initial commit

vendor/golang.org/x/image/tiff/reader_test.go

@@ -0,0 +1,183 @@
+// Copyright 2011 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 tiff
+
+import (
+	"image"
+	"io/ioutil"
+	"os"
+	"strings"
+	"testing"
+
+	_ "image/png"
+)
+
+const testdataDir = "../testdata/"
+
+// Read makes *buffer implements io.Reader, so that we can pass one to Decode.
+func (*buffer) Read([]byte) (int, error) {
+	panic("unimplemented")
+}
+
+func load(name string) (image.Image, error) {
+	f, err := os.Open(testdataDir + name)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	img, _, err := image.Decode(f)
+	if err != nil {
+		return nil, err
+	}
+	return img, nil
+}
+
+// TestNoRPS tries to decode an image that has no RowsPerStrip tag.
+// The tag is mandatory according to the spec but some software omits
+// it in the case of a single strip.
+func TestNoRPS(t *testing.T) {
+	_, err := load("no_rps.tiff")
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+// TestNoCompression tries to decode an images that has no Compression tag.
+// This tag is mandatory, but most tools interpret a missing value as no compression.
+func TestNoCompression(t *testing.T) {
+	_, err := load("no_compress.tiff")
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+// TestUnpackBits tests the decoding of PackBits-encoded data.
+func TestUnpackBits(t *testing.T) {
+	var unpackBitsTests = []struct {
+		compressed   string
+		uncompressed string
+	}{{
+		// Example data from Wikipedia.
+		"\xfe\xaa\x02\x80\x00\x2a\xfd\xaa\x03\x80\x00\x2a\x22\xf7\xaa",
+		"\xaa\xaa\xaa\x80\x00\x2a\xaa\xaa\xaa\xaa\x80\x00\x2a\x22\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa",
+	}}
+	for _, u := range unpackBitsTests {
+		buf, err := unpackBits(strings.NewReader(u.compressed))
+		if err != nil {
+			t.Fatal(err)
+		}
+		if string(buf) != u.uncompressed {
+			t.Fatalf("unpackBits: want %x, got %x", u.uncompressed, buf)
+		}
+	}
+}
+
+func compare(t *testing.T, img0, img1 image.Image) {
+	b0 := img0.Bounds()
+	b1 := img1.Bounds()
+	if b0.Dx() != b1.Dx() || b0.Dy() != b1.Dy() {
+		t.Fatalf("wrong image size: want %s, got %s", b0, b1)
+	}
+	x1 := b1.Min.X - b0.Min.X
+	y1 := 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 := img0.At(x, y)
+			c1 := img1.At(x+x1, y+y1)
+			r0, g0, b0, a0 := c0.RGBA()
+			r1, g1, b1, a1 := c1.RGBA()
+			if r0 != r1 || g0 != g1 || b0 != b1 || a0 != a1 {
+				t.Fatalf("pixel at (%d, %d) has wrong color: want %v, got %v", x, y, c0, c1)
+			}
+		}
+	}
+}
+
+// TestDecode tests that decoding a PNG image and a TIFF image result in the
+// same pixel data.
+func TestDecode(t *testing.T) {
+	img0, err := load("video-001.png")
+	if err != nil {
+		t.Fatal(err)
+	}
+	img1, err := load("video-001.tiff")
+	if err != nil {
+		t.Fatal(err)
+	}
+	img2, err := load("video-001-strip-64.tiff")
+	if err != nil {
+		t.Fatal(err)
+	}
+	img3, err := load("video-001-tile-64x64.tiff")
+	if err != nil {
+		t.Fatal(err)
+	}
+	img4, err := load("video-001-16bit.tiff")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	compare(t, img0, img1)
+	compare(t, img0, img2)
+	compare(t, img0, img3)
+	compare(t, img0, img4)
+}
+
+// TestDecodeLZW tests that decoding a PNG image and a LZW-compressed TIFF image
+// result in the same pixel data.
+func TestDecodeLZW(t *testing.T) {
+	img0, err := load("blue-purple-pink.png")
+	if err != nil {
+		t.Fatal(err)
+	}
+	img1, err := load("blue-purple-pink.lzwcompressed.tiff")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	compare(t, img0, img1)
+}
+
+// TestDecompress tests that decoding some TIFF images that use different
+// compression formats result in the same pixel data.
+func TestDecompress(t *testing.T) {
+	var decompressTests = []string{
+		"bw-uncompressed.tiff",
+		"bw-deflate.tiff",
+		"bw-packbits.tiff",
+	}
+	var img0 image.Image
+	for _, name := range decompressTests {
+		img1, err := load(name)
+		if err != nil {
+			t.Fatalf("decoding %s: %v", name, err)
+		}
+		if img0 == nil {
+			img0 = img1
+			continue
+		}
+		compare(t, img0, img1)
+	}
+}
+
+// benchmarkDecode benchmarks the decoding of an image.
+func benchmarkDecode(b *testing.B, filename string) {
+	b.StopTimer()
+	contents, err := ioutil.ReadFile(testdataDir + filename)
+	if err != nil {
+		panic(err)
+	}
+	r := &buffer{buf: contents}
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		_, err := Decode(r)
+		if err != nil {
+			b.Fatal("Decode:", err)
+		}
+	}
+}
+
+func BenchmarkDecodeCompressed(b *testing.B)   { benchmarkDecode(b, "video-001.tiff") }
+func BenchmarkDecodeUncompressed(b *testing.B) { benchmarkDecode(b, "video-001-uncompressed.tiff") }