golang-image/draw/scale_test.go
Nigel Tao 08593990c4 draw: add Transformer and Option types.
Just stub implementations for now. Actual implementations will be
follow-up changes.

Change-Id: Id21d9042a2073c2dc0f78c9977c4940f000a41df
Reviewed-on: https://go-review.googlesource.com/6805
Reviewed-by: Rob Pike <r@golang.org>
2015-03-10 00:41:02 +00:00

296 lines
9.0 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
import (
"bytes"
"flag"
"fmt"
"image"
"image/color"
"image/png"
"math/rand"
"os"
"reflect"
"testing"
_ "image/jpeg"
)
var genScaleFiles = flag.Bool("gen_scale_files", false, "whether to generate the TestScaleXxx golden files.")
// testScale tests that scaling the source image gives the exact destination
// image. This is to ensure that any refactoring or optimization of the scaling
// code doesn't change the scaling behavior. Changing the actual algorithm or
// kernel used by any particular quality setting will obviously change the
// resultant pixels. In such a case, use the gen_scale_files flag to regenerate
// the golden files.
func testScale(t *testing.T, w int, h int, direction, srcFilename string) {
f, err := os.Open("../testdata/go-turns-two-" + srcFilename)
if err != nil {
t.Fatalf("Open: %v", err)
}
defer f.Close()
src, _, err := image.Decode(f)
if err != nil {
t.Fatalf("Decode: %v", err)
}
testCases := map[string]Interpolator{
"nn": NearestNeighbor,
"ab": ApproxBiLinear,
"bl": BiLinear,
"cr": CatmullRom,
}
for name, q := range testCases {
gotFilename := fmt.Sprintf("../testdata/go-turns-two-%s-%s.png", direction, name)
got := image.NewRGBA(image.Rect(0, 0, w, h))
q.Scale(got, got.Bounds(), src, src.Bounds(), nil)
if *genScaleFiles {
g, err := os.Create(gotFilename)
if err != nil {
t.Errorf("Create: %v", err)
continue
}
defer g.Close()
if err := png.Encode(g, got); err != nil {
t.Errorf("Encode: %v", err)
continue
}
continue
}
g, err := os.Open(gotFilename)
if err != nil {
t.Errorf("Open: %v", err)
continue
}
defer g.Close()
want, err := png.Decode(g)
if err != nil {
t.Errorf("Decode: %v", err)
continue
}
if !reflect.DeepEqual(got, want) {
t.Errorf("%s: actual image differs from golden image", gotFilename)
continue
}
}
}
func TestScaleDown(t *testing.T) { testScale(t, 100, 100, "down", "280x360.jpeg") }
func TestScaleUp(t *testing.T) { testScale(t, 75, 100, "up", "14x18.png") }
func fillPix(r *rand.Rand, pixs ...[]byte) {
for _, pix := range pixs {
for i := range pix {
pix[i] = uint8(r.Intn(256))
}
}
}
func TestScaleClipCommute(t *testing.T) {
src := image.NewNRGBA(image.Rect(0, 0, 20, 20))
fillPix(rand.New(rand.NewSource(0)), src.Pix)
outer := image.Rect(1, 1, 8, 5)
inner := image.Rect(2, 3, 6, 5)
qs := []Interpolator{
NearestNeighbor,
ApproxBiLinear,
CatmullRom,
}
for _, q := range qs {
dst0 := image.NewRGBA(image.Rect(1, 1, 10, 10))
dst1 := image.NewRGBA(image.Rect(1, 1, 10, 10))
for i := range dst0.Pix {
dst0.Pix[i] = uint8(i / 4)
dst1.Pix[i] = uint8(i / 4)
}
// Scale then clip.
q.Scale(dst0, outer, src, src.Bounds(), nil)
dst0 = dst0.SubImage(inner).(*image.RGBA)
// Clip then scale.
