905 lines
24 KiB
Go
905 lines
24 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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//
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// The fundamental interface is called Image. An Image contains colors, which
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// are described in the image/color package.
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//
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// Values of the Image interface are created either by calling functions such
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// as NewRGBA and NewPaletted, or by calling Decode on an io.Reader containing
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// image data in a format such as GIF, JPEG or PNG. Decoding any particular
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// image format requires the prior registration of a decoder function.
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// Registration is typically automatic as a side effect of initializing that
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// format's package so that, to decode a PNG image, it suffices to have
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// import _ "image/png"
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// in a program's main package. The _ means to import a package purely for its
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// initialization side effects.
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//
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// See "The Go image package" for more details:
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// http://golang.org/doc/articles/image_package.html
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package image
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import (
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"image/color"
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)
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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 color.Model
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Width, Height int
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}
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// Image is a finite rectangular grid of color.Color values taken from a color
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// model.
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type Image interface {
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// ColorModel returns the Image's color model.
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ColorModel() color.Model
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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.Color
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}
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// PalettedImage is an image whose colors may come from a limited palette.
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// If m is a PalettedImage and m.ColorModel() returns a PalettedColorModel p,
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// then m.At(x, y) should be equivalent to p[m.ColorIndexAt(x, y)]. If m's
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// color model is not a PalettedColorModel, then ColorIndexAt's behavior is
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// undefined.
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type PalettedImage interface {
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// ColorIndexAt returns the palette index of the pixel at (x, y).
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ColorIndexAt(x, y int) uint8
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Image
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}
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// RGBA is an in-memory image whose At method returns color.RGBA 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() color.Model { return color.RGBAModel }
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func (p *RGBA) Bounds() Rectangle { return p.Rect }
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func (p *RGBA) At(x, y int) color.Color {
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if !(Point{x, y}.In(p.Rect)) {
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return color.RGBA{}
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}
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i := p.PixOffset(x, y)
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return color.RGBA{p.Pix[i+0], p.Pix[i+1], p.Pix[i+2], p.Pix[i+3]}
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}
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// PixOffset returns the index of the first element of Pix that corresponds to
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// the pixel at (x, y).
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func (p *RGBA) PixOffset(x, y int) int {
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return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4
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}
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func (p *RGBA) Set(x, y int, c color.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 := p.PixOffset(x, y)
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c1 := color.RGBAModel.Convert(c).(color.RGBA)
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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 color.RGBA) {
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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 := p.PixOffset(x, y)
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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 := p.PixOffset(r.Min.X, r.Min.Y)
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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 reports whether 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 bounds.
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func NewRGBA(r Rectangle) *RGBA {
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w, h := r.Dx(), r.Dy()
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buf := make([]uint8, 4*w*h)
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return &RGBA{buf, 4 * w, r}
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}
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// RGBA64 is an in-memory image whose At method returns color.RGBA64 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() color.Model { return color.RGBA64Model }
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func (p *RGBA64) Bounds() Rectangle { return p.Rect }
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func (p *RGBA64) At(x, y int) color.Color {
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if !(Point{x, y}.In(p.Rect)) {
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return color.RGBA64{}
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}
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i := p.PixOffset(x, y)
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return color.RGBA64{
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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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// PixOffset returns the index of the first element of Pix that corresponds to
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// the pixel at (x, y).
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func (p *RGBA64) PixOffset(x, y int) int {
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return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*8
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}
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func (p *RGBA64) Set(x, y int, c color.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 := p.PixOffset(x, y)
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c1 := color.RGBA64Model.Convert(c).(color.RGBA64)
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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 color.RGBA64) {
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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 := p.PixOffset(x, y)
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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 := p.PixOffset(r.Min.X, r.Min.Y)
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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 reports whether 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 bounds.
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func NewRGBA64(r Rectangle) *RGBA64 {
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w, h := r.Dx(), r.Dy()
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pix := make([]uint8, 8*w*h)
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return &RGBA64{pix, 8 * w, r}
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}
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// NRGBA is an in-memory image whose At method returns color.NRGBA 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() color.Model { return color.NRGBAModel }
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func (p *NRGBA) Bounds() Rectangle { return p.Rect }
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func (p *NRGBA) At(x, y int) color.Color {
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if !(Point{x, y}.In(p.Rect)) {
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return color.NRGBA{}
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}
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i := p.PixOffset(x, y)
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return color.NRGBA{p.Pix[i+0], p.Pix[i+1], p.Pix[i+2], p.Pix[i+3]}
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}
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// PixOffset returns the index of the first element of Pix that corresponds to
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// the pixel at (x, y).
