Initial commit

image/color/color.go

@@ -0,0 +1,9 @@
+package ucolor
+
+import "image/color"
+
+// Transparent returns whether or not a color has transparency.
+func Transparent (c color.Color) bool {
+	_, _, _, a := c.RGBA()
+	return a != 0xFFFF
+}

image/path/path.go

@@ -0,0 +1,38 @@
+package upath
+
+import "math"
+import "image"
+
+// P creates a path fom a list of integers that form X-Y pairs.
+func P (data ...int) []image.Point {
+	result := make([]image.Point, len(data) / 2)
+	for index := range result {
+		result[index].X = data[index * 2]
+		result[index].Y = data[index * 2 + 1]
+	}
+	return result
+}
+
+// Lerp linearally interpolates between two paths. If the paths differ in
+// length, the returned path will only be as long as the smaller one.
+func Lerp (fac float64, start, end []image.Point) []image.Point {
+	result := make([]image.Point, len(start))
+	for index, startPt := range start {
+		if index >= len(end) { return result[:index] }
+		endPt := end[index]
+		result[index] = image.Pt (
+			lerp(fac, startPt.X, endPt.X),
+			lerp(fac, startPt.Y, endPt.Y))
+	}
+	return result
+}
+
+// Distance returns the distance between two points.
+func Distance (start, end image.Point) float64 {
+	delta := start.Sub(end)
+	return math.Sqrt(float64(delta.X * delta.X) + float64(delta.Y * delta.Y))
+}
+
+func lerp (fac float64, x, y int) int {
+	return int(float64(x) * fac + float64(y) * (1.0 - fac))
+}