// The most common use of the cursor is to show a delay
// using the hour glass:

Screen.Cursor := crHourGlass;
TRY
  <lengthy operations>
FINALLY
  Screen.Cursor := crDefault
END;


// Instead of TRY..FINALLY when using the mouse, set the cursor on MouseDown and
// reset it on MouseUp.

procedure TFormLineStretch.ImageAreaMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  Screen.Cursor := crCross;
  RestrictCursorToDrawingArea(ImageArea)  // see below
end;


procedure TFormLineStretch.ImageAreaMouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  Screen.Cursor := crDefault;
  RemoveCursorRestrictions                // see below
end;



// Restrict cursor to given rectangular area of a TImage.  This is convenient
// while drawing on a canvas since leaving the drawing area can cause
// problems with some algorithms (e.g., dragging something off the screen
// to an area where the user will never find it!)

PROCEDURE RestrictCursorToDrawingArea (CONST Image:  TImage);
  VAR
    CursorClipArea:  TRect;
BEGIN
  CursorClipArea := Bounds(Image.ClientOrigin.X,
                           Image.ClientOrigin.Y,
                           Image.Width, Image.Height);
  Windows.ClipCursor(@CursorClipArea)
END {RestrictCursorToDrawingArea};


PROCEDURE RemoveCursorRestrictions;
BEGIN
  Windows.ClipCursor(NIL)
END {RemoveCursorRestrictions};