add circle loop

circleloop.go

@@ -0,0 +1,39 @@
+package generativeart
+
+import (
+	"github.com/fogleman/gg"
+	"math"
+)
+
+type circleLoop struct {
+	radius float64
+}
+
+func NewCircleLoop(radius float64) *circleLoop {
+	return &circleLoop{
+		radius: radius,
+	}
+}
+
+// Generative draws a Circle Loop images.
+func (cl *circleLoop) Generative(c *canva) {
+	ctex := gg.NewContextForRGBA(c.img)
+
+	r := cl.radius
+	var theta float64 = 0
+	for i:=0; i<c.opts.nIters; i++ {
+		ctex.Push()
+		ctex.Translate(float64(c.width/2), float64(c.height/2))
+		x := cl.radius*math.Cos(gg.Radians(theta))
+		y := cl.radius*math.Sin(gg.Radians(theta*2))
+
+		ctex.SetLineWidth(c.opts.lineWidth)
+		ctex.SetColor(c.opts.lineColor)
+		ctex.SetRGBA255(int(c.opts.lineColor.R), int(c.opts.lineColor.G), int(c.opts.lineColor.B), c.opts.alpha)
+		ctex.DrawEllipse(x, y, r/2, r/2)
+		ctex.Stroke()
+		ctex.Pop()
+		r+=math.Cos((theta))*math.Sin((theta/2))+math.Sin((theta))*math.Cos((theta/2))
+		theta += math.Pi/2
+	}
+}

example/example_circleloop.go

@@ -0,0 +1,20 @@
+package main
+
+import (
+	"generativeart"
+	"math/rand"
+	"time"
+)
+
+func main() {
+	rand.Seed(time.Now().Unix())
+	c := generativeart.NewCanva(500, 500, 2, 2)
+	c.SetBackground(generativeart.Black)
+	c.SetLineWidth(1)
+	c.SetLineColor(generativeart.Orange)
+	c.SetAlpha(30)
+	c.SetIterations(1000)
+	c.FillBackground()
+	c.Draw(generativeart.NewCircleLoop(100))
+	c.ToPNG("circleloop.png")
+}