[feat] add Linux screen capture fallback support for DRM and Wayland

src/screen_capturer/linux/screen_capturer_linux.h

@@ -0,0 +1,65 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2026-03-22
+ * Copyright (c) 2026 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _SCREEN_CAPTURER_LINUX_H_
+#define _SCREEN_CAPTURER_LINUX_H_
+
+#include <memory>
+#include <mutex>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#include "screen_capturer.h"
+
+namespace crossdesk {
+
+class ScreenCapturerLinux : public ScreenCapturer {
+ public:
+  ScreenCapturerLinux();
+  ~ScreenCapturerLinux();
+
+ public:
+  int Init(const int fps, cb_desktop_data cb) override;
+  int Destroy() override;
+  int Start(bool show_cursor) override;
+  int Stop() override;
+
+  int Pause(int monitor_index) override;
+  int Resume(int monitor_index) override;
+
+  int SwitchTo(int monitor_index) override;
+  int ResetToInitialMonitor() override;
+
+  std::vector<DisplayInfo> GetDisplayInfoList() override;
+
+ private:
+  enum class BackendType { kNone, kX11, kDrm, kWayland };
+
+ private:
+  int InitX11();
+  int InitDrm();
+  int InitWayland();
+  bool TryFallbackToDrm(bool show_cursor);
+  bool TryFallbackToX11(bool show_cursor);
+  bool TryFallbackToWayland(bool show_cursor);
+  void UpdateAliasesFromBackend(ScreenCapturer* backend);
+  std::string MapDisplayName(const char* display_name) const;
+
+ private:
+  std::unique_ptr<ScreenCapturer> impl_;
+  BackendType backend_ = BackendType::kNone;
+  int fps_ = 60;
+  cb_desktop_data callback_;
+  cb_desktop_data callback_orig_;
+  std::vector<DisplayInfo> canonical_displays_;
+  mutable std::mutex alias_mutex_;
+  std::unordered_map<std::string, std::string> label_alias_;
+};
+
+}  // namespace crossdesk
+
+#endif