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       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_BASEGFX_TOOLS_KEYSTOPLERP_HXX
      21             : #define INCLUDED_BASEGFX_TOOLS_KEYSTOPLERP_HXX
      22             : 
      23             : #include <basegfx/numeric/ftools.hxx>
      24             : #include <vector>
      25             : #include <basegfx/basegfxdllapi.h>
      26             : 
      27             : namespace com{ namespace sun{ namespace star{ namespace uno {
      28             :     template<typename T> class Sequence;
      29             : }}}}
      30             : 
      31             : namespace basegfx
      32             : {
      33             :     namespace tools
      34             :     {
      35             :         /** Lerp in a vector of key stops
      36             : 
      37             :             This class holds a key stop vector and provides the
      38             :             functionality to lerp inside it. Useful e.g. for
      39             :             multi-stop gradients, or the SMIL key time activity.
      40             : 
      41             :             For those, given a global [0,1] lerp alpha, one need to
      42             :             find the suitable bucket index from key stop vector, and
      43             :             then calculate the relative alpha between the two buckets
      44             :             found.
      45             :          */
      46           1 :         class BASEGFX_DLLPUBLIC KeyStopLerp
      47             :         {
      48             :         public:
      49             :             typedef std::pair<std::ptrdiff_t,double> ResultType;
      50             : 
      51             :             /** Create lerper with given vector of stops
      52             : 
      53             :                 @param rKeyStops
      54             : 
      55             :                 Vector of stops, must contain at least two elements
      56             :                 (though preferably more, otherwise you probably don't
      57             :                 need key stop lerping in the first place). All
      58             :                 elements must be of monotonically increasing value.
      59             :              */
      60             :             explicit KeyStopLerp( const std::vector<double>& rKeyStops );
      61             : 
      62             :             /** Create lerper with given sequence of stops
      63             : 
      64             :                 @param rKeyStops
      65             : 
      66             :                 Sequence of stops, must contain at least two elements
      67             :                 (though preferably more, otherwise you probably don't
      68             :                 need key stop lerping in the first place). All
      69             :                 elements must be of monotonically increasing value.
      70             :              */
      71             :             explicit KeyStopLerp( const ::com::sun::star::uno::Sequence<double>& rKeyStops );
      72             : 
      73             :             /** Find two nearest bucket index & interpolate
      74             : 
      75             :                 @param fAlpha
      76             :                 Find bucket index i, with keyStops[i] < fAlpha <=
      77             :                 keyStops[i+1]. Return new alpha value in [0,1),
      78             :                 proportional to fAlpha's position between keyStops[i]
      79             :                 and keyStops[i+1]
      80             :              */
      81             :             ResultType lerp(double fAlpha) const;
      82             : 
      83             :         private:
      84             :             std::vector<double>    maKeyStops;
      85             :             mutable std::ptrdiff_t mnLastIndex;
      86             :         };
      87             :     }
      88             : }
      89             : 
      90             : #endif
      91             : 
      92             : /* vim:set shiftwidth=4 softtabstop=4 expandtab: */