code cleanup

.vscode/launch.json

@@ -10,7 +10,7 @@
       "env":{
         "SLIDESHOW_INTERVAL": "10",
         "SLIDESHOW_DIRECTORY": "/home/velvettear/images",
-        "SLIDESHOW_SCANINTERVAL": "300",
+        "SLIDESHOW_SCANINTERVAL": "10",
         "SLIDESHOW_RESOLUTION": "600x1024",
         "SLIDESHOW_LOGLEVEL": "debug",
         "SLIDESHOW_PALETTE": "/tmp/.slideshow.palette",

internal/slideshow/palette.go

@@ -62,23 +62,6 @@ func getColorPaletteRaw(data []byte) ([]color.Color, error) {
 	return colors, error
 }
 
-// extract the given amount of dominant colors of an image
-func getColorPalette(image string) ([]color.Color, error) {
-	var colors []color.Color
-	if !config.IsPaletteSet() {
-		return colors, nil
-	}
-	timestamp := time.Now().UnixMilli()
-	amount := config.PaletteColors
-	colors, error := color_thief.GetPaletteFromFile(image, amount, config.PaletteAlgorithm)
-	if error != nil {
-		loggo.ErrorTimed("encountered an error generating the color palette from image", timestamp, "image: "+image, "colors: "+strconv.Itoa(amount))
-	} else {
-		loggo.DebugTimed("generated color palette from image", timestamp, "image: "+image, "colors: "+strconv.Itoa(amount))
-	}
-	return colors, error
-}
-
 // parse rgb color values to hex
 func rgbToHex(color color.Color) string {
 	r, g, b, _ := color.RGBA()

internal/slideshow/slideshow.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"image/color"
 	"io"
+	"os"
 	"os/exec"
 	"strconv"
 	"strings"
@@ -22,9 +23,16 @@ func Start() {
 	loggo.Info("starting the image slideshow...", "interval: "+strconv.FormatFloat(config.Interval.Seconds(), 'f', 0, 64)+" seconds")
 	var sleepTime time.Duration
 	var loopTime time.Duration
-	scaleImages := config.IsResolutionSet()
 	for {
 		loopTimestamp := time.Now()
+		for !scanner.HasFoundImages() {
+			sleepTime := time.Until(scanner.GetNextScan().Add(scanner.GetLastScanDuration()))
+			if sleepTime <= 0 {
+				continue
+			}
+			loggo.Info("there have no images been found yet, waiting for " + strconv.FormatInt(sleepTime.Milliseconds(), 10) + "ms...")
+			time.Sleep(sleepTime)
+		}
 		var image string
 		var palette []color.Color
 		var data []byte
@@ -34,70 +42,39 @@ func Start() {
 				break
 			}
 		}
-		if scaleImages {
+		if config.IsResolutionSet() {
 			tmp, error := scale(image)
 			if error != nil {
 				loggo.Error("encountered an error scaling an image", "image: "+image, error.Error())
 				continue
 			}
 			data = tmp
-			palette, _ = getColorPaletteRaw(data)
 		} else {
-			palette, _ = getColorPalette(image)
+			tmp, error := os.ReadFile(image)
+			if error != nil {
+				loggo.Error("encountered an erro reading an image", "image: "+image, error.Error())
+				continue
+			}
+			data = tmp
 		}
+		palette, _ = getColorPaletteRaw(data)
 		loopTime = time.Since(loopTimestamp)
 		if sleepTime > 0 {
 			loggo.Debug("sleeping for " + strconv.FormatInt(sleepTime.Milliseconds(), 10) + "ms before next image will be displayed...")
 			time.Sleep(sleepTime)
 		}
 		go exportPalette(palette)
-		if scaleImages {
-			error := setBackgroundPiped(data)
-			if error != nil {
-				loggo.Error("encountered an error setting the background via pipe to feh's stdin", error.Error())
-			}
-			loggo.Info("set new scaled background image", "image: "+image, "resolution: "+config.Resolution)
-		} else {
-			error := setBackgroundImage(image)
-			if error != nil {
-				loggo.Error("encountered an error setting the background image", "image: "+image, error.Error())
-			}
-			loggo.Info("set new background image", "image: "+image)
+		error := setBackground(data)
+		if error != nil {
+			loggo.Error("encountered an error setting the background image", error.Error())
 		}
+		loggo.Info("set new background image", "image: "+image)
 		sleepTime = config.Interval - loopTime
 	}
 }
 
