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`)
 
@@ -56,12 +56,13 @@ cd pkg && makepkg -sf && sudo pacman -U moongreet-git-<version>-x86_64.pkg.tar.z
 - **Async Login**: `glib::spawn_future_local` + `gio::spawn_blocking` statt raw Threads
 - **Socket-Cancellation**: `Arc<Mutex<Option<UnixStream>>>` + `AtomicBool` für saubere Abbrüche
 - **Avatar-Cache**: `HashMap<String, gdk::Texture>` in `Rc<RefCell<GreeterState>>`
-- **Symmetrie mit moonset**: Gleiche Patterns (i18n, config, users, power, GResource)
+- **GPU-Blur via GskBlurNode**: `Snapshot::push_blur()` + `GskRenderer::render_texture()` im `connect_realize` Callback — kein CPU-Blur, kein Disk-Cache, kein `image`-Crate
+- **Symmetrie mit moonlock/moonset**: Gleiche Patterns (i18n, config, users, power, GResource, GPU-Blur)
 - **Session-Validierung**: Relative Pfade erlaubt (greetd löst PATH auf), nur `..`/Null-Bytes werden abgelehnt
 - **GTK-Theme-Validierung**: Nur alphanumerisch + `_-+.` erlaubt, verhindert Path-Traversal über Config
 - **Journal-Logging**: `systemd-journal-logger` statt File-Logging — `journalctl -t moongreet`, Debug-Level per `MOONGREET_DEBUG` Env-Var
 - **File Permissions**: Cache-Dateien 0o600
 - **Testbare Persistence**: `save_*_to`/`load_*_from` Varianten mit konfigurierbarem Pfad für Unit-Tests
-- **Shared Wallpaper Texture**: `gdk::Texture` wird einmal in `load_background_texture()` dekodiert und per Ref-Count an alle Fenster (Greeter + Wallpaper-Windows) geteilt — vermeidet redundante JPEG-Dekodierung pro Monitor
+- **Shared Wallpaper Texture**: `gdk::Texture` wird einmal in `load_background_texture()` dekodiert und per Ref-Count an alle Fenster geteilt — vermeidet redundante JPEG-Dekodierung pro Monitor
 - **Wallpaper-Validierung**: GResource-Zweig via `resources_lookup_data()` + `from_bytes()` (kein Abort bei fehlendem Pfad), Dateigröße-Limit 50 MB, non-UTF-8-Pfade → `None`
 - **Error-Detail-Filterung**: GDK/greetd-Fehlerdetails nur auf `debug!`-Level, `warn!` ohne interne Details — verhindert Systeminfo-Leak ins Journal

Cargo.lock

@@ -2,12 +2,6 @@
 # It is not intended for manual editing.
 version = 4
 
-[[package]]
-name = "adler2"
-version = "2.0.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "320119579fcad9c21884f5c4861d16174d0e06250625266f50fe6898340abefa"
-
 [[package]]
 name = "anyhow"
 version = "1.0.102"
@@ -26,18 +20,6 @@ version = "2.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "843867be96c8daad0d758b57df9392b6d8d271134fce549de6ce169ff98a92af"
 
-[[package]]
-name = "bytemuck"
-version = "1.25.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c8efb64bd706a16a1bdde310ae86b351e4d21550d98d056f22f8a7f7a2183fec"
-
-[[package]]
-name = "byteorder-lite"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8f1fe948ff07f4bd06c30984e69f5b4899c516a3ef74f34df92a2df2ab535495"
-
 [[package]]
 name = "cairo-rs"
 version = "0.22.0"
@@ -77,15 +59,6 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
-[[package]]
-name = "crc32fast"
-version = "1.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9481c1c90cbf2ac953f07c8d4a58aa3945c425b7185c9154d67a65e4230da511"
-dependencies = [
- "cfg-if",
-]
-
 [[package]]
 name = "equivalent"
 version = "1.0.2"
@@ -108,15 +81,6 @@ version = "2.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "37909eebbb50d72f9059c3b6d82c0463f2ff062c9e95845c43a6c9c0355411be"
 
-[[package]]
-name = "fdeflate"
-version = "0.3.7"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e6853b52649d4ac5c0bd02320cddc5ba956bdb407c4b75a2c6b75bf51500f8c"
-dependencies = [
- "simd-adler32",
-]
-
 [[package]]
 name = "field-offset"
 version = "0.3.6"
@@ -127,16 +91,6 @@ dependencies = [
  "rustc_version",
 ]
 
-[[package]]
-name = "flate2"
-version = "1.1.9"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "843fba2746e448b37e26a819579957415c8cef339bf08564fe8b7ddbd959573c"
-dependencies = [
- "crc32fast",
- "miniz_oxide",
-]
-
 [[package]]
 name = "foldhash"
 version = "0.1.5"
@@ -550,21 +504,6 @@ version = "2.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3d3067d79b975e8844ca9eb072e16b31c3c1c36928edf9c6789548c524d0d954"
 
