initial draft for libcamera backend support

i18n/en/camera.ftl

@@ -28,6 +28,8 @@ settings-camera = Camera
 settings-video = Video
 settings-device = Device
 settings-format = Format
+settings-backend = Backend
+settings-backend-description = Camera backend to use. PipeWire is recommended for most systems. Libcamera is for mobile Linux devices.
 settings-microphone = Microphone
 settings-encoder = Encoder
 settings-quality = Quality
@@ -40,6 +42,10 @@ settings-bug-reports = Bug reports
 settings-report-bug = Report bug
 settings-show-report = Show Report
 settings-resolution = Resolution
+
+# Backend options
+backend-pipewire = PipeWire
+backend-libcamera = libcamera
 settings-version = Version { $version }
 settings-version-flatpak = Version { $version } (Flatpak)
 

src/app/camera_ops.rs

@@ -21,7 +21,7 @@ impl AppModel {
         let camera_path = &camera.path;
 
         // Get formats for the new mode
-        let backend = crate::backends::camera::get_backend();
+        let backend = crate::backends::camera::get_backend(self.config.backend);
         let device = crate::backends::camera::types::CameraDevice {
             name: camera.name.clone(),
             path: camera_path.clone(),
@@ -230,8 +230,8 @@ impl AppModel {
         };
         let camera_path = camera.path.clone();
 
-        // Get formats for this camera using PipeWire backend
-        let backend = crate::backends::camera::get_backend();
+        // Get formats for this camera using the configured backend
+        let backend = crate::backends::camera::get_backend(self.config.backend);
         let device = crate::backends::camera::types::CameraDevice {
             name: camera.name.clone(),
             path: camera_path.clone(),

src/app/mod.rs

@@ -243,6 +243,26 @@ impl cosmic::Application for AppModel {
                 .iter()
                 .map(|p| p.display_name().to_string())
                 .collect(),
+            backend_dropdown_options: {
+                let mut options = Vec::new();
+                if crate::backends::camera::pipewire::is_pipewire_available() {
+                    options.push(fl!("backend-pipewire"));
+                }
+                if crate::backends::camera::libcamera::is_libcamera_available() {
+                    options.push(fl!("backend-libcamera"));
+                }
+                options
+            },
+            available_backends: {
+                let mut backends = Vec::new();
+                if crate::backends::camera::pipewire::is_pipewire_available() {
+                    backends.push(crate::backends::camera::CameraBackendType::PipeWire);
+                }
+                if crate::backends::camera::libcamera::is_libcamera_available() {
+                    backends.push(crate::backends::camera::CameraBackendType::Libcamera);
+                }
+                backends
+            },
             bitrate_info_visible: false,
             transition_state: crate::app::state::TransitionState::default(),
             // QR detection enabled by default
@@ -269,7 +289,7 @@ impl cosmic::Application for AppModel {
 
                 // Enumerate cameras (can be slow, especially with multiple devices)
                 info!(backend = %backend_type, "Enumerating cameras asynchronously");
-                let backend = crate::backends::camera::get_backend();
+                let backend = crate::backends::camera::get_backend(backend_type);
                 let cameras = backend.enumerate_cameras();
                 info!(count = cameras.len(), backend = %backend_type, "Found camera(s)");
 

src/app/settings/view.rs

@@ -33,8 +33,15 @@ impl AppModel {
             .position(|p| *p == self.config.bitrate_preset)
             .unwrap_or(1); // Default to Medium (index 1)
 
-        // Camera section
-        let camera_section = widget::settings::section()
+        // Current backend index for dropdown (find in available backends list)
+        let current_backend_index = self
+            .available_backends
+            .iter()
+            .position(|b| *b == self.config.backend)
+            .unwrap_or(0);
+
+        // Camera section - conditionally add backend dropdown only if multiple backends available
+        let mut camera_section = widget::settings::section()
             .title(fl!("settings-camera"))
             .add(
                 widget::settings::item::builder(fl!("settings-device")).control(widget::dropdown(
@@ -51,6 +58,19 @@ impl AppModel {
                 )),
             );
 
