1 files changed, 93 insertions, 0 deletions
diff --git a/mandelbrot.go b/mandelbrot.go
new file mode 100644
index 0000000..27d7bdb
--- /dev/null
+++ b/mandelbrot.go
@@ -0,0 +1,93 @@
+package main
+
+import (
+	"fmt"
+	"golang.org/x/term"
+	"log"
+	"math/big"
+	"time"
+)
+
+type color int
+
+const (
+	black color = iota
+	red
+	yellow
+	green
+	cyan
+	blue
+	magenta
+)
+
+func (c color) print() {
+	var i int
+	switch c {
+	case red:
+		i = 41
+	case yellow:
+		i = 43
+	case green:
+		i = 42
+	case cyan:
+		i = 46
+	case blue:
+		i = 44
+	case magenta:
+		i = 45
+	default:
+		i = 40
+	}
+	if _, err := fmt.Printf("\033[%dm ", i); err != nil {
+		log.Fatal(err)
+	}
+}
+
+var rat2 = big.NewRat(2, 1)
+
+func mandelbrot(x0, y0 *big.Rat) color {
+	x := new(big.Rat)
+	y := new(big.Rat)
+	x2 := new(big.Rat)
+	y2 := new(big.Rat)
+	i := 0
+	for ; x2.Cmp(rat2) <= 0 && y2.Cmp(rat2) <= 0; i++ {
+		y.Add(y, y).Mul(y, x).Add(y, y0)
+		x.Sub(x2, y2).Add(x, x0)
+		x2.Mul(x, x)
+		y2.Mul(y, y)
+	}
+	return color(i-1)%magenta + 1
+}
+
+func printMandelbrot(xMin, xRange, yMin, yRange *big.Rat) {
+	width, height, err := term.GetSize(0)
+	if err != nil {
+		log.Fatalf("Terminal size: %s.", err)
+	}
+
+	xStep := new(big.Rat).Quo(xRange, big.NewRat(int64(width), 1))
+	yStep := new(big.Rat).Quo(yRange, big.NewRat(int64(height), 1))
+	grid := make([]color, width*height)
+	y := new(big.Rat)
+	x := new(big.Rat)
+	y.Set(yMin)
+	for i := 0; i < height; i++ {
+		x.Set(xMin)
+		for j := 0; j < width; j++ {
+			go func(i, j int, x, y *big.Rat) {
+				grid[i*width+j] = mandelbrot(x, y)
+			}(i, j, new(big.Rat).Set(x), new(big.Rat).Set(y))
+			x.Add(x, xStep)
+		}
+		y.Add(y, yStep)
+	}
+	time.Sleep(time.Minute)
+	for _, c := range grid {
+		c.print()
+	}
+}
+
+func main() {
+	printMandelbrot(big.NewRat(-3, 2), big.NewRat(247, 100), big.NewRat(-112, 100), big.NewRat(224, 100))
+}