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-rw-r--r--src/image/png/writer_test.go407
1 files changed, 407 insertions, 0 deletions
diff --git a/src/image/png/writer_test.go b/src/image/png/writer_test.go
new file mode 100644
index 0000000..6dac8ec
--- /dev/null
+++ b/src/image/png/writer_test.go
@@ -0,0 +1,407 @@
+// 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"
+ "compress/zlib"
+ "encoding/binary"
+ "fmt"
+ "image"
+ "image/color"
+ "image/draw"
+ "io"
+ "testing"
+)
+
+func diff(m0, m1 image.Image) 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): %T%v vs %T%v", x, y, c0, c0, c1, c1)
+ }
+ }
+ }
+ return nil
+}
+
+func encodeDecode(m image.Image) (image.Image, error) {
+ var b bytes.Buffer
+ err := Encode(&b, m)
+ if err != nil {
+ return nil, err
+ }
+ return Decode(&b)
+}
+
+func convertToNRGBA(m image.Image) *image.NRGBA {
+ b := m.Bounds()
+ ret := image.NewNRGBA(b)
+ draw.Draw(ret, b, m, b.Min, draw.Src)
+ return ret
+}
+
+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)
+ continue
+ }
+ m2, err := encodeDecode(m1)
+ if err != nil {
+ t.Error(fn, err)
+ continue
+ }
+ // Compare the two.
+ err = diff(m0, m2)
+ if err != nil {
+ t.Error(fn, err)
+ continue
+ }
+ }
+}
+
+func TestWriterPaletted(t *testing.T) {
+ const width, height = 32, 16
+
+ testCases := []struct {
+ plen int
+ bitdepth uint8
+ datalen int
+ }{
+
+ {
+ plen: 256,
+ bitdepth: 8,
+ datalen: (1 + width) * height,
+ },
+
+ {
+ plen: 128,
+ bitdepth: 8,
+ datalen: (1 + width) * height,
+ },
+
+ {
+ plen: 16,
+ bitdepth: 4,
+ datalen: (1 + width/2) * height,
+ },
+
+ {
+ plen: 4,
+ bitdepth: 2,
+ datalen: (1 + width/4) * height,
+ },
+
+ {
+ plen: 2,
+ bitdepth: 1,
+ datalen: (1 + width/8) * height,
+ },
+ }
+
+ for _, tc := range testCases {
+ t.Run(fmt.Sprintf("plen-%d", tc.plen), func(t *testing.T) {
+ // Create a paletted image with the correct palette length
+ palette := make(color.Palette, tc.plen)
+ for i := range palette {
+ palette[i] = color.NRGBA{
+ R: uint8(i),
+ G: uint8(i),
+ B: uint8(i),
+ A: 255,
+ }
+ }
+ m0 := image.NewPaletted(image.Rect(0, 0, width, height), palette)
+
+ i := 0
+ for y := 0; y < height; y++ {
+ for x := 0; x < width; x++ {
+ m0.SetColorIndex(x, y, uint8(i%tc.plen))
+ i++
+ }
+ }
+
+ // Encode the image
+ var b bytes.Buffer
+ if err := Encode(&b, m0); err != nil {
+ t.Error(err)
+ return
+ }
+ const chunkFieldsLength = 12 // 4 bytes for length, name and crc
+ data := b.Bytes()
+ i = len(pngHeader)
+
+ for i < len(data)-chunkFieldsLength {
+ length := binary.BigEndian.Uint32(data[i : i+4])
+ name := string(data[i+4 : i+8])
+
+ switch name {
+ case "IHDR":
+ bitdepth := data[i+8+8]
+ if bitdepth != tc.bitdepth {
+ t.Errorf("got bitdepth %d, want %d", bitdepth, tc.bitdepth)
+ }
+ case "IDAT":
+ // Uncompress the image data
+ r, err := zlib.NewReader(bytes.NewReader(data[i+8 : i+8+int(length)]))
+ if err != nil {
+ t.Error(err)
+ return
+ }
+ n, err := io.Copy(io.Discard, r)
+ if err != nil {
+ t.Errorf("got error while reading image data: %v", err)
+ }
+ if n != int64(tc.datalen) {
+ t.Errorf("got uncompressed data length %d, want %d", n, tc.datalen)
+ }
+ }
+
+ i += chunkFieldsLength + int(length)
+ }
+ })
+
+ }
+}
+
+func TestWriterLevels(t *testing.T) {
+ m := image.NewNRGBA(image.Rect(0, 0, 100, 100))
+
+ var b1, b2 bytes.Buffer
+ if err := (&Encoder{}).Encode(&b1, m); err != nil {
+ t.Fatal(err)
+ }
+ noenc := &Encoder{CompressionLevel: NoCompression}
+ if err := noenc.Encode(&b2, m); err != nil {
+ t.Fatal(err)
+ }
+
+ if b2.Len() <= b1.Len() {
+ t.Error("DefaultCompression encoding was larger than NoCompression encoding")
+ }
+ if _, err := Decode(&b1); err != nil {
+ t.Error("cannot decode DefaultCompression")
+ }
+ if _, err := Decode(&b2); err != nil {
+ t.Error("cannot decode NoCompression")
+ }
+}
+
+func TestSubImage(t *testing.T) {
+ m0 := image.NewRGBA(image.Rect(0, 0, 256, 256))
+ for y := 0; y < 256; y++ {
+ for x := 0; x < 256; x++ {
+ m0.Set(x, y, color.RGBA{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 TestWriteRGBA(t *testing.T) {