dst1 = dst1.SubImage(inner).(*image.RGBA)
q.Scale(dst1, outer, src, src.Bounds(), nil)
loop:
for y := inner.Min.Y; y < inner.Max.Y; y++ {
for x := inner.Min.X; x < inner.Max.X; x++ {
if c0, c1 := dst0.RGBAAt(x, y), dst1.RGBAAt(x, y); c0 != c1 {
t.Errorf("q=%T: at (%d, %d): c0=%v, c1=%v", q, x, y, c0, c1)
break loop
}
}
}
}
}
// The fooWrapper types wrap the dst or src image to avoid triggering the
// type-specific fast path implementations.
type (
dstWrapper struct{ Image }
srcWrapper struct{ image.Image }
)
// TestFastPaths tests that the fast path implementations produce identical
// results to the generic implementation.
func TestFastPaths(t *testing.T) {
drs := []image.Rectangle{
image.Rect(0, 0, 10, 10), // The dst bounds.
image.Rect(3, 4, 8, 6), // A strict subset of the dst bounds.
image.Rect(-3, -5, 2, 4), // Partial out-of-bounds #0.
image.Rect(4, -2, 6, 12), // Partial out-of-bounds #1.
image.Rect(12, 14, 23, 45), // Complete out-of-bounds.
image.Rect(5, 5, 5, 5), // Empty.
}
srs := []image.Rectangle{
image.Rect(0, 0, 12, 9), // The src bounds.
image.Rect(2, 2, 10, 8), // A strict subset of the src bounds.
image.Rect(10, 5, 20, 20), // Partial out-of-bounds #0.
image.Rect(-40, 0, 40, 8), // Partial out-of-bounds #1.
image.Rect(-8, -8, -4, -4), // Complete out-of-bounds.
image.Rect(5, 5, 5, 5), // Empty.
}
srcfs := []func(image.Rectangle) (image.Image, error){
srcGray,
srcNRGBA,
srcRGBA,
srcUniform,
srcYCbCr,
}
var srcs []image.Image
for _, srcf := range srcfs {
src, err := srcf(srs[0])
if err != nil {
t.Fatal(err)
}
srcs = append(srcs, src)
}
qs := []Interpolator{
NearestNeighbor,
ApproxBiLinear,
CatmullRom,
}
blue := image.NewUniform(color.RGBA{0x11, 0x22, 0x44, 0x7f})
for _, dr := range drs {
for _, src := range srcs {
for _, sr := range srs {
for _, q := range qs {
dst0 := image.NewRGBA(drs[0])
dst1 := image.NewRGBA(drs[0])
Draw(dst0, dst0.Bounds(), blue, image.Point{}, Src)
Draw(dstWrapper{dst1}, dst1.Bounds(), srcWrapper{blue}, image.Point{}, Src)
q.Scale(dst0, dr, src, sr, nil)
q.Scale(dstWrapper{dst1}, dr, srcWrapper{src}, sr, nil)
if !bytes.Equal(dst0.Pix, dst1.Pix) {
t.Errorf("pix differ for dr=%v, src=%T, sr=%v, q=%T", dr, src, sr, q)
}
}
}
}
}
}
func srcGray(boundsHint image.Rectangle) (image.Image, error) {
m := image.NewGray(boundsHint)
fillPix(rand.New(rand.NewSource(0)), m.Pix)
return m, nil
}
func srcNRGBA(boundsHint image.Rectangle) (image.Image, error) {
m := image.NewNRGBA(boundsHint)
fillPix(rand.New(rand.NewSource(1)), m.Pix)
return m, nil
}
func srcRGBA(boundsHint image.Rectangle) (image.Image, error) {
m := image.NewRGBA(boundsHint)
fillPix(rand.New(rand.NewSource(2)), m.Pix)
// RGBA is alpha-premultiplied, so the R, G and B values should
// be <= the A values.
