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package main
import (
"math"
"github.com/fogleman/gg"
)
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() {
n := 5
points := Polygon(n, 512, 512, 400)
dc := gg.NewContext(1024, 1024)
dc.SetHexColor("fff")
dc.Clear()
for i := 0; i < n+1; i++ {
index := (i * 2) % n
p := points[index]
dc.LineTo(p.X, p.Y)
}
dc.SetRGBA(0, 0.5, 0, 1)
dc.SetFillRule(gg.FillRuleEvenOdd)
dc.FillPreserve()
dc.SetRGBA(0, 1, 0, 0.5)
dc.SetLineWidth(16)
dc.Stroke()
dc.SavePNG("out.png")
}
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