5.1.11 Selection

Select Graphicals

This example defines a gesture that allows the user to set the selection of a graphical device to a specified graphical by left-clicking the graphical. With a SHIFT-left-click, the graphical is either removed from or added to the selection.

:- pce_global(@selection_gesture,
           new(handler_group(
             click_gesture(left, '', single,
                         message(@event?receiver?device,
                              selection, @event?receiver)),
             click_gesture(left, s, single,
                         message(@event?receiver,
                              toggle_selected))))).

select_demo :-
        new(P, picture('Select Demo')),
        send(P, display,
                 new(Box, box(100, 100))),
        send(P, display,
                 new(Bitmap, bitmap('pce.bm')), point(150,50)),

        send_list([Box, Bitmap], recogniser,
                          @selection_gesture),
        send(P, open).

%	Start the demo

:- select_demo.

See also

graphical->toggle_selected