.vscode/launch.json

@@ -2,23 +2,37 @@
   "version": "0.0.1",
   "configurations": [
     {
-      "name": "slideshow",
+      "name": "slideshow-scaled",
       "type": "go",
       "request": "launch",
       "mode": "auto",
       "program": "${workspaceFolder}/main.go",
       "env":{
-        "SLIDESHOW_API": "localhost:3000",
-        "SLIDESHOW_INTERVAL": "3",
-        "SLIDESHOW_RESOLUTION": "",
-        "SLIDESHOW_PALETTE": "",
-        "SLIDESHOW_PALETTE_ALGORITHM": "",
-        "SLIDESHOW_PALETTE_COLORS": "",
-        "SLIDESHOW_SCRIPT": "",
-        "SLIDESHOW_SCRIPT_ARGS": "",
-        "SLIDESHOW_SCRIPT_ASYNC": "",
-        "SLIDESHOW_SCRIPT_STAGE": "",
+        "SLIDESHOW_INTERVAL": "10",
+        "SLIDESHOW_DIRECTORY": "/home/velvettear/images",
+        "SLIDESHOW_SCANINTERVAL": "300",
+        "SLIDESHOW_RESOLUTION": "600x1024",
         "SLIDESHOW_LOGLEVEL": "debug",
+        "SLIDESHOW_PALETTE": "/tmp/.slideshow.palette",
+        "SLIDESHOW_PALETTE_ALGORITHM": "wsm",
+        "SLIDESHOW_PALETTE_COLORS": "32"
+      },
+      "console": "integratedTerminal"
+    },
+    {
+      "name": "slideshow-unscaled",
+      "type": "go",
+      "request": "launch",
+      "mode": "auto",
+      "program": "${workspaceFolder}/main.go",
+      "env":{
+        "SLIDESHOW_INTERVAL": "10",
+        "SLIDESHOW_DIRECTORY": "/home/velvettear/images",
+        "SLIDESHOW_SCANINTERVAL": "10",
+        "SLIDESHOW_LOGLEVEL": "debug",
+        "SLIDESHOW_PALETTE": "/tmp/.slideshow.palette",
+        "SLIDESHOW_PALETTE_ALGORITHM": "wsm",
+        "SLIDESHOW_PALETTE_COLORS": "16"
       },
       "console": "integratedTerminal"
     }

README.md

@@ -1,11 +1,11 @@
 # slideshow
 
-client for the [slideshow-api](https://git.velvettear.de/velvettear/slideshow-api).  
-sets (scaled) images as background via 'feh', retrieves color palettes (and executes a script).
+a simple cli application to start a background image slideshow using 'feh'.
 
 ## requirements
 
 - [feh](https://feh.finalrewind.org/)
+- [ImageMagick](https://imagemagick.org/) (optional)
 
 ## configuration
 
@@ -13,32 +13,19 @@ configuration is entirely done via environment variables.
 
 | variable                    | default           | description                                                |
 | --------------------------- | ----------------- | -----------------------------------------------------------|
-| SLIDESHOW_API               |                   | the address of the slideshow-api server                    |
 | SLIDESHOW_INTERVAL          | 60                | the interval of the slideshow in seconds                   |
+| SLIDESHOW_DIRECTORY         | "$HOME"           | path to a directory containing images                      |
+| SLIDESHOW_SCANINTERVAL      | 60                | the interval for directory scans in seconds 
 | SLIDESHOW_RESOLUTION        |                   | the resolution to which images are scaled (i.e. 1920x1080) | 
 | SLIDESHOW_PALETTE           |                   | path to a file where the color palette will be stored      |
 | SLIDESHOW_PALETTE_ALGORITHM | "wsm"             | the algorithm used to generate the color palette           |
 | SLIDESHOW_PALETTE_COLORS    | 16                | the amount of colors generated                             |
-| SLIDESHOW_SCRIPT            |                   | path to a script to execute each loop                      |
-| SLIDESHOW_SCRIPT_ARGS       |                   | arguments to pass to the script                            |
-| SLIDESHOW_SCRIPT_ASYNC      | false             | run the script asynchronously (in a goroutine)             |
-| SLIDESHOW_SCRIPT_STAGE      |                   | the stage at which the script is executed                  |
 | SLIDESHOW_LOGLEVEL          | "info"            | the log level                                              |
 
 **note:**  
+if no resolution is set the images will be displayed as they are (without any scaling).
 
-- if `SLIDESHOW_RESOLUTION` is unset images will be requested in their original resolution.
-- if `SLIDESHOW_PALETTE` is unset no color palettes will be requested.  
-- if `SLIDESHOW_SCRIPT_STAGE` is unset the script (if specified) will be executed **after** the background image has been set **and** the color palette file has been generated.
-
-### stages:
-
-- `pre_image`: executes the script **before** the background image will be set.
-- `post_image`: executes the script **after** the background image has been set.
-- `pre_palette`: executes the script **before** the color palette file will be generated.
-- `post_palette`: executes the script **after** the color palette has been generated.
-
-### log levels:
+**available log levels:**
 
