draw: test that the fast path implementations match the generic ones.

Change-Id: I34418bd8e5dec7b03e9c29efdab10f6116b4463f
Reviewed-on: https://go-review.googlesource.com/5730
Reviewed-by: Rob Pike <r@golang.org>
This commit is contained in:
Nigel Tao 2015-02-24 20:05:58 +11:00
parent 748adb17a1
commit 284bc4b702

View File

@ -5,10 +5,13 @@
package draw package draw
import ( import (
"bytes"
"flag" "flag"
"fmt" "fmt"
"image" "image"
"image/color"
"image/png" "image/png"
"math/rand"
"os" "os"
"reflect" "reflect"
"testing" "testing"
@ -81,33 +84,123 @@ func testScale(t *testing.T, w int, h int, direction, srcFilename string) {
func TestScaleDown(t *testing.T) { testScale(t, 100, 100, "down", "280x360.jpeg") } 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 TestScaleUp(t *testing.T) { testScale(t, 75, 100, "up", "14x18.png") }
// TODO: test that scaling concrete types like *image.RGBA and *image.YCbCr // The fooWrapper types wrap the dst or src image to avoid triggering the
// give the same results as scaling those images wrapped in another Image or // type-specific fast path implementations.
// image.Image type that would skip the fast-path type switch. type (
dstWrapper struct{ Image }
srcWrapper struct{ image.Image }
)
func srcNRGBA() (image.Image, error) { // TestFastPaths tests that the fast path implementations produce identical
return image.NewNRGBA(image.Rect(0, 0, 1024, 768)), nil // 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){
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)
Scale(dst0, dr, src, sr, q)
Scale(dstWrapper{dst1}, dr, srcWrapper{src}, sr, q)
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 srcRGBA() (image.Image, error) { func srcNRGBA(boundsHint image.Rectangle) (image.Image, error) {
return image.NewRGBA(image.Rect(0, 0, 1024, 768)), nil m := image.NewNRGBA(boundsHint)
r := rand.New(rand.NewSource(1))
for i := range m.Pix {
m.Pix[i] = uint8(r.Intn(256))
}
return m, nil
} }
func srcUniform() (image.Image, error) { func srcRGBA(boundsHint image.Rectangle) (image.Image, error) {
return image.White, nil m := image.NewRGBA(boundsHint)
r := rand.New(rand.NewSource(2))
for i := range m.Pix {
m.Pix[i] = uint8(r.Intn(256))
}
// 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 srcYCbCr() (image.Image, error) { func srcUniform(boundsHint image.Rectangle) (image.Image, error) {
return image.NewYCbCr(image.Rect(0, 0, 1024, 768), image.YCbCrSubsampleRatio420), nil return image.NewUniform(color.RGBA64{0x1234, 0x5555, 0x9181, 0xbeef}), nil
} }
func srcYCbCrLarge() (image.Image, error) { func srcYCbCr(boundsHint image.Rectangle) (image.Image, error) {
m := image.NewYCbCr(boundsHint, image.YCbCrSubsampleRatio420)
r := rand.New(rand.NewSource(3))
for i := range m.Y {
m.Y[i] = uint8(r.Intn(256))
}
for i := range m.Cb {
m.Cb[i] = uint8(r.Intn(256))
}
for i := range m.Cr {
m.Cr[i] = uint8(r.Intn(256))
}
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 // 3072 x 2304 is over 7 million pixels at 4:3, comparable to a
// 2015 smart-phone camera's output. // 2015 smart-phone camera's output.
return image.NewYCbCr(image.Rect(0, 0, 3072, 2304), image.YCbCrSubsampleRatio420), nil return srcYCbCr(image.Rect(0, 0, 3072, 2304))
} }
func srcTux() (image.Image, error) { func srcTux(boundsHint image.Rectangle) (image.Image, error) {
// tux.png is a 386 x 395 image. // tux.png is a 386 x 395 image.
f, err := os.Open("../testdata/tux.png") f, err := os.Open("../testdata/tux.png")
if err != nil { if err != nil {
@ -121,9 +214,9 @@ func srcTux() (image.Image, error) {
return src, nil return src, nil
} }
func benchScale(b *testing.B, srcf func() (image.Image, error), w int, h int, q Interpolator) { 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)) dst := image.NewRGBA(image.Rect(0, 0, w, h))
src, err := srcf() src, err := srcf(image.Rect(0, 0, 1024, 768))
if err != nil { if err != nil {
b.Fatal(err) b.Fatal(err)
} }