package MTools::Anim::MOpacity;
#	This program is free software; you can redistribute it and/or
#	modify it under the terms of the GNU LGPL Libray 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 Library General Public License for more details.
#
#	You should have received a copy of the GNU Library General Public License
#	along with this program; if not, write to the Free Software
#	Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA,
#	or refer to http://www.gnu.org/copyleft/lgpl.html
#
##################################################################

# MOpacity permet de realiser une animation sur la transparence d'un objet
# 
# proprietes :
#	* -visible : permet d'activer ou stopper l'animation
#	* from_opacity : valeur initiale de l'opacite au depart de l'animation
#	* to_opacity : valeur de l'opacite a la fin de l'animation
# 	* duration : duree de l'animation
#	* loop : marque le caractere repetitif ou non de l'animation
#	* targets : objet ou tableau d'objets cible de cette animation (de type MGroup ou autre type avec un attribut -alpha.
# Evenements :
#	* ANIMATION_END : Notifie lorque l'annimation se termine
#	* OPACITY_CHANGED : Notifie lorsque la valeur de l'opacite est changee au cours de l'animation
#	* ANIMATION_ABORD : Notifie lorsque l'animation est stoppee avant la fin
# Fonctions : 
#	* start : demarre l'animation
#	* stop: arrete l'animation
#	* isRunning : test si l'animation est en cours

use strict;
use MTools;
use MTools::MObjet;

use Anim;
use Anim::Pacing::Linear;
use Anim::Path::Rectilinear;

use vars qw /@ISA/;

BEGIN 
{
	@ISA = qw /MTools::MObjet/;
}

use Tk;

sub new {
	my ($class, %options) = @_;
	my $self = new MTools::MObjet ();
	bless $self, $class;

	$self -> recordProperty ('-visible', 0);
	$self -> recordProperty ('from_opacity', 0);
	$self -> recordProperty ('to_opacity', 0);
	$self -> recordProperty ('duration', 1);
	$self -> recordProperty ('loop', 0);
	$self -> recordProperty ('targets', undef);
	$self -> recordEvent ('ANIMATION_END');
	$self -> recordEvent ('OPACITY_CHANGED');
	$self -> recordEvent ('ANIMATION_ABORD');
	$self -> plisten ('-visible', sub { 
		my ($src, $key, $val) = @_;
		if ($val == 0)
		{
			$self -> stop ();
		}
		else
		{
			$self -> start ();
		}
	});
	$self -> {__animation} = undef;
	$self -> mconfigure (%options);
	return $self;
}

sub start {
	my ($self) = @_;
	my $pacing = new Anim::Pacing::Linear (-duration => $self -> mget ('duration'));
	$self -> {__opacitydep} = my $opacitydep = $self -> mget ('from_opacity');

	my $animationpath = new Anim::Path::Rectilinear (
		-xdep => 0,
		-ydep => 0,
		-xdest => $self -> mget ('to_opacity') - $opacitydep,
		-ydest => 0,
	);
	$self -> {__opacity} = $opacitydep;
	$self -> {__animation} = my $animation = new Anim (
		-pacing => $pacing,
		-resources => [
			$animationpath,
			-command => sub { $self -> __event (@_)},
			-endcommand => sub {$self -> {__animation} = undef;
					    $self -> notify ('ANIMATION_END');},
		],
		-stopcommand => sub {$self -> {__animation} = undef;
				     $self -> notify ('ANIMATION_ABORD', $self -> {__opacity});},
		-loop => $self -> mget ('loop'),
	);
	$animation -> start ();
}

sub stop {
	my ($self) = @_;
	if (defined $self -> {__animation})
	{
		$self -> {__animation} -> stop ();
	}
}

sub __event {
	my ($self, $opacity) = @_;
	$opacity += $self -> {__opacitydep};
	my @targets = ();
	my $target = $self -> mget ('targets');
	if (ref ($target) eq 'ARRAY')
	{
		@targets = @{$target};
	}
	else
	{
		push (@targets, $target);
	}
	for (my $i = 0; $i < @targets; $i++)
	{
		if (ref($targets [$i]) eq '')
		{
			mconfigure ($targets[$i], '-alpha' => $opacity);
		}
		else
		{
			$targets [$i] -> mconfigure ('-alpha' => $opacity);
		}
	}
	$self -> {__opacity} = $opacity;
	$self -> notify ('OPACITY_CHANGED', $opacity);
}

sub isRunning {
	my ($self) = @_;
	return defined $self -> {__animation};
}

1;