-// set the background image via 'feh'
-func setBackgroundImage(image string) error {
-	cmd := exec.Command("feh", "--no-fehbg", "--bg-fill", image)
-	stdout, stdoutError := cmd.StdoutPipe()
-	stderr, stderrError := cmd.StderrPipe()
-	cmd.Start()
-	if stdoutError != nil {
-		return stdoutError
-	}
-	if stderrError != nil {
-		return stderrError
-	}
-	_, stdoutError = io.ReadAll(stdout)
-	if stdoutError != nil {
-		return stdoutError
-	}
-	errorBytes, stderrError := io.ReadAll(stderr)
-	if stderrError != nil {
-		return stderrError
-	}
-	cmd.Wait()
-	error := strings.TrimSpace(string(errorBytes))
-	if len(error) > 0 {
-		return errors.New(error)
-	}
-	return nil
-}
-
 // pipe data to 'feh' via stdin to set the background image
-func setBackgroundPiped(data []byte) error {
+func setBackground(data []byte) error {
 	cmd := exec.Command("feh", "--no-fehbg", "--bg-fill", "-")
 	stdin, stdinError := cmd.StdinPipe()
 	stdout, stdoutError := cmd.StdoutPipe()

main.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"sync"
 	"time"
 
 	"git.velvettear.de/velvettear/loggo"
@@ -13,11 +12,8 @@ import (
 func main() {
 	timestamp := time.Now().UnixMilli()
 	loggo.Info("slideshow is starting now...")
-	var waitgroup sync.WaitGroup
-	waitgroup.Add(1)
 	config.Initialize()
 	scanner.Initialize()
 	slideshow.Start()
-	waitgroup.Wait()
 	loggo.InfoTimed("slideshow is shutting down now!", timestamp)
 }

scanner/scanner.go

@@ -18,6 +18,12 @@ var images []string
 // temporary slice of images
 var tmpImages []string
 
+// time of next scan
+var nextScan time.Time
+
+// duration of the last scan
+var lastScanDuration time.Duration
+
 // scan the specified directories for images
 func Initialize() {
 	directory := config.Directory
@@ -29,21 +35,39 @@ func GetRandomImage() string {
 	return images[rand.Intn(len(images))]
 }
 
+// check if images has been found
+func HasFoundImages() bool {
+	return len(images) > 0
+}
+
+// get the time of the next scan
+func GetNextScan() time.Time {
+	return nextScan
+}
+
+// get the duration of the last scan
+func GetLastScanDuration() time.Duration {
+	return lastScanDuration
+}
+
 // scan the specified directory
 func scan(directory string) {
-	timestamp := time.Now().UnixMilli()
+	timestamp := time.Now()
 	loggo.Info("scanning directory for images and subdirectories...", "interval: "+strconv.FormatFloat(config.ScanInterval.Seconds(), 'f', 0, 64)+" seconds", "directory: "+directory)
 	filepath.WalkDir(directory, checkDirectory)
 	images = tmpImages
 	tmpImages = nil
-	loggo.InfoTimed("found "+strconv.Itoa(len(images))+" image(s)", timestamp)
-	go scheduleRescan(directory)
+	loggo.InfoTimed("found "+strconv.Itoa(len(images))+" image(s)", timestamp.UnixMilli())
+	lastScanDuration = time.Since(timestamp)
+	nextScan = time.Now().Add(config.ScanInterval)
+	go scheduleRescan(directory, nextScan)
 }
 
 // sleep the specified interval and then trigger a rescan of the specified directory
-func scheduleRescan(directory string) {
-	loggo.Debug("sleeping for " + strconv.FormatInt(config.ScanInterval.Milliseconds(), 10) + "ms before next scan...")
-	time.Sleep(config.ScanInterval)
+func scheduleRescan(directory string, timestamp time.Time) {
+	sleepTime := time.Until(timestamp)
+	loggo.Debug("sleeping for " + strconv.FormatInt(sleepTime.Milliseconds(), 10) + "ms before next scan...")
+	time.Sleep(sleepTime)
 	scan(directory)
 }