Windows 10 has thin invisible borders on left, right, and bottom, it is used to grip the mouse for resizing. The borders might look like this: 7,0,7,7
(left, top, right, bottom)
When you call SetWindowPos
to put the window at this coordinates:
0, 0, 1280, 1024
The window will pick those exact coordinates, and GetWindowRect
will return the same coordinates. But visually, the window appears to be here:
7, 0, 1273, 1017
You can fool the window and tell it to go here instead:
-7, 0, 1287, 1031
To do that, we get Windows 10 border thickness:
RECT rect, frame;
GetWindowRect(hwnd, &rect);
DwmGetWindowAttribute(hwnd, DWMWA_EXTENDED_FRAME_BOUNDS, &frame, sizeof(RECT));
//rect should be `0, 0, 1280, 1024`
//frame should be `7, 0, 1273, 1017`
RECT border;
border.left = frame.left - rect.left;
border.top = frame.top - rect.top;
border.right = rect.right - frame.right;
border.bottom = rect.bottom - frame.bottom;
//border should be `7, 0, 7, 7`
Then offset the rectangle like so:
rect.left -= border.left;
rect.top -= border.top;
rect.right += border.left + border.right;
rect.bottom += border.top + border.bottom;
//new rect should be `-7, 0, 1287, 1031`
Unless there is a simpler solution!