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cmd/playground/circles/circles.go

@@ -1,11 +1,11 @@
 package main
 
 import (
-	"math/rand"
 	"image"
 	"image/color"
 	"image/draw"
 	"image/png"
+	"math/rand"
 	"os"
 
 	iu "git.nkpl.cc/twocookedfaggots/imageutils"
@@ -19,36 +19,71 @@ func Circles(b image.Rectangle, radius int) chan iu.Circle {
 		defer close(ch)
 		for {
 			x, y := rand.Int()%b.Dx(), rand.Int()%b.Dy()
-			dxdy := b.Dx()*b.Dy()
-			r := rand.Int() % (dxdy/(dxdy/radius))
+			dxdy := b.Dx() * b.Dy()
+			r := rand.Int() % (dxdy / (dxdy / radius))
 			ch <- iu.Circle{image.Point{x, y}, r}
 		}
 	}()
 	return ch
 }
 
-// Converts color.Opaque and color.Transparent to color.Black and color.White respectively.
-var BlackAndWhite = color.ModelFunc(
+var Opaque, Transparent = color.Alpha{0xff}, color.Alpha{0}
+
+type xor struct{ dst, src image.Image }
+
+func (t xor) ColorModel() color.Model { return t.dst.ColorModel() }
+func (t xor) Bounds() image.Rectangle { return t.src.Bounds() }
+func (t xor) At(x, y int) color.Color {
+	dstColor := t.ColorModel().Convert(t.dst.At(x, y))
+	srcColor := t.ColorModel().Convert(t.src.At(x, y))
+
+	
+	if ((dstColor == color.Opaque) || (srcColor == color.Opaque)) && 
+		!((dstColor == color.Opaque) && (srcColor == color.Opaque)) {
+		return color.Opaque
+	}
+	return color.Transparent
+}
+
+var exchange = color.ModelFunc(
 	func(c color.Color) color.Color {
-		if color.AlphaModel.Convert(c) == color.Opaque {
-			return color.Black
+		if color.Alpha16Model.Convert(c) == color.Transparent{
+			return color.Opaque
 		}
-		return color.White
+		return color.Transparent
 	},
 )
 
+type Exchange struct { image.Image }
+
+func (e Exchange) ColorModel() color.Model { return color.Alpha16Model }
+func (e Exchange) Bounds() image.Rectangle { return e.Image.Bounds() }
+func (e Exchange) At(x, y int) color.Color {
+	c := e.ColorModel().Convert(e.Image.At(x, y))
+	return exchange.Convert(c)
+}
+
 func main() {
-	canvas := image.NewRGBA(square(1024))
-	circles := Circles(canvas.Bounds(), 1024/16)
+	canvas := image.NewAlpha16(square(1024))
+	circles := Circles(canvas.Bounds(), 1024/7)
 
 	// draw n circles
-	for i := 0; i < 100; i++ {
+	for i := 0; i < 500; i++ {
 		c := <-circles
+
+		draw.Draw(canvas, c.Bounds(), xor{c, canvas}, c.Bounds().Min, draw.Src)
+		/*
 		draw.DrawMask(
-			canvas, canvas.Bounds(), &image.Uniform{color.White}, 
-			image.Point{}, c, image.Point{}, draw.Over,
+			canvas, canvas.Bounds(), &image.Uniform{color.White},
+			image.Point{}, xor{c, canvas}, image.Point{}, draw.Src,
 		)
+		*/
 	}
+	/*
+		newCanvas := image.NewRGBA(canvas.Bounds())
+		draw.Draw(newCanvas, newCanvas.Bounds(), &image.Uniform{color.RGBA{255, 255, 0, 255}}, image.ZP, draw.Over)
+		draw.Draw(newCanvas, newCanvas.Bounds(), canvas, image.ZP, draw.Over)
+	*/
 	err := png.Encode(os.Stdout, canvas)
 	if err != nil {
 		panic(err)