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
  22 namespace basegfx
  23 {
  24     double snapToNearestMultiple(double v, const double fStep)
  25     {
  26         if(fTools::equalZero(fStep))
  27         {
  28             // with a zero step, all snaps to 0.0
  29             return 0.0;
  30         }
  31         else
  32         {
  33             const double fHalfStep(fStep * 0.5);
  34             const double fChange(fHalfStep - fmod(v + fHalfStep, fStep));
  35
  36             if(basegfx::fTools::equal(fabs(v), fabs(fChange)))
  37             {
  38                 return 0.0;
  39             }
  40             else
  41             {
  42                 return v + fChange;
  43             }
  44         }
  45     }
  46
  47     double snapToZeroRange(double v, double fWidth)
  48     {
  49         if(fTools::equalZero(fWidth))
  50         {
  51             // with no range all snaps to range bound
  52             return 0.0;
  53         }
  54         else
  55         {
  56             if(v < 0.0 || v > fWidth)
  57             {
  58                 double fRetval(fmod(v, fWidth));
  59
  60                 if(fRetval < 0.0)
  61                 {
  62                     fRetval += fWidth;
  63                 }
  64
  65                 return fRetval;
  66             }
  67             else
  68             {
  69                 return v;
  70             }
  71         }
  72     }
  73
  74     double snapToRange(double v, double fLow, double fHigh)
  75     {
  76         if(fTools::equal(fLow, fHigh))
  77         {
  78             // with no range all snaps to range bound
  79             return 0.0;
  80         }
  81         else
  82         {
  83             if(fLow > fHigh)
  84             {
  85                 // correct range order. Evtl. assert this (?)
  86                 std::swap(fLow, fHigh);
  87             }
  88
  89             if(v < fLow || v > fHigh)
  90             {
  91                 return snapToZeroRange(v - fLow, fHigh - fLow) + fLow;
  92             }
  93             else
  94             {
  95                 return v;
  96             }
  97         }
  98     }
  99
 100     double normalizeToRange(double v, const double fRange)
 101     {
 102         if(fRange <= 0.0)
 103         {
 104             // with a zero (or less) range, all normalizes to 0.0
 105             return 0.0;
 106         }
 107
 108         if(v < 0.0)
 109         {
 110             if(fTools::moreOrEqual(v, -fRange))
 111             {
 112                 // in range [-fRange, 0.0[, shift one step
 113                 return v + fRange;
 114             }
 115
 116             // re-calculate
 117             return v - (floor(v/fRange)*fRange);
 118         }
 119         else
 120         {
 121             if(fTools::less(v, fRange))
 122             {
 123                 // already in range [0.0, fRange[, nothing to do
 124                 return v;
 125             }
 126
 127             // re-calculate
 128             return v - (floor(v/fRange)*fRange);
 129         }
 130     }
 131 } // end of namespace basegfx
 132
 133 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */