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     double snapToNearestMultiple(double v, const double fStep)
  26     {
  27         if(fTools::equalZero(fStep))
  28         {
  29             // with a zero step, all snaps to 0.0
  30             return 0.0;
  31         }
  32         else
  33         {
  34             const double fHalfStep(fStep * 0.5);
  35             const double fChange(fHalfStep - fmod(v + fHalfStep, fStep));
  36
  37             if(basegfx::fTools::equal(fabs(v), fabs(fChange)))
  38             {
  39                 return 0.0;
  40             }
  41             else
  42             {
  43                 return v + fChange;
  44             }
  45         }
  46     }
  47
  48     double snapToZeroRange(double v, double fWidth)
  49     {
  50         if(fTools::equalZero(fWidth))
  51         {
  52             // with no range all snaps to range bound
  53             return 0.0;
  54         }
  55         else
  56         {
  57             if(v < 0.0 || v > fWidth)
  58             {
  59                 double fRetval(fmod(v, fWidth));
  60
  61                 if(fRetval < 0.0)
  62                 {
  63                     fRetval += fWidth;
  64                 }
  65
  66                 return fRetval;
  67             }
  68             else
  69             {
  70                 return v;
  71             }
  72         }
  73     }
  74
  75     double snapToRange(double v, double fLow, double fHigh)
  76     {
  77         if(fTools::equal(fLow, fHigh))
  78         {
  79             // with no range all snaps to range bound
  80             return 0.0;
  81         }
  82         else
  83         {
  84             if(fLow > fHigh)
  85             {
  86                 // correct range order. Evtl. assert this (?)
  87                 std::swap(fLow, fHigh);
  88             }
  89
  90             if(v < fLow || v > fHigh)
  91             {
  92                 return snapToZeroRange(v - fLow, fHigh - fLow) + fLow;
  93             }
  94             else
  95             {
  96                 return v;
  97             }
  98         }
  99     }
 100
 101     double normalizeToRange(double v, const double fRange)
 102     {
 103         if(fTools::lessOrEqual(fRange, 0.0))
 104         {
 105             // with a zero (or less) range, all normalizes to 0.0
 106             return 0.0;
 107         }
 108
 109         const bool bNegative(fTools::less(v, 0.0));
 110
 111         if(bNegative)
 112         {
 113             if(fTools::moreOrEqual(v, -fRange))
 114             {
 115                 // in range [-fRange, 0.0[, shift one step
 116                 return v + fRange;
 117             }
 118
 119             // re-calculate
 120             return v - (floor(v/fRange)*fRange);
 121         }
 122         else
 123         {
 124             if(fTools::less(v, fRange))
 125             {
 126                 // already in range [0.0, fRange[, nothing to do
 127                 return v;
 128             }
 129
 130             // re-calculate
 131             return v - (floor(v/fRange)*fRange);
 132         }
 133     }
 134 } // end of namespace basegfx
 135
 136 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */