From dd5567cfb4e908b31cfa00fa58eb8a4903233df6 Mon Sep 17 00:00:00 2001
From: Michael Fogleman <fogleman@gmail.com>
Date: Thu, 18 Feb 2016 21:30:24 -0500
Subject: [PATCH] star example

---
 examples/star.go | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 examples/star.go

diff --git a/examples/star.go b/examples/star.go
new file mode 100644
index 0000000..cbc29f6
--- /dev/null
+++ b/examples/star.go
@@ -0,0 +1,39 @@
+package main
+
+import (
+	"math"
+
+	"github.com/fogleman/dd"
+)
+
+type Point struct {
+	X, Y float64
+}
+
+func Polygon(n int, x, y, r float64) []Point {
+	result := make([]Point, n)
+	for i := 0; i < n; i++ {
+		a := float64(i)*2*math.Pi/float64(n) - math.Pi/2
+		result[i] = Point{x + r*math.Cos(a), y + r*math.Sin(a)}
+	}
+	return result
+}
+
+func main() {
+	points := Polygon(5, 512, 512, 400)
+	indexes := []int{0, 2, 4, 1, 3, 0}
+	dc := dd.NewContext(1024, 1024)
+	dc.SetSourceRGB(1, 1, 1)
+	dc.Paint()
+	for _, index := range indexes {
+		p := points[index]
+		dc.LineTo(p.X, p.Y)
+	}
+	dc.SetSourceRGBA(1, 0, 0, 0.5)
+	dc.SetFillRule(dd.FillRuleEvenOdd)
+	dc.FillPreserve()
+	dc.SetSourceRGB(0, 0, 0)
+	dc.SetLineWidth(8)
+	dc.Stroke()
+	dc.WriteToPNG("out.png")
+}