-[[package]]
-name = "image"
-version = "0.25.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "85ab80394333c02fe689eaf900ab500fbd0c2213da414687ebf995a65d5a6104"
-dependencies = [
- "bytemuck",
- "byteorder-lite",
- "moxcms",
- "num-traits",
- "png",
- "zune-core",
- "zune-jpeg",
-]
-
 [[package]]
 name = "indexmap"
 version = "2.13.0"
@@ -628,28 +567,18 @@ dependencies = [
  "autocfg",
 ]
 
-[[package]]
-name = "miniz_oxide"
-version = "0.8.9"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1fa76a2c86f704bdb222d66965fb3d63269ce38518b83cb0575fca855ebb6316"
-dependencies = [
- "adler2",
- "simd-adler32",
-]
-
 [[package]]
 name = "moongreet"
-version = "0.4.0"
+version = "0.5.3"
 dependencies = [
  "gdk-pixbuf",
  "gdk4",
  "gio",
  "glib",
  "glib-build-tools",
+ "graphene-rs",
  "gtk4",
  "gtk4-layer-shell",
- "image",
  "log",
  "serde",
  "serde_json",
@@ -658,25 +587,6 @@ dependencies = [
  "toml 0.8.23",
 ]
 
-[[package]]
-name = "moxcms"
-version = "0.8.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bb85c154ba489f01b25c0d36ae69a87e4a1c73a72631fc6c0eb6dde34a73e44b"
-dependencies = [
- "num-traits",
- "pxfm",
-]
-
-[[package]]
-name = "num-traits"
-version = "0.2.19"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
-dependencies = [
- "autocfg",
-]
-
 [[package]]
 name = "once_cell"
 version = "1.21.4"
@@ -719,19 +629,6 @@ version = "0.3.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7edddbd0b52d732b21ad9a5fab5c704c14cd949e5e9a1ec5929a24fded1b904c"
 
-[[package]]
-name = "png"
-version = "0.18.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "60769b8b31b2a9f263dae2776c37b1b28ae246943cf719eb6946a1db05128a61"
-dependencies = [
- "bitflags",
- "crc32fast",
- "fdeflate",
- "flate2",
- "miniz_oxide",
-]
-
 [[package]]
 name = "prettyplease"
 version = "0.2.37"
@@ -760,12 +657,6 @@ dependencies = [
  "unicode-ident",
 ]
 
-[[package]]
-name = "pxfm"
-version = "0.1.28"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5a041e753da8b807c9255f28de81879c78c876392ff2469cde94799b2896b9d"
-
 [[package]]
 name = "quote"
 version = "1.0.45"
@@ -870,12 +761,6 @@ dependencies = [
  "serde_core",
 ]
 
-[[package]]
-name = "simd-adler32"
-version = "0.3.9"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "703d5c7ef118737c72f1af64ad2f6f8c5e1921f818cdcb97b8fe6fc69bf66214"
-
 [[package]]
 name = "slab"
 version = "0.4.12"
@@ -1244,18 +1129,3 @@ name = "zmij"
 version = "1.0.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b8848ee67ecc8aedbaf3e4122217aff892639231befc6a1b58d29fff4c2cabaa"
-
-[[package]]
-name = "zune-core"
-version = "0.5.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cb8a0807f7c01457d0379ba880ba6322660448ddebc890ce29bb64da71fb40f9"
-
-[[package]]
-name = "zune-jpeg"
-version = "0.5.15"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "27bc9d5b815bc103f142aa054f561d9187d191692ec7c2d1e2b4737f8dbd7296"
-dependencies = [
- "zune-core",
-]

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "moongreet"
-version = "0.4.0"
+version = "0.5.3"
 edition = "2024"
 description = "A greetd greeter for Wayland with GTK4 and Layer Shell"
 license = "MIT"
@@ -15,7 +15,7 @@ gio = "0.22"
 toml = "0.8"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
-image = { version = "0.25", default-features = false, features = ["jpeg", "png"] }
+graphene-rs = { version = "0.22", package = "graphene-rs" }
 log = "0.4"
 systemd-journal-logger = "2.2"
 

DECISIONS.md

@@ -1,6 +1,20 @@
 # Decisions
 
-## 2026-03-28 – Optional background blur via `image` crate
+## 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
+- **Why**: CPU-side Gaussian blur (`image` crate) blocked the GTK main thread for 500ms–2s on 4K wallpapers at cold cache. Disk cache and async orchestration added significant complexity.
+- **Tradeoffs**: GPU blur quality is slightly different (box-blur approximation vs true Gaussian), acceptable for wallpaper backgrounds. Removes `image` crate dependency entirely (~15 transitive crates eliminated). No disk cache needed.
+- **How**: `Snapshot::push_blur()` + `GskRenderer::render_texture()` on `connect_realize`. Blur happens once on the GPU when the widget gets its renderer, producing a concrete `gdk::Texture`. Zero startup latency. Symmetric with moonlock and moonset.
+
+## 2026-03-28 – Optional background blur via `image` crate (superseded)
 
