[gtk+] win32: fix pasting screenshots taken with PrintScreen or Alt+PrintScreen

[Alexander Larsson <alexl src gnome org>]

commit 68d28aad97894c5b1fa6875b2cb3a9baa0c8284f
Author: Dieter Verfaillie <dieterv optionexplicit be>
Date:   Fri Nov 4 09:44:35 2011 +0100

    win32: fix pasting screenshots taken with PrintScreen or Alt+PrintScreen
    
    These are found on the clipboard in the biCompression == BI_BITFIELDS &&
    biBitCount >= 16 format. In this case the BITMAPINFOHEADER is followed
    by three DWORD specifying the masks of the red green and blue components,
    but bfOffBits was not being adjusted accordingly.
    
    Based on Massimo's comment on bug 631384 and verified on
    http://msdn.microsoft.com/en-us/library/dd183386%28v=VS.85%29.aspx
    
    https://bugzilla.gnome.org/show_bug.cgi?id=631384

 gdk/win32/gdkselection-win32.c |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)
---
diff --git a/gdk/win32/gdkselection-win32.c b/gdk/win32/gdkselection-win32.c
index f4e600b..c734b0b 100644
--- a/gdk/win32/gdkselection-win32.c
+++ b/gdk/win32/gdkselection-win32.c
@@ -721,6 +721,17 @@ _gdk_win32_display_convert_selection (GdkDisplay *display,
 				       bi->biSize +
 				       bi->biClrUsed * sizeof (RGBQUAD));
 
+		      if (bi->biCompression == BI_BITFIELDS && bi->biBitCount >= 16)
+		        {
+                          /* Screenshots taken with PrintScreen or
+                           * Alt + PrintScreen are found on the clipboard in
+                           * this format. In this case the BITMAPINFOHEADER is
+                           * followed by three DWORD specifying the masks of the
+                           * red green and blue components, so adjust the offset
+                           * accordingly. */
+		          bf->bfOffBits += (3 * sizeof (DWORD));
+		        }
+
 		      memcpy ((char *) data + sizeof (BITMAPFILEHEADER),
 			      bi,
 			      data_length);