 - `debug`
 - `info`

go.mod

@@ -6,7 +6,8 @@ require git.velvettear.de/velvettear/loggo v0.0.0-20231113084149-980a00b4e084
 
 require (
 	github.com/fatih/color v1.16.0 // indirect
+	github.com/kennykarnama/color-thief v0.0.0-20230222041546-c1bf65ec0808
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
-	golang.org/x/sys v0.15.0 // indirect
+	golang.org/x/sys v0.14.0 // indirect
 )

go.sum

@@ -2,6 +2,8 @@ git.velvettear.de/velvettear/loggo v0.0.0-20231113084149-980a00b4e084 h1:13S20q+
 git.velvettear.de/velvettear/loggo v0.0.0-20231113084149-980a00b4e084/go.mod h1:Jjjno0vz7v1Y6tCnpQHnq2TVL2+5m7TXkmNNYYREIMo=
 github.com/fatih/color v1.16.0 h1:zmkK9Ngbjj+K0yRhTVONQh1p/HknKYSlNT+vZCzyokM=
 github.com/fatih/color v1.16.0/go.mod h1:fL2Sau1YI5c0pdGEVCbKQbLXB6edEj1ZgiY4NijnWvE=
+github.com/kennykarnama/color-thief v0.0.0-20230222041546-c1bf65ec0808 h1:9JJaKNm4eDnB/ad7rWfejfMw+1ufpchM8Eik9VcQzUQ=
+github.com/kennykarnama/color-thief v0.0.0-20230222041546-c1bf65ec0808/go.mod h1:9qLIEhoYLAXPjhQQpgR0nVnhJxNXBtAqRZAp2Dj87WQ=
 github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
 github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
 github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
@@ -11,5 +13,3 @@ golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.14.0 h1:Vz7Qs629MkJkGyHxUlRHizWJRG2j8fbQKjELVSNhy7Q=
 golang.org/x/sys v0.14.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/sys v0.15.0 h1:h48lPFYpsTvQJZF4EKyI4aLHaev3CxivZmv7yZig9pc=
-golang.org/x/sys v0.15.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

images/cache.go

@@ -0,0 +1,105 @@
+package images
+
+// import (
+// 	"runtime"
+// 	"strconv"
+// 	"sync"
+// 	"time"
+
+// 	"git.velvettear.de/velvettear/image-frame/config"
+// 	"git.velvettear.de/velvettear/loggo"
+// )
+
+// // cache for scaled images
+// var cache []scaledImage
+
+// // timestamp of the next cache rotation
+// var NextRotation time.Time
+
+// // get the previous image from the history and set it as the first scaled image in the cache
+// func SetPreviousImage() error {
+// 	previousImage, error := getLatestFromHistory()
+// 	if error != nil {
+// 		return error
+// 	}
+// 	var tmpCache []scaledImage
+// 	tmpCache = append(tmpCache, previousImage)
+// 	tmpCache = append(tmpCache, cache...)
+// 	cache = tmpCache
+// 	tmpCache = nil
+// 	return nil
+// }
+
+// // get the first scaled image from the cache
+// func GetCachedImage() scaledImage {
+// 	return cache[0]
+// }
+
+// // replace the first element in the cache with the last one and add a new scaled image to the cache
+// func RotateCache() {
+// 	addToHistory(GetCachedImage())
+// 	loggo.Debug("removing first element from image cache...")
+// 	cacheSize := len(cache)
+// 	if cacheSize == 1 {
+// 		cache = nil
+// 		cacheImages()
+// 		return
+// 	}
+// 	cacheSize--
+// 	cache[0] = cache[cacheSize]
+// 	cache = cache[:cacheSize]
+// 	go cacheImages()
+// }
+
+// // start the "slideshow" in a goroutine - rotate the cache based on the set interval
+// func startSlideshow() {
+// 	go func() {
+// 		interval := time.Duration(config.GetImageSlideshowInterval()) * time.Second
+// 		for {
+// 			NextRotation = time.Now().Add(interval)
+// 			time.Sleep(interval)
+// 			RotateCache()
+// 		}
+// 	}()
+// }
+
+// // fill the cache with scaled images
+// func cacheImages() {
+// 	timestamp := time.Now().UnixMilli()
+// 	imageCount := len(images)
+// 	cacheSize := len(cache)
+// 	cacheLimit := config.GetImageCache()
+// 	if imageCount < cacheLimit {
+// 		cacheLimit = imageCount
+// 	}
+// 	imagesToCache := cacheLimit - cacheSize
+// 	if imagesToCache <= 0 {
+// 		return
+// 	}
+// 	concurrency := runtime.NumCPU()
+// 	if imagesToCache < concurrency {
+// 		concurrency = imagesToCache
+// 	}
+// 	loggo.Debug("filling image cache with "+strconv.Itoa(imagesToCache)+" element(s)", "concurrency: "+strconv.Itoa(concurrency))
+// 	var waitgroup sync.WaitGroup
+// 	waitgroup.Add(imagesToCache)
+// 	channel := make(chan struct{}, concurrency)
+// 	var cached int
+// 	for cached = 0; cached < imagesToCache; cached++ {
+// 		channel <- struct{}{}
+// 		var randomScaledImage scaledImage
+// 		randomScaledImage.Name = getRandomImage()
+// 		if randomScaledImage.isCached() {
+// 			continue
+// 		}
+// 		go func(randomScaledImage scaledImage) {
+// 			randomScaledImage.Data = scale(randomScaledImage.Name, config.GetImageWidth(), config.GetImageHeight())
+// 			cache = append(cache, randomScaledImage)
+// 			loggo.Debug("added scaled image '" + randomScaledImage.Name + "' to cache")
+// 			<-channel
+// 			waitgroup.Done()
+// 		}(randomScaledImage)
+// 	}
+// 	waitgroup.Wait()
+// 	loggo.DebugTimed("filled image cache with "+strconv.Itoa(cached)+" images", timestamp)
+// }

