Exercise: Images

练习题目:

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.

联系程序:

package main

import "golang.org/x/tour/pic"
import "image"
import "image/color"

type Image struct {
}

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

func (i Image) Bounds() image.Rectangle {
    return image.Rect(0, 0, 255, 255)
}

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

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

运行结果:

 学习笔记：该题目通过为结构体Image实现Go中Image接口定义的三个方法，从而达到生成一张自定义图片的功能。ColorModel定义图片的色彩模型，Bounds定义图片的大小，At定义了图片中每个点的颜色值(程序中，每个点的颜色值是通过点位坐标(x,y)相加获得，也可以修改为x*y等取值方式)。