A Tour of Go: Exercise Images, https://go-tour-jp.appspot.com/methods/25

exercise-images.go

package main

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

type Image struct {
	width  int
	height int
}

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

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

func (img Image) At(x, y int) color.Color {
	return color.RGBA{uint8(x % 256), uint8(y % 256), 255, 255}
}

func main() {
	m := Image{200, 200}
	pic.ShowImage(m)
}