From ce00de7a4ea9e15ad93f17d34d466b97e74c8ef1 Mon Sep 17 00:00:00 2001
From: Max Medina <maxmedina05@gmail.com>
Date: Fri, 17 Jul 2026 11:32:14 +0200
Subject: [PATCH] fix(linux): use a real screen source on X11 instead of the
 portal sentinel

The Linux HUD does not render a source picker, so `getSelectedSource()`
is always null when recording starts. startRecording then substituted
the `screen:linux-portal` sentinel for every Linux session, forcing
capture through getDisplayMedia and the xdg-desktop-portal ScreenCast
dialog.

On X11 that dialog never opens, so capture failed with:

  Failed to start recording: Could not start video source

Main already resolves screens per session type via
getScreenSourceIdForDisplay(): the portal sentinel on Wayland, a real
desktop-capturer id on X11. The renderer just never asked for it.

Prefer a real screen id when one is available and keep the sentinel as
the fallback, so Wayland behaviour is unchanged and X11 uses direct
capture. Fallback ids (screen:fallback:*) are skipped so the existing
"Selected display is not available" guard still applies.

Verified on Ubuntu 24.04 (GNOME, X11): resolution now yields a real
source id and captures at 3840x2160@60.

Refs #137, #364, #441

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 src/hooks/useScreenRecorder.ts | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/src/hooks/useScreenRecorder.ts b/src/hooks/useScreenRecorder.ts
index c5cd70056..7554fb103 100644
--- a/src/hooks/useScreenRecorder.ts
+++ b/src/hooks/useScreenRecorder.ts
@@ -121,6 +121,34 @@ const LINUX_PORTAL_SOURCE: ProcessedDesktopSource = {
 	sourceType: "screen",
 };
 
+// The Linux HUD has no source picker, so recording starts with no selected
+// source. Main already resolves screens per session type: the portal sentinel
+// on Wayland, a real desktop-capturer id on X11. Prefer a real id when one
+// exists, because the X11 portal dialog never opens and capture then fails
+// with "Could not start video source".
+async function resolveDefaultLinuxSource(): Promise<ProcessedDesktopSource> {
+	try {
+		const sources = await window.electronAPI.getSources({
+			types: ["screen"],
+			thumbnailSize: { width: 1, height: 1 },
+			fetchWindowIcons: false,
+		});
+		const captureableScreen = sources.find(
+			(candidate) =>
+				candidate.id?.startsWith("screen:") &&
+				candidate.id !== LINUX_PORTAL_SOURCE.id &&
+				!candidate.id.startsWith("screen:fallback:"),
+		);
+		if (captureableScreen) {
+			return captureableScreen;
+		}
+	} catch (error) {
+		console.warn("Failed to resolve a default Linux screen source:", error);
+	}
+
+	return LINUX_PORTAL_SOURCE;
+}
+
 type DesktopCaptureMediaDevices = {
 	getUserMedia: (constraints: unknown) => Promise<MediaStream>;
 	getDisplayMedia: (constraints: unknown) => Promise<MediaStream>;
@@ -1379,7 +1407,7 @@ export function useScreenRecorder(): UseScreenRecorderReturn {
 			hideEditorOverlayCursorByDefault.current = false;
 			const existingSource = await window.electronAPI.getSelectedSource();
 			const selectedSource =
-				existingSource ?? (platform === "linux" ? LINUX_PORTAL_SOURCE : null);
+				existingSource ?? (platform === "linux" ? await resolveDefaultLinuxSource() : null);
 			if (!selectedSource) {
 				alert("Please select a source to record");
 				return;