---
name: "Tk::Derived"
section: "3pm"
platform: "linux"
package: "perl-tk"
version: "804.036-9"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/Tk::Derived"
---

# Tk::Derived(3pm)

Base class for widgets derived from others

## NAME

Tk::Derived - Base class for widgets derived from others

## SYNOPSIS

```
    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
   }
```

## DESCRIPTION

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:

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

  ## SEE ALSO

Tk::ConfigSpecs Tk::mega Tk::composite