allow wildcards for monitors

README.md

@@ -29,7 +29,7 @@ wallpaper = monitor,/path/to/image.png
 # .. more monitors
 ```
 
-Preload will tell Hyprland to load a particular image (supported formats: png, jpg, jpeg). Wallpaper will apply the wallpaper to the selected output (`monitor` is the monitor's name, easily can be retrieved with `hyprctl monitors`)
+Preload will tell Hyprland to load a particular image (supported formats: png, jpg, jpeg). Wallpaper will apply the wallpaper to the selected output (`monitor` is the monitor's name, easily can be retrieved with `hyprctl monitors`. You can leave it empty for a wildcard (aka fallback))
 
 You may add `contain:` before the file path in `wallpaper=` to set the mode to contain instead of cover:
 

src/Hyprpaper.cpp

@@ -261,6 +261,21 @@ void CHyprpaper::ensureMonitorHasActiveWallpaper(SMonitor* pMonitor) {
         }
     }
 
+    if (!it->second) {
+        // try to find a wildcard
+        for (auto&[mon, path1] : m_mMonitorActiveWallpapers) {
+            if (mon.empty()) {
+                for (auto&[path2, target] : m_mWallpaperTargets) {
+                    if (path1 == path2) {
+                        it->second = ⌖
+                        break;
+                    }
+                }
+                break;
+            }
+        }
+    }
+
     if (!it->second) {
         pMonitor->hasATarget = false;
         Debug::log(WARN, "Monitor %s does not have a target! A wallpaper will not be created.", pMonitor->name.c_str());