dom/smil/SMILIntegerType.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "SMILIntegerType.h"
   8
   9 #include "mozilla/SMILValue.h"
  10 #include "nsDebug.h"
  11 #include <math.h>
  12
  13 namespace mozilla {
  14
  15 void SMILIntegerType::Init(SMILValue& aValue) const {
  16   MOZ_ASSERT(aValue.IsNull(), "Unexpected value type");
  17   aValue.mU.mInt = 0;
  18   aValue.mType = this;
  19 }
  20
  21 void SMILIntegerType::Destroy(SMILValue& aValue) const {
  22   MOZ_ASSERT(aValue.mType == this, "Unexpected SMIL value");
  23   aValue.mU.mInt = 0;
  24   aValue.mType = SMILNullType::Singleton();
  25 }
  26
  27 nsresult SMILIntegerType::Assign(SMILValue& aDest,
  28                                  const SMILValue& aSrc) const {
  29   MOZ_ASSERT(aDest.mType == aSrc.mType, "Incompatible SMIL types");
  30   MOZ_ASSERT(aDest.mType == this, "Unexpected SMIL value");
  31   aDest.mU.mInt = aSrc.mU.mInt;
  32   return NS_OK;
  33 }
  34
  35 bool SMILIntegerType::IsEqual(const SMILValue& aLeft,
  36                               const SMILValue& aRight) const {
  37   MOZ_ASSERT(aLeft.mType == aRight.mType, "Incompatible SMIL types");
  38   MOZ_ASSERT(aLeft.mType == this, "Unexpected type for SMIL value");
  39
  40   return aLeft.mU.mInt == aRight.mU.mInt;
  41 }
  42
  43 nsresult SMILIntegerType::Add(SMILValue& aDest, const SMILValue& aValueToAdd,
  44                               uint32_t aCount) const {
  45   MOZ_ASSERT(aValueToAdd.mType == aDest.mType, "Trying to add invalid types");
  46   MOZ_ASSERT(aValueToAdd.mType == this, "Unexpected source type");
  47   aDest.mU.mInt += aValueToAdd.mU.mInt * aCount;
  48   return NS_OK;
  49 }
  50
  51 nsresult SMILIntegerType::ComputeDistance(const SMILValue& aFrom,
  52                                           const SMILValue& aTo,
  53                                           double& aDistance) const {
  54   MOZ_ASSERT(aFrom.mType == aTo.mType, "Trying to compare different types");
  55   MOZ_ASSERT(aFrom.mType == this, "Unexpected source type");
  56   aDistance = fabs(double(aTo.mU.mInt - aFrom.mU.mInt));
  57   return NS_OK;
  58 }
  59
  60 nsresult SMILIntegerType::Interpolate(const SMILValue& aStartVal,
  61                                       const SMILValue& aEndVal,
  62                                       double aUnitDistance,
  63                                       SMILValue& aResult) const {
  64   MOZ_ASSERT(aStartVal.mType == aEndVal.mType,
  65              "Trying to interpolate different types");
  66   MOZ_ASSERT(aStartVal.mType == this, "Unexpected types for interpolation");
  67   MOZ_ASSERT(aResult.mType == this, "Unexpected result type");
  68
  69   const double startVal = double(aStartVal.mU.mInt);
  70   const double endVal = double(aEndVal.mU.mInt);
  71   const double currentVal = startVal + (endVal - startVal) * aUnitDistance;
  72
  73   // When currentVal is exactly midway between its two nearest integers, we
  74   // jump to the "next" integer to provide simple, easy to remember and
  75   // consistent behaviour (from the SMIL author's point of view).
  76
  77   if (startVal < endVal) {
  78     aResult.mU.mInt = int64_t(floor(currentVal + 0.5));  // round mid up
  79   } else {
  80     aResult.mU.mInt = int64_t(ceil(currentVal - 0.5));  // round mid down
  81   }
  82
  83   return NS_OK;
  84 }
  85
  86 }  // namespace mozilla