1 // Copyright 2015 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package image 6 7 import ( 8 "fmt" 9 "testing" 10 ) 11 12 func TestRectangle(t *testing.T) { 13 // in checks that every point in f is in g. 14 in := func(f, g Rectangle) error { 15 if !f.In(g) { 16 return fmt.Errorf("f=%s, f.In(%s): got false, want true", f, g) 17 } 18 for y := f.Min.Y; y < f.Max.Y; y++ { 19 for x := f.Min.X; x < f.Max.X; x++ { 20 p := Point{x, y} 21 if !p.In(g) { 22 return fmt.Errorf("p=%s, p.In(%s): got false, want true", p, g) 23 } 24 } 25 } 26 return nil 27 } 28 29 rects := []Rectangle{ 30 Rect(0, 0, 10, 10), 31 Rect(1, 2, 3, 4), 32 Rect(4, 6, 10, 10), 33 Rect(2, 3, 12, 5), 34 Rect(-1, -2, 0, 0), 35 Rect(-1, -2, 4, 6), 36 Rect(-10, -20, 30, 40), 37 Rect(8, 8, 8, 8), 38 Rect(88, 88, 88, 88), 39 Rect(6, 5, 4, 3), 40 } 41 42 // r.Eq(s) should be equivalent to every point in r being in s, and every 43 // point in s being in r. 44 for _, r := range rects { 45 for _, s := range rects { 46 got := r.Eq(s) 47 want := in(r, s) == nil && in(s, r) == nil 48 if got != want { 49 t.Errorf("Eq: r=%s, s=%s: got %t, want %t", r, s, got, want) 50 } 51 } 52 } 53 54 // The intersection should be the largest rectangle a such that every point 55 // in a is both in r and in s. 56 for _, r := range rects { 57 for _, s := range rects { 58 a := r.Intersect(s) 59 if err := in(a, r); err != nil { 60 t.Errorf("Intersect: r=%s, s=%s, a=%s, a not in r: %v", r, s, a, err) 61 } 62 if err := in(a, s); err != nil { 63 t.Errorf("Intersect: r=%s, s=%s, a=%s, a not in s: %v", r, s, a, err) 64 } 65 if a.Empty() == r.Overlaps(s) { 66 t.Errorf("Intersect: r=%s, s=%s, a=%s: empty=%t same as overlaps=%t", 67 r, s, a, a.Empty(), r.Overlaps(s)) 68 } 69 largerThanA := [4]Rectangle{a, a, a, a} 70 largerThanA[0].Min.X-- 71 largerThanA[1].Min.Y-- 72 largerThanA[2].Max.X++ 73 largerThanA[3].Max.Y++ 74 for i, b := range largerThanA { 75 if b.Empty() { 76 // b isn't actually larger than a. 77 continue 78 } 79 if in(b, r) == nil && in(b, s) == nil { 80 t.Errorf("Intersect: r=%s, s=%s, a=%s, b=%s, i=%d: intersection could be larger", 81 r, s, a, b, i) 82 } 83 } 84 } 85 } 86 87 // The union should be the smallest rectangle a such that every point in r 88 // is in a and every point in s is in a. 89 for _, r := range rects { 90 for _, s := range rects { 91 a := r.Union(s) 92 if err := in(r, a); err != nil { 93 t.Errorf("Union: r=%s, s=%s, a=%s, r not in a: %v", r, s, a, err) 94 } 95 if err := in(s, a); err != nil { 96 t.Errorf("Union: r=%s, s=%s, a=%s, s not in a: %v", r, s, a, err) 97 } 98 if a.Empty() { 99 // You can't get any smaller than a. 100 continue 101 } 102 smallerThanA := [4]Rectangle{a, a, a, a} 103 smallerThanA[0].Min.X++ 104 smallerThanA[1].Min.Y++ 105 smallerThanA[2].Max.X-- 106 smallerThanA[3].Max.Y-- 107 for i, b := range smallerThanA { 108 if in(r, b) == nil && in(s, b) == nil { 109 t.Errorf("Union: r=%s, s=%s, a=%s, b=%s, i=%d: union could be smaller", 110 r, s, a, b, i) 111 } 112 } 113 } 114 } 115 } 116
