slideshow/source/inc/activity.hxx

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   9  * This file incorporates work covered by the following license notice:
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  19
  20 #ifndef INCLUDED_SLIDESHOW_SOURCE_INC_ACTIVITY_HXX
  21 #define INCLUDED_SLIDESHOW_SOURCE_INC_ACTIVITY_HXX
  22
  23 #include <sal/types.h>
  24
  25 #include <boost/shared_ptr.hpp>
  26
  27 #include "disposable.hxx"
  28
  29
  30 /* Definition of Activity interface */
  31
  32 namespace slideshow
  33 {
  34     namespace internal
  35     {
  36
  37         class Activity : public Disposable
  38         {
  39         public:
  40             /** Perform the activity associated with this interface's
  41                 implementation.
  42
  43                 @return true, if activity continues, or false, if activity has
  44                 ended.
  45             */
  46             virtual bool perform() = 0;
  47
  48             /** Calculates whether the activity lags time.
  49
  50                 If this method returns a time lag greater than 0.0,
  51                 the ActivitiesQueue will adjust the global slideshow
  52                 time, by subtracting the given amount of lag.
  53
  54                 @return time lag or 0.0. Value must be greater or
  55                 equal than zero.
  56             */
  57             virtual double calcTimeLag() const = 0;
  58
  59             /** Query whether this activity is still continuing
  60
  61                 @return true, if this activity still
  62                 continues. Returns false, if activity has ended. It is
  63                 required that operator() returns false, when
  64                 isActive() returns false. Furthermore, it is required
  65                 that the inactive state is persistent; an activity
  66                 that has become inactive (i.e. isActive() once
  67                 returned false) must stay in that state eternally.
  68             */
  69             virtual bool isActive() const = 0;
  70
  71             /** Notifies the Activity that it has now left the
  72                 ActivitiesQueue
  73
  74                 Use this method to react on the queue removal
  75                 event. For animated shapes, this is e.g. used to
  76                 switch back to the non-sprite presentation mode of the
  77                 shape.
  78              */
  79             virtual void dequeued() = 0;
  80
  81             /** Forces this activity deactivate and get to its end state
  82                 (if possible), but does _not_ dispose.
  83             */
  84             virtual void end() = 0;
  85         };
  86
  87         typedef ::boost::shared_ptr< Activity > ActivitySharedPtr;
  88
  89     }
  90 }
  91
  92 #endif // INCLUDED_SLIDESHOW_SOURCE_INC_ACTIVITY_HXX
  93
  94 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */