Add Translate function

image/path/path.go

@@ -74,6 +74,13 @@ func DistanceToLine (point, line1, line2 image.Point) float64 {
 	return triangle / Distance(line1, line2)
 }
 
+// Translate adds delta to all points in path. This modifies the slice contents.
+func Translate (delta image.Point, path []image.Point) {
+	for index, point := range path {
+		path[index] = point.Add(delta)
+	}
+}
+
 func lerp (fac float64, x, y int) int {
 	return int(float64(x) * fac + float64(y) * (1.0 - fac))
 }