gecko-dev/layout/style/nsTransitionManager.h

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/* vim: set shiftwidth=2 tabstop=8 autoindent cindent expandtab: */
/* 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/. */
/* Code to start and animate CSS transitions. */
#ifndef nsTransitionManager_h_
#define nsTransitionManager_h_
#include "mozilla/Attributes.h"
#include "mozilla/MemoryReporting.h"
#include "AnimationCommon.h"
#include "nsCSSPseudoElements.h"
class nsStyleContext;
class nsPresContext;
class nsCSSPropertySet;
struct nsTransition;
struct ElementDependentRuleProcessorData;
/*****************************************************************************
* Per-Element data *
*****************************************************************************/
struct ElementPropertyTransition : public mozilla::ElementAnimation
{
virtual ElementPropertyTransition* AsTransition() { return this; }
virtual const ElementPropertyTransition* AsTransition() const { return this; }
// This is the start value to be used for a check for whether a
// transition is being reversed. Normally the same as
// mProperties[0].mSegments[0].mFromValue, except when this transition
// started as the reversal of another in-progress transition.
// Needed so we can handle two reverses in a row.
nsStyleAnimation::Value mStartForReversingTest;
// Likewise, the portion (in value space) of the "full" reversed
// transition that we're actually covering. For example, if a :hover
// effect has a transition that moves the element 10px to the right
// (by changing 'left' from 0px to 10px), and the mouse moves in to
// the element (starting the transition) but then moves out after the
// transition has advanced 4px, the second transition (from 10px/4px
// to 0px) will have mReversePortion of 0.4. (If the mouse then moves
// in again when the transition is back to 2px, the mReversePortion
// for the third transition (from 0px/2px to 10px) will be 0.8.
double mReversePortion;
// Compute the portion of the *value* space that we should be through
// at the given time. (The input to the transition timing function
// has time units, the output has value units.)
double ValuePortionFor(mozilla::TimeStamp aRefreshTime) const;
bool IsRemovedSentinel() const
{
// Note that mozilla::ElementAnimation::IsRunningAt depends on removed
// sentinels being represented by a null mStartTime.
return mStartTime.IsNull();
}
void SetRemovedSentinel()
{
// assign the null time stamp
mStartTime = mozilla::TimeStamp();
}
};
struct ElementTransitions MOZ_FINAL
: public mozilla::css::CommonElementAnimationData
{
ElementTransitions(mozilla::dom::Element *aElement, nsIAtom *aElementProperty,
nsTransitionManager *aTransitionManager,
mozilla::TimeStamp aNow);
void EnsureStyleRuleFor(mozilla::TimeStamp aRefreshTime);
virtual bool HasAnimationOfProperty(nsCSSProperty aProperty) const MOZ_OVERRIDE;
// If aFlags contains CanAnimate_AllowPartial, returns whether the
// state of this element's transitions at the current refresh driver
// time contains transition data that can be done on the compositor
// thread. (This is useful for determining whether a layer should be
// active, or whether to send data to the layer.)
// If aFlags does not contain CanAnimate_AllowPartial, returns whether
// the state of this element's transitions at the current refresh driver
// time can be fully represented by data sent to the compositor.
// (This is useful for determining whether throttle the transition
// (suppress main-thread style updates).)
// Note that when CanPerformOnCompositorThread returns true, it also,
// as a side-effect, notifies the ActiveLayerTracker. FIXME: This
// should probably move to the relevant callers.
virtual bool CanPerformOnCompositorThread(CanAnimateFlags aFlags) const MOZ_OVERRIDE;
};
class nsTransitionManager MOZ_FINAL
: public mozilla::css::CommonAnimationManager
{
public:
nsTransitionManager(nsPresContext *aPresContext)
: mozilla::css::CommonAnimationManager(aPresContext)
{
}
static ElementTransitions* GetTransitions(nsIContent* aContent) {
return static_cast<ElementTransitions*>
(aContent->GetProperty(nsGkAtoms::transitionsProperty));
}
// Returns true if aContent or any of its ancestors has a transition.
