.. py:module:: scene

The class Scene
===============
	       

The class :py:class:`Scene` is a container of items that can be `RImage`, `Surface` or `Volume`.
 `name`.

.. py:class::  Scene()

   A container of objects (`RImage`, `Surface` or `Volume`) used  within the interface of image_viewer.

   .. rubric:: Instance attribute
    
   .. py:attribute:: current_item

      Current item, the one being visualized or/and operated with.

   .. rubric:: Instance methods:
      
   .. py:method:: add_item(name)

      Adds an item to the scene. If the scene already has an item with that name, it modifies the name of the item adding to it the suffx _n
      where n is the number of items of the scene with the same name minus 1.

   .. py:method:: number_items(item_cat)

      Returns the number of items of the given category `item_cat` in the scene.


   .. py:method:: iter_cat()

      Returns an iterator over the classes of the items of the scene

   This class supports the following operations:
  
   +--------------------------+----------------------------------------------------+
   | Operatiom                | Result                                             |
   +==========================+====================================================+
   | ``s[name]``              | Returns the item of the scene `s` that has the     |
   |                          | name `name`.                                       |                                 
   +--------------------------+----------------------------------------------------+
   | ``name in s``            | Returns True if the scene has an item with name    |
   |                          | `name`.                                            |
   +--------------------------+----------------------------------------------------+

   The class is iterable over items.

   The implementation of the class is given together other files in a zip file as described in :ref:`image_viewer`.