Wallpaper+Overview: Always process(resize&crop) the wallpaper first then do the blurry overview. Avoid cpu contention.

Modules/Background/Background.qml

@@ -361,6 +361,7 @@ Variants {
           var solidPath = WallpaperService.createSolidColorPath(Settings.data.wallpaper.solidColor.toString());
           futureWallpaper = solidPath;
           performStartupTransition();
+          WallpaperService.wallpaperProcessingComplete(modelData.name, solidPath, "");
           return;
         }
 
@@ -370,6 +371,7 @@ Variants {
         if (WallpaperService.isSolidColorPath(wallpaperPath)) {
           futureWallpaper = wallpaperPath;
           performStartupTransition();
+          WallpaperService.wallpaperProcessingComplete(modelData.name, wallpaperPath, "");
           return;
         }
 
@@ -385,6 +387,8 @@ Variants {
             futureWallpaper = wallpaperPath;
           }
           performStartupTransition();
+          // Pass cached path for blur optimization (already resized)
+          WallpaperService.wallpaperProcessingComplete(modelData.name, wallpaperPath, success ? cachedPath : "");
         });
       }
 
@@ -402,6 +406,7 @@ Variants {
         if (WallpaperService.isSolidColorPath(originalPath)) {
           futureWallpaper = originalPath;
           debounceTimer.restart();
+          WallpaperService.wallpaperProcessingComplete(modelData.name, originalPath, "");
           return;
         }
 
@@ -410,12 +415,18 @@ Variants {
         const targetHeight = Math.round(modelData.height * compositorScale);
 
         ImageCacheService.getLarge(originalPath, targetWidth, targetHeight, function (cachedPath, success) {
+          // Ignore stale callback if we've moved on to a different wallpaper
+          if (originalPath !== transitioningToOriginalPath) {
+            return;
+          }
           if (success) {
             futureWallpaper = cachedPath;
           } else {
             futureWallpaper = originalPath;
           }
           debounceTimer.restart();
+          // Pass cached path for blur optimization (already resized)
+          WallpaperService.wallpaperProcessingComplete(modelData.name, originalPath, success ? cachedPath : "");
         });
       }
 

Modules/Background/Overview.qml

@@ -17,6 +17,7 @@ Loader {
 
       required property ShellScreen modelData
       property string wallpaper: ""
+      property string preprocessedWallpaper: "" // Pre-resized wallpaper from Background.qml for blur optimization
       property string cachedWallpaper: ""
       property string pendingWallpaper: ""
       property bool isSolidColor: false
@@ -36,33 +37,23 @@ Loader {
         bgImage.source = "";
       }
 
-      // External state management
+      // External state management - wait for wallpaper processing to complete
+      // before starting blur, to avoid CPU contention on slower systems
       Connections {
         target: WallpaperService
-        function onWallpaperChanged(screenName, path) {
+        function onWallpaperProcessingComplete(screenName, path, cachedPath) {
           if (screenName === modelData.name) {
+            // Use pre-resized image for blur optimization (avoids re-reading/resizing 4K images)
+            preprocessedWallpaper = cachedPath || "";
             wallpaper = path;
           }
         }
       }
 
       function setWallpaperInitial() {
-        if (!WallpaperService || !WallpaperService.isInitialized) {
-          Qt.callLater(setWallpaperInitial);
-          return;
-        }
-
-        // Check if we're in solid color mode
-        if (Settings.data.wallpaper.useSolidColor) {
-          var solidPath = WallpaperService.createSolidColorPath(Settings.data.wallpaper.solidColor.toString());
-          wallpaper = solidPath;
-          return;
-        }
-
-        const wallpaperPath = WallpaperService.getWallpaper(modelData.name);
-        if (wallpaperPath && wallpaperPath !== wallpaper) {
-          wallpaper = wallpaperPath;
-        }
+        // Overview now receives the initial wallpaper via wallpaperProcessingComplete signal
+        // from Background.qml, ensuring blur only starts after main wallpaper is processed.
+        // No direct wallpaper assignment needed here.
       }
 
       function requestBlurredOverview() {
@@ -82,7 +73,10 @@ Loader {
           fadeOutAnim.start();
         }
 
-        ImageCacheService.getBlurredOverview(wallpaper, targetWidth, targetHeight, tint, isDarkMode, function (path, success) {
+        // Use pre-resized image if available (optimization: avoids re-reading/resizing large images)
+        const sourceImage = preprocessedWallpaper || wallpaper;
+
+        ImageCacheService.getBlurredOverview(sourceImage, targetWidth, targetHeight, tint, isDarkMode, function (path, success) {
           if (path) {
             useQtBlur = !success; // Use Qt blur fallback if ImageMagick failed
             pendingWallpaper = path;

Services/UI/WallpaperService.qml

@@ -41,6 +41,8 @@ Singleton {
   // Signals for reactive UI updates
   signal wallpaperChanged(string screenName, string path)
   // Emitted when a wallpaper changes
+  signal wallpaperProcessingComplete(string screenName, string path, string cachedPath)
+  // Emitted when wallpaper processing (resize/cache) is complete. cachedPath is the resized version.
   signal wallpaperDirectoryChanged(string screenName, string directory)
   // Emitted when a monitor's directory changes
   signal wallpaperListChanged(string screenName, int count)