 - **Who**: Selene, Dom
 - **Why**: Blurred wallpaper as greeter background is a common UX pattern for login screens

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.
+/// Priority: config background_path > Moonarch system default > None (GTK background color).
-pub fn resolve_background_path(config: &Config) -> PathBuf {
+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: no wallpaper found, using GTK background color");
-    log::debug!("Wallpaper: using GResource fallback");
+    None
-    PathBuf::from(format!("{GRESOURCE_PREFIX}/wallpaper.jpg"))
 }
 
 #[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

@@ -6,17 +6,12 @@ use gdk_pixbuf::Pixbuf;
 use glib::clone;
 use gtk4::prelude::*;
 use gtk4::{self as gtk, gio};
-use image::imageops;
 use std::cell::RefCell;
 use std::collections::HashMap;
-use std::fs;
-use std::io::Write;
-use std::os::unix::fs::OpenOptionsExt;
 use std::os::unix::net::UnixStream;
 use std::path::{Path, PathBuf};
 use std::rc::Rc;
 use std::sync::{Arc, Mutex};
-use std::time::SystemTime;
 
 use crate::config::Config;
 use crate::i18n::{faillock_warning, load_strings, Strings};
@@ -97,30 +92,11 @@ fn is_valid_username(name: &str) -> bool {
         return false;
     }
     name.chars()
-        .all(|c| c.is_ascii_alphanumeric() || c == '_' || c == '.' || c == '-')
+        .all(|c| c.is_ascii_alphanumeric() || c == '_' || c == '.' || c == '-' || c == '@')
 }
 
-/// Load the background image as a shared texture (decode once, reuse everywhere).
+/// Load background texture from filesystem.
-/// When `blur_radius` is `Some(sigma)` with sigma > 0, a Gaussian blur is applied.
+pub fn load_background_texture(bg_path: &Path) -> Option<gdk::Texture> {
-pub fn load_background_texture(bg_path: &Path, blur_radius: Option<f32>) -> Option<gdk::Texture> {
-    let path_str = bg_path.to_str()?;
-    let texture = 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
     {
@@ -138,146 +114,46 @@ pub fn load_background_texture(bg_path: &Path, blur_radius: Option<f32>) -> Opti
             None
         }
     }
-    }?;
-
-    match blur_radius {
-        Some(sigma) if sigma > 0.0 => Some(load_blurred_with_cache(bg_path, &texture, sigma)),
-        _ => Some(texture),
-    }
 }
 
-// -- Blur cache ----------------------------------------------------------------
+// -- GPU blur via GskBlurNode -------------------------------------------------
 
-const BLUR_CACHE_PNG: &str = "blur-cache.png";
+/// Render a blurred texture using the GPU via GskBlurNode.
-const BLUR_CACHE_META: &str = "blur-cache.meta";
+///
-
+/// To avoid edge darkening (blur samples transparent pixels outside bounds),
-fn blur_cache_dir() -> Option<PathBuf> {
+/// the texture is rendered with padding equal to 3x the blur sigma. The blur
-    Some(PathBuf::from("/var/cache/moongreet"))
+/// is applied to the padded area, then cropped back to the original size.
-}
+fn render_blurred_texture(
-
+    widget: &impl IsA<gtk::Widget>,
-/// Build the cache key string for the current wallpaper + sigma.
-fn build_cache_meta(bg_path: &Path, sigma: f32) -> Option<String> {
-    if bg_path.starts_with("/dev/moonarch/") {
-        let binary = std::env::current_exe().ok()?;
-        let binary_mtime = fs::metadata(&binary)
-            .ok()?
-            .modified()
-            .ok()?
-            .duration_since(SystemTime::UNIX_EPOCH)
-            .ok()?
-            .as_secs();
-        Some(format!(
-            "path={}\nbinary_mtime={}\nsigma={}\n",
-            bg_path.display(), binary_mtime, sigma,
-        ))
-    } else {
-        let meta = fs::metadata(bg_path).ok()?;
-        let mtime = meta
-            .modified()
-            .ok()?
-            .duration_since(SystemTime::UNIX_EPOCH)
-            .ok()?
-            .as_secs();
-        Some(format!(
-            "path={}\nsize={}\nmtime={}\nsigma={}\n",
-            bg_path.display(), meta.len(), mtime, sigma,
-        ))
-    }
-}
-
-/// Try to load a cached blurred texture if the cache key matches.
-fn load_cached_blur(cache_dir: &Path, expected_meta: &str) -> Option<gdk::Texture> {
-    let stored_meta = fs::read_to_string(cache_dir.join(BLUR_CACHE_META)).ok()?;
-    if stored_meta != expected_meta {
-        log::debug!("Blur cache meta mismatch, will re-blur");
-        return None;
-    }
-    let file = gio::File::for_path(cache_dir.join(BLUR_CACHE_PNG));
-    match gdk::Texture::from_file(&file) {
-        Ok(texture) => {
-            log::debug!("Loaded blurred wallpaper from cache");
-            Some(texture)
-        }
-        Err(e) => {
-            log::debug!("Failed to load cached blur PNG: {e}");
-            None
-        }
-    }
-}
-
-/// Save a blurred texture to the cache directory.
-fn save_blur_cache(cache_dir: &Path, texture: &gdk::Texture, meta: &str) {
-    if let Err(e) = save_blur_cache_inner(cache_dir, texture, meta) {
-        log::debug!("Failed to save blur cache: {e}");
-    }
-}
-
-fn save_blur_cache_inner(
-    cache_dir: &Path,
     texture: &gdk::Texture,
-    meta: &str,
+    sigma: f32,
-) -> Result<(), Box<dyn std::error::Error>> {
+) -> Option<gdk::Texture> {
-    fs::create_dir_all(cache_dir)?;
+    let native = widget.native()?;
+    let renderer = native.renderer()?;
 
