blob: bcb46629cc580013fd3671ae50f556526d5c7d24 [file] [log] [blame]
 // Copyright 2015 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package draw_test import ( "fmt" "image" "image/color" "image/png" "log" "math" "os" "golang.org/x/image/draw" "golang.org/x/image/math/f64" ) func ExampleDraw() { fSrc, err := os.Open("../testdata/blue-purple-pink.png") if err != nil { log.Fatal(err) } defer fSrc.Close() src, err := png.Decode(fSrc) if err != nil { log.Fatal(err) } dst := image.NewRGBA(image.Rect(0, 0, 400, 300)) green := image.NewUniform(color.RGBA{0x00, 0x1f, 0x00, 0xff}) draw.Copy(dst, image.Point{}, green, dst.Bounds(), draw.Src, nil) qs := []draw.Interpolator{ draw.NearestNeighbor, draw.ApproxBiLinear, draw.CatmullRom, } const cos60, sin60 = 0.5, 0.866025404 t := f64.Aff3{ +2 * cos60, -2 * sin60, 100, +2 * sin60, +2 * cos60, 100, } draw.Copy(dst, image.Point{20, 30}, src, src.Bounds(), draw.Over, nil) for i, q := range qs { q.Scale(dst, image.Rect(200+10*i, 100*i, 600+10*i, 150+100*i), src, src.Bounds(), draw.Over, nil) } draw.NearestNeighbor.Transform(dst, t, src, src.Bounds(), draw.Over, nil) red := image.NewNRGBA(image.Rect(0, 0, 16, 16)) for y := 0; y < 16; y++ { for x := 0; x < 16; x++ { red.SetNRGBA(x, y, color.NRGBA{ R: uint8(x * 0x11), A: uint8(y * 0x11), }) } } red.SetNRGBA(0, 0, color.NRGBA{0xff, 0xff, 0x00, 0xff}) red.SetNRGBA(15, 15, color.NRGBA{0xff, 0xff, 0x00, 0xff}) ops := []draw.Op{ draw.Over, draw.Src, } for i, op := range ops { dr := image.Rect(120+10*i, 150+60*i, 170+10*i, 200+60*i) draw.NearestNeighbor.Scale(dst, dr, red, red.Bounds(), op, nil) t := f64.Aff3{ +cos60, -sin60, float64(190 + 10*i), +sin60, +cos60, float64(140 + 50*i), } draw.NearestNeighbor.Transform(dst, t, red, red.Bounds(), op, nil) } dr := image.Rect(0, 0, 128, 128) checkerboard := image.NewAlpha(dr) for y := dr.Min.Y; y < dr.Max.Y; y++ { for x := dr.Min.X; x < dr.Max.X; x++ { if (x/20)%2 == (y/20)%2 { checkerboard.SetAlpha(x, y, color.Alpha{0xff}) } } } sr := image.Rect(0, 0, 16, 16) circle := image.NewAlpha(sr) for y := sr.Min.Y; y < sr.Max.Y; y++ { for x := sr.Min.X; x < sr.Max.X; x++ { dx, dy := x-10, y-8 if d := 32 * math.Sqrt(float64(dx*dx)+float64(dy*dy)); d < 0xff { circle.SetAlpha(x, y, color.Alpha{0xff - uint8(d)}) } } } cyan := image.NewUniform(color.RGBA{0x00, 0xff, 0xff, 0xff}) draw.NearestNeighbor.Scale(dst, dr, cyan, sr, draw.Over, &draw.Options{ DstMask: checkerboard, SrcMask: circle, }) // Change false to true to write the resultant image to disk. if false { fDst, err := os.Create("out.png") if err != nil { log.Fatal(err) } defer fDst.Close() err = png.Encode(fDst, dst) if err != nil { log.Fatal(err) } } fmt.Printf("dst has bounds %v.\n", dst.Bounds()) // Output: // dst has bounds (0,0)-(400,300). }