spiral example

examples/spiral.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"math"
+
+	"github.com/fogleman/gg"
+)
+
+func main() {
+	const S = 1024
+	const N = 2048
+	dc := gg.NewContext(S, S)
+	dc.SetRGB(1, 1, 1)
+	dc.Clear()
+	dc.SetRGB(0, 0, 0)
+	for i := 0; i <= N; i++ {
+		t := float64(i) / N
+		d := t*S*0.4 + 10
+		a := t * math.Pi * 2 * 20
+		x := S/2 + math.Cos(a)*d
+		y := S/2 + math.Sin(a)*d
+		r := t * 8
+		dc.DrawCircle(x, y, r)
+	}
+	dc.Fill()
+	dc.SavePNG("out.png")
+}