40 lines
740 B
Go
40 lines
740 B
Go
package main
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import (
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"math"
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"github.com/fogleman/dd"
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)
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type Point struct {
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X, Y float64
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}
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func Polygon(n int, x, y, r float64) []Point {
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result := make([]Point, n)
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for i := 0; i < n; i++ {
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a := float64(i)*2*math.Pi/float64(n) - math.Pi/2
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result[i] = Point{x + r*math.Cos(a), y + r*math.Sin(a)}
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}
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return result
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}
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func main() {
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points := Polygon(5, 512, 512, 400)
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indexes := []int{0, 2, 4, 1, 3, 0}
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dc := dd.NewContext(1024, 1024)
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dc.SetSourceRGB(1, 1, 1)
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dc.Paint()
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for _, index := range indexes {
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p := points[index]
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dc.LineTo(p.X, p.Y)
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}
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dc.SetSourceRGBA(1, 0, 0, 0.5)
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dc.SetFillRule(dd.FillRuleEvenOdd)
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dc.FillPreserve()
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dc.SetSourceRGB(0, 0, 0)
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dc.SetLineWidth(8)
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dc.Stroke()
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dc.WriteToPNG("out.png")
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}
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