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/*
* Copyright (C) 2008 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_SVG_ANIMATION_SMIL_ANIMATION_SANDWICH_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_SVG_ANIMATION_SMIL_ANIMATION_SANDWICH_H_
#include "third_party/blink/renderer/core/svg/animation/smil_time.h"
#include "third_party/blink/renderer/platform/heap/handle.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"
namespace blink {
class SVGAnimationElement;
// This class implements/helps with implementing the "sandwich model" from SMIL.
// https://www.w3.org/TR/SMIL3/smil-animation.html#animationNS-AnimationSandwichModel
//
// A "sandwich" contains all the animation elements that targets a specific
// attribute (or property) on a certain element.
//
// Consider the following simple example:
//
// <svg>
// <rect id="foo" width="100" height="100" fill="yellow">
// <set id="s1" attributeName="fill" to="blue" begin="1s; 3s" dur="1s"/>
// <set id="s2" attributeName="fill" to="lightblue" begin="1.5s" dur="2s"/>
// </rect>
// </svg>
//
// In this case there is only one sandwich: <#foo, "fill">
//
// The sandwich is priority-sorted with the priority being derived from when
// the currently active interval began - later is higher. In the above example
// there are three intervals: [1s 2s) and [3s 4s) for the first <set> element
// (in tree-order) and [1.5s 3.5s) for the second <set> element. The animation
// elements are only active within the intervals defined (no fill="freeze").
//
// When the first interval of the first <set> starts (at 1s), it is the only
// active animation and thus the only one to apply. When the second interval
// starts (at 1.5s) its animation gets a higher priority and replaces the lower
// priority animation from the first <set>. The first <set> then ends at 2s,
// leaving the second <set> as the only active animation. When the first <set>
// then starts again at 3s it gets a higher priority because of the later begin
// time and replaces the animation from the second <set>. When the second <set>
// ends at 3.5s nothing changes because the first <set> is still active. When
// the second <set> ends again at 4s, no animation apply and the target reverts
// to the base value (yellow) again.
//
// Schematically (right hand side exclusive):
//
// 0s -> 1s: No animations apply (fill=yellow)
// Sandwich order: (s1) (s2) [both inactive]
// 1s -> 1.5s: The first <set> apply (fill=blue)
// Sandwich order: s1 (s2) [only s1 active]
// 1.5s -> 2s: The second <set> apply (fill=lightblue)
// Sandwich order: s1 s2
// 2s -> 3s: The second <set> apply (fill=lightblue)
// Sandwich order: (s1) s2
// 3s -> 3.5s: The first <set> apply (fill=blue)
// Sandwich order: s2 s1
// 3.5s -> 4s: The first <set> apply (fill=blue)
// Sandwich order: (s2) s1
// 4s -> ...: No animations apply (fill=yellow)
//
// -----
//
// Implementation details:
//
// UpdateActiveAnimationStack() handles the sorting described above and
// constructs a vector containing only the active elements.
//
// ApplyAnimationValues() computes the actual animation value based on the
// vector of active elements and applies it to the target element.
//
class SMILAnimationSandwich : public GarbageCollected<SMILAnimationSandwich> {
public:
SMILAnimationSandwich();
void Add(SVGAnimationElement* animation);
void Remove(SVGAnimationElement* animation);
void UpdateActiveAnimationStack(SMILTime presentation_time);
bool ApplyAnimationValues();
bool IsEmpty() { return sandwich_.IsEmpty(); }
void Trace(Visitor*);
private:
// Results are accumulated to the first animation element that animates and
// contributes to a particular element/attribute pair. We refer to this as
// the "result element".
SVGAnimationElement* ResultElement() const;
using AnimationsVector = HeapVector<Member<SVGAnimationElement>>;
// All the animation (really: timed) elements that make up the sandwich,
// sorted according to priority.
AnimationsVector sandwich_;
// The currently active animation elements in the sandwich. Retains the
// ordering of elements from |sandwich_| when created. This is the animation
// elements from which the animation value is computed.
AnimationsVector active_;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_CORE_SVG_ANIMATION_SMIL_ANIMATION_SANDWICH_H_
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