mandelbrot.go - Draw the Mandelbrot set using GO

mandelbrot.go

package main
 
import (
	"image"
	"image/color"
	"image/png"
	"log"
	"math/cmplx"
	"os"
)
 
type Canvas struct {
	image.RGBA
}
 
func mandelbrot(canvas *Canvas) {
	size := canvas.Bounds().Size()
	center := complex(-0.5, 0)
	zoom := 0.5
	iter := 50
 
	for x := 0; x < size.X; x++ {
		for y := 0; y < size.Y; y++ {
			n := 0
			z := complex(0, 0)
 
			xi := float64(x-size.X/2) / (zoom * float64(size.X/2))
			yi := float64(y-size.Y/2) / (zoom * float64(size.Y/2))
			c := center + complex(xi, yi)
 
			for cmplx.Abs(z) < 2 && n < iter {
				z = z*z + c
				n = n + 1
			}
 
			co := float64(n) / float64(iter)
 
			canvas.Set(x, y, color.RGBA{
				0,
				0,
				uint8(255 * co), 255})
		}
	}
}
 
func saveImage(canvas *Canvas) {
	outFilename := "mandelbrot.png"
	outFile, err := os.Create(outFilename)
	if err != nil {
		log.Fatal(err)
	}
	defer outFile.Close()
	png.Encode(outFile, canvas)
}
 
func main() {
	width, height := 800, 800
	canvas := new(Canvas)
	canvas.RGBA = *image.NewRGBA(image.Rect(0, 0, width, height))
	mandelbrot(canvas)
	saveImage(canvas)
}