mirror of
https://github.com/golang/go
synced 2024-11-22 05:54:40 -07:00
fc9f65a6a0
It was showing the same snippet twice instead of the type definition and snippet. R=golang-dev, iant CC=golang-dev https://golang.org/cl/5875045
143 lines
3.1 KiB
Go
143 lines
3.1 KiB
Go
// 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(image.Rect(0, 0, b.Dx(), b.Dy()))
|
|
draw.Draw(m, m.Bounds(), 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
|