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- // Copyright 2012 The Go Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style
- // license that can be found in the LICENSE file.
- // This file contains the code snippets included in "The Go image/draw package."
- package main
- import (
- "image"
- "image/color"
- "image/draw"
- )
- func main() {
- Color()
- Rect()
- RectAndScroll()
- ConvAndCircle()
- Glyph()
- }
- func Color() {
- c := color.RGBA{255, 0, 255, 255}
- r := image.Rect(0, 0, 640, 480)
- dst := image.NewRGBA(r)
- // ZERO OMIT
- // image.ZP is the zero point -- the origin.
- draw.Draw(dst, r, &image.Uniform{c}, image.ZP, draw.Src)
- // STOP OMIT
- // BLUE OMIT
- m := image.NewRGBA(image.Rect(0, 0, 640, 480))
- blue := color.RGBA{0, 0, 255, 255}
- draw.Draw(m, m.Bounds(), &image.Uniform{blue}, image.ZP, draw.Src)
- // STOP OMIT
- // RESET OMIT
- draw.Draw(m, m.Bounds(), image.Transparent, image.ZP, draw.Src)
- // STOP OMIT
- }
- func Rect() {
- dst := image.NewRGBA(image.Rect(0, 0, 640, 480))
- sr := image.Rect(0, 0, 200, 200)
- src := image.Black
- dp := image.Point{100, 100}
- // RECT OMIT
- r := image.Rectangle{dp, dp.Add(sr.Size())}
- draw.Draw(dst, r, src, sr.Min, draw.Src)
- // STOP OMIT
- }
- func RectAndScroll() {
- dst := image.NewRGBA(image.Rect(0, 0, 640, 480))
- sr := image.Rect(0, 0, 200, 200)
- src := image.Black
- dp := image.Point{100, 100}
- // RECT2 OMIT
- r := sr.Sub(sr.Min).Add(dp)
- draw.Draw(dst, r, src, sr.Min, draw.Src)
- // STOP OMIT
- m := dst
- // SCROLL OMIT
- b := m.Bounds()
- p := image.Pt(0, 20)
- // Note that even though the second argument is b,
- // the effective rectangle is smaller due to clipping.
- draw.Draw(m, b, m, b.Min.Add(p), draw.Src)
- dirtyRect := b.Intersect(image.Rect(b.Min.X, b.Max.Y-20, b.Max.X, b.Max.Y))
- // STOP OMIT
- _ = dirtyRect // noop
- }
- func ConvAndCircle() {
- src := image.NewRGBA(image.Rect(0, 0, 640, 480))
- dst := image.NewRGBA(image.Rect(0, 0, 640, 480))
- // CONV OMIT
- b := src.Bounds()
- m := image.NewRGBA(b)
- draw.Draw(m, b, src, b.Min, draw.Src)
- // STOP OMIT
- p := image.Point{100, 100}
- r := 50
- // CIRCLE2 OMIT
- draw.DrawMask(dst, dst.Bounds(), src, image.ZP, &circle{p, r}, image.ZP, draw.Over)
- // STOP OMIT
- }
- func theGlyphImageForAFont() image.Image {
- return image.NewRGBA(image.Rect(0, 0, 640, 480))
- }
- func theBoundsFor(index int) image.Rectangle {
- return image.Rect(0, 0, 32, 32)
- }
- func Glyph() {
- p := image.Point{100, 100}
- dst := image.NewRGBA(image.Rect(0, 0, 640, 480))
- glyphIndex := 42
- // GLYPH OMIT
- src := &image.Uniform{color.RGBA{0, 0, 255, 255}}
- mask := theGlyphImageForAFont()
- mr := theBoundsFor(glyphIndex)
- draw.DrawMask(dst, mr.Sub(mr.Min).Add(p), src, image.ZP, mask, mr.Min, draw.Over)
- // STOP OMIT
- }
- //CIRCLESTRUCT OMIT
- type circle struct {
- p image.Point
- r int
- }
- func (c *circle) ColorModel() color.Model {
- return color.AlphaModel
- }
- func (c *circle) Bounds() image.Rectangle {
- return image.Rect(c.p.X-c.r, c.p.Y-c.r, c.p.X+c.r, c.p.Y+c.r)
- }
- func (c *circle) At(x, y int) color.Color {
- xx, yy, rr := float64(x-c.p.X)+0.5, float64(y-c.p.Y)+0.5, float64(c.r)
- if xx*xx+yy*yy < rr*rr {
- return color.Alpha{255}
- }
- return color.Alpha{0}
- }
- //STOP OMIT
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