Fixed partially out of screen window capture in unix

webrtc/modules/desktop_capture/x11/x_server_pixel_buffer.cc

Index: webrtc/modules/desktop_capture/x11/x_server_pixel_buffer.cc
diff --git a/webrtc/modules/desktop_capture/x11/x_server_pixel_buffer.cc b/webrtc/modules/desktop_capture/x11/x_server_pixel_buffer.cc
index bcfcb7e02792a86c940852aab545d1783f7b329d..0d1027962d6bfbd1d173369d9038ac7b8176c7a8 100644
--- a/webrtc/modules/desktop_capture/x11/x_server_pixel_buffer.cc
+++ b/webrtc/modules/desktop_capture/x11/x_server_pixel_buffer.cc
@@ -60,10 +60,13 @@ bool IsXImageRGBFormat(XImage* image) {
 namespace webrtc {
 
 XServerPixelBuffer::XServerPixelBuffer()
-    : display_(NULL), window_(0),
+    : display_(NULL),
+      window_(0),
       x_image_(NULL),
-      shm_segment_info_(NULL), shm_pixmap_(0), shm_gc_(NULL) {
-}
+      shm_segment_info_(NULL),
+      shm_pixmap_(0),
+      shm_gc_(NULL),
+      is_xshmgetimage_success_(false) {}

[Sergey Ulanov, 2016/06/09 22:04:21]

Move all initializers to the class definition in the .h please.

[GeorgeZ, 2016/06/10 20:10:37]

Done.

 
 XServerPixelBuffer::~XServerPixelBuffer() {
   Release();
@@ -229,7 +232,10 @@ void XServerPixelBuffer::Synchronize() {
   if (shm_segment_info_ && !shm_pixmap_) {
     // XShmGetImage can fail if the display is being reconfigured.
     XErrorTrap error_trap(display_);
-    XShmGetImage(display_, window_, x_image_, 0, 0, AllPlanes);
+    if (XShmGetImage(display_, window_, x_image_, 0, 0, AllPlanes))

[Sergey Ulanov, 2016/06/09 22:04:21]

 is_xshmgetimage_success_  = XShmGetImage(...);

[Sergey Ulanov, 2016/06/09 22:04:21]

Add a comment that the call may also fail if the window is partially visible.

[GeorgeZ, 2016/06/10 20:10:37]

Done.

[GeorgeZ, 2016/06/10 20:10:37]

Done.

+      is_xshmgetimage_success_ = true;
+    else
+      is_xshmgetimage_success_ = false;
   }
 }
 
@@ -240,7 +246,7 @@ void XServerPixelBuffer::CaptureRect(const DesktopRect& rect,
 
   uint8_t* data;
 
-  if (shm_segment_info_) {
+  if (shm_segment_info_ && is_xshmgetimage_success_) {

[Sergey Ulanov, 2016/06/09 22:04:21]

This code won't work correctly when using shm_pixmap_ because when shm_pixmap_
is set then Synchronize won't set is_xshmgetimage_success_.
So I think you want to change this to 
 (shm_segment_info_ && (shm_pixmal || is_xshmgetimage_success_))

[GeorgeZ, 2016/06/10 20:10:37]

Done. Good to know.

     if (shm_pixmap_) {
       XCopyArea(display_, window_, shm_pixmap_, shm_gc_,
                 rect.left(), rect.top(), rect.width(), rect.height(),