Solution of Exercise: Images

exercise-images.go

package main

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

type Image struct{
	width, height int
}

// ColorModel returns the Image's color model.
func (img *Image) ColorModel() color.Model {
	return color.RGBAModel
}

// Bounds returns the domain for which At can return non-zero color.
// The bounds do not necessarily contain the point (0, 0).
func (img *Image) Bounds() image.Rectangle {
	return image.Rect(0, 0, img.width, img.height)
}

// At returns the color of the pixel at (x, y).
// At(Bounds().Min.X, Bounds().Min.Y) returns the upper-left pixel of the grid.
// At(Bounds().Max.X-1, Bounds().Max.Y-1) returns the lower-right one.
func (img *Image) At(x, y int) color.Color {
	r, g, b := uint8(x^y), uint8(x*y), uint8((x+y)/2)
	return color.RGBA{r, g, b, 255}
}

func main() {
	m := Image{1000, 1000}
	pic.ShowImage(&m)
}