images/history.go

@@ -0,0 +1,40 @@
+package images
+
+// import (
+// 	"errors"
+// 	"strconv"
+// 	"time"
+
+// 	"git.velvettear.de/velvettear/image-frame/config"
+// 	"git.velvettear.de/velvettear/loggo"
+// )
+
+// // internal history of displayed images
+// var history []scaledImage
+
+// // add a image to the history
+// func addToHistory(scaledImage scaledImage) {
+// 	timestamp := time.Now().UnixMilli()
+// 	historyLimit := config.GetImageSlideshowHistory()
+// 	if historyLimit <= 0 {
+// 		return
+// 	}
+// 	history = append(history, scaledImage)
+// 	diff := len(history) - historyLimit
+// 	if diff > 0 {
+// 		history = history[diff:]
+// 	}
+// 	loggo.DebugTimed("added image to history", timestamp, "history size: "+strconv.Itoa(len(history)))
+// }
+
+// // get and remove the latest image from history
+// func getLatestFromHistory() (scaledImage, error) {
+// 	var scaledImage scaledImage
+// 	if len(history) == 0 {
+// 		return scaledImage, errors.New("history is empty")
+// 	}
+// 	index := len(history) - 1
+// 	scaledImage = history[index]
+// 	history = history[:index]
+// 	return scaledImage, nil
+// }

images/initialize.go

@@ -0,0 +1,7 @@
+package images
+
+// func Initialize() {
+// 	scanForImages()
+// 	cacheImages()
+// 	startSlideshow()
+// }

images/scaledimage.go

@@ -0,0 +1,31 @@
+package images
+
+// import (
+// 	"math/rand"
+// )
+
+// // struct for scaled images
+// type scaledImage struct {
+// 	Name string
+// 	Data []byte
+// }
+
+// // get a random image
+// func getRandomImage() string {
+// 	return images[rand.Intn(len(images)-1)]
+// }
+
+// // check if the scaled image is already cached
+// func (scaledImage *scaledImage) isCached() bool {
+// 	return isCached(scaledImage.Name)
+// }
+
+// // check (by name) if the scaled image is already cached
+// func isCached(scaledImageName string) bool {
+// 	for _, cachedImage := range cache {
+// 		if cachedImage.Name == scaledImageName {
+// 			return true
+// 		}
+// 	}
+// 	return false
+// }

internal/config/config.go

@@ -2,7 +2,6 @@ package config
 
 import (
 	"os"
-	"os/exec"
 	"strconv"
 	"strings"
 	"time"
@@ -10,39 +9,49 @@ import (
 	"git.velvettear.de/velvettear/loggo"
 )
 
-var ApiAddress string
 var Interval time.Duration
+var Directory string
+var ScanInterval time.Duration
 var Resolution string
 var PaletteFile string
-var PaletteAlgorithm string
+var PaletteAlgorithm int
 var PaletteColors int
-var Script string
-var ScriptArgs []string
-var ScriptAsync bool
-var ScriptStage string
 
