This repository was archived by the owner on Apr 2, 2026. It is now read-only.
Repository navigation
Expand file tree
/
Copy pathaffine_test.go
More file actions
94 lines (80 loc) · 2.67 KB
/
Copy pathaffine_test.go
File metadata and controls
94 lines (80 loc) · 2.67 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
package curve
import (
"math"
"testing"
)
func assertNear(t *testing.T, p0 Point, p1 Point, epsilon float64) {
t.Helper()
if d := p1.Sub(p0).Hypot(); d > epsilon {
t.Fatalf("got %s, expected %s", p0, p1)
}
}
func TestAffineBasic(t *testing.T) {
const epsilon = 1e-9
p := Pt(3, 4)
assertNear(t, p.Transform(Identity), p, epsilon)
assertNear(t, p.Transform(Scale(2, 2)), Pt(6, 8), epsilon)
assertNear(t, p.Transform(Rotate(0)), p, epsilon)
assertNear(t, p.Transform(Rotate(math.Pi/2)), Pt(-4, 3), epsilon)
assertNear(t, p.Transform(Translate(Vec(5, 6))), Pt(8, 10), epsilon)
assertNear(t, p.Transform(Skew(0, 0)), p, epsilon)
assertNear(t, p.Transform(Skew(2, 4)), Pt(11, 16), epsilon)
}
func TestAffineMul(t *testing.T) {
const epsilon = 1e-9
a1 := Affine{1, 2, 3, 4, 5, 6}
a2 := Affine{0.1, 1.2, 2.3, 3.4, 4.5, 5.6}
px := Pt(1, 0)
py := Pt(0, 1)
pxy := Pt(1, 1)
assertNear(t, px.Transform(a2).Transform(a1), px.Transform(a1.Mul(a2)), epsilon)
assertNear(t, py.Transform(a2).Transform(a1), py.Transform(a1.Mul(a2)), epsilon)
assertNear(t, pxy.Transform(a2).Transform(a1), pxy.Transform(a1.Mul(a2)), epsilon)
}
func TestAffineInvert(t *testing.T) {
const epsilon = 1e-9
a := Affine{0.1, 1.2, 2.3, 3.4, 4.5, 5.6}
aInv := a.Invert()
px := Pt(1, 0)
py := Pt(0, 1)
pxy := Pt(1, 1)
assertNear(t, px.Transform(aInv).Transform(a), px, epsilon)
assertNear(t, py.Transform(aInv).Transform(a), py, epsilon)
assertNear(t, pxy.Transform(aInv).Transform(a), pxy, epsilon)
assertNear(t, px.Transform(a).Transform(aInv), px, epsilon)
assertNear(t, py.Transform(a).Transform(aInv), py, epsilon)
assertNear(t, pxy.Transform(a).Transform(aInv), pxy, epsilon)
}
func TestReflection(t *testing.T) {
affineAssertNear := func(a0, a1 Affine) {
a0a := a0.Coefficients()
a1a := a1.Coefficients()
for i := range 6 {
if d := math.Abs(a0a[i] - a1a[i]); d > 1e-9 {
t.Fatalf("%g > %g", d, 1e-9)
}
}
}
affineAssertNear(Reflect(Point{}, Vec(1, 0)), Affine{1, 0, 0, -1, 0, 0})
affineAssertNear(Reflect(Point{}, Vec(0, 1)), Affine{-1, 0, 0, 1, 0, 0})
affineAssertNear(Reflect(Point{}, Vec(1, 1)), Affine{0, 1, 1, 0, 0, 0})
const epsilon = 1e-9
{
// No translation
point := Pt(0, 0)
vec := Vec(1, 1)
aff := Reflect(point, vec)
assertNear(t, Pt(0, 0).Transform(aff), Pt(0, 0), epsilon)
assertNear(t, Pt(1, 1).Transform(aff), Pt(1, 1), epsilon)
assertNear(t, Pt(1, 2).Transform(aff), Pt(2, 1), epsilon)
}
{
// With translation
point := Pt(1, 0)
vec := Vec(1, 1)
aff := Reflect(point, vec)
assertNear(t, Pt(1, 0).Transform(aff), Pt(1, 0), epsilon)
assertNear(t, Pt(2, 1).Transform(aff), Pt(2, 1), epsilon)
assertNear(t, Pt(2, 2).Transform(aff), Pt(3, 1), epsilon)
}
}