content/smil/nsISMILAttr.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef NS_ISMILATTR_H_
   7 #define NS_ISMILATTR_H_
   8
   9 #include "nscore.h"
  10
  11 class nsSMILValue;
  12 class nsISMILType;
  13 class nsISMILAnimationElement;
  14 class nsIContent;
  15 class nsAString;
  16
  17 ////////////////////////////////////////////////////////////////////////
  18 // nsISMILAttr: A variable targeted by SMIL for animation and can therefore have
  19 // an underlying (base) value and an animated value For example, an attribute of
  20 // a particular SVG element.
  21 //
  22 // These objects only exist during the compositing phase of SMIL animation
  23 // calculations. They have a single owner who is responsible for deleting the
  24 // object.
  25
  26 class nsISMILAttr
  27 {
  28 public:
  29   /**
  30    * Creates a new nsSMILValue for this attribute from a string. The string is
  31    * parsed in the context of this attribute so that context-dependent values
  32    * such as em-based units can be resolved into a canonical form suitable for
  33    * animation (including interpolation etc.).
  34    *
  35    * @param aStr        A string defining the new value to be created.
  36    * @param aSrcElement The source animation element. This may be needed to
  37    *                    provided additional context data such as for
  38    *                    animateTransform where the 'type' attribute is needed to
  39    *                    parse the value.
  40    * @param[out] aValue Outparam for storing the parsed value.
  41    * @param[out] aPreventCachingOfSandwich
  42    *                    Outparam to indicate whether the attribute contains
  43    *                    dependencies on its context that should prevent the
  44    *                    result of the animation sandwich from being cached and
  45    *                    reused in future samples.
  46    * @return NS_OK on success or an error code if creation failed.
  47    */
  48   virtual nsresult ValueFromString(const nsAString& aStr,
  49                                    const nsISMILAnimationElement* aSrcElement,
  50                                    nsSMILValue& aValue,
  51                                    bool& aPreventCachingOfSandwich) const = 0;
  52
  53   /**
  54    * Gets the underlying value of this attribute.
  55    *
  56    * @return an nsSMILValue object. returned_object.IsNull() will be true if an
  57    * error occurred.
  58    */
  59   virtual nsSMILValue GetBaseValue() const = 0;
  60
  61   /**
  62    * Clears the animated value of this attribute.
  63    *
  64    * NOTE: The animation target is not guaranteed to be in a document when this
  65    * method is called. (See bug 523188)
  66    */
  67   virtual void ClearAnimValue() = 0;
  68
  69   /**
  70    * Sets the presentation value of this attribute.
  71    *
  72    * @param aValue  The value to set.
  73    * @return NS_OK on success or an error code if setting failed.
  74    */
  75   virtual nsresult SetAnimValue(const nsSMILValue& aValue) = 0;
  76
  77   /**
  78    * Returns the targeted content node, for any nsISMILAttr implementations
  79    * that want to expose that to the animation logic.  Otherwise, returns
  80    * null.
  81    *
  82    * @return the targeted content node, if this nsISMILAttr implementation
  83    * wishes to make it avaiable.  Otherwise, nullptr.
  84    */
  85   virtual const nsIContent* GetTargetNode() const { return nullptr; }
  86
  87   /**
  88    * Virtual destructor, to make sure subclasses can clean themselves up.
  89    */
  90   virtual ~nsISMILAttr() {}
  91 };
  92
  93 #endif // NS_ISMILATTR_H_