 // initialize the config
 func Initialize() {
 	loggo.SetLogLevelByName(os.Getenv("SLIDESHOW_LOGLEVEL"))
-	ApiAddress = os.Getenv("SLIDESHOW_API")
-	if len(ApiAddress) == 0 {
-		loggo.Fatal("no adress of the slideshow-api server has been specified")
-	}
-	if !strings.HasPrefix(ApiAddress, "http://") && !strings.HasPrefix(ApiAddress, "https://") {
-		ApiAddress = "http://" + ApiAddress
-	}
 	tmpInt, _ := strconv.Atoi(os.Getenv("SLIDESHOW_INTERVAL"))
 	if tmpInt <= 0 {
 		tmpInt = 60
 	}
 	Interval = time.Duration(tmpInt) * time.Second
+	Directory = os.Getenv("SLIDESHOW_DIRECTORY")
+	if len(Directory) == 0 {
+		tmp, error := os.UserHomeDir()
+		if error != nil {
+			loggo.Fatal("encountered an error getting the current user's home directory", error.Error())
+		}
+		Directory = tmp
+	}
+	stats, error := os.Stat(Directory)
+	if error != nil {
+		loggo.Fatal("encountered an error checking the directory '"+Directory+"'", error.Error())
+	}
+	if !stats.IsDir() {
+		loggo.Fatal("configured directory '" + Directory + "' is not a valid directory")
+	}
+	tmpInt, _ = strconv.Atoi(os.Getenv("SLIDESHOW_SCANINTERVAL"))
+	if tmpInt <= 0 {
+		tmpInt = 60
+	}
+	ScanInterval = time.Duration(tmpInt) * time.Second
 	Resolution = os.Getenv("SLIDESHOW_RESOLUTION")
 	if len(Resolution) > 0 {
 		width, height, found := strings.Cut(Resolution, "x")
 		if !found {
 			loggo.Fatal("encountered an error parsing the configured resolution, make sure to specify the format like '1920x1080'")
 		}
-		_, error := strconv.Atoi(width)
+		_, error = strconv.Atoi(width)
 		if error != nil {
 			loggo.Fatal("encountered an error parsing the configured width '" + width + "'")
 		}
@@ -52,67 +61,17 @@ func Initialize() {
 		}
 	}
 	PaletteFile = os.Getenv("SLIDESHOW_PALETTE")
-	PaletteAlgorithm = os.Getenv("SLIDESHOW_PALETTE_ALGORITHM")
+	tmpString := os.Getenv("SLIDESHOW_PALETTE_ALGORITHM")
+	if strings.ToLower(tmpString) == "wu" {
+		PaletteAlgorithm = 0
+	} else {
+		PaletteAlgorithm = 1
+	}
 	tmpInt, _ = strconv.Atoi(os.Getenv("SLIDESHOW_PALETTE_COLORS"))
 	if tmpInt <= 0 {
 		tmpInt = 16
 	}
 	PaletteColors = tmpInt
-	Script = os.Getenv("SLIDESHOW_SCRIPT")
-	ScriptArgs = strings.Split(os.Getenv("SLIDESHOW_SCRIPT_ARGS"), " ")
-	ScriptAsync, _ = strconv.ParseBool(os.Getenv("SLIDESHOW_SCRIPT_ASYNC"))
-	ScriptStage = strings.ToLower(os.Getenv("SLIDESHOW_SCRIPT_STAGE"))
-	checkScript()
-	checkFehCommand()
-}
-
-// check if a script has been specified and exists
-func checkScript() {
-	if len(Script) == 0 {
-		return
-	}
-	stats, error := os.Stat(Script)
-	if error != nil {
-		loggo.Warning("encountered an error getting stats for the script '"+Script+"', script execution is unavailable", error.Error())
-		Script = ""
-		return
-	}
-	if stats.IsDir() {
-		loggo.Warning("the script '"+Script+"' seems to be a directory, script execution is unavailable", error.Error())
-		Script = ""
-		return
-	}
-	if string(stats.Mode().Perm().String()[3]) != "x" {
-		loggo.Warning("the script '"+Script+"' seems to be a directory, script execution is unavailable", error.Error())
-		Script = ""
-	}
-	checkScriptStage()
-}
-
-// check if the specified script stage is valid
-func checkScriptStage() {
-	switch ScriptStage {
-	case "pre_image":
-		fallthrough
-	case "post_image":
-		fallthrough
-	case "pre_palette":
-		fallthrough
-	case "post_palette":
-		return
-	default:
-		ScriptStage = ""
-	}
-}
-
-// check if 'feh' is available
-func checkFehCommand() {
-	cmd := exec.Command("which", "feh")
-	error := cmd.Run()
-	if error == nil {
-		return
-	}
-	loggo.Fatal("could not find command 'feh'")
 }
 
 // check if a resolution has been specified
@@ -124,33 +83,3 @@ func IsResolutionSet() bool {
 func IsPaletteSet() bool {
 	return len(PaletteFile) > 0
 }
-
-// check if a script has been specified
-func IsScriptSet() bool {
-	return len(Script) > 0
-}
-
-// check if a script stage has been specified
-func IsScriptStageSet() bool {
-	return len(ScriptStage) > 0
-}
-
-// check if script stage 'pre_image' has been specified
-func IsScriptStagePreImage() bool {
-	return ScriptStage == "pre_image"
-}
-
-// check if script stage 'post_image' has been specified
-func IsScriptStagePostImage() bool {
-	return ScriptStage == "post_image"
-}
-
-// check if script stage 'pre_palette' has been specified
-func IsScriptStagePrePalette() bool {
-	return ScriptStage == "pre_palette"
-}
-
-// check if script stage 'post_palette' has been specified
-func IsScriptStagePostPalette() bool {
-	return ScriptStage == "post_palette"
-}

