golang-image/bmp/writer_test.go

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// Copyright 2013 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 bmp
import (
"bytes"
"fmt"
"image"
"image/draw"
"io/ioutil"
"os"
"testing"
"time"
)
func openImage(filename string) (image.Image, error) {
f, err := os.Open(testdataDir + filename)
if err != nil {
return nil, err
}
defer f.Close()
return Decode(f)
}
func convertToRGBA(in image.Image) image.Image {
b := in.Bounds()
out := image.NewRGBA(b)
draw.Draw(out, b, in, b.Min, draw.Src)
return out
}
func convertToNRGBA(in image.Image) image.Image {
b := in.Bounds()
out := image.NewNRGBA(b)
draw.Draw(out, b, in, b.Min, draw.Src)
return out
}
func TestEncode(t *testing.T) {
testCases := []string{
"video-001.bmp",
"yellow_rose-small.bmp",
}
for _, tc := range testCases {
img0, err := openImage(tc)
if err != nil {
t.Errorf("%s: Open BMP: %v", tc, err)
continue
}
buf := new(bytes.Buffer)
err = Encode(buf, img0)
if err != nil {
t.Errorf("%s: Encode BMP: %v", tc, err)
continue
}
img1, err := Decode(buf)
if err != nil {
t.Errorf("%s: Decode BMP: %v", tc, err)
continue
}
err = compare(img0, img1)
if err != nil {
t.Errorf("%s: Compare BMP: %v", tc, err)
continue
}
buf2 := new(bytes.Buffer)
rgba := convertToRGBA(img0)
err = Encode(buf2, rgba)
if err != nil {
t.Errorf("%s: Encode pre-multiplied BMP: %v", tc, err)
continue
}
img2, err := Decode(buf2)
if err != nil {
t.Errorf("%s: Decode pre-multiplied BMP: %v", tc, err)
continue
}
// We need to do another round trip to NRGBA to compare to, since
// the conversion process is lossy.
img3 := convertToNRGBA(rgba)
err = compare(img3, img2)
if err != nil {
t.Errorf("%s: Compare pre-multiplied BMP: %v", tc, err)
}
}
}
// TestZeroWidthVeryLargeHeight tests that encoding and decoding a degenerate
// image with zero width but over one billion pixels in height is faster than
// naively calling an io.Reader or io.Writer method once per row.
func TestZeroWidthVeryLargeHeight(t *testing.T) {
c := make(chan error, 1)
go func() {
b := image.Rect(0, 0, 0, 0x3fffffff)
var buf bytes.Buffer
if err := Encode(&buf, image.NewRGBA(b)); err != nil {
c <- err
return
}
m, err := Decode(&buf)
if err != nil {
c <- err
return
}
if got := m.Bounds(); got != b {
c <- fmt.Errorf("bounds: got %v, want %v", got, b)
return
}
c <- nil
}()
select {
case err := <-c:
if err != nil {
t.Fatal(err)
}
case <-time.After(3 * time.Second):
t.Fatalf("timed out")
}
}
// BenchmarkEncode benchmarks the encoding of an image.
func BenchmarkEncode(b *testing.B) {
img, err := openImage("video-001.bmp")
if err != nil {
b.Fatal(err)
}
s := img.Bounds().Size()
b.SetBytes(int64(s.X * s.Y * 4))
b.ResetTimer()
for i := 0; i < b.N; i++ {
Encode(ioutil.Discard, img)
}
}