixel at |
| // (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*2]. |
| Pix []uint8 |
| // Stride is the Pix stride (in bytes) between vertically adjacent pixels. |
| Stride int |
| // Rect is the image's bounds. |
| Rect Rectangle |
| } |
| |
| func (p *Alpha16) ColorModel() ColorModel { return Alpha16ColorModel } |
| |
| func (p *Alpha16) Bounds() Rectangle { return p.Rect } |
| |
| func (p *Alpha16) At(x, y int) Color { |
| if !(Point{x, y}.In(p.Rect)) { |
| return Alpha16Color{} |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*2 |
| return Alpha16Color{uint16(p.Pix[i+0])<<8 | uint16(p.Pix[i+1])} |
| } |
| |
| func (p *Alpha16) Set(x, y int, c Color) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*2 |
| c1 := toAlpha16Color(c).(Alpha16Color) |
| p.Pix[i+0] = uint8(c1.A >> 8) |
| p.Pix[i+1] = uint8(c1.A) |
| } |
| |
| func (p *Alpha16) SetAlpha16(x, y int, c Alpha16Color) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*2 |
| p.Pix[i+0] = uint8(c.A >> 8) |
| p.Pix[i+1] = uint8(c.A) |
| } |
| |
| // 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 { |
| r = r.Intersect(p.Rect) |
| // If r1 and r2 are Rectangles, r1.Intersect(r2) is not guaranteed to be inside |
| // either r1 or r2 if the intersection is empty. Without explicitly checking for |
| // this, the Pix[i:] expression below can panic. |
| if r.Empty() { |
| return &Alpha16{} |
| } |
| i := (r.Min.Y-p.Rect.Min.Y)*p.Stride + (r.Min.X-p.Rect.Min.X)*2 |
| return &Alpha16{ |
| Pix: p.Pix[i:], |
| Stride: p.Stride, |
| Rect: r, |
| } |
| } |
| |
| // Opaque scans the entire image and returns whether or not it is fully opaque. |
| func (p *Alpha16) Opaque() bool { |
| if p.Rect.Empty() { |
| return true |
| } |
| i0, i1 := 0, p.Rect.Dx()*2 |
| for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ { |
| for i := i0; i < i1; i += 2 { |
| if p.Pix[i+0] != 0xff || p.Pix[i+1] != 0xff { |
| return false |
| } |
| } |
| i0 += p.Stride |
| i1 += p.Stride |
| } |
| return true |
| } |
| |
| // NewAlpha16 returns a new Alpha16 with the given width and height. |
| func NewAlpha16(w, h int) *Alpha16 { |
| pix := make([]uint8, 2*w*h) |
| return &Alpha16{pix, 2 * w, Rectangle{ZP, Point{w, h}}} |
| } |
| |
| // Gray is an in-memory image of GrayColor values. |
| type Gray struct { |
| // Pix holds the image's pixels, as gray values. The pixel at |
| // (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*1]. |
| Pix []uint8 |
| // Stride is the Pix stride (in bytes) between vertically adjacent pixels. |
| Stride int |
| // Rect is the image's bounds. |
| Rect Rectangle |
| } |
| |
| func (p *Gray) ColorModel() ColorModel { return GrayColorModel } |
| |
| func (p *Gray) Bounds() Rectangle { return p.Rect } |
| |
| func (p *Gray) At(x, y int) Color { |
| if !(Point{x, y}.In(p.Rect)) { |
| return GrayColor{} |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x - p.Rect.Min.X) |
| return GrayColor{p.Pix[i]} |
| } |
| |
| func (p *Gray) Set(x, y int, c Color) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x - p.Rect.Min.X) |
| p.Pix[i] = toGrayColor(c).(GrayColor).Y |
| } |
| |
| func (p *Gray) SetGray(x, y int, c GrayColor) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x - p.Rect.Min.X) |
| p.Pix[i] = c.Y |
| } |
| |
| // 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 { |
