/*  $Id$

    Part of XPCE --- The SWI-Prolog GUI toolkit

    Author:        Jan Wielemaker and Anjo Anjewierden
    E-mail:        jan@swi.psy.uva.nl
    WWW:           http://www.swi.psy.uva.nl/projects/xpce/
    Copyright (C): 1985-2002, University of Amsterdam

    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License
    as published by the Free Software Foundation; either version 2
    of the License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

    As a special exception, if you link this library with other files,
    compiled with a Free Software compiler, to produce an executable, this
    library does not by itself cause the resulting executable to be covered
    by the GNU General Public License. This exception does not however
    invalidate any other reasons why the executable file might be covered by
    the GNU General Public License.
*/

:- module(pce_arrow_item, []).
:- use_module(library(pce)).
:- require([ forall/2
	   , send_list/3
	   ]).

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Class arrow_item defines an item for editing   an arrow object. The item
does not edit the specified arrow itself,  but just uses its attributes.
Also, the <-selection returns a `fresh' arrow.

This module can be seen as an  advanced example of using class label_box
for creating compound dialog items.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

:- pce_autoload(colour_item, library(pce_colour_item)).

:- pce_begin_class(arrow_item, label_box,
		   "Extry for viewing/editing an arrow-head").

initialise(AI, Name:[name], Default:[function|arrow], Message:[code]*) :->
	send(AI, send_super, initialise, Name, Message),
	send(AI, display, new(line)),
	send(AI, append, new(Arrow, arrow)),
	send(Arrow, points, 100, 0, 0, 0),
	send(AI, append, new(WI, int_item(wing,   0, @nil, 0, 50))),
	send(AI, append, new(LI, int_item(length, 0, @nil, 0, 50)), right),
	send(AI, append, new(PI, int_item(pen,    0, @nil, 0,  1)), right),
	send(AI, append, new(Style, menu(style, choice, @nil))),
	send(AI, append, new(Fill, menu(fill_pattern, choice, @nil)), right),
	styles(Style),
	fill_patterns(Fill),
	send(AI, append,
	     new(SelCol, button(select_colour,
				message(AI, select_colour))),
	     right),
	send_list([PI, SelCol], alignment, left),
	send_list([Style, Fill], show_label, @off),
	send_list([Style, Fill], auto_label_align, @off),
	send_list([WI, LI, PI, Style, Fill, SelCol], reference, point(0,0)),
	fix_labels(AI),
	(   Default \== @default
	->  send(AI, default, Default)
	;   new(Proto, arrow),
	    copy_attributes(AI, Proto)
	).

fill_pattern(@nil).
fill_pattern(@white_image).
fill_pattern(@black_image).

fill_patterns(Menu) :-
	fill_pattern(Pattern),
	new(I, image(@nil, 30, 16)),
	new(A, arrow(20, 10, closed, Pattern)),
	new(L, line(0, 7, 25, 7)),
	send(A, pen, 1),
	send(L, second_arrow, A),
	send(I, draw_in, L),
	send(Menu, append, menu_item(Pattern, @default, I)),
	fail.
fill_patterns(_).

style(open).
style(closed).

styles(Menu) :-
	style(Style),
	new(I, image(@nil, 30, 16)),
	new(A, arrow(20, 10, Style, @nil)),
	send(A, pen, 1),
	new(L, line(0, 7, 25, 7)),
	send(L, second_arrow, A),
	send(I, draw_in, L),
	send(Menu, append, menu_item(Style, @default, I)),
	fail.
styles(_).

%	->layout_dialog
%
%	Does the normal layout, but afterwards adjusts the arrow and its
%	line, as this doesn't fit in the automatic layout specification.
%	Note that the arrow is not part of the line (see `joint->second_arrow')
%	because changes to the line will not be visualised then.

layout_dialog(AI) :->
	send(AI, send_super, layout_dialog),
	get(AI, member, arrow, Arrow),
	get(AI, member, line, Line),
	get(AI, reference, point(_, RY)),
	send(Arrow, points, 100, RY, 0, RY),
	send(Line, points, 0, RY, 100, RY).

		 /*******************************
		 *	       LABELS		*
		 *******************************/

%	The code below assigns the image labels.  This is easier to addapt
%	and more flexible then direct sending of messages.  Also, fix_label
%	takes care of the case where the image cannot be located.

label(wing,		'16x16/arrow_wing.xpm').
label(length,		'16x16/arrow_length.xpm').
label(select_colour,	'16x16/cpalette2.xpm').
label(pen,		'16x16/pen.xpm').

resource(Name, image, image(File)) :-
	label(Name, File).

fix_labels(AI) :-
	send(AI?graphicals, for_all, message(@prolog, fix_label, @arg1)).

fix_label(Gr) :-
	get(Gr, name, Name),
	label(Name, _),
	new(I, image(resource(Name))),
	send(Gr, label, I).
fix_label(_).

:- pce_group(selection).

selection(AI, Selection:arrow) :->
	"Set the selection"::
	copy_attributes(AI, Selection),
	send(AI, modified, @off).
selection(AI, Selection:arrow) :<-
	"Get the selection"::
	new(Selection, arrow),
	get_attributes(AI, Selection),
	send(AI, modified, @off).

clear(_AI) :-> true.

get_attributes(AI, Into) :-
	get(AI, member, arrow, Arrow),
	edited_attribute(Attribute),
	get(Arrow, Attribute, Value),
	send(Into, Attribute, Value),
	fail.
get_attributes(_, _).

copy_attributes(AI, Proto) :-
	edited_attribute(Attribute),
	get(Proto, Attribute, Value),
	set_value(AI, Attribute, Value),
	fail.
copy_attributes(_, _).

edited_attribute(wing).
edited_attribute(length).
edited_attribute(pen).
edited_attribute(style).
edited_attribute(fill_pattern).
edited_attribute(colour).

set_value(AI, Attribute, Value) :-
	get(AI, member, arrow, Arrow),
	send(Arrow, Attribute, Value),
	(   get(AI, member, Attribute, Item)
	->  send(Item, selection, Value)
	;   true
	).


:- pce_group(edit).

rule(fill_pattern = @black_image,	pen = 0).
rule(fill_pattern = @black_image,	style = closed).
rule(fill_pattern = @nil,		pen = 1).
rule(fill_pattern = @white_image,	pen = 1).
rule(style        = open,		fill_pattern = @nil).

apply_rules(AI, Sel, Val) :-
	set_value(AI, Sel, Val),
	forall(rule(Sel=Val, Sel2=Val2),
	       apply_rules(AI, Sel2, Val2)).


modified_item(AI, Item:graphical, _Modified:bool) :->
	get(Item, name, Sel),
	get(Item, selection, Val),
	apply_rules(AI, Sel, Val),
	send(AI, modified, @on),
	send(AI?device, modified_item, AI, @on).

select_colour(AI) :->
	"Query a colour"::
	get(AI, member, arrow, Arrow),
	get(Arrow, colour, Old),
	new(D, dialog('Select colour')),
	send(D, transient_for, AI?frame),
	send(D, append, new(CI,	colour_item(colour, Old))),
	send(D, append, button(ok, message(D, return, CI?selection))),
	send(D, append, button(cancel, message(D, return, @nil))),
	get(D, confirm_centered, AI?frame?area?center, Rval),
	(   Rval == @nil
	->  true
	;   send(Arrow, colour, Rval),
	    send(AI, modified, @on),
	    send(AI?device, modified_item, AI, @on)
	),
	send(D, destroy).

:- pce_end_class.

test :-
	new(D, dialog),
	send(D, append, new(_AI, arrow_item)),
	send(D, open).
