本筆記是GoLang學習教程的一道習題，題目要求及一種參考實現如下所示。
備註：由於天朝GFW屏蔽了GAE，所以GoLang官網及學習教程需要翻牆才能訪問。
Exercise: Images
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 call pic.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.
參考實現如下：
package main
import (
"code.google.com/p/go-tour/pic"
"image"
"image/color"
)
type Image struct{
x, y, w, h int
v uint8
}
func (img Image) ColorModel() color.Model {
return color.RGBAModel
}
func (img Image) Bounds() image.Rectangle {
return image.Rect(0, 0, img.w, img.h)
}
func (img Image) At(x, y int) color.Color {
return color.RGBA{img.v, img.v, 255, 255}
}
func main() {
m := Image{1, 2, 200, 30, 11}
pic.ShowImage(m)
}========================= EOF ===================