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// Copyright 2020 Nick White.
// Use of this source code is governed by the GPLv3
// license that can be found in the LICENSE file.
package integralimg
import (
"image"
"image/draw"
_ "image/png"
"os"
"testing"
)
func TestFromPNG(t *testing.T) {
f, err := os.Open("testdata/in.png")
if err != nil {
t.Fatalf("Could not open file %s: %v\n", "testdata/in.png", err)
}
defer f.Close()
img, _, err := image.Decode(f)
if err != nil {
t.Fatalf("Could not decode image: %v\n", err)
}
b := img.Bounds()
integral := NewImage(b)
draw.Draw(integral, b, img, b.Min, draw.Src)
if !imgsequal(img, integral) {
t.Errorf("Read png image differs to integral image\n")
}
}
func TestSqFromPNG(t *testing.T) {
f, err := os.Open("testdata/in.png")
if err != nil {
t.Fatalf("Could not open file %s: %v\n", "testdata/in.png", err)
}
defer f.Close()
img, _, err := image.Decode(f)
if err != nil {
t.Fatalf("Could not decode image: %v\n", err)
}
b := img.Bounds()
integral := NewSqImage(b)
draw.Draw(integral, b, img, b.Min, draw.Src)
if !imgsequal(img, integral) {
t.Errorf("Read png image differs to square integral image\n")
}
}
func TestSum(t *testing.T) {
f, err := os.Open("testdata/in.png")
if err != nil {
t.Fatalf("Could not open file %s: %v\n", "testdata/in.png", err)
}
defer f.Close()
img, _, err := image.Decode(f)
if err != nil {
t.Fatalf("Could not decode image: %v\n", err)
}
b := img.Bounds()
imgplus := newGray16Plus(b)
integral := NewImage(b)
draw.Draw(imgplus, b, img, b.Min, draw.Src)
draw.Draw(integral, b, img, b.Min, draw.Src)
cases := []struct {
name string
r image.Rectangle
}{
{"fullimage", b},
{"small", image.Rect(1, 1, 5, 5)},
{"toobig", image.Rect(0, 0, 2000, b.Dy())},
{"toosmall", image.Rect(-1, -1, 4, 5)},
{"small2", image.Rect(0, 0, 4, 4)},
}
for _, c := range cases{
t.Run(c.name, func(t *testing.T) {
sumimg := imgplus.sum(c.r)
sumint := integral.Sum(c.r)
if sumimg != sumint {
t.Errorf("Sum of integral image differs to regular image: regular: %d, integral: %d\n", sumimg, sumint)
}
})
}
}
func imgsequal(img1, img2 image.Image) bool {
b := img1.Bounds()
if !b.Eq(img2.Bounds()) {
return false
}
for y := b.Min.Y; y < b.Max.Y; y++ {
for x := b.Min.X; x < b.Max.X; x++ {
r0, g0, b0, a0 := img1.At(x, y).RGBA()
r1, g1, b1, a1 := img2.At(x, y).RGBA()
if r0 != r1 {
return false
}
if g0 != g1 {
return false
}
if b0 != b1 {
return false
}
if a0 != a1 {
return false
}
}
}
return true
}
type grayPlus struct {
image.Gray16
}
func newGray16Plus(r image.Rectangle) *grayPlus {
var g grayPlus
g.Gray16 = *image.NewGray16(r)
return &g
}
func (i grayPlus) sum(r image.Rectangle) uint64 {
var sum uint64
for y := r.Min.Y; y < r.Max.Y; y++ {
for x := r.Min.X; x < r.Max.X; x++ {
c := i.Gray16At(x, y).Y
sum += uint64(c)
}
}
return sum
}
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