+ const width, height = 640, 480
+ transparentImg := image.NewRGBA(image.Rect(0, 0, width, height))
+ opaqueImg := image.NewRGBA(image.Rect(0, 0, width, height))
+ mixedImg := image.NewRGBA(image.Rect(0, 0, width, height))
+ translucentImg := image.NewRGBA(image.Rect(0, 0, width, height))
+ for y := 0; y < height; y++ {
+ for x := 0; x < width; x++ {
+ opaqueColor := color.RGBA{uint8(x), uint8(y), uint8(y + x), 255}
+ translucentColor := color.RGBA{uint8(x) % 128, uint8(y) % 128, uint8(y+x) % 128, 128}
+ opaqueImg.Set(x, y, opaqueColor)
+ translucentImg.Set(x, y, translucentColor)
+ if y%2 == 0 {
+ mixedImg.Set(x, y, opaqueColor)
+ }
+ }
+ }
+
+ testCases := []struct {
+ name string
+ img image.Image
+ }{
+ {"Transparent RGBA", transparentImg},
+ {"Opaque RGBA", opaqueImg},
+ {"50/50 Transparent/Opaque RGBA", mixedImg},
+ {"RGBA with variable alpha", translucentImg},
+ }
+
+ for _, tc := range testCases {
+ t.Run(tc.name, func(t *testing.T) {
+ m0 := tc.img
+ m1, err := encodeDecode(m0)
+ if err != nil {
+ t.Fatal(err)
+ }
+ err = diff(convertToNRGBA(m0), m1)
+ if err != nil {
+ t.Error(err)
+ }
+ })
+ }
+}
+
+func BenchmarkEncodeGray(b *testing.B) {
+ img := image.NewGray(image.Rect(0, 0, 640, 480))
+ b.SetBytes(640 * 480 * 1)
+ b.ReportAllocs()
+ b.ResetTimer()
+ for i := 0; i < b.N; i++ {
+ Encode(io.Discard, img)
+ }
+}
+
+type pool struct {
+ b *EncoderBuffer
+}
+
+func (p *pool) Get() *EncoderBuffer {
+ return p.b
+}
+
+func (p *pool) Put(b *EncoderBuffer) {
+ p.b = b
+}
+
+func BenchmarkEncodeGrayWithBufferPool(b *testing.B) {
+ img := image.NewGray(image.Rect(0, 0, 640, 480))
+ e := Encoder{
+ BufferPool: &pool{},
+ }
+ b.SetBytes(640 * 480 * 1)
+ b.ReportAllocs()
+ b.ResetTimer()
+ for i := 0; i < b.N; i++ {
+ e.Encode(io.Discard, img)
+ }
+}
+
+func BenchmarkEncodeNRGBOpaque(b *testing.B) {
+ img := image.NewNRGBA(image.Rect(0, 0, 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, color.NRGBA{0, 0, 0, 255})
+ }
+ }
+ if !img.Opaque() {
+ b.Fatal("expected image to be opaque")
+ }
+ b.SetBytes(640 * 480 * 4)
+ b.ReportAllocs()
+ b.ResetTimer()
+ for i := 0; i < b.N; i++ {
+ Encode(io.Discard, img)
+ }
+}
+
+func BenchmarkEncodeNRGBA(b *testing.B) {
+ img := image.NewNRGBA(image.Rect(0, 0, 640, 480))
+ if img.Opaque() {
+ b.Fatal("expected image not to be opaque")
+ }
+ b.SetBytes(640 * 480 * 4)
+ b.ReportAllocs()
+ b.ResetTimer()
+ for i := 0; i < b.N; i++ {
+ Encode(io.Discard, img)
+ }
+}
+
+func BenchmarkEncodePaletted(b *testing.B) {
+ img := image.NewPaletted(image.Rect(0, 0, 640, 480), color.Palette{
+ color.RGBA{0, 0, 0, 255},
+ color.RGBA{255, 255, 255, 255},
+ })
+ b.SetBytes(640 * 480 * 1)
+ b.ReportAllocs()
+ b.ResetTimer()
+ for i := 0; i < b.N; i++ {
+ Encode(io.Discard, img)
+ }
+}
+
+func BenchmarkEncodeRGBOpaque(b *testing.B) {
+ img := image.NewRGBA(image.Rect(0, 0, 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, color.RGBA{0, 0, 0, 255})
+ }
+ }
+ if !img.Opaque() {
+ b.Fatal("expected image to be opaque")
+ }
+ b.SetBytes(640 * 480 * 4)
+ b.ReportAllocs()
+ b.ResetTimer()
+ for i := 0; i < b.N; i++ {
+ Encode(io.Discard, img)
+ }
+}
+
+func BenchmarkEncodeRGBA(b *testing.B) {
+ const width, height = 640, 480
+ img := image.NewRGBA(image.Rect(0, 0, width, height))
+ for y := 0; y < height; y++ {
+ for x := 0; x < width; x++ {
+ percent := (x + y) % 100
+ switch {
+ case percent < 10: // 10% of pixels are translucent (have alpha >0 and <255)
+ img.Set(x, y, color.NRGBA{uint8(x), uint8(y), uint8(x * y), uint8(percent)})
+ case percent < 40: // 30% of pixels are transparent (have alpha == 0)
+ img.Set(x, y, color.NRGBA{uint8(x), uint8(y), uint8(x * y), 0})
+ default: // 60% of pixels are opaque (have alpha == 255)
+ img.Set(x, y, color.NRGBA{uint8(x), uint8(y), uint8(x * y), 255})
+ }
+ }
+ }
+ if img.Opaque() {
+ b.Fatal("expected image not to be opaque")
+ }
+ b.SetBytes(width * height * 4)
+ b.ReportAllocs()
+ b.ResetTimer()
+ for i := 0; i < b.N; i++ {
+ Encode(io.Discard, img)
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-30 01:28:11 +0000