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@@ -0,0 +1,53 @@
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+package main
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+
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+import (
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+ "image"
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+ "image/color"
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+ "image/gif"
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+ "io"
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+ "math"
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+ "math/rand"
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+ "os"
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+ "time"
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+)
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+
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+var palette = []color.Color{color.White, color.Black}
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+
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+const (
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+ whiteIndex = 0
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+ blackIndex = 1
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+)
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+
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+func main() {
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+ rand.Seed(time.Now().UTC().UnixNano())
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+ lissajous(os.Stdout)
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+}
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+
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+func lissajous(out io.Writer) {
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+ const (
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+ cycles = 5
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+ res = 0.001
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+ size = 100
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+ nframes = 64
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+ delay = 8
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+ )
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+
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+ freq := rand.Float64() * 3.0
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+ anim := gif.GIF{LoopCount: nframes}
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+ phase := 0.0
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+ for i := 0; i < nframes; i++ {
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+ rect := image.Rect(0, 0, 2*size+1, 2*size+1)
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+ img := image.NewPaletted(rect, palette)
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+ for t := 0.0; t < cycles*2*math.Pi; t += res {
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+ x := math.Sin(t)
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+ y := math.Sin(t*freq + phase)
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+ img.SetColorIndex(size+int(x*size+0.5),
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+ size+int(y*size+0.5),
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+ blackIndex)
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+ }
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+ phase += 0.1
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+ anim.Delay = append(anim.Delay, delay)
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+ anim.Image = append(anim.Image, img)
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+ }
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+ gif.EncodeAll(out, &anim)
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+}
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