go_png.go

package main

import (
	"image"
	"image/color"
	"image/png"
	"math"
	"os"
)

func airy(x, y int) color.Gray16 {
	s := math.Pow(float64(340-x), 2) + math.Pow(float64(240-y), 2)
	return color.Gray16{uint16(s)}
}

func main() {
	f, ferr := os.Create("test.png")
	defer f.Close()
	if ferr != nil {
		panic(ferr)
	}
	rect := image.Rect(0, 0, 640, 480)
	gray := image.NewGray16(rect)
	for i := 0; i < 640; i++ {
		for j := 0; j < 480; j++ {
			gray.SetGray16(i, j, airy(i, j))
		}
	}
	err := png.Encode(f, gray)
	if err != nil {
		panic(err)
	}
}