Generate simple random images

img_gen.go

package main

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

var (
	imgSize  int
	imgCount int
	rectSize int
	rectExp  int
)

func main() {

	flag.IntVar(&imgSize, "img.size", 256, "ImaSize of the image in pixels.")
	flag.IntVar(&imgCount, "img.count", 1, "Number of generated images.")
	flag.IntVar(&rectSize, "rect.size", 64, "Size of the rectangles inside the image.")
	flag.IntVar(&rectExp, "rect.exp", 3, "Number from 1 to MAX_INT64. Lower means more rectangles.")
	flag.Parse()

	imgSize = clamp(imgSize, 1, 4096)
	imgCount = clamp(imgCount, 1, 10000)
	rectSize = clamp(rectSize, 1, imgSize)
	rectExp = clamp(rectExp, 1, math.MaxInt64)

	log.Printf("Image size: %d", imgSize)
	log.Printf("Image count: %d", imgCount)
	log.Printf("Rectangles size: %d", rectSize)
	log.Printf("Rectangles magic number: %d", rectExp)

	rand.Seed(time.Now().UnixNano())

	for x := 0; x < imgCount; x++ {
		generateImage(fmt.Sprintf("image_%dpx_%05d", imgSize, x+1))
	}
}

func generateImage(name string) {
	img := image.NewRGBA(image.Rect(0, 0, imgSize, imgSize))

	bgColor := color.RGBA{uint8(rand.Int()), uint8(rand.Int()), uint8(rand.Int()), 255}
	for y := 0; y < imgSize; y++ {
		for x := 0; x < imgSize; x++ {
			img.SetRGBA(x, y, bgColor)
		}
	}

	rectColor := color.RGBA{uint8(rand.Int()), uint8(rand.Int()), uint8(rand.Int()), 255}
	for y := 0; y < imgSize; y += rectSize {
		for x := 0; x < imgSize; x += rectSize {
			if rand.Intn(rectExp) == 0 {
				for h := y; h < y+rectSize; h++ {
					for w := x; w < x+rectSize; w++ {
						img.SetRGBA(w, h, rectColor)
					}
				}
			}
		}
	}

	file, err := os.Create(name + ".png")
	if err != nil {
		log.Fatal(err)
	}
	err = png.Encode(file, img)
	if err != nil {
		log.Fatal(err)
	}
	log.Printf("Image created as: %s", name+".png")
}

func clamp(num, min, max int) int {
	return int(math.Min(math.Max(float64(num), float64(min)), float64(max)))
}

go run main.go --img.size 512 --img.count 10 --rect.size 64 --rect.exp 3