Use factory method to create screen capturer

src/screen_capturer/linux/screen_capturer_x11.h

@@ -0,0 +1,80 @@
+#ifndef _SCREEN_CAPTURER_X11_H_
+#define _SCREEN_CAPTURER_X11_H_
+
+#include <atomic>
+#include <functional>
+#include <string>
+#include <thread>
+
+#include "screen_capturer.h"
+#ifdef __cplusplus
+extern "C" {
+#endif
+#include <libavcodec/avcodec.h>
+#include <libavdevice/avdevice.h>
+#include <libavformat/avformat.h>
+#include <libavutil/imgutils.h>
+#include <libswscale/swscale.h>
+#ifdef __cplusplus
+};
+#endif
+
+class ScreenCapturerX11 : public ScreenCapturer {
+ public:
+  ScreenCapturerX11();
+  ~ScreenCapturerX11();
+
+ public:
+  virtual int Init(const RECORD_DESKTOP_RECT &rect, const int fps,
+                   cb_desktop_data cb);
+
+  virtual int Destroy();
+
+  virtual int Start();
+
+  int Pause();
+  int Resume();
+  int Stop();
+
+  void OnFrame();
+
+ protected:
+  void CleanUp();
+
+ private:
+  std::atomic_bool _running;
+  std::atomic_bool _paused;
+  std::atomic_bool _inited;
+
+  std::thread _thread;
+
+  std::string _device_name;
+
+  RECORD_DESKTOP_RECT _rect;
+
+  int _fps;
+
+  cb_desktop_data _on_data;
+
+ private:
+  int i_ = 0;
+  int videoindex_ = 0;
+  int got_picture_ = 0;
+  int fps_ = 0;
+  // ffmpeg
+  AVFormatContext *pFormatCtx_ = nullptr;
+  AVCodecContext *pCodecCtx_ = nullptr;
+  AVCodec *pCodec_ = nullptr;
+  AVCodecParameters *pCodecParam_ = nullptr;
+  AVDictionary *options_ = nullptr;
+  AVInputFormat *ifmt_ = nullptr;
+  AVFrame *pFrame_ = nullptr;
+  AVFrame *pFrameNv12_ = nullptr;
+  AVPacket *packet_ = nullptr;
+  struct SwsContext *img_convert_ctx_ = nullptr;
+
+  // thread
+  std::unique_ptr<std::thread> capture_thread_ = nullptr;
+};
+
+#endif