On Windows 7 and older versions of Windows, calling GetCurrentObject(hdc, OBJ_BITMAP) for a display device context will return a valid handle. However, this handle will fail for GetObject(). On newer versions of Windows, GetCurrentObject(hdc, OBJ_BITMAP) for display device contexts returns a bitmap of virtual screen size and its size changes after display mode changes. This behavior is tested in the _check_display_dc() function in user32/tests/monitor.c.
The screen shot function of WeChat depends on GetObject() to either return failure or a valid size for the bitmap from display device contexts. Since Wine currently report Windows 7 as default and to save memory, the Windows 7 behavior is implemented.
Signed-off-by: Zhiyi Zhang zzhang@codeweavers.com