for i := 0; i < len(m.Pix); i += 4 {
m.Pix[i+0] = uint8(uint32(m.Pix[i+0]) * uint32(m.Pix[i+3]) / 0xff)
m.Pix[i+1] = uint8(uint32(m.Pix[i+1]) * uint32(m.Pix[i+3]) / 0xff)
m.Pix[i+2] = uint8(uint32(m.Pix[i+2]) * uint32(m.Pix[i+3]) / 0xff)
}
return m, nil
}
func srcUniform(boundsHint image.Rectangle) (image.Image, error) {
return image.NewUniform(color.RGBA64{0x1234, 0x5555, 0x9181, 0xbeef}), nil
}
func srcYCbCr(boundsHint image.Rectangle) (image.Image, error) {
m := image.NewYCbCr(boundsHint, image.YCbCrSubsampleRatio420)
fillPix(rand.New(rand.NewSource(3)), m.Y, m.Cb, m.Cr)
return m, nil
}
func srcYCbCrLarge(boundsHint image.Rectangle) (image.Image, error) {
// 3072 x 2304 is over 7 million pixels at 4:3, comparable to a
// 2015 smart-phone camera's output.
return srcYCbCr(image.Rect(0, 0, 3072, 2304))
}
func srcTux(boundsHint image.Rectangle) (image.Image, error) {
// tux.png is a 386 x 395 image.
f, err := os.Open("../testdata/tux.png")
if err != nil {
return nil, fmt.Errorf("Open: %v", err)
}
defer f.Close()
src, err := png.Decode(f)
if err != nil {
return nil, fmt.Errorf("Decode: %v", err)
}
return src, nil
}
func benchScale(b *testing.B, srcf func(image.Rectangle) (image.Image, error), w int, h int, q Interpolator) {
dst := image.NewRGBA(image.Rect(0, 0, w, h))
src, err := srcf(image.Rect(0, 0, 1024, 768))
if err != nil {
b.Fatal(err)
}
dr, sr := dst.Bounds(), src.Bounds()
scaler := Scaler(q)
if n, ok := q.(interface {
NewScaler(int, int, int, int) Scaler
}); ok {
scaler = n.NewScaler(dr.Dx(), dr.Dy(), sr.Dx(), sr.Dy())
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
scaler.Scale(dst, dr, src, sr, nil)
}
}
func BenchmarkScaleLargeDownNN(b *testing.B) { benchScale(b, srcYCbCrLarge, 200, 150, NearestNeighbor) }
func BenchmarkScaleLargeDownAB(b *testing.B) { benchScale(b, srcYCbCrLarge, 200, 150, ApproxBiLinear) }
func BenchmarkScaleLargeDownBL(b *testing.B) { benchScale(b, srcYCbCrLarge, 200, 150, BiLinear) }
func BenchmarkScaleLargeDownCR(b *testing.B) { benchScale(b, srcYCbCrLarge, 200, 150, CatmullRom) }
func BenchmarkScaleDownNN(b *testing.B) { benchScale(b, srcTux, 120, 80, NearestNeighbor) }
func BenchmarkScaleDownAB(b *testing.B) { benchScale(b, srcTux, 120, 80, ApproxBiLinear) }
func BenchmarkScaleDownBL(b *testing.B) { benchScale(b, srcTux, 120, 80, BiLinear) }
func BenchmarkScaleDownCR(b *testing.B) { benchScale(b, srcTux, 120, 80, CatmullRom) }
func BenchmarkScaleUpNN(b *testing.B) { benchScale(b, srcTux, 800, 600, NearestNeighbor) }
func BenchmarkScaleUpAB(b *testing.B) { benchScale(b, srcTux, 800, 600, ApproxBiLinear) }
func BenchmarkScaleUpBL(b *testing.B) { benchScale(b, srcTux, 800, 600, BiLinear) }
func BenchmarkScaleUpCR(b *testing.B) { benchScale(b, srcTux, 800, 600, CatmullRom) }
func BenchmarkScaleSrcGray(b *testing.B) { benchScale(b, srcGray, 200, 150, ApproxBiLinear) }
func BenchmarkScaleSrcNRGBA(b *testing.B) { benchScale(b, srcNRGBA, 200, 150, ApproxBiLinear) }
func BenchmarkScaleSrcRGBA(b *testing.B) { benchScale(b, srcRGBA, 200, 150, ApproxBiLinear) }
func BenchmarkScaleSrcUniform(b *testing.B) { benchScale(b, srcUniform, 200, 150, ApproxBiLinear) }
func BenchmarkScaleSrcYCbCr(b *testing.B) { benchScale(b, srcYCbCr, 200, 150, ApproxBiLinear) }