| r = r.Intersect(p.Rect) |
| // If r1 and r2 are Rectangles, r1.Intersect(r2) is not guaranteed to be inside |
| // either r1 or r2 if the intersection is empty. Without explicitly checking for |
| // this, the Pix[i:] expression below can panic. |
| if r.Empty() { |
| return &Gray{} |
| } |
| i := (r.Min.Y-p.Rect.Min.Y)*p.Stride + (r.Min.X-p.Rect.Min.X)*1 |
| return &Gray{ |
| Pix: p.Pix[i:], |
| Stride: p.Stride, |
| Rect: r, |
| } |
| } |
| |
| // Opaque scans the entire image and returns whether or not it is fully opaque. |
| func (p *Gray) Opaque() bool { |
| return true |
| } |
| |
| // NewGray returns a new Gray with the given width and height. |
| func NewGray(w, h int) *Gray { |
| pix := make([]uint8, 1*w*h) |
| return &Gray{pix, 1 * w, Rectangle{ZP, Point{w, h}}} |
| } |
| |
| // Gray16 is an in-memory image of Gray16Color values. |
| type Gray16 struct { |
| // Pix holds the image's pixels, as gray values in big-endian format. The pixel at |
| // (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*2]. |
| Pix []uint8 |
| // Stride is the Pix stride (in bytes) between vertically adjacent pixels. |
| Stride int |
| // Rect is the image's bounds. |
| Rect Rectangle |
| } |
| |
| func (p *Gray16) ColorModel() ColorModel { return Gray16ColorModel } |
| |
| func (p *Gray16) Bounds() Rectangle { return p.Rect } |
| |
| func (p *Gray16) At(x, y int) Color { |
| if !(Point{x, y}.In(p.Rect)) { |
| return Gray16Color{} |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*2 |
| return Gray16Color{uint16(p.Pix[i+0])<<8 | uint16(p.Pix[i+1])} |
| } |
| |
| func (p *Gray16) Set(x, y int, c Color) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*2 |
| c1 := toGray16Color(c).(Gray16Color) |
| p.Pix[i+0] = uint8(c1.Y >> 8) |
| p.Pix[i+1] = uint8(c1.Y) |
| } |
| |
| func (p *Gray16) SetGray16(x, y int, c Gray16Color) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*2 |
| p.Pix[i+0] = uint8(c.Y >> 8) |
| p.Pix[i+1] = uint8(c.Y) |
| } |
| |
| // 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 { |
| r = r.Intersect(p.Rect) |
| // If r1 and r2 are Rectangles, r1.Intersect(r2) is not guaranteed to be inside |
| // either r1 or r2 if the intersection is empty. Without explicitly checking for |
| // this, the Pix[i:] expression below can panic. |
| if r.Empty() { |
| return &Gray16{} |
| } |
| i := (r.Min.Y-p.Rect.Min.Y)*p.Stride + (r.Min.X-p.Rect.Min.X)*2 |
| return &Gray16{ |
| Pix: p.Pix[i:], |
| Stride: p.Stride, |
| Rect: r, |
| } |
| } |
| |
| // Opaque scans the entire image and returns whether or not it is fully opaque. |
| func (p *Gray16) Opaque() bool { |
| return true |
| } |
| |
| // NewGray16 returns a new Gray16 with the given width and height. |
| func NewGray16(w, h int) *Gray16 { |
| pix := make([]uint8, 2*w*h) |
| return &Gray16{pix, 2 * w, Rectangle{ZP, Point{w, h}}} |
| } |
| |
| // A PalettedColorModel represents a fixed palette of at most 256 colors. |
| type PalettedColorModel []Color |
| |
| func diff(a, b uint32) uint32 { |
| if a > b { |
| return a - b |
| } |
| return b - a |
| } |
| |
| // Convert returns the palette color closest to c in Euclidean R,G,B space. |
| func (p PalettedColorModel) Convert(c Color) Color { |
| if len(p) == 0 { |
| return nil |
| } |
| return p[p.Index(c)] |
