feat(notification): route to source app output

assets/translations/en.json

@@ -2274,6 +2274,10 @@
           "description": "Screen position for notification toasts",
           "label": "Screen Position"
         },
+        "route-to-source-output": {
+          "description": "Use the monitor containing a uniquely matched source-app window; otherwise use the selected monitors",
+          "label": "Route to Source App Monitor"
+        },
         "scale": {
           "description": "Scale notification toasts relative to the shell UI scale",
           "label": "Size"

example.toml

@@ -171,6 +171,7 @@ scale              = 1.0            # notification size multiplier applied on to
 background_opacity = 0.97
 offset_x           = 20             # absolute horizontal margin from the screen edge
 offset_y           = 8              # absolute vertical margin from the screen edge
+route_to_source_output = false      # use a uniquely matched source-app monitor when available
 # [notification.filter.rhythmbox]
 # enabled         = true
 # match           = "rhythmbox"

src/app/application_services.cpp

@@ -805,6 +805,7 @@ void Application::initWaylandCallbacks() {
     m_bar.refresh();
     m_dock.refresh();
     m_windowSwitcher.onToplevelChange();
+    m_notificationToast.onToplevelChange();
   });
   if constexpr (kLockKeysEnabled) {
     if (lockKeysConsumersEnabled(m_configService.config())) {

src/app/application_ui.cpp

@@ -706,7 +706,9 @@ void Application::initPanelManagerAndPanels() {
 }
 
 void Application::initNotificationAndOsd() {
-  m_notificationToast.initialize(m_wayland, &m_configService, &m_notificationManager, &m_renderContext, &m_httpClient);
+  m_notificationToast.initialize(
+      m_wayland, &m_configService, &m_notificationManager, &m_renderContext, &m_compositorPlatform, &m_httpClient
+  );
   m_configService.addReloadCallback([this]() { m_notificationToast.onConfigReload(); });
   auto applyNotificationFilterConfig = [this]() {
     m_notificationManager.setFilters(m_configService.config().notification.filters);

src/config/config_types.h

@@ -747,6 +747,7 @@ struct NotificationConfig {
   int offsetX = 20;                // absolute horizontal margin from the screen edge
   int offsetY = 8;                 // absolute vertical margin from the screen edge
   std::vector<std::string> monitors;
+  bool routeToSourceOutput = false;
   bool collapseOnDismiss = true;
   int historyRetentionHours = 0;
   int maxVisible = 0; // 0 = unlimited (space-based only)

src/config/schema/config_schema.cpp

@@ -256,6 +256,7 @@ namespace noctalia::config::schema {
         field(&NotificationConfig::offsetX, "offset_x"),
         field(&NotificationConfig::offsetY, "offset_y"),
         field(&NotificationConfig::monitors, "monitors"),
+        field(&NotificationConfig::routeToSourceOutput, "route_to_source_output"),
         field(&NotificationConfig::collapseOnDismiss, "collapse_on_dismiss"),
         field(&NotificationConfig::historyRetentionHours, "history_retention_hours", Range<std::int64_t>{0, 8760}),
         field(&NotificationConfig::maxVisible, "max_visible", Range<std::int64_t>{0, 20}),

src/shell/notification/notification_toast.cpp

@@ -1,5 +1,6 @@
 #include "shell/notification/notification_toast.h"
 
+#include "compositors/compositor_platform.h"
 #include "config/config_service.h"
 #include "config/config_types.h"
 #include "core/deferred_call.h"
@@ -16,6 +17,8 @@
 #include "render/render_target.h"
 #include "render/scene/input_area.h"
 #include "shell/surface/edge_inset.h"
+#include "system/app_identity.h"
+#include "system/desktop_entry.h"
 #include "ui/builders.h"
 #include "ui/palette.h"
 #include "ui/style.h"
@@ -511,12 +514,13 @@ NotificationToast::~NotificationToast() {
 
 void NotificationToast::initialize(
     WaylandConnection& wayland, ConfigService* config, NotificationManager* notifications, RenderContext* renderContext,
-    HttpClient* httpClient
+    CompositorPlatform* platform, HttpClient* httpClient
 ) {
   m_wayland = &wayland;
   m_config = config;
   m_notifications = notifications;
   m_renderContext = renderContext;
+  m_platform = platform;
   m_httpClient = httpClient;
 
   m_callbackToken = m_notifications->addEventCallback([this](const Notification& n, NotificationEvent event) {
@@ -534,6 +538,7 @@ void NotificationToast::onConfigReload() {
     return;
   }
   ensureSurfaces();
+  refreshNotificationOutputs();
   std::vector<bool> wasPlaced(m_entries.size(), false);
   for (std::size_t i = 0; i < m_entries.size(); ++i) {
     wasPlaced[i] = hasPlacement(m_entries[i]);
@@ -573,12 +578,23 @@ void NotificationToast::onOutputChange() {
     return;
   }
   ensureSurfaces();
+  refreshNotificationOutputs();
   for (std::size_t i = 0; i < m_entries.size(); ++i) {
     syncEntryVisibility(i);
   }
   requestLayout();
 }
 
