1 files changed, 149 insertions, 0 deletions
diff --git a/src/pkg/image/png/writer_test.go b/src/pkg/image/png/writer_test.go
new file mode 100644
index 000000000..1599791b3
--- /dev/null
+++ b/src/pkg/image/png/writer_test.go
@@ -0,0 +1,149 @@
+// Copyright 2009 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 png
+
+import (
+	"bytes"
+	"fmt"
+	"image"
+	"io/ioutil"
+	"os"
+	"testing"
+)
+
+func diff(m0, m1 image.Image) os.Error {
+	b0, b1 := m0.Bounds(), m1.Bounds()
+	if !b0.Size().Eq(b1.Size()) {
+		return fmt.Errorf("dimensions differ: %v vs %v", b0, b1)
+	}
+	dx := b1.Min.X - b0.Min.X
+	dy := b1.Min.Y - b0.Min.Y
+	for y := b0.Min.Y; y < b0.Max.Y; y++ {
+		for x := b0.Min.X; x < b0.Max.X; x++ {
+			c0 := m0.At(x, y)
+			c1 := m1.At(x+dx, y+dy)
+			r0, g0, b0, a0 := c0.RGBA()
+			r1, g1, b1, a1 := c1.RGBA()
+			if r0 != r1 || g0 != g1 || b0 != b1 || a0 != a1 {
+				return fmt.Errorf("colors differ at (%d, %d): %v vs %v", x, y, c0, c1)
+			}
+		}
+	}
+	return nil
+}
+
+func encodeDecode(m image.Image) (image.Image, os.Error) {
+	b := bytes.NewBuffer(nil)
+	err := Encode(b, m)
+	if err != nil {
+		return nil, err
+	}
+	m, err = Decode(b)
+	if err != nil {
+		return nil, err
+	}
+	return m, nil
+}
+
+func TestWriter(t *testing.T) {
+	// The filenames variable is declared in reader_test.go.
+	names := filenames
+	if testing.Short() {
+		names = filenamesShort
+	}
+	for _, fn := range names {
+		qfn := "testdata/pngsuite/" + fn + ".png"
+		// Read the image.
+		m0, err := readPng(qfn)
+		if err != nil {
+			t.Error(fn, err)
+			continue
+		}
+		// Read the image again, encode it, and decode it.
+		m1, err := readPng(qfn)
+		if err != nil {
+			t.Error(fn, err)
+			return
+		}
+		m2, err := encodeDecode(m1)
+		if err != nil {
+			t.Error(fn, err)
+			return
+		}
+		// Compare the two.
+		err = diff(m0, m2)
+		if err != nil {
+			t.Error(fn, err)
+			continue
+		}
+	}
+}
+
+func TestSubImage(t *testing.T) {
+	m0 := image.NewRGBA(256, 256)
+	for y := 0; y < 256; y++ {
+		for x := 0; x < 256; x++ {
+			m0.Set(x, y, image.RGBAColor{uint8(x), uint8(y), 0, 255})
+		}
+	}
+	m0 = m0.SubImage(image.Rect(50, 30, 250, 130)).(*image.RGBA)
+	m1, err := encodeDecode(m0)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	err = diff(m0, m1)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+}
+
+func BenchmarkEncodePaletted(b *testing.B) {
+	b.StopTimer()
+	img := image.NewPaletted(640, 480,
+		[]image.Color{
+			image.RGBAColor{0, 0, 0, 255},
+			image.RGBAColor{255, 255, 255, 255},
+		})
+	b.SetBytes(640 * 480 * 1)
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		Encode(ioutil.Discard, img)
+	}
+}
+
+func BenchmarkEncodeRGBOpaque(b *testing.B) {
+	b.StopTimer()
+	img := image.NewRGBA(640, 480)
+	// Set all pixels to 0xFF alpha to force opaque mode.
+	bo := img.Bounds()
+	for y := bo.Min.Y; y < bo.Max.Y; y++ {
+		for x := bo.Min.X; x < bo.Max.X; x++ {
+			img.Set(x, y, image.RGBAColor{0, 0, 0, 255})
+		}
+	}
+	if !img.Opaque() {
+		panic("expected image to be opaque")
+	}
+	b.SetBytes(640 * 480 * 4)
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		Encode(ioutil.Discard, img)
+	}
+}
+
+func BenchmarkEncodeRGBA(b *testing.B) {
+	b.StopTimer()
+	img := image.NewRGBA(640, 480)
+	if img.Opaque() {
+		panic("expected image to not be opaque")
+	}
+	b.SetBytes(640 * 480 * 4)
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		Encode(ioutil.Discard, img)
+	}
+}