Merge pull request #2179 from adishavit:feature-SupportClipboardCopyOnWindows

modules/highgui/doc/user_interface.rst

@@ -83,6 +83,9 @@ If window was created with OpenGL support, ``imshow`` also support :ocv:class:`o
 
 .. note:: This function should be followed by ``waitKey`` function which displays the image for specified milliseconds. Otherwise, it won't display the image. For example, ``waitKey(0)`` will display the window infinitely until any keypress (it is suitable for image display). ``waitKey(25)`` will display a frame for 25 ms, after which display will be automatically closed. (If you put it in a loop to read videos, it will display the video frame-by-frame)
 
+.. note::
+
+    [Windows Backend Only] Pressing Ctrl+C will copy the image to the clipboard.
 
 namedWindow
 ---------------

modules/highgui/src/window_w32.cpp

@@ -1286,6 +1286,10 @@ MainWindowProc( HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam )
 
     switch(uMsg)
     {
+    case WM_COPY:
+        ::WindowProc(hwnd, uMsg, wParam, lParam); // call highgui proc. There may be a better way to do this.
+        break;
+
     case WM_DESTROY:
 
         icvRemoveWindow(window);
@@ -1448,6 +1452,81 @@ static LRESULT CALLBACK HighGUIProc( HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM
     // Process the message
     switch(uMsg)
     {
+    case WM_COPY:
+        {
+            if (!::OpenClipboard(hwnd) )
+                break;
+
+            HDC hDC       = 0;
+            HDC memDC     = 0;
+            HBITMAP memBM = 0;
+
+            // We'll use a do-while(0){} scope as a single-run breakable scope
+            // Upon any error we can jump out of the single-time while scope to clean up the resources.
+            do
+            {
+                if (!::EmptyClipboard())
+                    break;
+
+                if(!window->image)
+                    break;
+
+                // Get window device context
+                if (0 == (hDC = ::GetDC(hwnd)))
+                    break;
+
+                // Create another DC compatible with hDC
+                if (0 == (memDC = ::CreateCompatibleDC( hDC )))
+                    break;
+
+                // Determine the bitmap's dimensions
+                int nchannels = 3;
+                SIZE size = {0,0};
+                icvGetBitmapData( window, &size, &nchannels, 0 );
+
+                // Create bitmap to draw on and it in the new DC
+                if (0 == (memBM = ::CreateCompatibleBitmap ( hDC, size.cx, size.cy)))
+                    break;
+
+                if (!::SelectObject( memDC, memBM ))
+                    break;
+
+                // Begin drawing to DC
+                if (!::SetStretchBltMode(memDC, COLORONCOLOR))
+                    break;
+
+                RGBQUAD table[256];
+                if( 1 == nchannels )
+                {
+                    for(int i = 0; i < 256; ++i)
+                    {
+                        table[i].rgbBlue = (unsigned char)i;
+                        table[i].rgbGreen = (unsigned char)i;
+                        table[i].rgbRed = (unsigned char)i;
+                    }
+                    if (!::SetDIBColorTable(window->dc, 0, 255, table))
+                        break;
+                }
+
+                // The image copied to the clipboard will be in its original size, regardless if the window itself was resized.
+
+                // Render the image to the dc/bitmap (at original size).
+                if (!::BitBlt( memDC, 0, 0, size.cx, size.cy, window->dc, 0, 0, SRCCOPY ))
+                    break;
+
+                // Finally, set bitmap to clipboard
+                ::SetClipboardData(CF_BITMAP, memBM);
+            } while (0,0); // (0,0) instead of (0) to avoid MSVC compiler warning C4127: "conditional expression is constant"
+
+            //////////////////////////////////////////////////////////////////////////
+            // if handle is allocated (i.e. != 0) then clean-up.
+            if (memBM) ::DeleteObject(memBM);
+            if (memDC) ::DeleteDC(memDC);
+            if (hDC)   ::ReleaseDC(hwnd, hDC);
+            ::CloseClipboard();
+            break;
+        }
+
     case WM_WINDOWPOSCHANGING:
         {
             LPWINDOWPOS pos = (LPWINDOWPOS)lParam;
@@ -1798,6 +1877,11 @@ cvWaitKey( int delay )
                         is_processed = 1;
                         return (int)(message.wParam << 16);
                     }
+
+                    // Intercept Ctrl+C for copy to clipboard
+                    if ('C' == message.wParam && (::GetKeyState(VK_CONTROL)>>15))
+                        ::PostMessage(message.hwnd, WM_COPY, 0, 0);
+
                 default:
                     DispatchMessage(&message);
                     is_processed = 1;