LCOV - code coverage report
Current view: directory - objdir/dist/include - nsISMILType.h (source / functions) Found Hit Coverage
Test: app.info Lines: 4 2 50.0 %
Date: 2012-06-02 Functions: 3 2 66.7 %

       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 SMIL module.
      16                 :  *
      17                 :  * The Initial Developer of the Original Code is Brian Birtles.
      18                 :  * Portions created by the Initial Developer are Copyright (C) 2005
      19                 :  * the Initial Developer. All Rights Reserved.
      20                 :  *
      21                 :  * Contributor(s):
      22                 :  *   Robert O'Callahan <roc+moz@cs.cmu.edu>
      23                 :  *   Brian Birtles <birtles@gmail.com>
      24                 :  *
      25                 :  * Alternatively, the contents of this file may be used under the terms of
      26                 :  * either of the GNU General Public License Version 2 or later (the "GPL"),
      27                 :  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      28                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      29                 :  * of those above. If you wish to allow use of your version of this file only
      30                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      31                 :  * use your version of this file under the terms of the MPL, indicate your
      32                 :  * decision by deleting the provisions above and replace them with the notice
      33                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      34                 :  * the provisions above, a recipient may use your version of this file under
      35                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      36                 :  *
      37                 :  * ***** END LICENSE BLOCK ***** */
      38                 : 
      39                 : #ifndef NS_ISMILTYPE_H_
      40                 : #define NS_ISMILTYPE_H_
      41                 : 
      42                 : #include "nscore.h"
      43                 : 
      44                 : class nsSMILValue;
      45                 : 
      46                 : //////////////////////////////////////////////////////////////////////////////
      47                 : // nsISMILType: Interface for defining the basic operations needed for animating
      48                 : // a particular kind of data (e.g. lengths, colors, transformation matrices).
      49                 : //
      50                 : // This interface is never used directly but always through an nsSMILValue that
      51                 : // bundles together a pointer to a concrete implementation of this interface and
      52                 : // the data upon which it should operate.
      53                 : //
      54                 : // We keep the data and type separate rather than just providing different
      55                 : // subclasses of nsSMILValue. This is so that sizeof(nsSMILValue) is the same
      56                 : // for all value types, allowing us to have a type-agnostic nsTArray of
      57                 : // nsSMILValue objects (actual objects, not pointers). It also allows most
      58                 : // nsSMILValues (except those that need to allocate extra memory for their
      59                 : // data) to be allocated on the stack and directly assigned to one another
      60                 : // provided performance benefits for the animation code.
      61                 : //
      62                 : // Note that different types have different capabilities. Roughly speaking there
      63                 : // are probably three main types:
      64                 : //
      65                 : // +---------------------+---------------+-------------+------------------+
      66                 : // | CATEGORY:           | DISCRETE      | LINEAR      | ADDITIVE         |
      67                 : // +---------------------+---------------+-------------+------------------+
      68                 : // | Example:            | strings,      | path data?  | lengths,         |
      69                 : // |                     | color k/words?|             | RGB color values |
      70                 : // |                     |               |             |                  |
      71                 : // | -- Assign?          |     X         |    X        |    X             |
      72                 : // | -- Add?             |     -         |    X?       |    X             |
      73                 : // | -- SandwichAdd?     |     -         |    -?       |    X             |
      74                 : // | -- ComputeDistance? |     -         |    -        |    X?            |
      75                 : // | -- Interpolate?     |     -         |    X        |    X             |
      76                 : // +---------------------+---------------+-------------+------------------+
      77                 : //
      78                 : 
      79                 : class nsISMILType
      80           24888 : {
      81                 :   /**
      82                 :    * Only give the nsSMILValue class access to this interface.
      83                 :    */
      84                 :   friend class nsSMILValue;
      85                 : 
      86                 : protected:
      87                 :   /**
      88                 :    * Initialises aValue and sets it to some identity value such that adding
      89                 :    * aValue to another value of the same type has no effect.
