851 lines
23 KiB
Go
851 lines
23 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package image implements a basic 2-D image library.
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package image
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// Config holds an image's color model and dimensions.
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type Config struct {
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ColorModel ColorModel
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Width, Height int
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}
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// Image is a finite rectangular grid of Colors drawn from a ColorModel.
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type Image interface {
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// ColorModel returns the Image's ColorModel.
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ColorModel() ColorModel
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// Bounds returns the domain for which At can return non-zero color.
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// The bounds do not necessarily contain the point (0, 0).
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Bounds() Rectangle
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// At returns the color of the pixel at (x, y).
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// At(Bounds().Min.X, Bounds().Min.Y) returns the upper-left pixel of the grid.
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// At(Bounds().Max.X-1, Bounds().Max.Y-1) returns the lower-right one.
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At(x, y int) Color
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}
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// RGBA is an in-memory image of RGBAColor values.
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type RGBA struct {
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// Pix holds the image's pixels, in R, G, B, A order. The pixel at
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// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*4].
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Pix []uint8
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// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
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Stride int
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// Rect is the image's bounds.
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Rect Rectangle
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}
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func (p *RGBA) ColorModel() ColorModel { return RGBAColorModel }
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func (p *RGBA) Bounds() Rectangle { return p.Rect }
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func (p *RGBA) At(x, y int) Color {
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if !(Point{x, y}.In(p.Rect)) {
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return RGBAColor{}
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}
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i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4
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return RGBAColor{p.Pix[i+0], p.Pix[i+1], p.Pix[i+2], p.Pix[i+3]}
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}
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func (p *RGBA) Set(x, y int, c Color) {
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if !(Point{x, y}.In(p.Rect)) {
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return
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}
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i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4
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c1 := toRGBAColor(c).(RGBAColor)
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p.Pix[i+0] = c1.R
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p.Pix[i+1] = c1.G
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p.Pix[i+2] = c1.B
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p.Pix[i+3] = c1.A
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}
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func (p *RGBA) SetRGBA(x, y int, c RGBAColor) {
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if !(Point{x, y}.In(p.Rect)) {
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return
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}
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i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4
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p.Pix[i+0] = c.R
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p.Pix[i+1] = c.G
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p.Pix[i+2] = c.B
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p.Pix[i+3] = c.A
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}
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// SubImage returns an image representing the portion of the image p visible
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// through r. The returned value shares pixels with the original image.
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func (p *RGBA) SubImage(r Rectangle) Image {
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r = r.Intersect(p.Rect)
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// If r1 and r2 are Rectangles, r1.Intersect(r2) is not guaranteed to be inside
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// either r1 or r2 if the intersection is empty. Without explicitly checking for
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// this, the Pix[i:] expression below can panic.
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if r.Empty() {
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return &RGBA{}
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}
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i := (r.Min.Y-p.Rect.Min.Y)*p.Stride + (r.Min.X-p.Rect.Min.X)*4
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return &RGBA{
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Pix: p.Pix[i:],
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Stride: p.Stride,
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Rect: r,
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}
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}
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// Opaque scans the entire image and returns whether or not it is fully opaque.
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func (p *RGBA) Opaque() bool {
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if p.Rect.Empty() {
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return true
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}
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i0, i1 := 3, p.Rect.Dx()*4
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for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
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for i := i0; i < i1; i += 4 {
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if p.Pix[i] != 0xff {
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return false
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}
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}
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i0 += p.Stride
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i1 += p.Stride
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}
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return true
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}
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// NewRGBA returns a new RGBA with the given width and height.
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func NewRGBA(w, h int) *RGBA {
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buf := make([]uint8, 4*w*h)
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return &RGBA{buf, 4 * w, Rectangle{ZP, Point{w, h}}}
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}
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// RGBA64 is an in-memory image of RGBA64Color values.
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type RGBA64 struct {
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// Pix holds the image's pixels, in R, G, B, A order and big-endian format. The pixel at
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// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*8].