-    let png_bytes = texture.save_to_png_bytes();
+    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 mut f = fs::OpenOptions::new()
+    let snapshot = gtk::Snapshot::new();
-        .create(true).write(true).truncate(true).mode(0o600)
+    // Clip output to original texture size
-        .open(cache_dir.join(BLUR_CACHE_PNG))?;
+    snapshot.push_clip(&graphene_rs::Rect::new(pad, pad, w, h));
-    f.write_all(&png_bytes)?;
+    snapshot.push_blur(sigma as f64);
+    // 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 mut f = fs::OpenOptions::new()
+    let node = snapshot.to_node()?;
-        .create(true).write(true).truncate(true).mode(0o600)
+    let viewport = graphene_rs::Rect::new(pad, pad, w, h);
-        .open(cache_dir.join(BLUR_CACHE_META))?;
+    Some(renderer.render_texture(&node, Some(&viewport)))
-    f.write_all(meta.as_bytes())?;
-
-    log::debug!("Saved blur cache to {}", cache_dir.display());
-    Ok(())
-}
-
-/// Load blurred texture, using disk cache when available.
-fn load_blurred_with_cache(bg_path: &Path, texture: &gdk::Texture, sigma: f32) -> gdk::Texture {
-    if let Some(cache_dir) = blur_cache_dir() {
-        if let Some(meta) = build_cache_meta(bg_path, sigma) {
-            if let Some(cached) = load_cached_blur(&cache_dir, &meta) {
-                return cached;
-            }
-            let blurred = apply_blur(texture, sigma);
-            save_blur_cache(&cache_dir, &blurred, &meta);
-            return blurred;
-        }
-    }
-    apply_blur(texture, sigma)
-}
-
-// -- Blur implementation -------------------------------------------------------
-
-/// Apply Gaussian blur to a texture and return a blurred texture.
-fn apply_blur(texture: &gdk::Texture, sigma: f32) -> gdk::Texture {
-    let width = texture.width() as u32;
-    let height = texture.height() as u32;
-    let stride = width as usize * 4;
-    let mut pixel_data = vec![0u8; stride * height as usize];
-    texture.download(&mut pixel_data, stride);
-
-    let img = image::RgbaImage::from_raw(width, height, pixel_data)
-        .expect("pixel buffer size matches texture dimensions");
-    let blurred = imageops::blur(&image::DynamicImage::ImageRgba8(img), sigma);
-
-    let bytes = glib::Bytes::from(blurred.as_raw());
-    let mem_texture = gdk::MemoryTexture::new(
-        width as i32,
-        height as i32,
-        gdk::MemoryFormat::B8g8r8a8Premultiplied,
-        &bytes,
-        stride,
-    );
-    mem_texture.upcast()
 }
 
 /// Create a wallpaper-only window for secondary monitors.
 pub fn create_wallpaper_window(
     texture: &gdk::Texture,
+    blur_radius: Option<f32>,
     app: &gtk::Application,
 ) -> gtk::ApplicationWindow {
     let window = gtk::ApplicationWindow::builder()
@@ -285,18 +161,28 @@ pub fn create_wallpaper_window(
         .build();
     window.add_css_class("wallpaper");
 
-    let background = create_background_picture(texture);
+    let background = create_background_picture(texture, blur_radius);
     window.set_child(Some(&background));
 
     window
 }
 
-/// Create a Picture widget for the wallpaper background from a pre-loaded texture.
+/// Create a Picture widget for the wallpaper background, optionally with GPU blur.
-fn create_background_picture(texture: &gdk::Texture) -> gtk::Picture {
+fn create_background_picture(texture: &gdk::Texture, blur_radius: Option<f32>) -> gtk::Picture {
     let background = gtk::Picture::for_paintable(texture);
     background.set_content_fit(gtk::ContentFit::Cover);
     background.set_hexpand(true);
     background.set_vexpand(true);
+
+    if let Some(sigma) = blur_radius.filter(|s| *s > 0.0) {
+        let texture = texture.clone();
+        background.connect_realize(move |picture| {
+            if let Some(blurred) = render_blurred_texture(picture, &texture, sigma) {
+                picture.set_paintable(Some(&blurred));
+            }
+        });
+    }
+
     background
 }
 
