Delphi/Lazarus: Retrieve Cursor Position relative to Form/Window

With the function GetCursorPos(), you are able to get the cursor position relative to the screen. Here is a way of how to get the position of the cursor relative to a form (window):

var
  P: TPoint;
begin
  GetCursorPos(P);
  P := Form1.ScreenToClient(P);
  Form1.Caption := inttostr(P.X + ' ' + inttostr(P.Y));
end;

First, we are using GetCursorPos() to save the current mouse position to the point P. After that, we convert the screen coordinates to the form coordinates of Form1 by using ScreenToClient(). Finally, we output the converted coordinates as the caption of our window.