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func (p *NRGBA) PixOffset(x, y int) int {
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return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4
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}
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func (p *NRGBA) Set(x, y int, c color.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 := p.PixOffset(x, y)
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c1 := color.NRGBAModel.Convert(c).(color.NRGBA)
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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 color.NRGBA) {
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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 := p.PixOffset(x, y)
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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 := p.PixOffset(r.Min.X, r.Min.Y)
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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 reports whether 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 bounds.
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func NewNRGBA(r Rectangle) *NRGBA {
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w, h := r.Dx(), r.Dy()
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pix := make([]uint8, 4*w*h)
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return &NRGBA{pix, 4 * w, r}
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}
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// NRGBA64 is an in-memory image whose At method returns color.NRGBA64 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() color.Model { return color.NRGBA64Model }
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func (p *NRGBA64) Bounds() Rectangle { return p.Rect }
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func (p *NRGBA64) At(x, y int) color.Color {
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if !(Point{x, y}.In(p.Rect)) {
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return color.NRGBA64{}
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}
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i := p.PixOffset(x, y)
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return color.NRGBA64{
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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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// PixOffset returns the index of the first element of Pix that corresponds to
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// the pixel at (x, y).
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func (p *NRGBA64) PixOffset(x, y int) int {
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return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*8
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}
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func (p *NRGBA64) Set(x, y int, c color.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 := p.PixOffset(x, y)
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c1 := color.NRGBA64Model.Convert(c).(color.NRGBA64)
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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 color.NRGBA64) {
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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 := p.PixOffset(x, y)
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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 := p.PixOffset(r.Min.X, r.Min.Y)
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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 reports whether 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 {
|
|
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 bounds.
|
|
func NewNRGBA64(r Rectangle) *NRGBA64 {
|
|
w, h := r.Dx(), r.Dy()
|
|
pix := make([]uint8, 8*w*h)
|
|
return &NRGBA64{pix, 8 * w, r}
|
|
}
|
|
|
|
// Alpha is an in-memory image whose At method returns color.Alpha 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() color.Model { return color.AlphaModel }
|
|
|
|
func (p *Alpha) Bounds() Rectangle { return p.Rect }
|
|
|
|
func (p *Alpha) At(x, y int) color.Color {
|
|
if !(Point{x, y}.In(p.Rect)) {
|
|
return color.Alpha{}
|
|
}
|
|
i := p.PixOffset(x, y)
|
|
return color.Alpha{p.Pix[i]}
|
|
}
|
|
|
|
// PixOffset returns the index of the first element of Pix that corresponds to
|
|
// the pixel at (x, y).
|
|
func (p *Alpha) PixOffset(x, y int) int {
|
|
return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*1
|
|
}
|
|
|
|
func (p *Alpha) Set(x, y int, c color.Color) {
|
|
if !(Point{x, y}.In(p.Rect)) {
|
|
return
|
|
}
|
|
i := p.PixOffset(x, y)
|
|
p.Pix[i] = color.AlphaModel.Convert(c).(color.Alpha).A
|
|
}
|
|
|
|
func (p *Alpha) SetAlpha(x, y int, c color.Alpha) {
|
|
if !(Point{x, y}.In(p.Rect)) {
|
|
return
|
|
}
|
|
i := p.PixOffset(x, y)
|
|
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 := p.PixOffset(r.Min.X, r.Min.Y)
|
|
return &Alpha{
|
|
Pix: p.Pix[i:],
|
|
Stride: p.Stride,
|
|
Rect: r,
|
|
}
|
|
}
|
|
|
|
// Opaque scans the entire image and reports whether 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 bounds.
