Added check in linux for window change detection

Author: smasherprog

Example/Screen_Capture_Example.cpp

@@ -105,18 +105,20 @@ void createwindowgrabber()
         auto s = std::to_string(r) + std::string("WINDIF_") + std::string(".jpg");
         auto size = RowStride(img) * Height(img);
 
-   /*     auto imgbuffer(std::make_unique<unsigned char[]>(size));
+       /* auto imgbuffer(std::make_unique<unsigned char[]>(size));
         ExtractAndConvertToRGBA(img, imgbuffer.get(), size);
-        tje_encode_to_file(s.c_str(), Width(img), Height(img), 4, (const unsigned char*)imgbuffer.get());*/
+        tje_encode_to_file(s.c_str(), Width(img), Height(img), 4, (const unsigned char*)imgbuffer.get());
+        */
     })->onNewFrame([&](const SL::Screen_Capture::Image& img, const SL::Screen_Capture::Window& window) {
 
         auto r = realcounter.fetch_add(1);
         auto s = std::to_string(r) + std::string("WINNEW_") + std::string(".jpg");
-
-        auto size = RowStride(img) * Height(img);/*
-        auto imgbuffer(std::make_unique<unsigned char[]>(size));
+        auto size = RowStride(img) * Height(img);
+        
+       /* auto imgbuffer(std::make_unique<unsigned char[]>(size));
         ExtractAndConvertToRGBA(img, imgbuffer.get(), size);
-        tje_encode_to_file(s.c_str(), Width(img), Height(img), 4, (const unsigned char*)imgbuffer.get());*/
+        tje_encode_to_file(s.c_str(), Width(img), Height(img), 4, (const unsigned char*)imgbuffer.get());
+        */
         if (std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::high_resolution_clock::now() - onNewFramestart).count() >= 1000) {
             std::cout << "onNewFrame fps" << onNewFramecounter << std::endl;
             onNewFramecounter = 0;

src/linux/X11FrameProcessor.cpp

@@ -123,7 +123,13 @@ namespace Screen_Capture
         ret.left = ret.top = 0;
         ret.right = selectedwindow.Size.x;
         ret.bottom = selectedwindow.Size.y;
-        
+        XWindowAttributes wndattr;
+        if(XGetWindowAttributes(SelectedDisplay, SelectedWindow, &wndattr) ==0){
+            return DUPL_RETURN::DUPL_RETURN_ERROR_EXPECTED;//window might not be valid any more
+        }
+        if(wndattr.width != ret.right || wndattr.height != ret.bottom){
+            return DUPL_RETURN::DUPL_RETURN_ERROR_EXPECTED;//window size changed. This will rebuild everything
+        }
         if(!XShmGetImage(SelectedDisplay,
                          selectedwindow.Handle,
                          Image,