It helps to add new files

openlp/plugins/presentations/lib/presentationcontroller.py

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+# -*- coding: utf-8 -*-
+# vim: autoindent shiftwidth=4 expandtab textwidth=80 tabstop=4 softtabstop=4
+"""
+OpenLP - Open Source Lyrics Projection
+Copyright (c) 2008 Raoul Snyman
+Portions copyright (c) 2008-2009 Martin Thompson, Tim Bentley
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free Software
+Foundation; version 2 of the License.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+"""
+
+import logging
+
+class PresentationController(object):
+    """
+    Base class for presentation controllers to inherit from
+    Class to control interactions with presentations.
+    It creates the runtime environment, loads and closes the presentation as
+    well as triggering the correct activities based on the users input
+
+    **Basic Attributes**
+
+    ``name``
+        The name that appears in the options and the media manager
+    
+    ``plugin``
+        The presentationplugin object
+
+    **Hook Functions**
+    
+    ``kill()``
+        Called at system exit to clean up any running presentations
+
+    ``is_available()``
+        Returns True if presentation application is installed/can run on this machine
+
+    ``load_presentation(presentation)``
+        Load a presentation file
+
+    ``close_presentation()``
+        Close presentation and clean up objects
+
+    ``presentation_loaded()``
+        Returns True if presentation is currently loaded
+
+    ``is_active()``
+        Returns True if a presentation is currently running
+    
+    ``blank_screen()``
+        Blanks the screen, making it black.
+
+    ``unblank_screen()``
+        Unblanks the screen, restoring the output
+
+    ``stop_presentation()``
+        Stops the presentation, removing it from the output display
+
+    ``start_presentation()``
+        Starts the presentation from the beginning
+
+    ``get_slide_number()``
+        Returns the current slide number, from 1
+
+    ``get_slide_count()``
+        Returns total number of slides
+
+    ``goto_slide(slide_no)``
+        Jumps directly to the requested slide.
+
+    ``next_step()``
+       Triggers the next effect of slide on the running presentation
+
+    ``previous_step()``
+        Triggers the previous slide on the running presentation
+
+    ``get_slide_preview_file(slide_no)``
+        Returns a path to an image containing a preview for the requested slide
+
+    """
+    global log
+    log = logging.getLogger(u'PresentationController')
+    log.info(u'loaded')
+    
+    def __init__(self, plugin=None, name=u'PresentationController'):
+        """
+        This is the constructor for the presentationcontroller object.
+        This provides an easy way for descendent plugins to populate common data.
+        This method *must* be overridden, like so::
+
+            class MyPresentationController(PresentationController):
+                def __init__(self, plugin):
+                    PresentationController.__init(self, plugin, u'My Presenter App')
+
+        ``plugin``
+            Defaults to *None*. The presentationplugin object
+
+        ``name``
+            Name of the application, to appear in the application
+        """
+        self.plugin = plugin
+        self.name = name
+        self.start_process()
+
+    def is_available(self):
+        """
+        Presentation app is able to run on this machine
+        """
+        return False
+
+    def start_process(self):
+        """
+        Loads a running version of the presentation application in the background.
+        """
+        pass
+
+    def kill(self):
+        """
+        Called at system exit to clean up any running presentations and
+        close the application
+        """
+        log.debug(u'Kill')
+        self.close_presentation()
+
+    def load_presentation(self, presentation):
+        """
+        Called when a presentation is added to the SlideController.
+        Loads the presentation and starts it
+
+        ``presentation``
+        The file name of the presentatios to the run.
+        """
+        pass
+
+    def close_presentation(self):
+        """
+        Close presentation and clean up objects
+        Triggered by new object being added to SlideController
+        """
+        pass
+
+    def is_active(self):
+        """
+        Returns True if a presentation is currently running
+        """
+        return False
+
+    def is_loaded(self):
+        """
+        Returns true if a presentation is loaded
+        """
+        return False
+    
+    def blank_screen(self):
+        """
+        Blanks the screen, making it black.
+        """
+        pass
+
+    def unblank_screen(self):
+        """
+        Unblanks (restores) the presentationn
+        """
+        pass
+
+    def stop_presentation(self):
+        """
+        Stops the presentation, removing it from the output display
+        """
+        pass
+
+    def start_presentation(self):
+        """
+        Starts the presentation from the beginning
+        """
+        pass
+
+    def get_slide_number(self):
+        """
+        Returns the current slide number, from 1
+        """
+        return 0
+
+    def get_slide_count(self):
+        """
+        Returns total number of slides
+        """
+        return 0
+
+    def goto_slide(self, slide_no):
+        """
+        Jumps directly to the requested slide.
+
+        ``slide_no``
+            The slide to jump to, starting at 1
+        """
+        pass
+
+    def next_step(self):
+       """
+       Triggers the next effect of slide on the running presentation
+       This might be the next animation on the current slide, or the next slide
+       """
+       pass
+
+    def previous_step(self):
+        """
+        Triggers the previous slide on the running presentation
+        """
+        pass
+
+    def get_slide_preview_file(self, slide_no):
+        """
+        Returns an image path containing a preview for the requested slide
+
+        ``slide_no``
+            The slide an image is required for, starting at 1
+        """
+        return None