gardesk/garshot / dbfb5b1

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x11: add XComposite support for compositor-aware screen capture

Authored by mfwolffe <wolffemf@dukes.jmu.edu>
SHA
dbfb5b156d5414e26c98ffa8a34070d59a99e159
Parents
827a0ab
Tree
d5502a7

3 changed files

StatusFile+-
M Cargo.toml 1 1
M garshot/src/x11/connection.rs 73 0
M garshot/src/x11/shm.rs 7 3
Cargo.tomlmodified
@@ -11,7 +11,7 @@ authors = ["mfwolffe"]
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 [workspace.dependencies]
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 # X11
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-x11rb = { version = "0.13", features = ["randr", "shm", "xfixes", "shape"] }
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+x11rb = { version = "0.13", features = ["randr", "shm", "xfixes", "shape", "composite"] }
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 # Async runtime
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 tokio = { version = "1", features = ["full", "signal"] }
garshot/src/x11/connection.rsmodified
@@ -1,6 +1,7 @@
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 //! X11 connection management for garshot.
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 use x11rb::connection::Connection as X11Connection;
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+use x11rb::protocol::composite::ConnectionExt as CompositeExt;
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 use x11rb::protocol::xproto::*;
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 use x11rb::rust_connection::RustConnection;
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@@ -22,6 +23,10 @@ pub struct Connection {
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     pub depth: u8,
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     /// Root visual ID.
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     pub visual: Visualid,
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+    /// Whether a compositor is active.
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+    pub compositor_active: bool,
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+    /// Composite overlay window (if compositor is active).
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+    pub overlay_window: Option<Window>,
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 }
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 impl Connection {
@@ -44,6 +49,42 @@ impl Connection {
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             screen.root_depth
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         );
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+        // Check if a compositor is running by looking for _NET_WM_CM_S{screen} selection owner
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+        let compositor_active = Self::detect_compositor(&conn, screen_num, screen.root)?;
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+
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+        // Initialize composite extension and get overlay window if compositor is active
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+        let overlay_window = if compositor_active {
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+            // Query composite extension version
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+            if let Ok(reply) = conn.composite_query_version(0, 4)?.reply() {
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+                tracing::info!(
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+                    "Composite extension version {}.{}",
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+                    reply.major_version,
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+                    reply.minor_version
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+                );
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+
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+                // Get the overlay window - this is where composited content is rendered
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+                match conn.composite_get_overlay_window(screen.root)?.reply() {
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+                    Ok(overlay) => {
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+                        tracing::info!("Got composite overlay window: 0x{:x}", overlay.overlay_win);
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+                        Some(overlay.overlay_win)
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+                    }
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+                    Err(e) => {
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+                        tracing::warn!("Failed to get overlay window: {}", e);
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+                        None
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+                    }
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+                }
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+            } else {
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+                tracing::warn!("Composite extension not available");
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+                None
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+            }
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+        } else {
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+            None
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+        };
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+
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+        if compositor_active {
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+            tracing::info!("Compositor detected - will use overlay window for capture");
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+        }
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+
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         Ok(Self {
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             root: screen.root,
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             width: screen.width_in_pixels,
@@ -52,9 +93,29 @@ impl Connection {
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             visual: screen.root_visual,
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             conn,
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             screen_num,
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+            compositor_active,
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+            overlay_window,
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         })
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     }
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+    /// Detect if a compositor is running.
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+    fn detect_compositor(conn: &RustConnection, screen_num: usize, _root: Window) -> Result<bool> {
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+        // The compositor manager selection is _NET_WM_CM_S{screen}
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+        let atom_name = format!("_NET_WM_CM_S{}", screen_num);
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+        let atom = conn.intern_atom(false, atom_name.as_bytes())?.reply()?.atom;
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+
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+        // Check if the selection has an owner
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+        let owner = conn.get_selection_owner(atom)?.reply()?.owner;
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+
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+        if owner != x11rb::NONE {
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+            tracing::debug!("Compositor detected: _NET_WM_CM_S{} owner is 0x{:x}", screen_num, owner);
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+            Ok(true)
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+        } else {
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+            tracing::debug!("No compositor detected");
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+            Ok(false)
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+        }
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+    }
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+
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     /// Get the screen structure.
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     pub fn screen(&self) -> &Screen {
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         &self.conn.setup().roots[self.screen_num]
@@ -86,6 +147,18 @@ impl std::fmt::Debug for Connection {
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             .field("root", &format_args!("0x{:x}", self.root))
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             .field("size", &format_args!("{}x{}", self.width, self.height))
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             .field("depth", &self.depth)
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+            .field("compositor_active", &self.compositor_active)
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             .finish()
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     }
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 }
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+
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+impl Drop for Connection {
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+    fn drop(&mut self) {
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+        // Release the overlay window if we acquired it
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+        if let Some(overlay) = self.overlay_window {
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+            tracing::debug!("Releasing composite overlay window 0x{:x}", overlay);
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+            let _ = self.conn.composite_release_overlay_window(self.root);
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+            let _ = self.conn.flush();
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+        }
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+    }
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+}
garshot/src/x11/shm.rsmodified
@@ -149,16 +149,20 @@ impl ShmCapture {
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             )));
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         }
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+        // Use overlay window if compositor is active, otherwise use root
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+        let drawable = conn.overlay_window.unwrap_or(conn.root);
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+
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         tracing::debug!(
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-            "Capturing region {}x{}+{}+{} ({} bytes)",
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-            width, height, x, y, byte_count
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+            "Capturing region {}x{}+{}+{} ({} bytes) from drawable 0x{:x}{}",
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+            width, height, x, y, byte_count, drawable,
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+            if conn.compositor_active { " (compositor active)" } else { "" }
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         );
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         // Use shm_get_image to capture directly to shared memory
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         let reply = conn
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             .conn
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             .shm_get_image(
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-                conn.root,
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+                drawable,
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                 x,
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                 y,
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                 width,