internal/formatter.go

@@ -1,17 +0,0 @@
-package internal
-
-import "strconv"
-
-// format bytes
-func FormatBytes(bytes int64) string {
-	value := float64(bytes)
-	unit := "bytes"
-	if bytes > 1000000 {
-		value = value / 1000000
-		unit = "mega" + unit
-	} else if bytes > 1000 {
-		value = value / 1000
-		unit = "kilo" + unit
-	}
-	return strconv.FormatFloat(value, 'f', 2, 64) + " " + unit
-}

internal/requests.go

@@ -1,101 +0,0 @@
-package internal
-
-import (
-	"encoding/json"
-	"io"
-	"net/http"
-	"strconv"
-	"strings"
-	"time"
-
-	"git.velvettear.de/velvettear/loggo"
-	"git.velvettear.de/velvettear/slideshow/internal/config"
-)
-
-// get the endpoint url of the api
-func getEndpointUrl(endpoint string) string {
-	url := config.ApiAddress
-	if !strings.HasSuffix(url, "/") && endpoint != "/" {
-		url += "/"
-	}
-	if len(endpoint) > 0 {
-		url += endpoint
-	}
-	if !strings.HasSuffix(url, "/") {
-		url += "/"
-	}
-	return url
-}
-
-// request the name of an image from the api
-func requestImageName() (string, error) {
-	timestamp := time.Now().UnixMilli()
-	var name string
-	url := getEndpointUrl("/")
-	request, error := http.NewRequest("GET", url, nil)
-	if error != nil {
-		return name, error
-	}
-	client := http.Client{}
-	response, error := client.Do(request)
-	if error != nil {
-		return name, error
-	}
-	bytes, error := io.ReadAll(response.Body)
-	if error != nil {
-		return name, error
-	}
-	tmp := make(map[string]interface{})
-	error = json.Unmarshal(bytes, &tmp)
-	if error != nil {
-		return name, error
-	}
-	name = tmp["Content"].(string)
-	loggo.DebugTimed("successfully requested image '"+name+"'", timestamp, "url: "+url)
-	return name, nil
-}
-
-// request the data stream of an image by name from the api
-func requestImageData(name string) (io.ReadCloser, error) {
-	timestamp := time.Now().UnixMilli()
-	var stream io.ReadCloser
-	url := getEndpointUrl("/image/") + name
-	request, error := http.NewRequest("GET", url, nil)
-	if error != nil {
-		return stream, error
-	}
-	queryParameters := request.URL.Query()
-	if config.IsResolutionSet() {
-		queryParameters.Set("resolution", config.Resolution)
-	}
-	request.URL.RawQuery = queryParameters.Encode()
-	client := http.Client{}
-	response, error := client.Do(request)
-	if error != nil {
-		return stream, error
-	}
-	loggo.DebugTimed("successfully requested data stream for image '"+name+"'", timestamp)
-	return response.Body, nil
-}
-
-// request the color palette of an image by name from the api as stream
-func requestColorPalette(name string) (io.ReadCloser, error) {
-	timestamp := time.Now().UnixMilli()
-	var stream io.ReadCloser
-	url := getEndpointUrl("/palette/") + name
-	request, error := http.NewRequest("GET", url, nil)
-	if error != nil {
-		return stream, error
-	}
-	queryParameters := request.URL.Query()
-	queryParameters.Set("colors", strconv.Itoa(config.PaletteColors))
-	queryParameters.Set("algorithm", config.PaletteAlgorithm)
-	request.URL.RawQuery = queryParameters.Encode()
-	client := http.Client{}
-	response, error := client.Do(request)
-	if error != nil {
-		return stream, error
-	}
-	loggo.DebugTimed("successfully requested color palette stream for image '"+name+"'", timestamp)
-	return response.Body, nil
-}

