func (s *sysData) setWindowSize(width int, height int) error { var rect _RECT ret := make(chan uiret) defer close(ret) // we need the size to cover only the client rect // unfortunately, Windows only provides general client->window rect conversion functions (AdjustWindowRect()/AdjustWindowRectEx()), not any that can pull from an existing window // so as long as we don't change the window styles during execution we're good // now we tell it to adjust (0,0)..(width,height); this will give us the approrpiate rect to get the proper width/height from // then we call SetWindowPos() to set the size without moving the window // see also: http://blogs.msdn.com/b/oldnewthing/archive/2003/09/11/54885.aspx // TODO do the WM_NCCALCSIZE stuff on that post when adding menus rect.Right = int32(width) rect.Bottom = int32(height) uitask <- &uimsg{ call: _adjustWindowRectEx, p: []uintptr{ uintptr(unsafe.Pointer(&rect)), uintptr(classTypes[c_window].style), uintptr(_FALSE), // TODO change this when adding menus uintptr(classTypes[c_window].xstyle), }, ret: ret, } r := <-ret if r.ret == 0 { // failure panic(fmt.Errorf("error computing window rect from client rect for resize: %v", r.err)) } uitask <- &uimsg{ call: _setWindowPos, p: []uintptr{ uintptr(s.hwnd), uintptr(_NULL), // not changing the Z-order uintptr(0), uintptr(0), uintptr(rect.Right - rect.Left), uintptr(rect.Bottom - rect.Top), uintptr(_SWP_NOMOVE | _SWP_NOZORDER), }, ret: ret, } r = <-ret if r.ret == 0 { // failure return fmt.Errorf("error actually resizing window: %v", r.err) } return nil }