river/tags: Allow river tags to be styled based on monitor focus

include/modules/river/tags.hpp

@@ -20,6 +20,8 @@ class Tags : public waybar::AModule {
   void handle_focused_tags(uint32_t tags);
   void handle_view_tags(struct wl_array *tags);
   void handle_urgent_tags(uint32_t tags);
+  void handle_focused_output(struct wl_output *output);
+  void handle_unfocused_output(struct wl_output *output);
 
   void handle_primary_clicked(uint32_t tag);
   bool handle_button_press(GdkEventButton *event_button, uint32_t tag);
@@ -30,9 +32,11 @@ class Tags : public waybar::AModule {
 
  private:
   const waybar::Bar &bar_;
+  struct wl_output *output_;          // stores the output this module belongs to
   Gtk::Box box_;
   std::vector<Gtk::Button> buttons_;
   struct zriver_output_status_v1 *output_status_;
+  struct zriver_seat_status_v1 *seat_status_;
 };
 
 } /* namespace waybar::modules::river */

man/waybar-river-tags.5.scd

@@ -40,10 +40,13 @@ Addressed by *river/tags*
 - *#tags button.occupied*
 - *#tags button.focused*
 - *#tags button.urgent*
+- *#tags button.output*
 
-Note that occupied/focused/urgent status may overlap. That is, a tag may be
+Note that occupied/focused/urgent/output status may overlap. That is, a tag may be
 both occupied and focused at the same time.
 
+The *output* style is applied when the river output (e.g. monitor) of the current bar is focused.
+
 # SEE ALSO
 
 waybar(5), river(1)

src/modules/river/tags.cpp

@@ -27,12 +27,39 @@ static void listen_urgent_tags(void *data, struct zriver_output_status_v1 *zrive
   static_cast<Tags *>(data)->handle_urgent_tags(tags);
 }
 
+static void listen_focused_view(void *data, struct zriver_seat_status_v1 *zriver_seat_status_v1,
+                                const char *title) {
+  // This module doesn't care
+}
+
+static void listen_mode(void *data, struct zriver_seat_status_v1 *zriver_seat_status_v1,
+                        const char *mode) {
+  // This module doesn't care
+}
+
+static void listen_focused_output(void *data, struct zriver_seat_status_v1 *zriver_seat_status_v1,
+                                  struct wl_output *output) {
+  static_cast<Tags *>(data)->handle_focused_output(output);
+}
+
+static void listen_unfocused_output(void *data, struct zriver_seat_status_v1 *zriver_seat_status_v1,
+                                    struct wl_output *output) {
+  static_cast<Tags *>(data)->handle_unfocused_output(output);
+}
+
 static const zriver_output_status_v1_listener output_status_listener_impl{
     .focused_tags = listen_focused_tags,
     .view_tags = listen_view_tags,
     .urgent_tags = listen_urgent_tags,
 };
 
+static const zriver_seat_status_v1_listener seat_status_listener_impl{
+    .focused_output = listen_focused_output,
+    .unfocused_output = listen_unfocused_output,
+    .focused_view = listen_focused_view,
+    .mode = listen_mode,
+};
+
 static void listen_command_success(void *data,
                                    struct zriver_command_callback_v1 *zriver_command_callback_v1,
                                    const char *output) {
@@ -88,12 +115,15 @@ Tags::Tags(const std::string &id, const waybar::Bar &bar, const Json::Value &con
       seat_{nullptr},
       bar_(bar),
       box_{bar.orientation, 0},
-      output_status_{nullptr} {
+      output_status_{nullptr},
+      seat_status_{nullptr} {
   struct wl_display *display = Client::inst()->wl_display;
   struct wl_registry *registry = wl_display_get_registry(display);
   wl_registry_add_listener(registry, &registry_listener_impl, this);
   wl_display_roundtrip(display);
 
+  output_ = gdk_wayland_monitor_get_wl_output(bar_.output->monitor->gobj());
+
   if (!status_manager_) {
     spdlog::error("river_status_manager_v1 not advertised");
     return;
@@ -150,10 +180,12 @@ Tags::Tags(const std::string &id, const waybar::Bar &bar, const Json::Value &con
     button.show();
   }
 
-  struct wl_output *output = gdk_wayland_monitor_get_wl_output(bar_.output->monitor->gobj());
-  output_status_ = zriver_status_manager_v1_get_river_output_status(status_manager_, output);
+  output_status_ = zriver_status_manager_v1_get_river_output_status(status_manager_, output_);
   zriver_output_status_v1_add_listener(output_status_, &output_status_listener_impl, this);
 
+  seat_status_ = zriver_status_manager_v1_get_river_seat_status(status_manager_, seat_);
+  zriver_seat_status_v1_add_listener(seat_status_, &seat_status_listener_impl, this);
+
   zriver_status_manager_v1_destroy(status_manager_);
 }
 
@@ -162,6 +194,10 @@ Tags::~Tags() {
     zriver_output_status_v1_destroy(output_status_);
   }
 
+  if (seat_status_) {
+    zriver_seat_status_v1_destroy(seat_status_);
+  }
+
   if (control_) {
     zriver_control_v1_destroy(control_);
   }
@@ -224,4 +260,20 @@ void Tags::handle_urgent_tags(uint32_t tags) {
   }
 }
 
+void Tags::handle_focused_output(struct wl_output *output) {
+  if (output_ == output) {
+    for (size_t i = 0; i < buttons_.size(); ++i) {
+      buttons_[i].get_style_context()->add_class("output");
+    }
+  }
+}
+
+void Tags::handle_unfocused_output(struct wl_output *output) {
+  if (output_ == output) {
+    for (size_t i = 0; i < buttons_.size(); ++i) {
+      buttons_[i].get_style_context()->remove_class("output");
+    }
+  }
+}
+
 } /* namespace waybar::modules::river */