41 lines
719 B
Go
41 lines
719 B
Go
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")
|
|
}
|