Changed line has point algorithm to vector, x2 performance

geometry_line.go

@@ -75,27 +75,12 @@ func (ln Line) Segment(length float64) Line {
 
 // IsPointOnLine tests if the Point is on the Line.
 func (ln Line) IsPointOnLine(p Point) bool {
-	if ln.IsHorizontal() {
-		return ln.From.Y == p.Y
-	}
-	if ln.IsVertical() {
-		return ln.From.X == p.X
-	}
-
-	// diagonal
-	slope := ln.Slope()
-	yIntercept := ln.From.Y - slope*ln.From.X
-	expectedY := slope*p.X + yIntercept
-
-	return math.Round(p.Y) == math.Round(expectedY)
+	return isPointOnLine(ln, p, false)
 }
 
 // IsPointOnSegment tests if the Point is on the Line segment.
 func (ln Line) IsPointOnSegment(p Point) bool {
-	if !ln.Rect().IsContainsPoint(p) {
-		return false
-	}
-	return ln.IsPointOnLine(p)
+	return isPointOnLine(ln, p, true)
 }
 
 // LinesIntersection returns the crossing Point of two Lines.

geometry_line_test.go

@@ -221,6 +221,14 @@ func TestLine_IsPointOnLine(t *testing.T) {
 	}
 }
 
+func BenchmarkLine_IsPointOnLine(b *testing.B) {
+	line := Line{Point{0, 0}, Point{300, 300}}
+	point := Point{150, 150}
+	for i := 0; i < b.N; i++ {
+		line.IsPointOnLine(point)
+	}
+}
+
 func TestLine_IsPointOnSegment(t *testing.T) {
 	tests := []struct {
 		name string

geometry_utils.go

@@ -39,3 +39,22 @@ func linesIntersection(a, b Line, s1, s2 bool) (Point, bool) {
 		Y: a.From.Y + t*av.Y,
 	}, true
 }
+
+func isPointOnLine(ln Line, point Point, s bool) bool {
+	lv := ln.Vector()
+	pv := point.Sub(ln.From)
+
+	pcp := lv.X*pv.Y - lv.Y*pv.X
+	if pcp != 0 {
+		return false
+	}
+
+	if s {
+		dp := pv.X*lv.X + pv.Y*lv.Y
+		l := lv.X*lv.X + lv.Y*lv.Y
+
+		return dp >= 0 && dp <= l
+	}
+
+	return true
+}