      90                 :    *
      91                 :    * @pre  aValue.IsNull()
      92                 :    * @post aValue.mType == this
      93                 :    */
      94                 :   virtual void Init(nsSMILValue& aValue) const = 0;
      95                 : 
      96                 :   /**
      97                 :    * Destroys any data associated with a value of this type.
      98                 :    *
      99                 :    * @pre  aValue.mType == this
     100                 :    * @post aValue.IsNull()
     101                 :    */
     102                 :   virtual void Destroy(nsSMILValue& aValue) const = 0;
     103                 : 
     104                 :   /**
     105                 :    * Assign this object the value of another. Think of this as the assignment
     106                 :    * operator.
     107                 :    *
     108                 :    * @param   aDest       The left-hand side of the assignment.
     109                 :    * @param   aSrc        The right-hand side of the assignment.
     110                 :    * @return  NS_OK on success, an error code on failure such as when the
     111                 :    *          underlying type of the specified object differs.
     112                 :    *
     113                 :    * @pre aDest.mType == aSrc.mType == this
     114                 :    */
     115                 :   virtual nsresult Assign(nsSMILValue& aDest,
     116                 :                           const nsSMILValue& aSrc) const = 0;
     117                 : 
     118                 :   /**
     119                 :    * Test two nsSMILValue objects (of this nsISMILType) for equality.
     120                 :    *
     121                 :    * A return value of true represents a guarantee that aLeft and aRight are
     122                 :    * equal. (That is, they would behave identically if passed to the methods
     123                 :    * Add, SandwichAdd, ComputeDistance, and Interpolate).
     124                 :    *
     125                 :    * A return value of false simply indicates that we make no guarantee
     126                 :    * about equality.
     127                 :    *
     128                 :    * NOTE: It's perfectly legal for implementations of this method to return
     129                 :    * false in all cases.  However, smarter implementations will make this
     130                 :    * method more useful for optimization.
     131                 :    *
     132                 :    * @param   aLeft       The left-hand side of the equality check.
     133                 :    * @param   aRight      The right-hand side of the equality check.
     134                 :    * @return  true if we're sure the values are equal, false otherwise.
     135                 :    *
     136                 :    * @pre aDest.mType == aSrc.mType == this
     137                 :    */
     138                 :   virtual bool IsEqual(const nsSMILValue& aLeft,
     139                 :                          const nsSMILValue& aRight) const = 0;
     140                 : 
     141                 :   /**
     142                 :    * Adds two values.
     143                 :    *
     144                 :    * The count parameter facilitates repetition.
     145                 :    *
     146                 :    * By equation,
     147                 :    *
     148                 :    *   aDest += aValueToAdd * aCount
     149                 :    *
     150                 :    * Therefore, if aCount == 0, aDest will be unaltered.
     151                 :    *
     152                 :    * This method will fail if this data type is not additive or the value was
     153                 :    * not specified using an additive syntax.
     154                 :    *
     155                 :    * See SVG 1.1, section 19.2.5. In particular,
     156                 :    *
     157                 :    *   "If a given attribute or property can take values of keywords (which are
     158                 :    *   not additive) or numeric values (which are additive), then additive
     159                 :    *   animations are possible if the subsequent animation uses a numeric value
     160                 :    *   even if the base animation uses a keyword value; however, if the
     161                 :    *   subsequent animation uses a keyword value, additive animation is not
     162                 :    *   possible."
     163                 :    *
     164                 :    * If this method fails (e.g. because the data type is not additive), aDest
     165                 :    * will be unaltered.
     166                 :    *
     167                 :    * @param   aDest       The value to add to.
     168                 :    * @param   aValueToAdd The value to add.
     169                 :    * @param   aCount      The number of times to add aValueToAdd.
     170                 :    * @return  NS_OK on success, an error code on failure.
