fix: prevent edge darkening on GPU-blurred wallpaper (v0.5.3)

GskBlurNode samples pixels outside texture bounds as transparent,
causing visible darkening at wallpaper edges. Fix renders the texture
with 3x-sigma padding before blur, then clips back to original size.
Symmetric fix with moonset v0.7.1.

CLAUDE.md

@@ -17,7 +17,7 @@ Teil des Moonarch-Ökosystems.
 ## Projektstruktur
 
 - `src/` — Rust-Quellcode (main.rs, greeter.rs, ipc.rs, config.rs, users.rs, sessions.rs, i18n.rs, power.rs)
-- `resources/` — GResource-Assets (style.css, wallpaper.jpg, default-avatar.svg)
+- `resources/` — GResource-Assets (style.css, default-avatar.svg)
 - `config/` — Beispiel-Konfigurationsdateien für `/etc/moongreet/` und `/etc/greetd/`
 - `pkg/` — PKGBUILD für Arch-Linux-Paketierung (`makepkg -sf`)
 

Cargo.lock

@@ -569,7 +569,7 @@ dependencies = [
 
 [[package]]
 name = "moongreet"
-version = "0.5.0"
+version = "0.5.3"
 dependencies = [
  "gdk-pixbuf",
  "gdk4",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "moongreet"
-version = "0.5.1"
+version = "0.5.3"
 edition = "2024"
 description = "A greetd greeter for Wayland with GTK4 and Layer Shell"
 license = "MIT"

DECISIONS.md

@@ -1,5 +1,12 @@
 # Decisions
 
+## 2026-03-28 – Remove embedded wallpaper from binary
+
+- **Who**: Selene, Dom
+- **Why**: Wallpaper is installed by moonarch to /usr/share/moonarch/wallpaper.jpg. Embedding a 374K JPEG in the binary is redundant. GTK background color (Catppuccin Mocha base) is a clean fallback.
+- **Tradeoffs**: Without moonarch installed AND without config, greeter shows plain dark background instead of wallpaper. Acceptable — that's the expected minimal state.
+- **How**: Remove wallpaper.jpg from GResources, return None from resolve_background_path when no file found, skip wallpaper window creation and background picture when no path available.
+
 ## 2026-03-28 – GPU blur via GskBlurNode replaces CPU blur
 
 - **Who**: Ragnar, Dom

resources/resources.gresource.xml

@@ -2,7 +2,6 @@
 <gresources>
   <gresource prefix="/dev/moonarch/moongreet">
     <file>style.css</file>
-    <file>wallpaper.jpg</file>
     <file>default-avatar.svg</file>
   </gresource>
 </gresources>

src/config.rs

@@ -6,7 +6,6 @@ use std::fs;
 use std::path::{Path, PathBuf};
 
 const MOONARCH_WALLPAPER: &str = "/usr/share/moonarch/wallpaper.jpg";
-const GRESOURCE_PREFIX: &str = "/dev/moonarch/moongreet";
 
 /// Default config search path: system-wide config.
 fn default_config_paths() -> Vec<PathBuf> {
@@ -84,19 +83,19 @@ pub fn load_config(config_paths: Option<&[PathBuf]>) -> Config {
 
 /// Resolve the wallpaper path using the fallback hierarchy.
 ///
-/// Priority: config background_path > Moonarch system default > gresource fallback.
-pub fn resolve_background_path(config: &Config) -> PathBuf {
+/// Priority: config background_path > Moonarch system default > None (GTK background color).
+pub fn resolve_background_path(config: &Config) -> Option<PathBuf> {
     resolve_background_path_with(config, Path::new(MOONARCH_WALLPAPER))
 }
 
 /// Resolve with configurable moonarch wallpaper path (for testing).
-pub fn resolve_background_path_with(config: &Config, moonarch_wallpaper: &Path) -> PathBuf {
+pub fn resolve_background_path_with(config: &Config, moonarch_wallpaper: &Path) -> Option<PathBuf> {
     // User-configured path
     if let Some(ref bg) = config.background_path {
         let path = PathBuf::from(bg);
         if path.is_file() {
             log::debug!("Wallpaper: using config path {}", path.display());
-            return path;
+            return Some(path);
         }
         log::debug!("Wallpaper: config path {} not found, trying fallbacks", path.display());
     }
@@ -104,12 +103,11 @@ pub fn resolve_background_path_with(config: &Config, moonarch_wallpaper: &Path)
     // Moonarch ecosystem default
     if moonarch_wallpaper.is_file() {
         log::debug!("Wallpaper: using moonarch default {}", moonarch_wallpaper.display());
-        return moonarch_wallpaper.to_path_buf();
+        return Some(moonarch_wallpaper.to_path_buf());
     }
 
-    // GResource fallback path (loaded from compiled resources at runtime)
-    log::debug!("Wallpaper: using GResource fallback");
-    PathBuf::from(format!("{GRESOURCE_PREFIX}/wallpaper.jpg"))
+    log::debug!("Wallpaper: no wallpaper found, using GTK background color");
+    None
 }
 
 #[cfg(test)]
@@ -218,7 +216,7 @@ mod tests {
         };
         assert_eq!(
             resolve_background_path_with(&config, Path::new("/nonexistent")),
-            wallpaper
+            Some(wallpaper)
         );
     }
 
@@ -229,7 +227,7 @@ mod tests {
             ..Config::default()
         };
         let result = resolve_background_path_with(&config, Path::new("/nonexistent"));
-        assert!(result.to_str().unwrap().contains("moongreet"));
+        assert!(result.is_none());
     }
 
     #[test]
@@ -240,14 +238,14 @@ mod tests {
         let config = Config::default();
         assert_eq!(
             resolve_background_path_with(&config, &moonarch_wp),
-            moonarch_wp
+            Some(moonarch_wp)
         );
     }
 
