}
1;
+
+__END__
+
+=encoding utf-8
+
+=head1 NAME
+
+SL::Layout::Base - Base class for layouts
+
+=head1 SYNOPSIS
+
+ package SL::Layout::MyLayout;
+
+ use parent qw(SL::Layout::Base);
+
+=head1 DESCRIPTION
+
+For a description about the external interface of layouts in general see
+L<SL::Layout::Dispatcher>.
+
+This is a base class for layouts in general. It provides the basic interface
+and some capabilities to extend and cascade layouts.
+
+
+=head1 IMPLEMENTING LAYOUT CALLBACKS
+
+There are eight callbacks (C<pre_content>, C<post_content>, C<start_content>,
+C<end_content>, C<stylesheets>, C<stylesheets_inline>, C<javscripts>,
+C<javascripts_inline>) which are documented in L<SL::Layout::Dispatcher>. If
+you are writing a new simple layout, you can just override some of them like
+this:
+
+ package SL::Layout::MyEvilLayout;
+
+ sub pre_content {
+ '<h1>This is MY page now</h1>'
+ }
+
+ sub post_content {
+ '<p align="right"><small><em>Brought to you by my own layout class</em></small></p>'
+ }
+
+
+To preserve the sanitizing effects of C<stylesheets> and C<javascripts> you should instead do the following:
+
+ sub stylesheets {
+ $_[0]->add_stylesheets(qw(mystyle1.css mystyle2.css);
+ $_[0]->SUPER::stylesheets;
+ }
+
+If you want to add something to a different layout, you should write a sub
+layout and add it to the other layouts.
+
+
+=head1 SUB LAYOUTS
+
+Layouts can be aggregated, so that common elements can be used in different
+layouts. Currently this is used for the L<None|SL::Layout::None> sub layout,
+which contains a lot of the stylesheets and javascripts necessary. Another
+example is the L<Top|SL::Layout::Top> layout, which is used to generate a
+common top bar for all menu types.
+
+To add a sub layout to your layout just overwrite the sub_layout method:
+
+ package SL::Layout::MyFinalLayout;
+
+ sub init_sub_layout {
+ [
+ SL::Layout::None->new,
+ SL::Layout::MyEvilLayout->new,
+ ]
+ }
+
+You can also add a sublayout at runtime:
+
+ $layout->add_sub_layout(SL::Layout::SideBar->new);
+
+The standard implementation for the callbacks will see to it that the contents
+of all sub layouts will get rendered.
+
+
+=head1 COMBINING SUB LAYOUTS AND OWN BEHAVIOUR
+
+This is still somewhat rough, and improvements are welcome.
+
+For the C<*_content> callbacks this works if you just remember to dispatch to the base method:
+
+ sub post_content {
+ return $_[0]->render_status_bar .
+ $_[0]->SUPER::post_content
+ }
+
+For the stylesheet and javascript callbacks things are hard, because of the
+backwards compatibility, and the built-in sanity checks. The best way currently
+is to just add your content and dispatch to the base method.
+
+ sub stylesheets {
+ $_[0]->add_stylesheets(qw(mystyle1.css mystyle2.css);
+ $_[0]->SUPER::stylesheets;
+ }
+
+=head1 GORY DETAILS ABOUT JAVASCRIPT AND STYLESHEET OVERLOADING
+
+The original code used to store one stylehsheet in C<< $form->{stylesheet} >> and
+allowed/expected authors of potential C<bin/mozilla/> controllers to change
+that into their own modified stylesheet.
+
+This was at some point cleaned up into a method C<use stylesheet> which took a
+string of space separated stylesheets and processed them into the response.
+
+A lot of controllers are still using this methods so the layout interface
+supports it to change as few controller code as possible, while providing the
+more intuitive C<add_stylesheets> method.
+
+At the same time the following things need to be possible:
+
+=over 4
+
+=item 1.
+
+Runtime additions.
+
+ $layout->add_stylesheets(...)
+
+Since add_stylesheets adds to C<< $self->{stylesheets} >> there must be a way to read
+from it. Currently this is the deprecated C<use_stylesheet>.
+
+=item 2.
+
+Overriding Callbacks
+
+A leaf layout should be able to override a callback to return a list.
+
+=item 3.
+
+Sanitizing
+
+C<stylesheets> needs to retain it's sanitizing behaviour.
+
+=item 4.
+
+Aggregation
+
+The standard implementation should be able to collect from sub layouts.
+
+=item 5.
+
+Preserving of Inclusion Order
+
+Since there is currently no standard way of mixing own content and including
+sub layouts, this has to be done manually. Certain things like jquery get added
+in L<SL::Layout::None> so that they get rendered first.
+
+=back
+
+The current implementation provides no good candidate for overriding in sub
+classes, which should be changed. The other points work pretty well.
+
+=head1 BUGS
+
+None yet, if you don't count the horrible stylesheet/javascript interface.
+
+=head1 AUTHOR
+
+Sven Schöling E<lt>s.schoeling@linet-services.deE<gt>
+
+=cut
+
projects / kivitendo-erp.git / blobdiff