=head1 NAME

C<Tickit::Widget::Scroller::Item> - interface for renderable scroller items

=head1 DESCRIPTION

Items added to a C<Tickit::Widget::Scroller> must adhere to the interface
documented here.

=head1 METHODS

=head2 $height = $item->height_for_width( $width )

Returns the number of screen lines the item would occupy if rendered to the
given width. 

=head2 $item->render( $rb, %args )

Renders the item to the given L<Tickit::RenderBuffer>. C<%args> will contain
the following keys:

=over 8

=item firstline => INT

=item lastline => INT

The (inclusive) bounds of the line numbers to render. If these do not cover
the entire height of the item, then they imply that clipping will occur; the
item need draw only the lines indicated.

These are passed for informational purposes. Item implementations are free to
ignore this if they wish, as clipping will be performed by the RenderBuffer.

=item top => INT

The line of C<$rc> to consider as the top of the item. This is passed for
legacy purposes and will always be zero. Item implementations are free to
ignore this value, as it will now be performed using the C<translate> facility
of the RenderBuffer.

=item width => INT

=item height => INT

The width in columns and the height in lines to render the item. This will
correspond to the most recent call to C<height_for_width>, and is passed in
for consistency and convenience of the item's render method. This is given as
the full dimensions of the item, which may be larger than the subset of lines
requested by the C<firstline> and C<lastline> parameters.

=back

=head1 AUTHOR

Paul Evans <leonerd@leonerd.org.uk>

=cut