Example of generating an image

genimage/go.go

@@ -0,0 +1,28 @@
+package main
+
+import (
+	"learning/pic"
+    "flag"
+)
+
+func Pic(dx, dy int) [][]uint8 {
+	result := make([][]uint8, dy)
+	for i := 0; i < dx; i++ {
+		result[i] = make([]uint8, dx)
+	}
+    var ii, jj uint8
+	for i := 0; i < dy; i++ {
+		for j := 0; j < dy; j++ {
+            ii = uint8(i)
+            jj = uint8(j)
+			result[i][j] = ii ^ jj
+		}
+	}
+	return result
+}
+
+func main() {
+    flag.Parse()
+	image := pic.CalculateImage(Pic)
+	pic.SaveImage(flag.Arg(0), image)
+}

pic/pic.go

@@ -0,0 +1,43 @@
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package pic
+
+import (
+	"bytes"
+	"image"
+	"image/png"
+	"log"
+	"os"
+)
+
+func CalculateImage(f func(int, int) [][]uint8) image.Image {
+	const (
+		dx = 256
+		dy = 256
+	)
+	data := f(dx, dy)
+	m := image.NewNRGBA(image.Rect(0, 0, dx, dy))
+	for y := 0; y < dy; y++ {
+		for x := 0; x < dx; x++ {
+			v := data[y][x]
+			i := y*m.Stride + x*4
+			m.Pix[i] = v
+			m.Pix[i+1] = v
+			m.Pix[i+2] = 255
+			m.Pix[i+3] = 255
+		}
+	}
+	return m
+}
+
+func SaveImage(filename string, m image.Image) {
+	var buf bytes.Buffer
+	png.Encode(&buf, m)
+	if outfile, err := os.Create(filename); err != nil {
+		log.Fatal(err)
+	} else {
+		buf.WriteTo(outfile)
+	}
+}