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Pix []uint8
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// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
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Stride int
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// Rect is the image's bounds.
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Rect Rectangle
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}
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func (p *RGBA64) ColorModel() ColorModel { return RGBA64ColorModel }
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func (p *RGBA64) Bounds() Rectangle { return p.Rect }
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func (p *RGBA64) At(x, y int) Color {
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if !(Point{x, y}.In(p.Rect)) {
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return RGBA64Color{}
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}
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i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*8
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return RGBA64Color{
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uint16(p.Pix[i+0])<<8 | uint16(p.Pix[i+1]),
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uint16(p.Pix[i+2])<<8 | uint16(p.Pix[i+3]),
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uint16(p.Pix[i+4])<<8 | uint16(p.Pix[i+5]),
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uint16(p.Pix[i+6])<<8 | uint16(p.Pix[i+7]),
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}
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}
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func (p *RGBA64) Set(x, y int, c Color) {
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if !(Point{x, y}.In(p.Rect)) {
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return
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}
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i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*8
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c1 := toRGBA64Color(c).(RGBA64Color)
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p.Pix[i+0] = uint8(c1.R >> 8)
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p.Pix[i+1] = uint8(c1.R)
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p.Pix[i+2] = uint8(c1.G >> 8)
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p.Pix[i+3] = uint8(c1.G)
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p.Pix[i+4] = uint8(c1.B >> 8)
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p.Pix[i+5] = uint8(c1.B)
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p.Pix[i+6] = uint8(c1.A >> 8)
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p.Pix[i+7] = uint8(c1.A)
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}
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func (p *RGBA64) SetRGBA64(x, y int, c RGBA64Color) {
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if !(Point{x, y}.In(p.Rect)) {
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return
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}
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i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*8
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p.Pix[i+0] = uint8(c.R >> 8)
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p.Pix[i+1] = uint8(c.R)
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p.Pix[i+2] = uint8(c.G >> 8)
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p.Pix[i+3] = uint8(c.G)
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p.Pix[i+4] = uint8(c.B >> 8)
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p.Pix[i+5] = uint8(c.B)
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p.Pix[i+6] = uint8(c.A >> 8)
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p.Pix[i+7] = uint8(c.A)
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}
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// SubImage returns an image representing the portion of the image p visible
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// through r. The returned value shares pixels with the original image.
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func (p *RGBA64) SubImage(r Rectangle) Image {
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r = r.Intersect(p.Rect)
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// If r1 and r2 are Rectangles, r1.Intersect(r2) is not guaranteed to be inside
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// either r1 or r2 if the intersection is empty. Without explicitly checking for
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// this, the Pix[i:] expression below can panic.
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if r.Empty() {
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return &RGBA64{}
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}
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i := (r.Min.Y-p.Rect.Min.Y)*p.Stride + (r.Min.X-p.Rect.Min.X)*8
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return &RGBA64{
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Pix: p.Pix[i:],
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Stride: p.Stride,
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Rect: r,
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}
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}
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// Opaque scans the entire image and returns whether or not it is fully opaque.
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func (p *RGBA64) Opaque() bool {
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if p.Rect.Empty() {
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return true
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}
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i0, i1 := 6, p.Rect.Dx()*8
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for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
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for i := i0; i < i1; i += 8 {
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if p.Pix[i+0] != 0xff || p.Pix[i+1] != 0xff {
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return false
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}
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}
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i0 += p.Stride
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i1 += p.Stride
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}
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return true
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}
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// NewRGBA64 returns a new RGBA64 with the given width and height.
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func NewRGBA64(w, h int) *RGBA64 {
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pix := make([]uint8, 8*w*h)
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return &RGBA64{pix, 8 * w, Rectangle{ZP, Point{w, h}}}
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}
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// NRGBA is an in-memory image of NRGBAColor values.
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type NRGBA struct {
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// Pix holds the image's pixels, in R, G, B, A order. The pixel at
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// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*4].
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Pix []uint8
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// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
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Stride int
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// Rect is the image's bounds.
