/*  Part of XPCE

    This example code is in the public domain
*/

:- discontiguous
    send_event_text_box/2.

:- pce_begin_class(text_box, device, "Box with centered text").

resource(size,          size,   '100x50',               "Default size").
resource(label_font,    font,   '@helvetica_bold_12',   "Font for text").

initialise(TB, Label:[name]) :->
    "Create a box with centered editable text"::
    send(TB, send_super, initialise),
    get(TB, resource_value, size, size(W, H)),
    get(TB, resource_value, label_font, Font),
    send(TB, display, box(W, H)),
    send(TB, display, text(Label, center, Font)),
    send(TB, recenter).


recenter(TB) :->
    "Center text in box"::
    get(TB, member, box, Box),
    get(TB, member, text, Text),
    send(Text, center, Box?center).


geometry(TB, X:[int], Y:[int], W:[int], H:[int]) :->
    "Handle geometry-changes"::
    get(TB, member, box, Box),
    send(Box, set, 0, 0, W, H),
    send(TB, recenter),
    send(TB, send_super, geometry, X, Y).


fill_pattern(TB, Pattern:image*) :->
    "Specify fill-pattern of the box"::
    get(TB, member, box, Box),
    send(Box, fill_pattern, Pattern).
fill_pattern(TB, Pattern:image*) :<-
    "Read fill-pattern of the box"::
    get(TB, member, box, Box),
    get(Box, fill_pattern, Pattern).


string(TB, String:char_array) :->
    "Specify string of the text"::
    get(TB, member, text, Text),
    send(Text, string, String).
string(TB, String:char_array) :<-
    "Read string of the text"::
    get(TB, member, text, Text),
    get(Text, string, String).

:- pce_end_class.


                 /*******************************
                 *         GRAPH EDITOR         *
                 *******************************/

:- use_module(library(prompt)).

make_graph_editor(E) :-
    new(E, picture('Graph Editor')),
    send(E, popup, new(P, popup(options))),
    send_list(P, append,
              [ menu_item(add_new_box,
                          message(@prolog, add_new_box,
                                  E, E?focus_event?position)),
                menu_item(clear,
                          and(message(@display, confirm,
                                      'Clear entire drawing?'),
                              message(E, clear)))
              ]),
    send(E, open).


add_new_box(E, Pos) :-
    prompt('Name of box',
           [ name:name = Name
           ]),
    send(E, display, text_box(Name), Pos).


                 /*******************************
                 *            EDITING           *
                 *******************************/

:- pce_extend_class(text_box).

:- pce_global(@move_resize_recogniser,
              make_move_resize_recogniser).

make_move_resize_recogniser(R) :-
    new(R, handler_group(new(resize_gesture),
                         new(move_gesture),
                         popup_gesture(new(P, popup(options))))),
    TB = @arg1,
    send_list(P, append,
              [ menu_item(rename,
                          message(TB, rename),
                          end_group := @on),
                menu_item(delete,
                          message(TB, free))
              ]).


event(TB, Ev:event) :->
    (   send(TB, send_super, event, Ev)
    ->  true
    ;   send(@move_resize_recogniser, event, Ev)
    ).


rename(TB) :->
    "Prompt for new name"::
    prompt('Rename text box',
           [ name:name = Name/TB?string
           ]),
    send(TB, string, Name).

:- pce_end_class.


                 /*******************************
                 *           LINKING            *
                 *******************************/


:- pce_extend_class(text_box).

handle(0, h/2,  link,   west).
handle(w, h/2,  link,   east).
handle(w/2, 0,  link,   north).
handle(w/2, h,  link,   sourth).

:- pce_global(@link_recogniser, new(connect_gesture)).

event(TB, Ev:event) :->
    (   send(TB, send_super, event, Ev)
    ;   send(@move_resize_recogniser, event, Ev)
    ;   send(@link_recogniser, event, Ev)
    ).

:- pce_end_class.


                 /*******************************
                 *        DUMP TO PROLOG        *
                 *******************************/

assert_graph(E, Predicate) :-
    functor(Term, Predicate, 2),
    retractall(Term),
    send(E?graphicals, for_all,
         if(message(@arg1, instance_of, connection),
            send(@prolog, assert_link,
                 Predicate,
                 @arg1?from?string?value,
                 @arg2?from?string?value))).

assert_link(Predicate, From, To) :-
    Term =.. [Predicate, From, To],
    assert(Term).