From f8a12261ea342d73a61a6308b2a34034d36eaaa3 Mon Sep 17 00:00:00 2001
From: velvettear <daniel.sommer@velvettear.de>
Date: Tue, 21 Nov 2023 14:38:41 +0100
Subject: [PATCH] optimized color palette generation

---
 .vscode/launch.json             | 16 +++++++++-
 internal/slideshow/palette.go   | 52 +++++++++++++++++++--------------
 internal/slideshow/slideshow.go |  7 ++++-
 3 files changed, 51 insertions(+), 24 deletions(-)

diff --git a/.vscode/launch.json b/.vscode/launch.json
index 881313e..549a66e 100644
--- a/.vscode/launch.json
+++ b/.vscode/launch.json
@@ -2,7 +2,7 @@
   "version": "0.0.1",
   "configurations": [
     {
-      "name": "slideshow",
+      "name": "slideshow-scaled",
       "type": "go",
       "request": "launch",
       "mode": "auto",
@@ -15,6 +15,20 @@
         "SLIDESHOW_PALETTE": "/tmp/slideshow.palette"
       },
       "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_LOGLEVEL": "debug",
+        "SLIDESHOW_PALETTE": "/tmp/slideshow.palette"
+      },
+      "console": "integratedTerminal"
     }
   ]
 }
diff --git a/internal/slideshow/palette.go b/internal/slideshow/palette.go
index cd499af..ff139a6 100644
--- a/internal/slideshow/palette.go
+++ b/internal/slideshow/palette.go
@@ -1,7 +1,9 @@
 package slideshow
 
 import (
+	"bytes"
 	"fmt"
+	"image"
 	"image/color"
 	"os"
 	"strconv"
@@ -13,16 +15,11 @@ import (
 )
 
 // write the base16 color palette to a file
-func exportPalette(image string) {
-	if !config.IsPaletteSet() {
+func exportPalette(colors []color.Color) {
+	if len(colors) == 0 || !config.IsPaletteSet() {
 		return
 	}
 	var palette string
-	colors, error := getColorPalette(image, 16)
-	if error != nil {
-		loggo.Error("encountered an error getting the color palette for image", "image: "+image, error.Error())
-		return
-	}
 	for index, color := range colors {
 		if index > 0 {
 			palette += "\n"
@@ -34,33 +31,44 @@ func exportPalette(image string) {
 		tmp = "SLIDESHOW_COLOR" + tmp
 		palette += tmp + "=\"" + rgbToHex(color) + "\""
 	}
-	error = os.WriteFile(config.Palette, []byte(palette), 0775)
+	error := os.WriteFile(config.Palette, []byte(palette), 0775)
 	if error != nil {
-		loggo.Error("encountered an error exporting the color palette for image", "image: "+image, error.Error())
+		loggo.Error("encountered an error exporting a color palette", error.Error())
 	}
 }
 
-// get the base16 color palette from an image
-func GetBase16Colors(image string) (string, error) {
-	var base16 string
-	colors, error := getColorPalette(image, 16)
+// extract the given amount of dominant colors of raw image bytes
+func getColorPaletteRaw(data []byte, amount int) ([]color.Color, error) {
+	var colors []color.Color
+	if !config.IsPaletteSet() {
+		return colors, nil
+	}
+	timestamp := time.Now().UnixMilli()
+	img, _, error := image.Decode(bytes.NewReader(data))
 	if error != nil {
-		return base16, error
+		loggo.ErrorTimed("encountered an error decoding the provided raw image bytes to an image", timestamp, error.Error())
+		return colors, error
 	}
-	for index, color := range colors {
-		if index > 0 {
-			base16 += "\n"
-		}
-		base16 += rgbToHex(color)
+	colors, error = color_thief.GetPalette(img, amount, 0)
+	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 base16, nil
+	return colors, error
 }
 
-// extract the given amount of dominant colors an image
+// extract the given amount of dominant colors of an image
 func getColorPalette(image string, amount int) ([]color.Color, error) {
+	var colors []color.Color
+	if !config.IsPaletteSet() {
+		return colors, nil
+	}
 	timestamp := time.Now().UnixMilli()
 	colors, error := color_thief.GetPaletteFromFile(image, amount, 0)
-	if error == nil {
+	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
diff --git a/internal/slideshow/slideshow.go b/internal/slideshow/slideshow.go
index 5c4a453..ddf0d15 100644
--- a/internal/slideshow/slideshow.go
+++ b/internal/slideshow/slideshow.go
@@ -2,6 +2,7 @@ package slideshow
 
 import (
 	"errors"
+	"image/color"
 	"io"
 	"os/exec"
 	"strconv"
@@ -24,6 +25,7 @@ func Start() {
 	scaleImages := config.IsResolutionSet()
 	for {
 		var image string
+		var palette []color.Color
 		var data []byte
 		for {
 			image = watcher.GetRandomImage()
@@ -40,12 +42,15 @@ func Start() {
 			}
 			data = tmp
 			scaleTime = time.Since(scaleTimestamp)
+			palette, _ = getColorPaletteRaw(data, 16)
+		} else {
+			palette, _ = getColorPalette(image, 16)
 		}
 		if sleepTime > 0 {
 			loggo.Debug("sleeping for " + strconv.FormatInt(sleepTime.Milliseconds(), 10) + "ms")
 			time.Sleep(sleepTime)
 		}
-		go exportPalette(image)
+		go exportPalette(palette)
 		if scaleImages {
 			error := setBackgroundPiped(data)
 			if error != nil {