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Rect Rectangle
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}
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func (p *NRGBA) ColorModel() ColorModel { return NRGBAColorModel }
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func (p *NRGBA) Bounds() Rectangle { return p.Rect }
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func (p *NRGBA) At(x, y int) Color {
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if !(Point{x, y}.In(p.Rect)) {
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return NRGBAColor{}
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}
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i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4
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return NRGBAColor{p.Pix[i+0], p.Pix[i+1], p.Pix[i+2], p.Pix[i+3]}
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}
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func (p *NRGBA) Set(x, y int, c Color) {
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if !(Point{x, y}.In(p.Rect)) {
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return
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}
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i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4
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c1 := toNRGBAColor(c).(NRGBAColor)
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p.Pix[i+0] = c1.R
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p.Pix[i+1] = c1.G
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p.Pix[i+2] = c1.B
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p.Pix[i+3] = c1.A
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}
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func (p *NRGBA) SetNRGBA(x, y int, c NRGBAColor) {
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if !(Point{x, y}.In(p.Rect)) {
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return
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}
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i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4
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p.Pix[i+0] = c.R
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p.Pix[i+1] = c.G
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p.Pix[i+2] = c.B
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p.Pix[i+3] = c.A
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}
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// SubImage returns an image representing the portion of the image p visible
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// through r. The returned value shares pixels with the original image.
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func (p *NRGBA) SubImage(r Rectangle) Image {
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r = r.Intersect(p.Rect)
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// If r1 and r2 are Rectangles, r1.Intersect(r2) is not guaranteed to be inside
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// either r1 or r2 if the intersection is empty. Without explicitly checking for
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// this, the Pix[i:] expression below can panic.
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if r.Empty() {
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return &NRGBA{}
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}
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i := (r.Min.Y-p.Rect.Min.Y)*p.Stride + (r.Min.X-p.Rect.Min.X)*4
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return &NRGBA{
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Pix: p.Pix[i:],
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Stride: p.Stride,
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Rect: r,
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}
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}
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// Opaque scans the entire image and returns whether or not it is fully opaque.
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func (p *NRGBA) Opaque() bool {
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if p.Rect.Empty() {
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return true
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}
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i0, i1 := 3, p.Rect.Dx()*4
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for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
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for i := i0; i < i1; i += 4 {
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if p.Pix[i] != 0xff {
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return false
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}
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}
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i0 += p.Stride
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i1 += p.Stride
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}
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return true
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}
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// NewNRGBA returns a new NRGBA with the given width and height.
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func NewNRGBA(w, h int) *NRGBA {
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pix := make([]uint8, 4*w*h)
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return &NRGBA{pix, 4 * w, Rectangle{ZP, Point{w, h}}}
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}
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// NRGBA64 is an in-memory image of NRGBA64Color values.
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type NRGBA64 struct {
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// Pix holds the image's pixels, in R, G, B, A order and big-endian format. The pixel at
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// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*8].
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Pix []uint8
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// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
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Stride int
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// Rect is the image's bounds.