static bool ContentOrAncestorHasTransition(nsIContent* aContent) {
do {
if (GetTransitions(aContent)) {
return true;
}
} while ((aContent = aContent->GetParent()));
return false;
}
typedef mozilla::css::CommonElementAnimationData CommonElementAnimationData;
static ElementTransitions*
GetTransitionsForCompositor(nsIContent* aContent,
nsCSSProperty aProperty)
{
if (!aContent->MayHaveAnimations()) {
return nullptr;
}
ElementTransitions* transitions = GetTransitions(aContent);
if (!transitions ||
!transitions->HasAnimationOfProperty(aProperty) ||
!transitions->CanPerformOnCompositorThread(
CommonElementAnimationData::CanAnimate_AllowPartial)) {
return nullptr;
}
return transitions;
}
/**
* StyleContextChanged
*
* To be called from nsFrameManager::ReResolveStyleContext when the
* style of an element has changed, to initiate transitions from
* that style change. For style contexts with :before and :after
* pseudos, aElement is expected to be the generated before/after
* element.
*
* It may return a "cover rule" (see CoverTransitionStartStyleRule) to
* cover up some of the changes for the duration of the restyling of
* descendants. If it does, this function will take care of causing
* the necessary restyle afterwards, but the caller must restyle the
* element *again* with the original sequence of rules plus the
* returned cover rule as the most specific rule.
*/
already_AddRefed<nsIStyleRule>
StyleContextChanged(mozilla::dom::Element *aElement,
nsStyleContext *aOldStyleContext,
nsStyleContext *aNewStyleContext);
// nsIStyleRuleProcessor (parts)
virtual void RulesMatching(ElementRuleProcessorData* aData) MOZ_OVERRIDE;
virtual void RulesMatching(PseudoElementRuleProcessorData* aData) MOZ_OVERRIDE;
virtual void RulesMatching(AnonBoxRuleProcessorData* aData) MOZ_OVERRIDE;
#ifdef MOZ_XUL
virtual void RulesMatching(XULTreeRuleProcessorData* aData) MOZ_OVERRIDE;
#endif
virtual size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
MOZ_MUST_OVERRIDE MOZ_OVERRIDE;
virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
MOZ_MUST_OVERRIDE MOZ_OVERRIDE;
// nsARefreshObserver
virtual void WillRefresh(mozilla::TimeStamp aTime) MOZ_OVERRIDE;
void FlushTransitions(FlushFlags aFlags);
// Performs a 'mini-flush' to make styles from throttled transitions
// up-to-date prior to processing an unrelated style change, so that
// any transitions triggered by that style change produce correct
// results.
//
// In more detail: when we're able to run animations on the
// compositor, we sometimes "throttle" these animations by skipping
// updating style data on the main thread. However, whenever we
// process a normal (non-animation) style change, any changes in
// computed style on elements that have transition-* properties set
// may need to trigger new transitions; this process requires knowing
// both the old and new values of the property. To do this correctly,
// we need to have an up-to-date *old* value of the property on the
// primary frame. So the purpose of the mini-flush is to update the
// style for all throttled transitions and animations to the current
// animation state without making any other updates, so that when we
// process the queued style updates we'll have correct old data to
// compare against. When we do this, we don't bother touching frames
// other than primary frames.
void UpdateAllThrottledStyles();
ElementTransitions* GetElementTransitions(mozilla::dom::Element *aElement,
nsCSSPseudoElements::Type aPseudoType,
bool aCreateIfNeeded);
protected:
virtual void ElementDataRemoved() MOZ_OVERRIDE;
virtual void AddElementData(mozilla::css::CommonElementAnimationData* aData) MOZ_OVERRIDE;
private:
void ConsiderStartingTransition(nsCSSProperty aProperty,
const nsTransition& aTransition,
mozilla::dom::Element *aElement,
ElementTransitions *&aElementTransitions,
nsStyleContext *aOldStyleContext,
nsStyleContext *aNewStyleContext,
bool *aStartedAny,
nsCSSPropertySet *aWhichStarted);
void WalkTransitionRule(ElementDependentRuleProcessorData* aData,
nsCSSPseudoElements::Type aPseudoType);
// Update the animated styles of an element and its descendants.
// If the element has a transition, it is flushed back to its primary frame.
// If the element does not have a transition, then its style is reparented.
void UpdateThrottledStylesForSubtree(nsIContent* aContent,
nsStyleContext* aParentStyle,
nsStyleChangeList &aChangeList);
void UpdateAllThrottledStylesInternal();
};
#endif /* !defined(nsTransitionManager_h_) */