GetWindowRect too small on Windows 7

Question

The actual problem I\'m trying to solve is, I want to automatically find out the size of the margins around windows. If you can find a better way, please by all means answer

Answer 1

GetWindowRect on Windows 7 appears to not include the right and bottom window frame edges (at least with the Aero theme afaik), if the window was created without the WS_SIZEBOX style (i.e, you want a non-sizable window).

The problem is, WS_SIZEBOX is the same as WS_THICKFRAME, and on Aero, windows have the thickframe whether they can be resized or not. But the GetWindowRect function thinks that a non-resizable window is thinner.

The fix? You can create the window with WS_SIZEBOX, call GetWindowRect, then use SetWindowLongPtr(GWL_STYLE, ...) to turn off WS_SIZEBOX, but this will create an ugly white border inside the client area.

Instead, leave WS_SIZEBOX enabled, and simply return the same value for ptMinTrackSize and ptMaxTraceSize in the MINMAXINFO structure when responding to the WM_GETMINMAXINFO message. This will keep the window from being resizable and GetWindowRect will return proper data. The only downside is that the mouse cursor will still change to a resizing cursor when the mouse pointer goes over the window frame, but it's the lesser of the evils so far.