basegfx/source/numeric/ftools.cxx

   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 #include <basegfx/numeric/ftools.hxx>
  21 #include <algorithm>
  22
  23 namespace basegfx
  24 {
  25     // init static member of class fTools
  26     double ::basegfx::fTools::mfSmallValue = 0.000000001;
  27
  28     double snapToNearestMultiple(double v, const double fStep)
  29     {
  30         if(fTools::equalZero(fStep))
  31         {
  32             // with a zero step, all snaps to 0.0
  33             return 0.0;
  34         }
  35         else
  36         {
  37             const double fHalfStep(fStep * 0.5);
  38             const double fChange(fHalfStep - fmod(v + fHalfStep, fStep));
  39
  40             if(basegfx::fTools::equal(fabs(v), fabs(fChange)))
  41             {
  42                 return 0.0;
  43             }
  44             else
  45             {
  46                 return v + fChange;
  47             }
  48         }
  49     }
  50
  51     double snapToZeroRange(double v, double fWidth)
  52     {
  53         if(fTools::equalZero(fWidth))
  54         {
  55             // with no range all snaps to range bound
  56             return 0.0;
  57         }
  58         else
  59         {
  60             if(v < 0.0 || v > fWidth)
  61             {
  62                 double fRetval(fmod(v, fWidth));
  63
  64                 if(fRetval < 0.0)
  65                 {
  66                     fRetval += fWidth;
  67                 }
  68
  69                 return fRetval;
  70             }
  71             else
  72             {
  73                 return v;
  74             }
  75         }
  76     }
  77
  78     double snapToRange(double v, double fLow, double fHigh)
  79     {
  80         if(fTools::equal(fLow, fHigh))
  81         {
  82             // with no range all snaps to range bound
  83             return 0.0;
  84         }
  85         else
  86         {
  87             if(fLow > fHigh)
  88             {
  89                 // correct range order. Evtl. assert this (?)
  90                 std::swap(fLow, fHigh);
  91             }
  92
  93             if(v < fLow || v > fHigh)
  94             {
  95                 return snapToZeroRange(v - fLow, fHigh - fLow) + fLow;
  96             }
  97             else
  98             {
  99                 return v;
 100             }
 101         }
 102     }
 103 } // end of namespace basegfx
 104
 105 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */