Remember the picture generator you wrote earlier? Let's write another one, but this time it will return an implementation of image.Image instead of a slice of data.

Define your own Image type, implement the necessary methods, and callpic.ShowImage.

Bounds should return a image.Rectangle, like image.Rect(0, 0, w, h).

ColorModel should return color.RGBAModel.

At should return a color; the value v in the last picture generator corresponds to color.RGBA{v, v, 255, 255} in this one.

package main

import (
    "code.google.com/p/go-tour/pic"
    "image"
    "image/color"
)

type Image struct{}


func (img Image) ColorModel() color.Model {
    return color.RGBAModel
}

func (img Image) Bounds() image.Rectangle {
    return image.Rect(0, 0, 100, 100)
}


func (img Image) At(x, y int) color.Color {
    return color.RGBA{uint8(x), uint8(y), 255, 255}
}

func main() {
    m := Image{}
    pic.ShowImage(m)
}