@@ -360,7 +246,7 @@ pub fn create_greeter_window(
 
     // Background wallpaper
     if let Some(texture) = texture {
-        overlay.set_child(Some(&create_background_picture(texture)));
+        overlay.set_child(Some(&create_background_picture(texture, config.background_blur)));
     }
 
     // Main layout: 3 rows (top spacer, center login, bottom bar)
@@ -508,7 +394,7 @@ pub fn create_greeter_window(
         error_label,
         move |btn| {
             btn.set_sensitive(false);
-            execute_power_action(power::reboot, strings.reboot_failed, &error_label);
+            execute_power_action(power::reboot, strings.reboot_failed, &error_label, btn);
         }
     ));
     power_box.append(&reboot_btn);
@@ -522,7 +408,7 @@ pub fn create_greeter_window(
         error_label,
         move |btn| {
             btn.set_sensitive(false);
-            execute_power_action(power::shutdown, strings.shutdown_failed, &error_label);
+            execute_power_action(power::shutdown, strings.shutdown_failed, &error_label, btn);
         }
     ));
     power_box.append(&shutdown_btn);
@@ -742,16 +628,33 @@ fn set_avatar_from_file(
     username: Option<&str>,
     state: &Rc<RefCell<GreeterState>>,
 ) {
-    // Reject oversized files
+    // Re-check symlink status to narrow TOCTOU window from get_avatar_path_with()
-    if let Ok(meta) = std::fs::metadata(path) {
+    match std::fs::symlink_metadata(path) {
-        if meta.len() > MAX_AVATAR_FILE_SIZE {
+        Ok(meta) if meta.file_type().is_symlink() => {
+            log::warn!("Rejecting symlink avatar at load time: {}", path.display());
+            image.set_icon_name(Some("avatar-default-symbolic"));
+            return;
+        }
+        Ok(meta) if meta.len() > MAX_AVATAR_FILE_SIZE => {
             log::debug!("Avatar file too large ({} bytes): {}", meta.len(), path.display());
             image.set_icon_name(Some("avatar-default-symbolic"));
             return;
         }
+        Err(e) => {
+            log::debug!("Cannot stat avatar {}: {e}", path.display());
+            image.set_icon_name(Some("avatar-default-symbolic"));
+            return;
+        }
+        Ok(_) => {}
     }
 
-    match Pixbuf::from_file_at_scale(path.to_str().unwrap_or(""), AVATAR_SIZE, AVATAR_SIZE, true) {
+    let Some(path_str) = path.to_str() else {
+        log::debug!("Non-UTF-8 avatar path, skipping: {}", path.display());
+        image.set_icon_name(Some("avatar-default-symbolic"));
+        return;
+    };
+
+    match Pixbuf::from_file_at_scale(path_str, AVATAR_SIZE, AVATAR_SIZE, true) {
         Ok(pixbuf) => {
             let texture = gdk::Texture::for_pixbuf(&pixbuf);
             if let Some(name) = username {
@@ -869,6 +772,15 @@ fn show_error(
     password_entry.grab_focus();
 }
 
+/// Extract and length-check a greetd error description from a JSON response.
+fn extract_greetd_description<'a>(response: &'a serde_json::Value, fallback: &'a str) -> &'a str {
+    response
+        .get("description")
+        .and_then(|v| v.as_str())
+        .filter(|d| !d.is_empty() && d.len() <= MAX_GREETD_ERROR_LENGTH)
+        .unwrap_or(fallback)
+}
+
 /// Display a greetd error, using a fallback for missing or oversized descriptions.
 fn show_greetd_error(
     error_label: &gtk::Label,
@@ -876,15 +788,8 @@ fn show_greetd_error(
     response: &serde_json::Value,
     fallback: &str,
 ) {
-    let description = response
+    let message = extract_greetd_description(response, fallback);
-        .get("description")
+    show_error(error_label, password_entry, message);
-        .and_then(|v| v.as_str())
-        .unwrap_or("");
-    if !description.is_empty() && description.len() <= MAX_GREETD_ERROR_LENGTH {
-        show_error(error_label, password_entry, description);
-    } else {
-        show_error(error_label, password_entry, fallback);
-    }
 }
 
