Initial commit

artutil/util.go

@@ -0,0 +1,62 @@
+// Package artutil provides utility functions for working with art's interfaces.
+package artutil
+
+import "art"
+import "image"
+import "art/shatter"
+import "image/color"
+
+// Fill fills the destination canvas with the given pattern.
+func Fill (destination art.Canvas, source art.Pattern) (updated image.Rectangle) {
+	source.Draw(destination, destination.Bounds())
+	return destination.Bounds()
+}
+
+// DrawClip lets you draw several subsets of a pattern at once.
+func DrawClip (
+	destination art.Canvas,
+	source      art.Pattern,
+	bounds      image.Rectangle,
+	subsets     ...image.Rectangle,
+) (
+	updatedRegion image.Rectangle,
+) {
+	for _, subset := range subsets {
+		source.Draw(art.Cut(destination, subset), bounds)
+		updatedRegion = updatedRegion.Union(subset)
+	}
+	return
+}
+
+// DrawShatter is like an inverse of DrawClip, drawing nothing in the areas
+// specified by "rocks".
+func DrawShatter (
+	destination art.Canvas,
+	source      art.Pattern,
+	bounds      image.Rectangle,
+	rocks       ...image.Rectangle,
+) (
+	updatedRegion image.Rectangle,
+) {
+	tiles := shatter.Shatter(bounds, rocks...)
+	return DrawClip(destination, source, bounds, tiles...)
+}
+
+// AllocateSample returns a new canvas containing the result of a pattern. The
+// resulting canvas can be sourced from shape drawing functions. I beg of you
+// please do not call this every time you need to draw a shape with a pattern on
+// it because that is horrible and cruel to the computer.
+func AllocateSample (source art.Pattern, width, height int) art.Canvas {
+	allocated := art.NewBasicCanvas(width, height)
+	Fill(allocated, source)
+	return allocated
+}
+
+// Hex creates a color.RGBA value from an RGBA integer value.
+func Hex (color uint32) (c color.RGBA) {
+	c.A = uint8(color)
+	c.B = uint8(color >>  8)
+	c.G = uint8(color >> 16)
+	c.R = uint8(color >> 24)
+	return
+}