|
|
func NewAlpha(r Rectangle) *Alpha {
|
|
w, h := r.Dx(), r.Dy()
|
|
pix := make([]uint8, 1*w*h)
|
|
return &Alpha{pix, 1 * w, r}
|
|
}
|
|
|
|
// Alpha16 is an in-memory image whose At method returns color.Alpha64 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() color.Model { return color.Alpha16Model }
|
|
|
|
func (p *Alpha16) Bounds() Rectangle { return p.Rect }
|
|
|
|
func (p *Alpha16) At(x, y int) color.Color {
|
|
if !(Point{x, y}.In(p.Rect)) {
|
|
return color.Alpha16{}
|
|
}
|
|
i := p.PixOffset(x, y)
|
|
return color.Alpha16{uint16(p.Pix[i+0])<<8 | uint16(p.Pix[i+1])}
|
|
}
|
|
|
|
// PixOffset returns the index of the first element of Pix that corresponds to
|
|
// the pixel at (x, y).
|
|
func (p *Alpha16) PixOffset(x, y int) int {
|
|
return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*2
|
|
}
|
|
|
|
func (p *Alpha16) Set(x, y int, c color.Color) {
|
|
if !(Point{x, y}.In(p.Rect)) {
|
|
return
|
|
}
|
|
i := p.PixOffset(x, y)
|
|
c1 := color.Alpha16Model.Convert(c).(color.Alpha16)
|
|
p.Pix[i+0] = uint8(c1.A >> 8)
|
|
p.Pix[i+1] = uint8(c1.A)
|
|
}
|
|
|
|
func (p *Alpha16) SetAlpha16(x, y int, c color.Alpha16) {
|
|
if !(Point{x, y}.In(p.Rect)) {
|
|
return
|
|
}
|
|
i := p.PixOffset(x, y)
|
|
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 := p.PixOffset(r.Min.X, r.Min.Y)
|
|
return &Alpha16{
|
|
Pix: p.Pix[i:],
|
|
Stride: p.Stride,
|
|
Rect: r,
|
|
}
|
|
}
|
|
|
|
// Opaque scans the entire image and reports whether 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 bounds.
|
|
func NewAlpha16(r Rectangle) *Alpha16 {
|
|
w, h := r.Dx(), r.Dy()
|
|
pix := make([]uint8, 2*w*h)
|
|
return &Alpha16{pix, 2 * w, r}
|
|
}
|
|
|
|
// Gray is an in-memory image whose At method returns color.Gray 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() color.Model { return color.GrayModel }
|
|
|
|
func (p *Gray) Bounds() Rectangle { return p.Rect }
|
|
|
|
func (p *Gray) At(x, y int) color.Color {
|
|
if !(Point{x, y}.In(p.Rect)) {
|
|
return color.Gray{}
|
|
}
|
|
i := p.PixOffset(x, y)
|
|
return color.Gray{p.Pix[i]}
|
|
}
|
|
|
|
// PixOffset returns the index of the first element of Pix that corresponds to
|
|
// the pixel at (x, y).
|
|
func (p *Gray) PixOffset(x, y int) int {
|
|
return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*1
|
|
}
|
|
|
|
func (p *Gray) Set(x, y int, c color.Color) {
|
|
if !(Point{x, y}.In(p.Rect)) {
|
|
return
|
|
}
|
|
i := p.PixOffset(x, y)
|
|
p.Pix[i] = color.GrayModel.Convert(c).(color.Gray).Y
|
|
}
|
|
|
|
func (p *Gray) SetGray(x, y int, c color.Gray) {
|
|
if !(Point{x, y}.In(p.Rect)) {
|
|
return
|
|
}
|
|
i := p.PixOffset(x, y)
|
|
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 := p.PixOffset(r.Min.X, r.Min.Y)
|
|
return &Gray{
|
|
Pix: p.Pix[i:],
|
|
Stride: p.Stride,
|
|
Rect: r,
|
|
}
|
|
}
|
|
|
|
// Opaque scans the entire image and reports whether it is fully opaque.
|
|
func (p *Gray) Opaque() bool {
|
|
return true
|
|
}
|
|
|
|
// NewGray returns a new Gray with the given bounds.