 /// Cancel any in-progress greetd session.
@@ -1113,15 +1018,7 @@ fn login_worker(
             return Ok(LoginResult::Cancelled);
         }
         if response.get("type").and_then(|v| v.as_str()) == Some("error") {
-            let description = response
+            let message = extract_greetd_description(&response, strings.auth_failed).to_string();
-                .get("description")
-                .and_then(|v| v.as_str())
-                .unwrap_or("");
-            let message = if !description.is_empty() && description.len() <= MAX_GREETD_ERROR_LENGTH {
-                description.to_string()
-            } else {
-                strings.auth_failed.to_string()
-            };
             return Ok(LoginResult::Error { message });
         }
     }
@@ -1190,10 +1087,7 @@ fn login_worker(
             });
         } else {
             return Ok(LoginResult::Error {
-                message: response
+                message: extract_greetd_description(&response, strings.session_start_failed)
-                    .get("description")
-                    .and_then(|v| v.as_str())
-                    .unwrap_or(strings.session_start_failed)
                     .to_string(),
             });
         }
@@ -1209,10 +1103,13 @@ fn execute_power_action(
     action_fn: fn() -> Result<(), PowerError>,
     error_message: &'static str,
     error_label: &gtk::Label,
+    button: &gtk::Button,
 ) {
     glib::spawn_future_local(clone!(
         #[weak]
         error_label,
+        #[weak]
+        button,
         async move {
             let result = gio::spawn_blocking(move || action_fn()).await;
 
@@ -1222,11 +1119,13 @@ fn execute_power_action(
                     log::error!("Power action failed: {e}");
                     error_label.set_text(error_message);
                     error_label.set_visible(true);
+                    button.set_sensitive(true);
                 }
                 Err(_) => {
                     log::error!("Power action panicked");
                     error_label.set_text(error_message);
                     error_label.set_visible(true);
+                    button.set_sensitive(true);
                 }
             }
         }
@@ -1257,18 +1156,24 @@ fn save_last_user(username: &str) {
 
 fn save_last_user_to(path: &Path, username: &str) {
     log::debug!("Saving last user: {username}");
-    if let Some(parent) = path.parent() {
+    if let Some(parent) = path.parent()
-        let _ = std::fs::create_dir_all(parent);
+        && let Err(e) = std::fs::create_dir_all(parent)
+    {
+        log::warn!("Failed to create cache dir {}: {e}", parent.display());
+        return;
     }
     use std::os::unix::fs::OpenOptionsExt;
     use std::io::Write;
-    let _ = std::fs::OpenOptions::new()
+    if let Err(e) = std::fs::OpenOptions::new()
         .create(true)
         .write(true)
         .truncate(true)
         .mode(0o600)
         .open(path)
-        .and_then(|mut f| f.write_all(username.as_bytes()));
+        .and_then(|mut f| f.write_all(username.as_bytes()))
+    {
+        log::warn!("Failed to save last user to {}: {e}", path.display());
+    }
 }
 
 fn load_last_session(username: &str) -> Option<String> {
@@ -1313,13 +1218,16 @@ fn save_last_session_to(path: &Path, session_name: &str) {
     log::debug!("Saving last session: {session_name}");
     use std::os::unix::fs::OpenOptionsExt;
     use std::io::Write;
-    let _ = std::fs::OpenOptions::new()
+    if let Err(e) = std::fs::OpenOptions::new()
         .create(true)
         .write(true)
         .truncate(true)
         .mode(0o600)
         .open(path)
-        .and_then(|mut f| f.write_all(session_name.as_bytes()));
+        .and_then(|mut f| f.write_all(session_name.as_bytes()))
+    {
+        log::warn!("Failed to save last session to {}: {e}", path.display());
+    }
 }
 
 #[cfg(test)]
@@ -1333,6 +1241,8 @@ mod tests {
         assert!(is_valid_username("test-user"));
         assert!(is_valid_username("test.user"));
         assert!(is_valid_username("_admin"));
+        assert!(is_valid_username("user@domain"));
+        assert!(is_valid_username(&"a".repeat(MAX_USERNAME_LENGTH)));
     }
 
     #[test]
@@ -1340,6 +1250,7 @@ mod tests {
         assert!(!is_valid_username(""));
         assert!(!is_valid_username(".hidden"));
         assert!(!is_valid_username("-dash"));
+        assert!(!is_valid_username("@domain"));
         assert!(!is_valid_username("user/name"));
         assert!(!is_valid_username(&"a".repeat(MAX_USERNAME_LENGTH + 1)));
     }
@@ -1700,6 +1611,18 @@ mod tests {
         assert!(matches!(result, LoginResult::Cancelled));
     }
 
+    #[test]
+    fn login_worker_connect_failure() {
+        let cancelled = Arc::new(std::sync::atomic::AtomicBool::new(false));
+        let result = login_worker(
+            "alice", "pass", "/usr/bin/niri",
+            "/nonexistent/sock", &default_greetd_sock(), &cancelled,
+            load_strings(Some("en")),
+        );
+
+        assert!(result.is_err());
+    }
+
     #[test]
     fn login_worker_invalid_exec_cmd() {
         let (sock_path, handle) = fake_greetd(|stream| {
@@ -1768,7 +1691,7 @@ mod tests {
 