     #[test]
-    fn resolve_uses_gresource_fallback_as_last_resort() {
+    fn resolve_returns_none_when_no_wallpaper_found() {
         let config = Config::default();
         let result = resolve_background_path_with(&config, Path::new("/nonexistent"));
-        assert!(result.to_str().unwrap().contains("wallpaper.jpg"));
+        assert!(result.is_none());
     }
 }

src/greeter.rs

@@ -95,42 +95,23 @@ fn is_valid_username(name: &str) -> bool {
         .all(|c| c.is_ascii_alphanumeric() || c == '_' || c == '.' || c == '-' || c == '@')
 }
 
-/// Load background texture from GResource or filesystem.
+/// Load background texture from filesystem.
 pub fn load_background_texture(bg_path: &Path) -> Option<gdk::Texture> {
-    let path_str = bg_path.to_str()?;
-    if bg_path.starts_with("/dev/moonarch/moongreet") {
-        match gio::resources_lookup_data(path_str, gio::ResourceLookupFlags::NONE) {
-            Ok(bytes) => match gdk::Texture::from_bytes(&bytes) {
-                Ok(texture) => Some(texture),
-                Err(e) => {
-                    log::debug!("GResource texture decode error: {e}");
-                    log::warn!("Failed to decode background texture from GResource {path_str}");
-                    None
-                }
-            },
-            Err(e) => {
-                log::debug!("GResource lookup error: {e}");
-                log::warn!("Failed to load background texture from GResource {path_str}");
-                None
-            }
-        }
-    } else {
-        if let Ok(meta) = std::fs::metadata(bg_path)
-            && meta.len() > MAX_WALLPAPER_FILE_SIZE
-        {
-            log::warn!(
-                "Wallpaper file too large ({} bytes), skipping: {}",
-                meta.len(), bg_path.display()
-            );
-            return None;
-        }
-        match gdk::Texture::from_filename(bg_path) {
-            Ok(texture) => Some(texture),
-            Err(e) => {
-                log::debug!("Wallpaper load error: {e}");
-                log::warn!("Failed to load background texture from {}", bg_path.display());
-                None
-            }
+    if let Ok(meta) = std::fs::metadata(bg_path)
+        && meta.len() > MAX_WALLPAPER_FILE_SIZE
+    {
+        log::warn!(
+            "Wallpaper file too large ({} bytes), skipping: {}",
+            meta.len(), bg_path.display()
+        );
+        return None;
+    }
+    match gdk::Texture::from_filename(bg_path) {
+        Ok(texture) => Some(texture),
+        Err(e) => {
+            log::debug!("Wallpaper load error: {e}");
+            log::warn!("Failed to load background texture from {}", bg_path.display());
+            None
         }
     }
 }
@@ -138,6 +119,10 @@ pub fn load_background_texture(bg_path: &Path) -> Option<gdk::Texture> {
 // -- GPU blur via GskBlurNode -------------------------------------------------
 
 /// Render a blurred texture using the GPU via GskBlurNode.
+///
+/// To avoid edge darkening (blur samples transparent pixels outside bounds),
+/// the texture is rendered with padding equal to 3x the blur sigma. The blur
+/// is applied to the padded area, then cropped back to the original size.
 fn render_blurred_texture(
     widget: &impl IsA<gtk::Widget>,
     texture: &gdk::Texture,
@@ -145,15 +130,24 @@ fn render_blurred_texture(
 ) -> Option<gdk::Texture> {
     let native = widget.native()?;
     let renderer = native.renderer()?;
+
+    let w = texture.width() as f32;
+    let h = texture.height() as f32;
+    // Padding must cover the blur kernel radius (typically ~3x sigma)
+    let pad = (sigma * 3.0).ceil();
+
     let snapshot = gtk::Snapshot::new();
-    let bounds = graphene_rs::Rect::new(
-        0.0, 0.0, texture.width() as f32, texture.height() as f32,
-    );
+    // Clip output to original texture size
+    snapshot.push_clip(&graphene_rs::Rect::new(pad, pad, w, h));
     snapshot.push_blur(sigma as f64);
-    snapshot.append_texture(texture, &bounds);
-    snapshot.pop();
+    // Render texture with padding on all sides (edges repeat via oversized bounds)
+    snapshot.append_texture(texture, &graphene_rs::Rect::new(0.0, 0.0, w + 2.0 * pad, h + 2.0 * pad));
+    snapshot.pop(); // blur
+    snapshot.pop(); // clip
+
     let node = snapshot.to_node()?;
-    Some(renderer.render_texture(&node, None))
+    let viewport = graphene_rs::Rect::new(pad, pad, w, h);
+    Some(renderer.render_texture(&node, Some(&viewport)))
 }
 
 /// Create a wallpaper-only window for secondary monitors.

src/main.rs

@@ -51,15 +51,11 @@ fn activate(app: &gtk::Application) {
 
     // Load config and resolve wallpaper
     let config = config::load_config(None);
-    let bg_path = config::resolve_background_path(&config);
-    log::debug!("Background path: {}", bg_path.display());
-
-    // Load background texture once — shared across all windows
-    // Blur is applied on the GPU via GskBlurNode at widget realization time.
-    let bg_texture = greeter::load_background_texture(&bg_path);
-    if bg_texture.is_none() {
-        log::error!("Failed to load background texture — greeter will start without wallpaper");
-    }
+    let bg_texture = config::resolve_background_path(&config)
+        .and_then(|path| {
+            log::debug!("Background path: {}", path.display());
+            greeter::load_background_texture(&path)
+        });
 
     let use_layer_shell = std::env::var("MOONGREET_NO_LAYER_SHELL").is_err();
     log::debug!("Layer shell: {use_layer_shell}");