Goでのfield生成 https://qiita.com/tomowarkar/items/2aea52ac512e895b0a42

createfield.go

package main

import (
	"fmt"
	"image"
	"image/color"
	"image/png"
	"math/rand"
	"os"
	"time"
)

var (
	khaki         = color.RGBA{240, 230, 140, 255}
	darkgoldenrod = color.RGBA{184, 134, 11, 255}
	royalblue     = color.RGBA{65, 105, 225, 255}
	seagreen      = color.RGBA{46, 139, 87, 255}
	width         = 16
	height        = 10
	scale         = 40
)

func setField() []int {
	rand.Seed(time.Now().UnixNano())
	field := make([]int, width*height)
	for i := 0; i < len(field); i++ {
		field[i] = rand.Intn(4)
	}
	return field
}

func timestamp() string {
	t := time.Now()
	return fmt.Sprintf("%04d%02d%02d%02d%02d%02d",
		t.Year(), t.Month(), t.Day(),
		t.Hour(), t.Minute(), t.Second(),
	)
}

func main() {
	field := setField()
	img := image.NewRGBA(image.Rect(0, 0, width*scale, height*scale))
	for x := 0; x < width*scale; x++ {
		for y := 0; y < height*scale; y++ {
			switch field[y/scale*height+x/scale] {
			case 1:
				img.Set(x, y, khaki)
			case 2:
				img.Set(x, y, royalblue)
			case 3:
				img.Set(x, y, seagreen)
			default:
				img.Set(x, y, darkgoldenrod)
			}
		}
	}

	fpath := fmt.Sprintf("./img/image%s.png", timestamp())	
	f, _ := os.Create(fpath)
	defer f.Close()
	png.Encode(f, img)
}