author David Anderson <>
Mon, 17 Oct 2011 11:52:12 -0700
changeset 105267 f93960a93ad97a56d308bd9ce25d97cbc175d524
parent 105229 8cfeba5239a9e4f20c462d6fb20421b4e4e7c735
parent 78840 ec7577dec4fceef0ac2717416d9c48289402d935
child 106227 80e4ab0d24bc64ceaa7693ab5def36faffde7a40
permissions -rw-r--r--
Merge from mozilla-central.

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 * The Original Code is the Mozilla SVG project.
 * The Initial Developer of the Original Code is the Mozilla Foundation.
 * Portions created by the Initial Developer are Copyright (C) 2009
 * the Initial Developer. All Rights Reserved.
 * Contributor(s):
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
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 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 * ***** END LICENSE BLOCK ***** */


#include "nsISMILType.h"

class nsSMILValue;

namespace mozilla {

// SVGLengthListSMILType
// Operations for animating an SVGLengthList.
class SVGLengthListSMILType : public nsISMILType
  // Singleton for nsSMILValue objects to hold onto.
  static SVGLengthListSMILType sSingleton;

  // nsISMILType Methods
  // -------------------

   * When this method initializes the SVGLengthListAndInfo for its nsSMILValue
   * argument, it has to blindly set its mCanZeroPadList to true despite
   * the fact that some attributes can't be zero-padded. (See the explaination
   * that follows.) SVGAnimatedLengthList::SMILAnimatedLengthList's
   * GetBaseValue() and ValueFromString() methods then override this for the
   * nsSMILValue objects that they create to set this flag to the appropriate
   * value for the attribute in question.
   * The reason that we default to setting the mCanZeroPadList to true is
   * because the SMIL engine creates "zero" valued nsSMILValue objects for
   * intermediary calculations, and may pass such an nsSMILValue (along with an
   * nsSMILValue from an animation element - that is an nsSMILValue created by
   * SVGAnimatedLengthList::SMILAnimatedLengthList's GetBaseValue() or
   * ValueFromString() methods) into the Add(), ComputeDistance() or
   * Interpolate() methods below. Even in the case of animation of list
   * attributes that may *not* be padded with zeros (such as 'x' and 'y' on the
   * <text> element), we need to allow zero-padding of these "zero" valued
   * nsSMILValue's lists. One reason for this is illustrated by the following
   * example:
   *   <text x="2 4">foo
   *      <animate by="2 2" .../>
   *   </text>
   * In this example there are two SMIL animation layers to be sandwiched: the
   * base layer, and the layer created for the <animate> element. The SMIL
   * engine calculates the result of each layer *independently*, before
   * compositing the results together. Thus for the <animate> sandwich layer
   * the SMIL engine interpolates between a "zero" nsSMILValue that it creates
   * (since there is no explicit "from") and the "2 2", before the result of
   * that interpolation is added to the "2 4" from the base layer. Clearly for
   * the interpolation between the "zero" nsSMILValue and "2 2" to work, the
   * "zero" nsSMILValue's SVGLengthListAndInfo must be zero paddable - hence
   * why this method always sets mCanZeroPadList to true.
   * (Since the Add(), ComputeDistance() and Interpolate() methods may be
   * passed two input nsSMILValue objects for which CanZeroPadList() returns
   * opposite values, these methods must be careful what they set the flag to
   * on the nsSMILValue that they output. If *either* of the input nsSMILValues
   * has an SVGLengthListAndInfo for which CanZeroPadList() returns false,
   * then they must set the flag to false on the output nsSMILValue too. If
   * the methods failed to do that, then when the result nsSMILValue objects
   * from each sandwich layer are composited together, we could end up allowing
   * animation between lists of different length when we should not!)
  virtual void     Init(nsSMILValue& aValue) const;

  virtual void     Destroy(nsSMILValue& aValue) const;
  virtual nsresult Assign(nsSMILValue& aDest, const nsSMILValue& aSrc) const;
  virtual bool     IsEqual(const nsSMILValue& aLeft,
                           const nsSMILValue& aRight) const;
  virtual nsresult Add(nsSMILValue& aDest, const nsSMILValue& aValueToAdd,
                       PRUint32 aCount) const;
  virtual nsresult ComputeDistance(const nsSMILValue& aFrom,
                                   const nsSMILValue& aTo,
                                   double& aDistance) const;
  virtual nsresult Interpolate(const nsSMILValue& aStartVal,
                               const nsSMILValue& aEndVal,
                               double aUnitDistance,
                               nsSMILValue& aResult) const;

  // Private constructor & destructor: prevent instances beyond my singleton,
  // and prevent others from deleting my singleton.
  SVGLengthListSMILType() {}
  ~SVGLengthListSMILType() {}

} // namespace mozilla