NAME

Tk::Bounded - Base class for widgets derived and bound binded from others

SYNOPSIS

    package Tk::MyNewWidget;

    use Tk::widgets qw/BaseWidget, list of Tk widgets/;
    use base qw/Tk::Bounded Tk::BaseWidget/;

    Construct Tk::Widget 'MyNewWidget';

    sub ClassInit {
        my( $class, $mw ) = @_;
        #... e.g., class bindings here ...
        $class->SUPER::ClassInit( $mw );

        $mw -> bound( $class, '<Left>', [ qw/keybounds 0/ ], 
                [ 'testbEv', bEv('m'), bEv('t'), bEv('s'), bEv('c') ] );
    }

    sub Populate {
        my( $self, $args ) = @_;

        my $flag = delete $args->{-flag};
        if( defined $flag ) {
            # handle -flag => xxx which can only be done at create
            # time the delete above ensures that new() does not try
            # and do  $self->configure( -flag => xxx );
        }

        $self->SUPER::Populate( $args );

        $self = $self->Component( ... );

        $self->Delegates( ... );

        $self->ConfigSpecs(
            '-cursor'    => [ SELF, 'cursor', 'Cursor',   undef ],
            '-something' => [ METHOD, dbName,  dbClass, default ],
            '-text'      => [ $label, dbName,  dbClass, default ],
            '-heading'   => [ {-text => $head},
                                heading, Heading,  'My Heading' ],
       );
   }

   sub something {
       my( $self, $value) = @_;
       if ( @_ > 1 ) {
          # set it
       }
       return # current value
   }

   sub keybounds {
        my( $self, $limit ) = @_;

        return $self -> index( 'insert' ) == $self -> index( $limit ) ?
                nP : Np;
   }    

   sub testbEv {
        my( $self, $m, $t, $s, $c ) = @_;
        print "$m, $t, $s, $c\n";
        my $bev = $self -> bXEvent;
        $m = $bev -> m;
        print "$m\n";
        $bev = $Tk::bevent;
        $m = $bev -> m;
        print "$m\n";

        my $w = $Tk::bwidget;
        print "$w\n";
  }

DESCRIPTION

Tk::Bounded is used with Perl's multiple inheritance to override some methods normally inherited from Tk::Derived and Tk::Widget. It also specifies level 1 bound tags for caller class.

Tk::Bounded should precede any Tk widgets in the class's base class definition.

Tk::Bounded's main purpose is to apply wrappers to configure and cget methods of widgets to allow the derived widget to add to or modify behaviour of the configure options supported by the base widget.

The bounded class should normally override the Populate method provided by Tk::Bounded and call ConfigSpecs to declare configure options.

The public methods provided by Tk::Bounded are as follows:

->ConfigSpecs(-key => [kind, name, Class, default], ...)

SEE ALSO

Tk::Derived Tk::ConfigSpecs Tk::mega Tk::composite Tk::bound Tk::boundtags