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Rect Rectangle
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}
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func (p *NRGBA64) ColorModel() ColorModel { return NRGBA64ColorModel }
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func (p *NRGBA64) Bounds() Rectangle { return p.Rect }
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func (p *NRGBA64) At(x, y int) Color {
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if !(Point{x, y}.In(p.Rect)) {
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return NRGBA64Color{}
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}
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i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*8
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return NRGBA64Color{
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uint16(p.Pix[i+0])<<8 | uint16(p.Pix[i+1]),
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uint16(p.Pix[i+2])<<8 | uint16(p.Pix[i+3]),
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uint16(p.Pix[i+4])<<8 | uint16(p.Pix[i+5]),
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uint16(p.Pix[i+6])<<8 | uint16(p.Pix[i+7]),
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}
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}
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func (p *NRGBA64) Set(x, y int, c Color) {
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if !(Point{x, y}.In(p.Rect)) {
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return
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}
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i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*8
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c1 := toNRGBA64Color(c).(NRGBA64Color)
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p.Pix[i+0] = uint8(c1.R >> 8)
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p.Pix[i+1] = uint8(c1.R)
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p.Pix[i+2] = uint8(c1.G >> 8)
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p.Pix[i+3] = uint8(c1.G)
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p.Pix[i+4] = uint8(c1.B >> 8)
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p.Pix[i+5] = uint8(c1.B)
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p.Pix[i+6] = uint8(c1.A >> 8)
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p.Pix[i+7] = uint8(c1.A)
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}
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func (p *NRGBA64) SetNRGBA64(x, y int, c NRGBA64Color) {
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if !(Point{x, y}.In(p.Rect)) {
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return
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}
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i := (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*8
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p.Pix[i+0] = uint8(c.R >> 8)
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p.Pix[i+1] = uint8(c.R)
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p.Pix[i+2] = uint8(c.G >> 8)
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p.Pix[i+3] = uint8(c.G)
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p.Pix[i+4] = uint8(c.B >> 8)
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p.Pix[i+5] = uint8(c.B)
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p.Pix[i+6] = uint8(c.A >> 8)
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p.Pix[i+7] = uint8(c.A)
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}
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// SubImage returns an image representing the portion of the image p visible
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// through r. The returned value shares pixels with the original image.
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func (p *NRGBA64) SubImage(r Rectangle) Image {
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r = r.Intersect(p.Rect)
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// If r1 and r2 are Rectangles, r1.Intersect(r2) is not guaranteed to be inside
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// either r1 or r2 if the intersection is empty. Without explicitly checking for
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// this, the Pix[i:] expression below can panic.
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if r.Empty() {
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return &NRGBA64{}
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}
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i := (r.Min.Y-p.Rect.Min.Y)*p.Stride + (r.Min.X-p.Rect.Min.X)*8
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return &NRGBA64{
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Pix: p.Pix[i:],
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Stride: p.Stride,
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Rect: r,
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}
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}
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// Opaque scans the entire image and returns whether or not it is fully opaque.
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func (p *NRGBA64) Opaque() bool {
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if p.Rect.Empty() {
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return true
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}
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i0, i1 := 6, p.Rect.Dx()*8
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for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
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for i := i0; i < i1; i += 8 {
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if p.Pix[i+0] != 0xff || p.Pix[i+1] != 0xff {
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return false
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}
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}
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i0 += p.Stride
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i1 += p.Stride
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}
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return true
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}
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// NewNRGBA64 returns a new NRGBA64 with the given width and height.
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func NewNRGBA64(w, h int) *NRGBA64 {
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pix := make([]uint8, 8*w*h)
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return &NRGBA64{pix, 8 * w, Rectangle{ZP, Point{w, h}}}
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}
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// Alpha is an in-memory image of AlphaColor values.
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type Alpha struct {
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// Pix holds the image's pixels, as alpha values. The pixel at
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// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*1].
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Pix []uint8
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// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
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Stride int
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// Rect is the image's bounds.
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Rect Rectangle
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}
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func (p *Alpha) ColorModel() ColorModel { return AlphaColorModel }
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func (p *Alpha) Bounds() Rectangle { return p.Rect }
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func (p *Alpha) At(x, y int) Color {
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if !(Point{x, y}.In(p.Rect)) {
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return AlphaColor{}
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}
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i := (y-p.Rect.Min.Y)*p.Stride + (x - p.Rect.Min.X)
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return AlphaColor{p.Pix[i]}
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}
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func (p *Alpha) Set(x, y int, c Color) {
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if !(Point{x, y}.In(p.Rect)) {
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return
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}
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i := (y-p.Rect.Min.Y)*p.Stride + (x - p.Rect.Min.X)
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p.Pix[i] = toAlphaColor(c).(AlphaColor).A
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}
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func (p *Alpha) SetAlpha(x, y int, c AlphaColor) {
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if !(Point{x, y}.In(p.Rect)) {
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return
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}
|
|
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}
|
|
}
|