|
|
func NewGray(r Rectangle) *Gray {
|
|
w, h := r.Dx(), r.Dy()
|
|
pix := make([]uint8, 1*w*h)
|
|
return &Gray{pix, 1 * w, r}
|
|
}
|
|
|
|
// Gray16 is an in-memory image whose At method returns color.Gray16 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() color.Model { return color.Gray16Model }
|
|
|
|
func (p *Gray16) Bounds() Rectangle { return p.Rect }
|
|
|
|
func (p *Gray16) At(x, y int) color.Color {
|
|
if !(Point{x, y}.In(p.Rect)) {
|
|
return color.Gray16{}
|
|
}
|
|
i := p.PixOffset(x, y)
|
|
return color.Gray16{uint16(p.Pix[i+0])<<8 | uint16(p.Pix[i+1])}
|
|
}
|
|
|
|
// PixOffset returns the index of the first element of Pix that corresponds to
|
|
// the pixel at (x, y).
|
|
func (p *Gray16) PixOffset(x, y int) int {
|
|
return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*2
|
|
}
|
|
|
|
func (p *Gray16) Set(x, y int, c color.Color) {
|
|
if !(Point{x, y}.In(p.Rect)) {
|
|
return
|
|
}
|
|
i := p.PixOffset(x, y)
|
|
c1 := color.Gray16Model.Convert(c).(color.Gray16)
|
|
p.Pix[i+0] = uint8(c1.Y >> 8)
|
|
p.Pix[i+1] = uint8(c1.Y)
|
|
}
|
|
|
|
func (p *Gray16) SetGray16(x, y int, c color.Gray16) {
|
|
if !(Point{x, y}.In(p.Rect)) {
|
|
return
|
|
}
|
|
i := p.PixOffset(x, y)
|
|
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 := p.PixOffset(r.Min.X, r.Min.Y)
|
|
return &Gray16{
|
|
Pix: p.Pix[i:],
|
|
Stride: p.Stride,
|
|
Rect: r,
|
|
}
|
|
}
|
|
|
|
// Opaque scans the entire image and reports whether it is fully opaque.
|
|
func (p *Gray16) Opaque() bool {
|
|
return true
|
|
}
|
|
|
|
// NewGray16 returns a new Gray16 with the given bounds.
|
|
func NewGray16(r Rectangle) *Gray16 {
|
|
w, h := r.Dx(), r.Dy()
|
|
pix := make([]uint8, 2*w*h)
|
|
return &Gray16{pix, 2 * w, r}
|
|
}
|
|
|
|
// 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 color.Palette
|
|
}
|
|
|
|
func (p *Paletted) ColorModel() color.Model { return p.Palette }
|
|
|
|
func (p *Paletted) Bounds() Rectangle { return p.Rect }
|
|
|
|
func (p *Paletted) At(x, y int) color.Color {
|
|
if len(p.Palette) == 0 {
|
|
return nil
|
|
}
|
|
if !(Point{x, y}.In(p.Rect)) {
|
|
return p.Palette[0]
|
|
}
|
|
i := p.PixOffset(x, y)
|
|
return p.Palette[p.Pix[i]]
|
|
}
|
|
|
|
// PixOffset returns the index of the first element of Pix that corresponds to
|
|
// the pixel at (x, y).
|
|
func (p *Paletted) PixOffset(x, y int) int {
|
|
return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*1
|
|
}
|
|
|
|
func (p *Paletted) Set(x, y int, c color.Color) {
|
|
if !(Point{x, y}.In(p.Rect)) {
|
|
return
|
|
}
|
|
i := p.PixOffset(x, y)
|
|
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 := p.PixOffset(x, y)
|
|
return p.Pix[i]
|
|
}
|
|
|
|
func (p *Paletted) SetColorIndex(x, y int, index uint8) {
|
|
if !(Point{x, y}.In(p.Rect)) {
|
|
return
|
|
}
|
|
i := p.PixOffset(x, y)
|
|
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 := p.PixOffset(r.Min.X, r.Min.Y)
|
|
return &Paletted{
|
|
Pix: p.Pix[i:],
|
|
Stride: p.Stride,
|
|
Rect: p.Rect.Intersect(r),
|
|
Palette: p.Palette,
|
|
}
|
|
}
|
|
|
|
// Opaque scans the entire image and reports whether 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(r Rectangle, p color.Palette) *Paletted {
|
|
w, h := r.Dx(), r.Dy()
|
|
pix := make([]uint8, 1*w*h)
|
|
return &Paletted{pix, 1 * w, r, p}
|
|
}
|