| } |
| |
| // Index returns the index of the palette color closest to c in Euclidean |
| // R,G,B space. |
| func (p PalettedColorModel) Index(c Color) int { |
| cr, cg, cb, _ := c.RGBA() |
| // Shift by 1 bit to avoid potential uint32 overflow in sum-squared-difference. |
| cr >>= 1 |
| cg >>= 1 |
| cb >>= 1 |
| ret, bestSSD := 0, uint32(1<<32-1) |
| for i, v := range p { |
| vr, vg, vb, _ := v.RGBA() |
| vr >>= 1 |
| vg >>= 1 |
| vb >>= 1 |
| dr, dg, db := diff(cr, vr), diff(cg, vg), diff(cb, vb) |
| ssd := (dr * dr) + (dg * dg) + (db * db) |
| if ssd < bestSSD { |
| ret, bestSSD = i, ssd |
| } |
| } |
| return ret |
| } |
| |
| // Paletted is an in-memory image of uint8 indices into a given palette. |
| type Paletted struct { |
| // Pix holds the image's pixels, as palette indices. The pixel at |
| // (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*1]. |
| Pix []uint8 |
| // Stride is the Pix stride (in bytes) between vertically adjacent pixels. |
| Stride int |
| // Rect is the image's bounds. |
| Rect Rectangle |
| // Palette is the image's palette. |
| Palette PalettedColorModel |
| } |
| |
| func (p *Paletted) ColorModel() ColorModel { return p.Palette } |
| |
| func (p *Paletted) Bounds() Rectangle { return p.Rect } |
| |
| func (p *Paletted) At(x, y int) Color { |
| if len(p.Palette) == 0 { |
| return nil |
| } |
| if !(Point{x, y}.In(p.Rect)) { |
| return p.Palette[0] |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x - p.Rect.Min.X) |
| return p.Palette[p.Pix[i]] |
| } |
| |
| func (p *Paletted) Set(x, y int, c Color) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x - p.Rect.Min.X) |
| p.Pix[i] = uint8(p.Palette.Index(c)) |
| } |
| |
| func (p *Paletted) ColorIndexAt(x, y int) uint8 { |
| if !(Point{x, y}.In(p.Rect)) { |
| return 0 |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x - p.Rect.Min.X) |
| return p.Pix[i] |
| } |
| |
| func (p *Paletted) SetColorIndex(x, y int, index uint8) { |
| if !(Point{x, y}.In(p.Rect)) { |
| return |
| } |
| i := (y-p.Rect.Min.Y)*p.Stride + (x - p.Rect.Min.X) |
| p.Pix[i] = 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 { |
| r = r.Intersect(p.Rect) |
| // If r1 and r2 are Rectangles, r1.Intersect(r2) is not guaranteed to be inside |
| // either r1 or r2 if the intersection is empty. Without explicitly checking for |
| // this, the Pix[i:] expression below can panic. |
| if r.Empty() { |
| return &Paletted{ |
| Palette: p.Palette, |
| } |
| } |
| i := (r.Min.Y-p.Rect.Min.Y)*p.Stride + (r.Min.X-p.Rect.Min.X)*1 |
| return &Paletted{ |
| Pix: p.Pix[i:], |
| 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 { |
| var present [256]bool |
| i0, i1 := 0, p.Rect.Dx() |
| for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ { |
| for _, c := range p.Pix[i0:i1] { |
| present[c] = true |
| } |
| i0 += p.Stride |
| i1 += p.Stride |
| } |
| for i, c := range p.Palette { |
| if !present[i] { |
| continue |
| } |
| _, _, _, a := c.RGBA() |
| if a != 0xffff { |
| return false |
| } |
| } |
| return true |
| } |
| |
| // NewPaletted returns a new Paletted with the given width, height and palette. |
| func NewPaletted(w, h int, m PalettedColorModel) *Paletted { |
| pix := make([]uint8, 1*w*h) |
| return &Paletted{pix, 1 * w, Rectangle{ZP, Point{w, h}}, m} |
| } |