How to snap a window to the screen edge
WinAMP has this very useful feature. If you drag it to the edge of the screen it will automatically position itself. Sometimes you want to make room on the screen but you don't want to minimize your program and again you want to see it in full. The only way is the put it in a corner and set it exactly to the screen border. Well, this can be quite a challenge :-)
But there's no need to panic. All we have to do is intercept when the window is being moved and adjust it as needed.
This code adjusts the window within 30 pixels.
type Form1 = class(TForm) ... procedure WMExitSizeMove(var Msg: TMessage); message WM_EXITSIZEMOVE; ... end; procedure TForm1.WMExitSizeMove(var Msg: TMessage); var Pabd: APPBARDATA; iScreenWidth, iScreenHeight: Integer; ScreenRect, TaskBarRect: TRect; begin if Msg.Msg = WM_EXITSIZEMOVE then begin Pabd.cbSize := SizeOf(APPBARDATA); SHAppBarMessage(ABM_GETTASKBARPOS, Pabd); iScreenWidth := GetSystemMetrics(SM_CXSCREEN); iScreenHeight := GetSystemMetrics(SM_CYSCREEN); ScreenRect := Rect(0, 0, iScreenWidth, iScreenHeight); TaskBarRect := Pabd.rc; if (TaskBarRect.Left = -2) and (TaskBarRect.Bottom = iScreenHeight + 2) and (TaskBarRect.Right = iScreenWidth + 2) then ScreenRect.Bottom := TaskBarRect.Top else if (TaskBarRect.Top = -2) and (TaskBarRect.Left = -2) and (TaskBarRect.Right = iScreenWidth + 2) then ScreenRect.Top := TaskBarRect.Bottom else if (TaskBarRect.Left = -2) and (TaskBarRect.Top = -2) and (TaskBarRect.Bottom = iScreenHeight + 2) then ScreenRect.Left := TaskBarRect.Right else if (TaskBarRect.Right = iScreenWidth + 2) and (TaskBarRect.Top = -2) and (TaskBarRect.Bottom = iScreenHeight + 2) then ScreenRect.Right := TaskBarRect.Left; if Left < ScreenRect.Left + 30 then Left := ScreenRect.Left; if Top < ScreenRect.Top + 30 then Top := ScreenRect.Top; if Left + Width > ScreenRect.Right - 30 then Left := ScreenRect.Right - Width; if Top + Height > ScreenRect.Bottom - 30 then Top := ScreenRect.Bottom - Height; end; Msg.Result := 1; end;
Thanks to Thomas Jones for fixing a bug in the code that calculates which side of the screen the window should snap to.