internal/slideshow.go

@@ -1,115 +0,0 @@
-package internal
-
-import (
-	"os/exec"
-	"strconv"
-	"sync"
-	"time"
-
-	"git.velvettear.de/velvettear/loggo"
-	"git.velvettear.de/velvettear/slideshow/internal/config"
-)
-
-var loop int64
-
-// start the loop for the slideshow
-func StartSlideshow() {
-	for {
-		timestamp := time.Now().UnixMilli()
-		loop++
-		imageLoop()
-		loggo.InfoTimed("slideshow loop #"+strconv.FormatInt(loop, 10)+" finished", timestamp)
-		loggo.Debug("sleeping for " + strconv.FormatFloat(config.Interval.Seconds(), 'f', 0, 64) + " seconds...")
-		time.Sleep(config.Interval)
-	}
-}
-
-// the image loop of the slideshoow
-func imageLoop() {
-	name, error := requestImageName()
-	if error != nil {
-		loggo.Error("encountered an error requesting the name of an image", error.Error())
-		return
-	}
-	var waitgroup sync.WaitGroup
-	waitgroup.Add(2)
-	go setBackground(name, &waitgroup)
-	go exportColorPalette(name, &waitgroup)
-	waitgroup.Wait()
-	if !config.IsScriptStageSet() {
-		runScript(false)
-	}
-}
-
-// encapsulated method to set the background image in a goroutine
-func setBackground(name string, waitgroup *sync.WaitGroup) {
-	timestamp := time.Now().UnixMilli()
-	defer waitgroup.Done()
-	if config.IsScriptStagePreImage() {
-		runScript(false)
-	}
-	stream, error := requestImageData(name)
-	if error != nil {
-		loggo.Error("encountered an error requesting the data stream for image '"+name+"'", error.Error())
-		return
-	}
-	error = streamToFeh(stream)
-	if error != nil {
-		loggo.Error("encountered an error piping the data stream for image '"+name+"' to 'feh'", error.Error())
-	}
-	loggo.InfoTimed("set new background image '"+name+"' via 'feh'", timestamp)
-	if config.IsScriptStagePostImage() {
-		runScript(false)
-	}
-}
-
-// encapsulated method to set the background image in a goroutine
-func exportColorPalette(name string, waitgroup *sync.WaitGroup) {
-	timestamp := time.Now().UnixMilli()
-	defer waitgroup.Done()
-	if !config.IsPaletteSet() {
-		return
-	}
-	if config.IsScriptStagePrePalette() {
-		runScript(false)
-	}
-	stream, error := requestColorPalette(name)
-	if error != nil {
-		loggo.Error("encountered an error requesting the data stream for the color palette of image '"+name+"'", error.Error())
-		return
-	}
-	error = streamToFile(stream, config.PaletteFile)
-	if error != nil {
-		loggo.Error("encountered an error piping the data stream for the color palette of image '"+name+"' to file '"+config.PaletteFile+"'", error.Error())
-	}
-	loggo.InfoTimed("exported color palette of image '"+name+"' to  '"+config.PaletteFile+"'", timestamp)
-	if config.IsScriptStagePostPalette() {
-		runScript(false)
-	}
-}
-
-// encapsulated method to run the defined script
-func runScript(running bool) {
-	if !running && config.ScriptAsync {
-		go runScript(true)
-		return
-	}
-	timestamp := time.Now().UnixMilli()
-	if !config.IsScriptSet() {
-		return
-	}
-	cmd := exec.Command(config.Script, config.ScriptArgs...)
-	error := cmd.Run()
-	if error != nil {
-		loggo.Error("encountered an error executing the script '"+config.Script+"'", error.Error())
-		return
-	}
-	var extras []string
-	if config.ScriptAsync {
-		extras = append(extras, "async: "+strconv.FormatBool(config.ScriptAsync))
-	}
-	if config.IsScriptStageSet() {
-		extras = append(extras, "stage: "+config.ScriptStage)
-	}
-	loggo.InfoTimed("executed script '"+config.Script+"'", timestamp, extras...)
-}

internal/slideshow/palette.go

@@ -0,0 +1,86 @@
+package slideshow
+
+import (
+	"bytes"
+	"fmt"
+	"image"
+	"image/color"
+	"os"
+	"strconv"
+	"time"
+
+	"git.velvettear.de/velvettear/loggo"
+	"git.velvettear.de/velvettear/slideshow/internal/config"
+	color_thief "github.com/kennykarnama/color-thief"
+)
+
+// write the base16 color palette to a file
+func exportPalette(colors []color.Color) {
+	if len(colors) == 0 || !config.IsPaletteSet() {
+		return
+	}
+	timestamp := time.Now().UnixMilli()
+	var palette string
+	for index, color := range colors {
+		if index > 0 {
+			palette += "\n"
+		}
+		tmp := strconv.Itoa(index)
+		if len(tmp) < 2 {
+			tmp = "0" + tmp
+		}
+		tmp = "SLIDESHOW_COLOR" + tmp
+		palette += tmp + "=\"" + rgbToHex(color) + "\""
+	}
+	error := os.WriteFile(config.PaletteFile, []byte(palette), 0775)
+	if error != nil {
+		loggo.ErrorTimed("encountered an error exporting a color palette", timestamp, error.Error())
+	} else {
+		loggo.DebugTimed("exported color palette to filesystem", timestamp, "path: "+config.PaletteFile)
+	}
+}
+
+// extract the given amount of dominant colors of raw image bytes
+func getColorPaletteRaw(data []byte) ([]color.Color, error) {
+	var colors []color.Color
+	if !config.IsPaletteSet() {
+		return colors, nil
+	}
+	timestamp := time.Now().UnixMilli()
+	amount := config.PaletteColors
+	img, _, error := image.Decode(bytes.NewReader(data))
+	if error != nil {
+		loggo.ErrorTimed("encountered an error decoding the provided raw image bytes to an image", timestamp, error.Error())
+		return colors, error
+	}
+	colors, error = color_thief.GetPalette(img, amount, config.PaletteAlgorithm)
+	if error != nil {
+		loggo.ErrorTimed("encountered an error generating the color palette from raw image bytes", timestamp, "colors: "+strconv.Itoa(amount))
+	} else {
+		loggo.DebugTimed("generated color palette from raw image bytes", timestamp, "colors: "+strconv.Itoa(amount))
+	}
+	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()
+	return fmt.Sprintf("#%02x%02x%02x", uint8(r>>8), uint8(g>>8), uint8(b>>8))
+}