     #[test]
     fn load_background_texture_missing_file_returns_none() {
-        let result = load_background_texture(Path::new("/nonexistent/wallpaper.jpg"), None);
+        let result = load_background_texture(Path::new("/nonexistent/wallpaper.jpg"));
         assert!(result.is_none());
     }
 
@@ -1779,7 +1702,7 @@ mod tests {
         // Create a sparse file that exceeds MAX_WALLPAPER_FILE_SIZE
         let f = std::fs::File::create(&path).unwrap();
         f.set_len(MAX_WALLPAPER_FILE_SIZE + 1).unwrap();
-        let result = load_background_texture(&path, None);
+        let result = load_background_texture(&path);
         assert!(result.is_none());
     }
 
@@ -1790,63 +1713,32 @@ mod tests {
         // 0xFF is not valid UTF-8
         let non_utf8 = OsStr::from_bytes(&[0xff, 0xfe, 0xfd]);
         let path = Path::new(non_utf8);
-        let result = load_background_texture(path, None);
+        let result = load_background_texture(path);
-        assert!(result.is_none());
-    }
-
-    // -- Blur cache tests --
-
-    #[test]
-    fn build_cache_meta_for_file() {
-        let dir = tempfile::tempdir().unwrap();
-        let file = dir.path().join("wallpaper.jpg");
-        std::fs::write(&file, b"fake image").unwrap();
-        let meta = build_cache_meta(&file, 20.0);
-        assert!(meta.is_some());
-        let meta = meta.unwrap();
-        assert!(meta.contains("path="));
-        assert!(meta.contains("size=10"));
-        assert!(meta.contains("sigma=20"));
-    }
-
-    #[test]
-    fn build_cache_meta_for_gresource() {
-        let path = Path::new("/dev/moonarch/moongreet/wallpaper.jpg");
-        let meta = build_cache_meta(path, 15.0);
-        assert!(meta.is_some());
-        let meta = meta.unwrap();
-        assert!(meta.contains("binary_mtime="));
-        assert!(meta.contains("sigma=15"));
-        assert!(!meta.contains("size="));
-    }
-
-    #[test]
-    fn build_cache_meta_missing_file() {
-        let meta = build_cache_meta(Path::new("/nonexistent/wallpaper.jpg"), 20.0);
-        assert!(meta.is_none());
-    }
-
-    #[test]
-    fn cache_meta_mismatch_returns_none() {
-        let dir = tempfile::tempdir().unwrap();
-        std::fs::write(
-            dir.path().join(BLUR_CACHE_META),
-            "path=/old.jpg\nsize=100\nmtime=1\nsigma=20\n",
-        ).unwrap();
-        let result = load_cached_blur(
-            dir.path(),
-            "path=/new.jpg\nsize=200\nmtime=2\nsigma=20\n",
-        );
         assert!(result.is_none());
     }
 
     #[test]
-    fn cache_missing_meta_returns_none() {
+    fn extract_greetd_description_normal() {
-        let dir = tempfile::tempdir().unwrap();
+        let resp = serde_json::json!({"type": "error", "description": "bad password"});
-        let result = load_cached_blur(
+        assert_eq!(extract_greetd_description(&resp, "fallback"), "bad password");
-            dir.path(),
+    }
-            "path=/any.jpg\nsize=1\nmtime=1\nsigma=20\n",
+
-        );
+    #[test]
-        assert!(result.is_none());
+    fn extract_greetd_description_oversized() {
+        let long = "x".repeat(MAX_GREETD_ERROR_LENGTH + 1);
+        let resp = serde_json::json!({"type": "error", "description": long});
+        assert_eq!(extract_greetd_description(&resp, "fallback"), "fallback");
+    }
+
+    #[test]
+    fn extract_greetd_description_empty() {
+        let resp = serde_json::json!({"type": "error", "description": ""});
+        assert_eq!(extract_greetd_description(&resp, "fallback"), "fallback");
+    }
+
+    #[test]
+    fn extract_greetd_description_missing() {
+        let resp = serde_json::json!({"type": "error"});
+        assert_eq!(extract_greetd_description(&resp, "fallback"), "fallback");
     }
 }

src/i18n.rs

@@ -28,7 +28,6 @@ pub struct Strings {
     pub session_start_failed: &'static str,
     pub reboot_failed: &'static str,
     pub shutdown_failed: &'static str,
-    pub connection_error: &'static str,
     pub socket_error: &'static str,
     pub unexpected_greetd_response: &'static str,
 