+void NotificationToast::onToplevelChange() {
+  if (m_entries.empty() || m_config == nullptr || !m_config->config().notification.routeToSourceOutput) {
+    return;
+  }
+  refreshNotificationOutputs();
+  for (std::size_t i = 0; i < m_entries.size(); ++i) {
+    syncEntryVisibility(i);
+  }
+}
+
 void NotificationToast::hideDndSuppressed() {
   std::erase_if(m_pendingAdds, [](const Notification& pending) {
     return pending.dndPolicy == NotificationDndPolicy::Respect;
@@ -650,6 +666,8 @@ void NotificationToast::onNotificationEvent(const Notification& n, NotificationE
         const float previousHeight = m_entries[i].height;
         const int prevToastBodyLines = m_entries[i].toastBodyLines;
         const bool previouslyPlaced = hasPlacement(m_entries[i]);
+        const wl_output* previousOutput = m_entries[i].targetOutput;
+        m_entries[i].targetOutput = resolveNotificationOutput(n);
         m_entries[i].appName = notificationDisplayAppName(n);
         m_entries[i].summary = n.summary;
         m_entries[i].body = n.body;
@@ -817,7 +835,7 @@ void NotificationToast::onNotificationEvent(const Notification& n, NotificationE
           m_notifications->pauseExpiry(n.id);
         }
 
-        if (!hasPlacement(m_entries[i])) {
+        if (previousOutput != m_entries[i].targetOutput || !hasPlacement(m_entries[i])) {
           syncEntryVisibility(i);
           revealQueuedEntries();
         } else if (std::abs(previousHeight - m_entries[i].height) > 0.5F) {
@@ -870,6 +888,7 @@ void NotificationToast::addPopup(const Notification& n) {
 
   PopupEntry entry;
   entry.notificationId = n.id;
+  entry.targetOutput = resolveNotificationOutput(n);
   entry.appName = notificationDisplayAppName(n);
   entry.summary = n.summary;
   entry.body = n.body;
@@ -903,7 +922,10 @@ void NotificationToast::addPopup(const Notification& n) {
   revealQueuedEntries();
   enforceMaxVisible();
 
-  kLog.debug("notification toast: showing #{}", n.id);
+  const auto* output = m_wayland != nullptr ? m_wayland->findOutputByWl(m_entries[index].targetOutput) : nullptr;
+  kLog.debug(
+      "notification toast: showing #{} on {}", n.id, output != nullptr ? output->connectorName : "all eligible outputs"
+  );
 }
 
 void NotificationToast::requestClose(uint32_t notificationId, CloseReason reason) {
@@ -1001,7 +1023,9 @@ void NotificationToast::finishRemoval(uint32_t notificationId) {
 
 void NotificationToast::addCardToInstance(Instance& inst, std::size_t entryIndex) {
   auto& entry = m_entries[entryIndex];
-  if (!hasPlacement(entry) || !fitsOnSurface(entry, static_cast<float>(inst.surface->height()))) {
+  if (!hasPlacement(entry)
+      || (entry.targetOutput != nullptr && entry.targetOutput != inst.output)
+      || !fitsOnSurface(entry, static_cast<float>(inst.surface->height()))) {
     return;
   }
 
@@ -1182,6 +1206,7 @@ void NotificationToast::syncEntryVisibility(std::size_t entryIndex) {
 
     auto& cs = inst->cards[entryIndex];
     const bool shouldShow = hasPlacement(m_entries[entryIndex])
+        && (m_entries[entryIndex].targetOutput == nullptr || m_entries[entryIndex].targetOutput == inst->output)
         && fitsOnSurface(m_entries[entryIndex], static_cast<float>(inst->surface->height()));
     if (shouldShow) {
       if (cs.cardNode == nullptr) {
@@ -1980,6 +2005,59 @@ uint32_t NotificationToast::surfaceHeightForOutput(wl_output* output) const {
   return fallbackSurfaceHeight(notificationUiScale(m_config));
 }
 
