1 /* 2 * Copyright 2018 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef MODULES_DESKTOP_CAPTURE_LINUX_X11_SCREEN_CAPTURER_X11_H_ 12 #define MODULES_DESKTOP_CAPTURE_LINUX_X11_SCREEN_CAPTURER_X11_H_ 13 14 #include <X11/X.h> 15 #include <X11/Xlib.h> 16 #include <X11/extensions/Xdamage.h> 17 #include <X11/extensions/Xfixes.h> 18 #include <X11/extensions/Xrandr.h> 19 20 #include <memory> 21 22 #include "modules/desktop_capture/desktop_capture_options.h" 23 #include "modules/desktop_capture/desktop_capturer.h" 24 #include "modules/desktop_capture/desktop_frame.h" 25 #include "modules/desktop_capture/desktop_region.h" 26 #include "modules/desktop_capture/linux/x11/shared_x_display.h" 27 #include "modules/desktop_capture/linux/x11/x_atom_cache.h" 28 #include "modules/desktop_capture/linux/x11/x_server_pixel_buffer.h" 29 #include "modules/desktop_capture/screen_capture_frame_queue.h" 30 #include "modules/desktop_capture/screen_capturer_helper.h" 31 #include "modules/desktop_capture/shared_desktop_frame.h" 32 33 namespace webrtc { 34 35 // A class to perform video frame capturing for Linux on X11. 36 // 37 // If XDamage is used, this class sets DesktopFrame::updated_region() according 38 // to the areas reported by XDamage. Otherwise this class does not detect 39 // DesktopFrame::updated_region(), the field is always set to the entire frame 40 // rectangle. ScreenCapturerDifferWrapper should be used if that functionality 41 // is necessary. 42 class ScreenCapturerX11 : public DesktopCapturer, 43 public SharedXDisplay::XEventHandler { 44 public: 45 ScreenCapturerX11(); 46 ~ScreenCapturerX11() override; 47 48 ScreenCapturerX11(const ScreenCapturerX11&) = delete; 49 ScreenCapturerX11& operator=(const ScreenCapturerX11&) = delete; 50 51 static std::unique_ptr<DesktopCapturer> CreateRawScreenCapturer( 52 const DesktopCaptureOptions& options); 53 54 // TODO(ajwong): Do we really want this to be synchronous? 55 bool Init(const DesktopCaptureOptions& options); 56 57 // DesktopCapturer interface. 58 void Start(Callback* delegate) override; 59 void CaptureFrame() override; 60 bool GetSourceList(SourceList* sources) override; 61 bool SelectSource(SourceId id) override; 62 63 private: display()64 Display* display() { return options_.x_display()->display(); } 65 66 // SharedXDisplay::XEventHandler interface. 67 bool HandleXEvent(const XEvent& event) override; 68 69 void InitXDamage(); 70 void InitXrandr(); 71 void UpdateMonitors(); 72 73 // Capture screen pixels to the current buffer in the queue. In the DAMAGE 74 // case, the ScreenCapturerHelper already holds the list of invalid rectangles 75 // from HandleXEvent(). In the non-DAMAGE case, this captures the 76 // whole screen, then calculates some invalid rectangles that include any 77 // differences between this and the previous capture. 78 std::unique_ptr<DesktopFrame> CaptureScreen(); 79 80 // Called when the screen configuration is changed. 81 void ScreenConfigurationChanged(); 82 83 // Synchronize the current buffer with `last_buffer_`, by copying pixels from 84 // the area of `last_invalid_rects`. 85 // Note this only works on the assumption that kNumBuffers == 2, as 86 // `last_invalid_rects` holds the differences from the previous buffer and 87 // the one prior to that (which will then be the current buffer). 88 void SynchronizeFrame(); 89 90 void DeinitXlib(); 91 92 DesktopCaptureOptions options_; 93 94 Callback* callback_ = nullptr; 95 96 // X11 graphics context. 97 GC gc_ = nullptr; 98 Window root_window_ = BadValue; 99 100 // XRandR 1.5 monitors. 101 bool use_randr_ = false; 102 int randr_event_base_ = 0; 103 XRRMonitorInfo* monitors_ = nullptr; 104 int num_monitors_ = 0; 105 DesktopRect selected_monitor_rect_; 106 // selected_monitor_name_ will be changed to kFullDesktopScreenId 107 // by a call to SelectSource() at the end of Init() because 108 // selected_monitor_rect_ should be updated as well. 109 // Setting it to kFullDesktopScreenId here might be misleading. 110 Atom selected_monitor_name_ = 0; 111 typedef XRRMonitorInfo* (*get_monitors_func)(Display*, Window, Bool, int*); 112 typedef void (*free_monitors_func)(XRRMonitorInfo*); 113 get_monitors_func get_monitors_ = nullptr; 114 free_monitors_func free_monitors_ = nullptr; 115 116 // XFixes. 117 bool has_xfixes_ = false; 118 int xfixes_event_base_ = -1; 119 int xfixes_error_base_ = -1; 120 121 // XDamage information. 122 bool use_damage_ = false; 123 Damage damage_handle_ = 0; 124 int damage_event_base_ = -1; 125 int damage_error_base_ = -1; 126 XserverRegion damage_region_ = 0; 127 128 // Access to the X Server's pixel buffer. 129 XServerPixelBuffer x_server_pixel_buffer_; 130 131 // A thread-safe list of invalid rectangles, and the size of the most 132 // recently captured screen. 133 ScreenCapturerHelper helper_; 134 135 // Queue of the frames buffers. 136 ScreenCaptureFrameQueue<SharedDesktopFrame> queue_; 137 138 // Invalid region from the previous capture. This is used to synchronize the 139 // current with the last buffer used. 140 DesktopRegion last_invalid_region_; 141 142 std::unique_ptr<XAtomCache> atom_cache_; 143 }; 144 145 } // namespace webrtc 146 147 #endif // MODULES_DESKTOP_CAPTURE_LINUX_X11_SCREEN_CAPTURER_X11_H_ 148