slideshow/source/engine/transitions/parametricpolypolygon.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #ifndef INCLUDED_SLIDESHOW_SOURCE_ENGINE_TRANSITIONS_PARAMETRICPOLYPOLYGON_HXX
  21 #define INCLUDED_SLIDESHOW_SOURCE_ENGINE_TRANSITIONS_PARAMETRICPOLYPOLYGON_HXX
  22
  23 #include <basegfx/polygon/b2dpolypolygon.hxx>
  24 #include <boost/shared_ptr.hpp>
  25
  26
  27 /* Definition of ParametricPolyPolygon interface */
  28
  29 namespace slideshow
  30 {
  31     namespace internal
  32     {
  33         /** Interface defining a parametric poly-polygon.
  34
  35             This interface defines a poly-polygon, whose actual shape
  36             is parameterized by a floating point value. This is
  37             e.g. used to generically access the various clip polygon
  38             generators for transition effects.
  39
  40             Since for every parametric poly-polygon, there is a set of
  41             variations, which can easily be generated by simple
  42             transformations or change in parameter range sweep
  43             direction, objects implementing this interface only
  44             generate <em>one</em> prototypical instance of the
  45             parametric poly-polygon. Generally speaking, the main
  46             effect direction should be horizontal, it should make
  47             increasingly more area visible (transition 'in'), and when
  48             there is a designated direction given, that should be
  49             left-to-right.
  50          */
  51         class ParametricPolyPolygon
  52         {
  53         public:
  54             virtual ~ParametricPolyPolygon() {}
  55
  56             /** Retrieve the poly-polygon for value t.
  57
  58                 @param t
  59                 Current parameter value to retrieve the corresponding
  60                 poly-polygon for. Permissible values for t must be in
  61                 the range [0,1].
  62
  63                 @return a poly-polygon corresponding to the given
  64                 parameter value. The poly-polygon is interpreted as
  65                 living in the unit rectangle (i.e. [0,1]x[0,1]), but
  66                 is not necessarily constrained to completely lie in
  67                 this area (this very much depends on the actual effect
  68                 to be generated). Although, from a performance
  69                 perspective, it currently <em>is</em> advantageous to
  70                 try to keep the poly-polygon within these bounds (at
  71                 least if there are no hard reasons not to do so),
  72                 because then reversion or out transformations are
  73                 potentially faster to compute (see the
  74                 TransitionInfo::meReverseMethod member in
  75                 transitionfactory.cxx). Furthermore, if one of the
  76                 polygon modifications involve subtraction (also see
  77                 TransitionInfo::meReverseMethod), all generated
  78                 polygons should be oriented clock-wise
  79                 (i.e. traversing the polygon vertices with increasing
  80                 vertex index should generate a clock-wise movement).
  81              */
  82             virtual ::basegfx::B2DPolyPolygon operator()( double t ) = 0;
  83         };
  84
  85         typedef ::boost::shared_ptr< ParametricPolyPolygon > ParametricPolyPolygonSharedPtr;
  86
  87     }
  88 }
  89
  90 #endif // INCLUDED_SLIDESHOW_SOURCE_ENGINE_TRANSITIONS_PARAMETRICPOLYPOLYGON_HXX
  91
  92 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */