// 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 = 1024
	)
	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)
	}
}