+        // Only show backend dropdown if multiple backends are available
+        if self.available_backends.len() > 1 {
+            camera_section = camera_section.add(
+                widget::settings::item::builder(fl!("settings-backend"))
+                    .description(fl!("settings-backend-description"))
+                    .control(widget::dropdown(
+                        &self.backend_dropdown_options,
+                        Some(current_backend_index),
+                        Message::SelectBackend,
+                    )),
+            );
+        }
+
         // Video section
         let video_section = widget::settings::section()
             .title(fl!("settings-video"))

src/app/state.rs

@@ -348,6 +348,10 @@ pub struct AppModel {
     pub codec_dropdown_options: Vec<String>,
     /// Bitrate preset dropdown options
     pub bitrate_preset_dropdown_options: Vec<String>,
+    /// Backend dropdown options
+    pub backend_dropdown_options: Vec<String>,
+    /// Available backend types (corresponding to dropdown options)
+    pub available_backends: Vec<crate::backends::camera::CameraBackendType>,
     /// Whether the bitrate info matrix is visible
     pub bitrate_info_visible: bool,
 
@@ -599,6 +603,8 @@ pub enum Message {
     SelectAudioDevice(usize),
     /// Select video encoder
     SelectVideoEncoder(usize),
+    /// Select camera backend
+    SelectBackend(usize),
     /// Toggle virtual camera feature enabled
     ToggleVirtualCameraEnabled,
 

src/app/update.rs

@@ -117,6 +117,7 @@ impl AppModel {
             Message::UpdateConfig(config) => self.handle_update_config(config),
             Message::SelectAudioDevice(index) => self.handle_select_audio_device(index),
             Message::SelectVideoEncoder(index) => self.handle_select_video_encoder(index),
+            Message::SelectBackend(index) => self.handle_select_backend(index),
 
             // ===== System & Recovery =====
             Message::CameraRecoveryStarted {
@@ -2133,6 +2134,74 @@ impl AppModel {
         Task::none()
     }
 
+    fn handle_select_backend(&mut self, index: usize) -> Task<cosmic::Action<Message>> {
+        // Get the backend type from the available backends list
+        let new_backend = match self.available_backends.get(index) {
+            Some(backend) => *backend,
+            None => return Task::none(),
+        };
+
+        // Don't do anything if the backend is the same
+        if new_backend == self.config.backend {
+            return Task::none();
+        }
+
+        info!(old = %self.config.backend, new = %new_backend, "Switching camera backend");
+
+        // Update config
+        self.config.backend = new_backend;
+        if let Some(handler) = self.config_handler.as_ref() {
+            if let Err(err) = self.config.write_entry(handler) {
+                error!(?err, "Failed to save backend selection");
+            }
+        }
+
+        // Change the backend in the manager
+        if let Some(ref manager) = self.backend_manager {
+            if let Err(err) = manager.change_backend(new_backend) {
+                error!(?err, "Failed to change backend");
+                return Task::none();
+            }
+        }
+
+        // Clear current state and re-enumerate cameras with the new backend
+        self.available_cameras.clear();
+        self.available_formats.clear();
+        self.active_format = None;
+        self.current_frame = None;
+
+        // Re-enumerate cameras with the new backend
+        let backend = crate::backends::camera::get_backend(new_backend);
+        let cameras = backend.enumerate_cameras();
+        info!(count = cameras.len(), backend = %new_backend, "Re-enumerated cameras with new backend");
+
+        if !cameras.is_empty() {
+            self.available_cameras = cameras;
+            self.current_camera_index = 0;
+
+            // Update camera dropdown
+            self.camera_dropdown_options = self
+                .available_cameras
+                .iter()
+                .map(|c| c.name.clone())
+                .collect();
+
+            // Get formats for the first camera
+            let device = &self.available_cameras[0];
+            self.available_formats = backend.get_formats(device, false);
+
+            // Select the first format if available
+            if !self.available_formats.is_empty() {
+                self.active_format = self.available_formats.first().cloned();
+            }
+
+            // Update all dropdowns
+            self.update_all_dropdowns();
+        }
+
+        Task::none()
+    }
+
     // =========================================================================
     // System & Recovery Handlers
     // =========================================================================