     171                 :    *
     172                 :    * @pre aValueToAdd.mType == aDest.mType == this
     173                 :    */
     174                 :   virtual nsresult Add(nsSMILValue& aDest,
     175                 :                        const nsSMILValue& aValueToAdd,
     176                 :                        PRUint32 aCount) const = 0;
     177                 : 
     178                 :   /**
     179                 :    * Adds aValueToAdd to the underlying value in the animation sandwich, aDest.
     180                 :    *
     181                 :    * For most types this operation is identical to a regular Add() but for some
     182                 :    * types (notably <animateTransform>) the operation differs. For
     183                 :    * <animateTransform> Add() corresponds to simply adding together the
     184                 :    * transform parameters and is used when calculating cumulative values or
     185                 :    * by-animation values. On the other hand SandwichAdd() is used when adding to
     186                 :    * the underlying value and requires matrix post-multiplication. (This
     187                 :    * distinction is most clearly indicated by the SVGT1.2 test suite. It is not
     188                 :    * obvious within the SMIL specifications.)
     189                 :    *
     190                 :    * @param   aDest       The value to add to.
     191                 :    * @param   aValueToAdd The value to add.
     192                 :    * @return  NS_OK on success, an error code on failure.
     193                 :    *
     194                 :    * @pre aValueToAdd.mType == aDest.mType == this
     195                 :    */
     196               0 :   virtual nsresult SandwichAdd(nsSMILValue& aDest,
     197                 :                                const nsSMILValue& aValueToAdd) const
     198                 :   {
     199               0 :     return Add(aDest, aValueToAdd, 1);
     200                 :   }
     201                 : 
     202                 :   /**
     203                 :    * Calculates the 'distance' between two values. This is the distance used in
     204                 :    * paced interpolation.
     205                 :    *
     206                 :    * @param   aFrom     The start of the interval for which the distance should
     207                 :    *                    be calculated.
     208                 :    * @param   aTo       The end of the interval for which the distance should be
     209                 :    *                    calculated.
     210                 :    * @param   aDistance The result of the calculation.
     211                 :    * @return  NS_OK on success, or an appropriate error code if there is no
     212                 :    *          notion of distance for the underlying data type or the distance
     213                 :    *          could not be calculated.
     214                 :    *
     215                 :    * @pre aFrom.mType == aTo.mType == this
     216                 :    */
     217                 :   virtual nsresult ComputeDistance(const nsSMILValue& aFrom,
     218                 :                                    const nsSMILValue& aTo,
     219                 :                                    double& aDistance) const = 0;
     220                 : 
     221                 :   /**
     222                 :    * Calculates an interpolated value between two values using the specified
     223                 :    * proportion.
     224                 :    *
     225                 :    * @param   aStartVal     The value defining the start of the interval of
     226                 :    *                        interpolation.
     227                 :    * @param   aEndVal       The value defining the end of the interval of
     228                 :    *                        interpolation.
     229                 :    * @param   aUnitDistance A number between 0.0 and 1.0 (inclusive) defining
     230                 :    *                        the distance of the interpolated value in the
     231                 :    *                        interval.
     232                 :    * @param   aResult       The interpolated value.
     233                 :    * @return  NS_OK on success, NS_ERROR_FAILURE if this data type cannot be
     234                 :    *          interpolated or NS_ERROR_OUT_OF_MEMORY if insufficient memory was
     235                 :    *          available for storing the result.
     236                 :    *
     237                 :    * @pre aStartVal.mType == aEndVal.mType == aResult.mType == this
     238                 :    */
     239                 :   virtual nsresult Interpolate(const nsSMILValue& aStartVal,
     240                 :                                const nsSMILValue& aEndVal,
     241                 :                                double aUnitDistance,
     242                 :                                nsSMILValue& aResult) const = 0;
     243                 : 
     244                 :   /**
     245                 :    * Protected destructor, to ensure that no one accidentally deletes an
     246                 :    * instance of this class.
     247                 :    * (The only instances in existence should be singletons - one per subclass.)
     248                 :    */
     249           25279 :   ~nsISMILType() {}
     250                 : };
     251                 : 
     252                 : #endif // NS_ISMILTYPE_H_

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