gecko-dev/content/smil/nsISMILAttr.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef NS_ISMILATTR_H_
#define NS_ISMILATTR_H_
#include "nscore.h"
class nsSMILValue;
class nsISMILType;
class nsISMILAnimationElement;
class nsIContent;
class nsAString;
////////////////////////////////////////////////////////////////////////
// nsISMILAttr: A variable targeted by SMIL for animation and can therefore have
// an underlying (base) value and an animated value For example, an attribute of
// a particular SVG element.
//
// These objects only exist during the compositing phase of SMIL animation
// calculations. They have a single owner who is responsible for deleting the
// object.
class nsISMILAttr
{
public:
/**
* Creates a new nsSMILValue for this attribute from a string. The string is
* parsed in the context of this attribute so that context-dependent values
* such as em-based units can be resolved into a canonical form suitable for
* animation (including interpolation etc.).
*
* @param aStr A string defining the new value to be created.
* @param aSrcElement The source animation element. This may be needed to
* provided additional context data such as for
* animateTransform where the 'type' attribute is needed to
* parse the value.
* @param[out] aValue Outparam for storing the parsed value.
* @param[out] aPreventCachingOfSandwich
* Outparam to indicate whether the attribute contains
* dependencies on its context that should prevent the
* result of the animation sandwich from being cached and
* reused in future samples.
* @return NS_OK on success or an error code if creation failed.
*/
virtual nsresult ValueFromString(const nsAString& aStr,
const nsISMILAnimationElement* aSrcElement,
nsSMILValue& aValue,
bool& aPreventCachingOfSandwich) const = 0;
/**
* Gets the underlying value of this attribute.
*
* @return an nsSMILValue object. returned_object.IsNull() will be true if an
* error occurred.
*/
virtual nsSMILValue GetBaseValue() const = 0;
/**
* Clears the animated value of this attribute.
*
* NOTE: The animation target is not guaranteed to be in a document when this
* method is called. (See bug 523188)
*/
virtual void ClearAnimValue() = 0;
/**
* Sets the presentation value of this attribute.
*
* @param aValue The value to set.
* @return NS_OK on success or an error code if setting failed.
*/
virtual nsresult SetAnimValue(const nsSMILValue& aValue) = 0;
/**
* Returns the targeted content node, for any nsISMILAttr implementations
* that want to expose that to the animation logic. Otherwise, returns
* null.
*
* @return the targeted content node, if this nsISMILAttr implementation
* wishes to make it avaiable. Otherwise, nullptr.
*/
virtual const nsIContent* GetTargetNode() const { return nullptr; }
/**
* Virtual destructor, to make sure subclasses can clean themselves up.
*/
virtual ~nsISMILAttr() {}
};
#endif // NS_ISMILATTR_H_