working random wallpaper

config.json

@@ -0,0 +1,7 @@
+{
+
+"colorize":[ 247,40,60 ],
+"contrast":-35,
+"gamma":0.8,
+"root":"/home/andrzej/bgs"
+}

files.go

@@ -0,0 +1,16 @@
+package main
+
+import (
+	"math/rand"
+	"os"
+)
+
+func getRandomFile(dir string) (string, error) {
+	files, err := os.ReadDir(dir)
+	if err != nil {
+		return "", err
+	}
+	randomIndex := rand.Intn(len(files))
+	randomImg := files[randomIndex]
+	return dir + "/" + randomImg.Name(), nil
+}

go.mod

@@ -0,0 +1,5 @@
+module go-img
+
+go 1.23.2
+
+require github.com/disintegration/gift v1.2.1

go.sum

@@ -0,0 +1,2 @@
+github.com/disintegration/gift v1.2.1 h1:Y005a1X4Z7Uc+0gLpSAsKhWi4qLtsdEcMIbbdvdZ6pc=
+github.com/disintegration/gift v1.2.1/go.mod h1:Jh2i7f7Q2BM7Ezno3PhfezbR1xpUg9dUg3/RlKGr4HI=

hyprpaper.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"errors"
+	"os/exec"
+)
+
+func hyprpaperPreload(path string) error {
+	var err error
+	var out []byte
+	out, err = exec.Command("hyprctl", "hyprpaper", "preload", path).Output()
+	if err != nil {
+		return err
+	}
+	str := string(out)
+	if str != "ok\n" {
+		return errors.New(str)
+	}
+	return nil
+}
+
+func hyprpaperWallpaper(path string) error {
+	var err error
+	var out []byte
+	out, err = exec.Command("hyprctl", "hyprpaper", "wallpaper", ","+path).Output()
+	if err != nil {
+		return err
+	}
+	str := string(out)
+	if str != "ok\n" {
+		return errors.New(str)
+	}
+	return nil
+}

image.go

@@ -0,0 +1,58 @@
+package main
+
+import (
+	"github.com/disintegration/gift"
+	"image"
+	"log"
+	"os"
+
+	_ "image/jpeg"
+	"image/png"
+)
+
+type Config struct {
+	Colorize [3]float32
+	Contrast int
+	Gamma    float64
+	Root     string
+}
+
+func loadImage(filename string) image.Image {
+	f, err := os.Open(filename)
+	if err != nil {
+		log.Fatalf("os.Open failed: %v", err)
+	}
+	defer f.Close()
+	img, _, err := image.Decode(f)
+	if err != nil {
+		log.Fatalf("image.Decode failed: %v", err)
+	}
+	return img
+}
+
+func saveImage(filename string, img image.Image) {
+	f, err := os.Create(filename)
+	if err != nil {
+		log.Fatalf("os.Create failed: %v", err)
+	}
+	defer f.Close()
+	err = png.Encode(f, img)
+	if err != nil {
+		log.Fatalf("png.Encode failed: %v", err)
+	}
+}
+
+func processImage(img image.Image, config Config) image.Image {
+
+	cArgs := config.Colorize
+	g := gift.New(
+		gift.Colorize(cArgs[0], cArgs[1], cArgs[2]),
+		gift.Contrast(float32(config.Contrast)),
+		gift.Gamma(float32(config.Gamma)),
+	)
+
+	dst := image.NewRGBA(g.Bounds(img.Bounds()))
+	g.Draw(dst, img)
+
+	return dst
+}

main.go

@@ -0,0 +1,62 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"os"
+)
+
+func main() {
+	var err error
+
+	config := loadConfig()
+
+	//get working directory
+	wd, err := os.Getwd()
+	if err != nil {
+		log.Fatal("couldn't find working directory", err)
+	}
+
+	curr := wd + "/curr.png"
+	// apply curr.png if already preloaded
+	err = hyprpaperWallpaper(curr)
+	if err != nil {
+		//preload curr.png if not
+		err = hyprpaperPreload(curr)
+		if err != nil {
+			fmt.Println("could not preload (this is fine)", err)
+		}
+	}
+
+	dir := config.Root + "/chsck"
+	randomImg, _ := getRandomFile(dir)
+	img := loadImage(randomImg)
+	dst := processImage(img, config)
+
+	saveImage("curr.png", dst)
+
+	path := wd + "/curr.png"
+	err = hyprpaperPreload(path)
+	if err != nil {
+		log.Fatal("preload failed!", err)
+	}
+	err = hyprpaperWallpaper(path)
+	if err != nil {
+		log.Fatal("set wallpaper failed!", err)
+	}
+}
+
+func loadConfig() Config {
+	configRaw, err := os.ReadFile("./config.json")
+	if err != nil {
+		log.Fatal("Couldn't open config file!", err)
+	}
+
+	var config Config
+	err = json.Unmarshal(configRaw, &config)
+	if err != nil {
+		log.Fatal("Couldn't unmarshal config!", err)
+	}
+	return config
+}