internal/slideshow/scale.go

@@ -0,0 +1,44 @@
+package slideshow
+
+import (
+	"errors"
+	"io"
+	"os/exec"
+	"strconv"
+	"strings"
+	"time"
+
+	"git.velvettear.de/velvettear/loggo"
+	"git.velvettear.de/velvettear/slideshow/internal/config"
+)
+
+// scale an image
+func scale(image string) ([]byte, error) {
+	timestamp := time.Now().UnixMilli()
+	cmd := exec.Command("convert", image, "-resize", config.Resolution+"^", "-gravity", "center", "-extent", config.Resolution, "-")
+	stdout, stdoutError := cmd.StdoutPipe()
+	stderr, stderrError := cmd.StderrPipe()
+	var data []byte
+	cmd.Start()
+	if stdoutError != nil {
+		return data, stdoutError
+	}
+	if stderrError != nil {
+		return data, stdoutError
+	}
+	data, stdoutError = io.ReadAll(stdout)
+	if stdoutError != nil {
+		return data, stdoutError
+	}
+	errorBytes, stderrError := io.ReadAll(stderr)
+	if stderrError != nil {
+		return data, stdoutError
+	}
+	cmd.Wait()
+	errorMessage := strings.TrimSpace(string(errorBytes))
+	if len(errorMessage) > 0 {
+		return data, errors.New(errorMessage)
+	}
+	loggo.DebugTimed("successfully scaled image", timestamp, "image: "+image, "resolution: "+config.Resolution, "size: "+strconv.Itoa(len(data)))
+	return data, nil
+}

internal/slideshow/slideshow.go

@@ -0,0 +1,138 @@
+package slideshow
+
+import (
+	"errors"
+	"image/color"
+	"io"
+	"os/exec"
+	"strconv"
+	"strings"
+	"time"
+
+	"git.velvettear.de/velvettear/loggo"
+	"git.velvettear.de/velvettear/slideshow/internal/config"
+	"git.velvettear.de/velvettear/slideshow/scanner"
+)
+
+// remember last shown image
+var previousImage string
+
+// start the slideshow
+func Start() {
+	loggo.Info("starting the image slideshow...", "interval: "+strconv.FormatFloat(config.Interval.Seconds(), 'f', 0, 64)+" seconds")
+	var sleepTime time.Duration
+	var scaleTime time.Duration
+	scaleImages := config.IsResolutionSet()
+	for {
+		var image string
+		var palette []color.Color
+		var data []byte
+		for {
+			image = scanner.GetRandomImage()
+			if image != previousImage {
+				break
+			}
+		}
+		if scaleImages {
+			scaleTimestamp := time.Now()
+			tmp, error := scale(image)
+			if error != nil {
+				loggo.Error("encountered an error scaling an image", "image: "+image, error.Error())
+				continue
+			}
+			data = tmp
+			scaleTime = time.Since(scaleTimestamp)
+			palette, _ = getColorPaletteRaw(data)
+		} else {
+			palette, _ = getColorPalette(image)
+		}
+		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)
+		}
+		sleepTime = config.Interval - scaleTime
+	}
+}
+
+// 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 {
+	cmd := exec.Command("feh", "--no-fehbg", "--bg-fill", "-")
+	stdin, stdinError := cmd.StdinPipe()
+	stdout, stdoutError := cmd.StdoutPipe()
+	stderr, stderrError := cmd.StderrPipe()
+	cmd.Start()
+	if stdinError != nil {
+		return stdinError
+	}
+	if stdoutError != nil {
+		return stdoutError
+	}
+	if stderrError != nil {
+		return stderrError
+	}
+	defer stdin.Close()
+	defer stdout.Close()
+	defer stderr.Close()
+	_, stdinError = stdin.Write(data)
+	if stdinError != nil {
+		return stdinError
+	} else {
+		stdin.Close()
+	}
+	_, 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
+}

