From 2e923f2991d4070d86bd5d63a5434f30ce570fd3 Mon Sep 17 00:00:00 2001
From: Nick White <git@njw.name>
Date: Tue, 4 Aug 2020 13:29:06 +0100
Subject: Rename package from integralimg to integral

---
 integral_test.go | 185 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 185 insertions(+)
 create mode 100644 integral_test.go

(limited to 'integral_test.go')

diff --git a/integral_test.go b/integral_test.go
new file mode 100644
index 0000000..513c7c4
--- /dev/null
+++ b/integral_test.go
@@ -0,0 +1,185 @@
+// Copyright 2020 Nick White.
+// Use of this source code is governed by the GPLv3
+// license that can be found in the LICENSE file.
+
+package integral
+
+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 TestMean(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) {
+			meanimg := imgplus.mean(c.r)
+			meanint := integral.Mean(c.r)
+			if meanimg != meanint {
+				t.Errorf("Mean of integral image differs to regular image: regular: %f, integral: %f\n", meanimg, meanint)
+			}
+		})
+	}
+}
+
+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
+}
+
+func (i grayPlus) mean(r image.Rectangle) float64 {
+	in := r.Intersect(i.Bounds())
+	return float64(i.sum(r)) / float64(in.Dx()*in.Dy())
+}
-- 
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