Tk::Derived - Base class for widgets derived from others
package Tk::MyNewWidget; use Tk::widgets qw/ BaseWidget, list of Tk widgets /; use base qw/ Tk::Derived Tk::BaseWidget /; Construct Tk::Widget MyNewWidget; sub ClassInit { my( $class, $mw ) = @_; #... e.g., class bindings here ... $class->SUPER::ClassInit( $mw ); } 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 }
Tk::Derived is used with Perl's multiple inheritance to override some methods normally inherited from Tk::Widget.
Tk::Derived should precede any Tk widgets in the class's base class definition.
Tk::Derived'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 derived class should normally override the Populate
method provided by Tk::Derived and call ConfigSpecs to
declare configure options.
The public methods provided by Tk::Derived are as follows:
Tk::ConfigSpecs Tk::mega Tk::composite