internal/streams.go

@@ -1,73 +0,0 @@
-package internal
-
-import (
-	"errors"
-	"io"
-	"os"
-	"os/exec"
-	"strings"
-	"time"
-
-	"git.velvettear.de/velvettear/loggo"
-)
-
-// pipe data from a stream to 'feh'
-func streamToFeh(stream io.ReadCloser) error {
-	timestamp := time.Now().UnixMilli()
-	defer stream.Close()
-	cmd := exec.Command("feh", "--no-fehbg", "--bg-fill", "-")
-	stdin, stdinError := cmd.StdinPipe()
-	if stdinError != nil {
-		return stdinError
-	}
-	defer stdin.Close()
-	stdout, stdoutError := cmd.StdoutPipe()
-	if stdoutError != nil {
-		return stdoutError
-	}
-	defer stdout.Close()
-	stderr, stderrError := cmd.StderrPipe()
-	if stderrError != nil {
-		return stderrError
-	}
-	defer stderr.Close()
-	cmd.Start()
-	written, copyError := io.Copy(stdin, stream)
-	if copyError != nil {
-		return copyError
-	}
-	if written == 0 {
-		_, stdoutError = io.ReadAll(stdout)
-		if stdoutError != nil {
-			return stdoutError
-		}
-		errorBytes, stderrError := io.ReadAll(stderr)
-		if stderrError != nil {
-			return stderrError
-		}
-		error := strings.TrimSpace(string(errorBytes))
-		if len(error) > 0 {
-			return errors.New(error)
-		}
-	}
-	stdin.Close()
-	cmd.Wait()
-	loggo.DebugTimed("successfully piped the data stream to 'feh''", timestamp, "size: "+FormatBytes(written))
-	return nil
-}
-
-// write data from a stream to a file
-func streamToFile(stream io.ReadCloser, path string) error {
-	timestamp := time.Now().UnixMilli()
-	defer stream.Close()
-	file, error := os.Create(path)
-	if error != nil {
-		return error
-	}
-	written, error := io.Copy(file, stream)
-	if error != nil {
-		return error
-	}
-	loggo.DebugTimed("successfully piped the data stream to file '"+path+"'", timestamp, "size: "+FormatBytes(written))
-	return nil
-}

main.go

@@ -1,17 +1,23 @@
 package main
 
 import (
+	"sync"
 	"time"
 
 	"git.velvettear.de/velvettear/loggo"
-	"git.velvettear.de/velvettear/slideshow/internal"
 	"git.velvettear.de/velvettear/slideshow/internal/config"
+	"git.velvettear.de/velvettear/slideshow/internal/slideshow"
+	"git.velvettear.de/velvettear/slideshow/scanner"
 )
 
 func main() {
 	timestamp := time.Now().UnixMilli()
 	loggo.Info("slideshow is starting now...")
+	var waitgroup sync.WaitGroup
+	waitgroup.Add(1)
 	config.Initialize()
-	internal.StartSlideshow()
+	scanner.Initialize()
+	slideshow.Start()
+	waitgroup.Wait()
 	loggo.InfoTimed("slideshow is shutting down now!", timestamp)
 }

scanner/scanner.go

@@ -0,0 +1,66 @@
+package scanner
+
+import (
+	"io/fs"
+	"math/rand"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+
+	"git.velvettear.de/velvettear/loggo"
+	"git.velvettear.de/velvettear/slideshow/internal/config"
+)
+
+// slice of images
+var images []string
+
+// temporary slice of images
+var tmpImages []string
+
+// scan the specified directories for images
+func Initialize() {
+	directory := config.Directory
+	scan(directory)
+}
+
+// get a random image
+func GetRandomImage() string {
+	return images[rand.Intn(len(images))]
+}
+
+// scan the specified directory
+func scan(directory string) {
+	timestamp := time.Now().UnixMilli()
+	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)
+}
+
+// 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)
+	scan(directory)
+}
+
+// add image files to the slice of images and subdirectoies to the watcher
+func checkDirectory(path string, dir fs.DirEntry, err error) error {
+	if err != nil {
+		return err
+	}
+	if dir.IsDir() || !isImage(path) {
+		return nil
+	}
+	tmpImages = append(tmpImages, path)
+	loggo.Debug("added image to temporary slice of images", path)
+	return nil
+}
+
+// check if a file is an image
+func isImage(file string) bool {
+	return strings.HasSuffix(file, ".jpeg") || strings.HasSuffix(file, ".jpg") || strings.HasSuffix(file, ".png")
+}

slideshow.service

@@ -5,17 +5,14 @@ Description=slideshow
 Type=simple
 User=velvettear
 Environment="DISPLAY=:0"
-ENVIRONMENT="SLIDESHOW_API=localhost:3000"
 Environment="SLIDESHOW_INTERVAL=60"
-Environment="SLIDESHOW_RESOLUTION="
+Environment="SLIDESHOW_DIRECTORY=$HOME"
+Environment="SLIDESHOW_SCANINTERVAL=60"
+Environment="SLIDESHOW_RESOLUTION=1920x1080"
+Environment="SLIDESHOW_LOGLEVEL=info"
 Environment="SLIDESHOW_PALETTE=/tmp/.slideshow.palette"
-Environment="SLIDESHOW_PALETTE_ALGORITHM="
-Environment="SLIDESHOW_PALETTE_COLORS="
-Environment="SLIDESHOW_SCRIPT="
-Environment="SLIDESHOW_SCRIPT_ARGS="
-Environment="SLIDESHOW_SCRIPT_ASYNC="
-Environment="SLIDESHOW_SCRIPT_STAGE="
-Environment="SLIDESHOW_LOGLEVEL=debug"
+Environment="SLIDESHOW_PALETTE_ALGORITHM=wsm"
+Environment="SLIDESHOW_PALETTE_COLORS=16"
 ExecStart=/opt/slideshow/slideshow
 
 [Install]