golang-image/draw/example_test.go
Nigel Tao 87013da148 draw: implement NearestNeighbor and ApproxBiLinear Transform.
Change-Id: I70a5e3703dea436354e9591fce7b704ec749c2d1
Reviewed-on: https://go-review.googlesource.com/7541
Reviewed-by: Rob Pike <r@golang.org>
2015-03-16 23:32:22 +00:00

65 lines
1.3 KiB
Go

// 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/png"
"log"
"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)
}
sr := src.Bounds()
dst := image.NewRGBA(image.Rect(0, 0, 400, 300))
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, sr, nil)
for i, q := range qs {
q.Scale(dst, image.Rect(200+10*i, 100*i, 600+10*i, 150+100*i), src, sr, nil)
}
draw.NearestNeighbor.Transform(dst, t, src, sr, nil)
// 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).
}