LCOV - code coverage report
Current view: directory - content/svg/content/src - SVGLengthListSMILType.h (source / functions) Found Hit Coverage
Test: app.info Lines: 2 2 100.0 %
Date: 2012-06-02 Functions: 2 2 100.0 %

       1                 : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2                 : /* ***** BEGIN LICENSE BLOCK *****
       3                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
       4                 :  *
       5                 :  * The contents of this file are subject to the Mozilla Public License Version
       6                 :  * 1.1 (the "License"); you may not use this file except in compliance with
       7                 :  * the License. You may obtain a copy of the License at
       8                 :  * http://www.mozilla.org/MPL/
       9                 :  *
      10                 :  * Software distributed under the License is distributed on an "AS IS" basis,
      11                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
      12                 :  * for the specific language governing rights and limitations under the
      13                 :  * License.
      14                 :  *
      15                 :  * The Original Code is the Mozilla SVG project.
      16                 :  *
      17                 :  * The Initial Developer of the Original Code is the Mozilla Foundation.
      18                 :  * Portions created by the Initial Developer are Copyright (C) 2009
      19                 :  * the Initial Developer. All Rights Reserved.
      20                 :  *
      21                 :  * Contributor(s):
      22                 :  *
      23                 :  * Alternatively, the contents of this file may be used under the terms of
      24                 :  * either of the GNU General Public License Version 2 or later (the "GPL"),
      25                 :  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      26                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      27                 :  * of those above. If you wish to allow use of your version of this file only
      28                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      29                 :  * use your version of this file under the terms of the MPL, indicate your
      30                 :  * decision by deleting the provisions above and replace them with the notice
      31                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      32                 :  * the provisions above, a recipient may use your version of this file under
      33                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      34                 :  *
      35                 :  * ***** END LICENSE BLOCK ***** */
      36                 : 
      37                 : #ifndef MOZILLA_SVGLENGTHLISTSMILTYPE_H_
      38                 : #define MOZILLA_SVGLENGTHLISTSMILTYPE_H_
      39                 : 
      40                 : #include "nsISMILType.h"
      41                 : 
      42                 : class nsSMILValue;
      43                 : 
      44                 : namespace mozilla {
      45                 : 
      46                 : ////////////////////////////////////////////////////////////////////////
      47                 : // SVGLengthListSMILType
      48                 : //
      49                 : // Operations for animating an SVGLengthList.
      50                 : //
      51                 : class SVGLengthListSMILType : public nsISMILType
      52                 : {
      53                 : public:
      54                 :   // Singleton for nsSMILValue objects to hold onto.
      55                 :   static SVGLengthListSMILType sSingleton;
      56                 : 
      57                 : protected:
      58                 :   // nsISMILType Methods
      59                 :   // -------------------
      60                 : 
      61                 :   /**
      62                 :    * When this method initializes the SVGLengthListAndInfo for its nsSMILValue
      63                 :    * argument, it has to blindly set its mCanZeroPadList to true despite
      64                 :    * the fact that some attributes can't be zero-padded. (See the explaination
      65                 :    * that follows.) SVGAnimatedLengthList::SMILAnimatedLengthList's
      66                 :    * GetBaseValue() and ValueFromString() methods then override this for the
      67                 :    * nsSMILValue objects that they create to set this flag to the appropriate
      68                 :    * value for the attribute in question.
      69                 :    *
      70                 :    * The reason that we default to setting the mCanZeroPadList to true is
      71                 :    * because the SMIL engine creates "zero" valued nsSMILValue objects for
      72                 :    * intermediary calculations, and may pass such an nsSMILValue (along with an
      73                 :    * nsSMILValue from an animation element - that is an nsSMILValue created by
      74                 :    * SVGAnimatedLengthList::SMILAnimatedLengthList's GetBaseValue() or
      75                 :    * ValueFromString() methods) into the Add(), ComputeDistance() or
      76                 :    * Interpolate() methods below. Even in the case of animation of list
      77                 :    * attributes that may *not* be padded with zeros (such as 'x' and 'y' on the
      78                 :    * <text> element), we need to allow zero-padding of these "zero" valued
      79                 :    * nsSMILValue's lists. One reason for this is illustrated by the following
      80                 :    * example:
      81                 :    *
      82                 :    *   <text x="2 4">foo
      83                 :    *      <animate by="2 2" .../>
      84                 :    *   </text>
      85                 :    *
      86                 :    * In this example there are two SMIL animation layers to be sandwiched: the
      87                 :    * base layer, and the layer created for the <animate> element. The SMIL
      88                 :    * engine calculates the result of each layer *independently*, before
      89                 :    * compositing the results together. Thus for the <animate> sandwich layer
      90                 :    * the SMIL engine interpolates between a "zero" nsSMILValue that it creates
      91                 :    * (since there is no explicit "from") and the "2 2", before the result of
      92                 :    * that interpolation is added to the "2 4" from the base layer. Clearly for
      93                 :    * the interpolation between the "zero" nsSMILValue and "2 2" to work, the
      94                 :    * "zero" nsSMILValue's SVGLengthListAndInfo must be zero paddable - hence
      95                 :    * why this method always sets mCanZeroPadList to true.
      96                 :    *
      97                 :    * (Since the Add(), ComputeDistance() and Interpolate() methods may be
      98                 :    * passed two input nsSMILValue objects for which CanZeroPadList() returns
      99                 :    * opposite values, these methods must be careful what they set the flag to
     100                 :    * on the nsSMILValue that they output. If *either* of the input nsSMILValues
     101                 :    * has an SVGLengthListAndInfo for which CanZeroPadList() returns false,
     102                 :    * then they must set the flag to false on the output nsSMILValue too. If
     103                 :    * the methods failed to do that, then when the result nsSMILValue objects
     104                 :    * from each sandwich layer are composited together, we could end up allowing
     105                 :    * animation between lists of different length when we should not!)
     106                 :    */
     107                 :   virtual void     Init(nsSMILValue& aValue) const;
     108                 : 
     109                 :   virtual void     Destroy(nsSMILValue& aValue) const;
     110                 :   virtual nsresult Assign(nsSMILValue& aDest, const nsSMILValue& aSrc) const;
     111                 :   virtual bool     IsEqual(const nsSMILValue& aLeft,
     112                 :                            const nsSMILValue& aRight) const;
     113                 :   virtual nsresult Add(nsSMILValue& aDest, const nsSMILValue& aValueToAdd,
     114                 :                        PRUint32 aCount) const;
     115                 :   virtual nsresult ComputeDistance(const nsSMILValue& aFrom,
     116                 :                                    const nsSMILValue& aTo,
     117                 :                                    double& aDistance) const;
     118                 :   virtual nsresult Interpolate(const nsSMILValue& aStartVal,
     119                 :                                const nsSMILValue& aEndVal,
     120                 :                                double aUnitDistance,
     121                 :                                nsSMILValue& aResult) const;
     122                 : 
     123                 : private:
     124                 :   // Private constructor & destructor: prevent instances beyond my singleton,
     125                 :   // and prevent others from deleting my singleton.
     126            1464 :   SVGLengthListSMILType() {}
     127            1487 :   ~SVGLengthListSMILType() {}
     128                 : };
     129                 : 
     130                 : } // namespace mozilla
     131                 : 
     132                 : #endif // MOZILLA_SVGLENGTHLISTSMILTYPE_H_

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