Function TestPathLength

path_test.go:398–424

for quadratic Bézier use https://www.wolframalpha.com/input/?i=length+of+the+curve+%7Bx%3D2*(1-t)*t*50.00+%2B+t%5E2*100.00,+y%3D2*(1-t)*t*66.67+%2B+t%5E2*0.00%7D+from+0+to+1 for cubic Bézier use https://www.wolframalpha.com/input/?i=length+of+the+curve+%7Bx%3D3*(1-t)%5E2*t*0.00+%2B+3*(1-t)*t%5E2*100

(t *testing.T)

// for cubic Bézier use https://www.wolframalpha.com/input/?i=length+of+the+curve+%7Bx%3D3*(1-t)%5E2*t*0.00+%2B+3*(1-t)*t%5E2*100.00+%2B+t%5E3*100.00,+y%3D3*(1-t)%5E2*t*66.67+%2B+3*(1-t)*t%5E2*66.67+%2B+t%5E3*0.00%7D+from+0+to+1
// for ellipse use https://www.wolframalpha.com/input/?i=length+of+the+curve+%7Bx%3D10.00*cos(t),+y%3D20.0*sin(t)%7D+from+0+to+pi
func TestPathLength(t *testing.T) {
	var tts = []struct {
		p      string
		length float64
	}{
		{"M10 0z", 0.0},
		{"Q50 66.67 100 0", 124.533},
		{"Q100 0 100 0", 100.0000},
		{"C0 66.67 100 66.67 100 0", 158.5864},
		{"C0 0 100 66.67 100 0", 125.746},
		{"C0 0 100 0 100 0", 100.0000},
		{"C100 66.67 0 66.67 100 0", 143.9746},
		{"A10 20 0 0 0 20 0", 48.4422},
		{"A10 20 0 0 1 20 0", 48.4422},
		{"A10 20 0 1 0 20 0", 48.4422},
		{"A10 20 0 1 1 20 0", 48.4422},
		{"A10 20 30 0 0 20 0", 31.4622},
	}
	for _, tt := range tts {
		t.Run(tt.p, func(t *testing.T) {
			length := MustParseSVGPath(tt.p).Length()
			if math.Abs(tt.length-length)/length > 0.01 {
				test.Fail(t, length, "!=", tt.length, "±1%")
			}
		})
	}
}

func TestPathTransform(t *testing.T) {
	var tts = []struct {