experiments and stuff

pkg/dithering/grid.go

@@ -0,0 +1,63 @@
+package dithering
+
+import (
+	"image"
+	"image/color"
+)
+
+const side = 16
+
+type grid struct {
+	color.Gray
+}
+
+func (_ grid) ColorModel() color.Model {
+	return color.RGBAModel
+}
+
+func (_ grid) Bounds() image.Rectangle {
+	return image.Rect(0, 0, side, side)
+}
+
+func (g grid) At(x, y int) color.Color {
+	n := uint8(g.Gray.Y * 10)
+
+	if n == 0 {
+		return color.Black
+	}
+	step := int((side*side-1) / n)
+	if (y*side+x)%step == 0 {
+		return color.White
+	}
+	return color.Black
+}
+
+type uniformGrid struct {
+	image.Image
+}
+
+func (g uniformGrid) ColorModel() color.Model {
+	return g.Image.ColorModel()
+}
+
+func (g uniformGrid) Bounds() image.Rectangle {
+	// just need to return something
+	return g.Image.Bounds()
+}
+
+func (g uniformGrid) At(x, y int) color.Color {
+	dx, dy := g.Image.Bounds().Dx(), g.Image.Bounds().Dy()
+	return g.Image.At(x%dx, y%dy)
+}
+
+type Dithering struct {
+	image.Image
+}
+
+func (d Dithering) ColorModel() color.Model { return color.GrayModel }
+func (d Dithering) Bounds() image.Rectangle { return d.Image.Bounds() }
+func (d Dithering) At(x, y int) color.Color {
+	c := color.GrayModel.Convert(d.Image.At(x, y))
+	return uniformGrid{grid{c.(color.Gray)}}.
+		At(x, y)
+}