@@ -53,7 +52,6 @@ const STRINGS_DE: Strings = Strings {
     session_start_failed: "Session konnte nicht gestartet werden",
     reboot_failed: "Neustart fehlgeschlagen",
     shutdown_failed: "Herunterfahren fehlgeschlagen",
-    connection_error: "Verbindungsfehler",
     socket_error: "Socket-Fehler",
     unexpected_greetd_response: "Unerwartete Antwort von greetd",
     faillock_attempts_remaining: "Noch {n} Versuch(e) vor Kontosperrung!",
@@ -76,7 +74,6 @@ const STRINGS_EN: Strings = Strings {
     session_start_failed: "Failed to start session",
     reboot_failed: "Reboot failed",
     shutdown_failed: "Shutdown failed",
-    connection_error: "Connection error",
     socket_error: "Socket error",
     unexpected_greetd_response: "Unexpected response from greetd",
     faillock_attempts_remaining: "{n} attempt(s) remaining before lockout!",

src/main.rs

@@ -51,14 +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);
+    let bg_texture = config::resolve_background_path(&config)
-    log::debug!("Background path: {}", bg_path.display());
+        .and_then(|path| {
-
+            log::debug!("Background path: {}", path.display());
-    // Load background texture once — shared across all windows
+            greeter::load_background_texture(&path)
-    let bg_texture = greeter::load_background_texture(&bg_path, config.background_blur);
+        });
-    if bg_texture.is_none() {
-        log::error!("Failed to load background texture — greeter will start without wallpaper");
-    }
 
     let use_layer_shell = std::env::var("MOONGREET_NO_LAYER_SHELL").is_err();
     log::debug!("Layer shell: {use_layer_shell}");
@@ -81,7 +78,7 @@ fn activate(app: &gtk::Application) {
                 .item(i)
                 .and_then(|obj| obj.downcast::<gdk::Monitor>().ok())
             {
-                let wallpaper = greeter::create_wallpaper_window(texture, app);
+                let wallpaper = greeter::create_wallpaper_window(texture, config.background_blur, app);
                 setup_layer_shell(&wallpaper, false, gtk4_layer_shell::Layer::Bottom);
                 wallpaper.set_monitor(Some(&monitor));
                 wallpaper.present();
@@ -91,10 +88,16 @@ fn activate(app: &gtk::Application) {
 }
 
 fn setup_logging() {
-    systemd_journal_logger::JournalLog::new()
+    match systemd_journal_logger::JournalLog::new() {
-        .unwrap()
+        Ok(logger) => {
-        .install()
+            if let Err(e) = logger.install() {
-        .unwrap();
+                eprintln!("Failed to install journal logger: {e}");
+            }
+        }
+        Err(e) => {
+            eprintln!("Failed to create journal logger: {e}");
+        }
+    }
     let level = if std::env::var("MOONGREET_DEBUG").is_ok() {
         log::LevelFilter::Debug
     } else {

src/power.rs

@@ -41,8 +41,7 @@ fn run_command(action: &'static str, program: &str, args: &[&str]) -> Result<(),
 
     if output.status.success() {
         log::debug!("Power action {action} completed successfully");
-    }
+    } else {
-    if !output.status.success() {
         let stderr = String::from_utf8_lossy(&output.stderr);
         return Err(PowerError::CommandFailed {
             action,
@@ -100,7 +99,7 @@ mod tests {
 
     #[test]
     fn run_command_passes_args() {
-        let result = run_command("test", "echo", &["hello", "world"]);
+        let result = run_command("test", "true", &["--ignored-arg"]);
         assert!(result.is_ok());
     }
 }

src/sessions.rs

@@ -12,6 +12,7 @@ const DEFAULT_XSESSION_DIRS: &[&str] = &["/usr/share/xsessions"];
 pub struct Session {
     pub name: String,
     pub exec_cmd: String,
+    #[allow(dead_code)] // Retained for future Wayland-only filtering
     pub session_type: String,
 }
 

src/users.rs

@@ -23,9 +23,11 @@ const NOLOGIN_SHELLS: &[&str] = &[
 #[derive(Debug, Clone)]
 pub struct User {
     pub username: String,
+    #[allow(dead_code)] // Retained for debugging and future UID-based features
     pub uid: u32,
     pub gecos: String,
     pub home: PathBuf,
+    #[allow(dead_code)] // Retained for debugging and future shell-based filtering
     pub shell: String,
 }
 
@@ -55,16 +57,13 @@ pub fn get_users(passwd_path: Option<&Path>) -> Vec<User> {
     let mut users = Vec::new();
 
     for line in content.lines() {
-        let parts: Vec<&str> = line.split(':').collect();
+        let mut fields = line.splitn(7, ':');
-        if parts.len() < 7 {
+        let (Some(username), Some(_pw), Some(uid_str), Some(_gid), Some(gecos), Some(home), Some(shell)) =
+            (fields.next(), fields.next(), fields.next(), fields.next(),
+             fields.next(), fields.next(), fields.next())
+        else {
             continue;
-        }
+        };
-
-        let username = parts[0];
-        let uid_str = parts[2];
-        let gecos = parts[4];
-        let home = parts[5];
-        let shell = parts[6];
 
         let uid = match uid_str.parse::<u32>() {
             Ok(u) => u,