+wl_output* NotificationToast::resolveNotificationOutput(const Notification& notification) const {
+  if (m_config == nullptr || !m_config->config().notification.routeToSourceOutput || m_platform == nullptr) {
+    return nullptr;
+  }
+
+  std::string appKey = notification.desktopEntry.value_or("");
+  if (StringUtils::isBlank(appKey)) {
+    appKey = notification.appName;
+  }
+  if (appKey.ends_with(".desktop")) {
+    appKey.resize(appKey.size() - std::string_view(".desktop").size());
+  }
+  if (const auto slash = appKey.find_last_of('/'); slash != std::string::npos) {
+    appKey.erase(0, slash + 1);
+  }
+  if (StringUtils::isBlank(appKey)) {
+    return nullptr;
+  }
+
+  std::string idLower = StringUtils::toLower(appKey);
+  std::string wmClassLower = idLower;
+  if (const auto entry = app_identity::findDesktopEntry(appKey, desktopEntries()); entry.has_value()) {
+    idLower = !entry->idLower.empty() ? entry->idLower : StringUtils::toLower(entry->id);
+    wmClassLower = !entry->startupWmClassLower.empty() ? entry->startupWmClassLower : idLower;
+  }
+
+  wl_output* match = nullptr;
+  for (const auto& inst : m_instances) {
+    if (inst == nullptr
+        || inst->output == nullptr
+        || m_platform->enrichedWindowsForApp(idLower, wmClassLower, inst->output).empty()) {
+      continue;
+    }
+    if (match != nullptr) {
+      return nullptr;
+    }
+    match = inst->output;
+  }
+  return match;
+}
+
+void NotificationToast::refreshNotificationOutputs() {
+  if (m_notifications == nullptr) {
+    return;
+  }
+  for (auto& entry : m_entries) {
+    const auto notification = std::ranges::find(m_notifications->all(), entry.notificationId, &Notification::id);
+    if (notification != m_notifications->all().end()) {
+      entry.targetOutput = resolveNotificationOutput(*notification);
+    }
+  }
+}
+
 // --- Surface lifecycle ---
 
 void NotificationToast::ensureSurfaces() {

src/shell/notification/notification_toast.h

@@ -12,6 +12,7 @@
 #include <vector>
 
 class ConfigService;
+class CompositorPlatform;
 class HttpClient;
 class Input;
 class InputArea;
@@ -40,10 +41,11 @@ class NotificationToast {
 
   void initialize(
       WaylandConnection& wayland, ConfigService* config, NotificationManager* notifications,
-      RenderContext* renderContext, HttpClient* httpClient = nullptr
+      RenderContext* renderContext, CompositorPlatform* platform, HttpClient* httpClient = nullptr
   );
   void onConfigReload();
   void onOutputChange();
+  void onToplevelChange();
   void hideDndSuppressed();
   void requestLayout();
   void requestRedraw();
@@ -57,6 +59,7 @@ class NotificationToast {
   // Per-notification visual state (shared across all instances)
   struct PopupEntry {
     uint32_t notificationId = 0;
+    wl_output* targetOutput = nullptr;
     std::string appName;
     std::string summary;
     std::string body;
@@ -189,6 +192,8 @@ class NotificationToast {
   [[nodiscard]] std::optional<float>
   findPlacementY(float entryHeight, std::optional<uint32_t> ignoreNotificationId = std::nullopt) const;
   [[nodiscard]] uint32_t surfaceHeightForOutput(wl_output* output) const;
+  [[nodiscard]] wl_output* resolveNotificationOutput(const Notification& notification) const;
+  void refreshNotificationOutputs();
   // Configured render scale of a notification output, for pre-surface sizing.
   [[nodiscard]] float notificationScale() const;
   [[nodiscard]] std::string resolveNotificationIconPath(const PopupEntry& entry);
@@ -197,6 +202,7 @@ class NotificationToast {
   ConfigService* m_config = nullptr;
   NotificationManager* m_notifications = nullptr;
   RenderContext* m_renderContext = nullptr;
+  CompositorPlatform* m_platform = nullptr;
   HttpClient* m_httpClient = nullptr;
 
   std::vector<PopupEntry> m_entries;

src/shell/settings/settings_registry.cpp

@@ -2953,6 +2953,12 @@ namespace settings {
         ListSetting{.items = cfg.notification.monitors, .suggestedOptions = env.availableOutputs},
         "monitor output display screen"
     ));
+    entries.push_back(makeEntry(
+        SettingsSection::Notifications, "toasts", tr("settings.schema.notifications.route-to-source-output.label"),
+        tr("settings.schema.notifications.route-to-source-output.description"),
+        {"notification", "route_to_source_output"}, ToggleSetting{cfg.notification.routeToSourceOutput},
+        "source application monitor output route"
+    ));
     entries.push_back(makeEntry(
         SettingsSection::Notifications, "history", tr("settings.schema.notifications.history-retention-hours.label"),
         tr("settings.schema.notifications.history-retention-hours.description"),

tests/config_schema_roundtrip_test.cpp

@@ -377,6 +377,7 @@ location = "https://example.invalid/bad"
         .offsetX = 12,
         .offsetY = 6,
         .monitors = {"DP-2"},
+        .routeToSourceOutput = true,
         .collapseOnDismiss = false,
         .historyRetentionHours = 48,
         .filters = {NotificationFilterConfig{