Add option to capture the focused monitor

include/CursorTrackerX11.hpp

@@ -0,0 +1,20 @@
+#pragma once
+
+#include "CursorTracker.hpp"
+
+typedef struct _XDisplay Display;
+
+namespace gsr {
+    class CursorTrackerX11 : public CursorTracker {
+    public:
+        CursorTrackerX11(Display *dpy);
+        CursorTrackerX11(const CursorTrackerX11&) = delete;
+        CursorTrackerX11& operator=(const CursorTrackerX11&) = delete;
+        ~CursorTrackerX11() = default;
+
+        void update() override {}
+        std::optional<CursorInfo> get_latest_cursor_info() override;
+    private:
+        Display *dpy = nullptr;
+    };
+}