255 lines
6.9 KiB
C
255 lines
6.9 KiB
C
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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_dom_ResizeObserver_h
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#define mozilla_dom_ResizeObserver_h
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#include "mozilla/dom/ResizeObserverBinding.h"
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namespace mozilla {
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namespace dom {
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/**
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* ResizeObserver interfaces and algorithms are based on
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* https://wicg.github.io/ResizeObserver/#api
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*/
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class ResizeObserver final
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: public nsISupports
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, public nsWrapperCache
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{
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public:
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NS_DECL_CYCLE_COLLECTING_ISUPPORTS
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NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(ResizeObserver)
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ResizeObserver(already_AddRefed<nsPIDOMWindowInner>&& aOwner,
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ResizeObserverCallback& aCb)
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: mOwner(aOwner)
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, mCallback(&aCb)
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{
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MOZ_ASSERT(mOwner, "Need a non-null owner window");
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}
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static already_AddRefed<ResizeObserver>
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Constructor(const GlobalObject& aGlobal,
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ResizeObserverCallback& aCb,
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ErrorResult& aRv);
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JSObject* WrapObject(JSContext* aCx,
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JS::Handle<JSObject*> aGivenProto) override
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{
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return ResizeObserverBinding::Wrap(aCx, this, aGivenProto);
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}
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nsISupports* GetParentObject() const
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{
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return mOwner;
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}
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void Observe(Element* aTarget, ErrorResult& aRv);
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void Unobserve(Element* aTarget, ErrorResult& aRv);
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void Disconnect();
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/*
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* Gather all observations which have an observed target with size changed
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* since last BroadcastActiveObservations() in this ResizeObserver.
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* An observation will be skipped if the depth of its observed target is less
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* or equal than aDepth. All gathered observations will be added to
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* mActiveTargets.
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*/
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void GatherActiveObservations(uint32_t aDepth);
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/*
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* Returns whether this ResizeObserver has any active observations
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* since last GatherActiveObservations().
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*/
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bool HasActiveObservations() const;
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/*
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* Returns whether this ResizeObserver has any skipped observations
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* since last GatherActiveObservations().
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*/
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bool HasSkippedObservations() const;
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/*
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* Deliver the callback function in JavaScript for all active observations
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* and pass the sequence of ResizeObserverEntry so JavaScript can access them.
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* The broadcast size of observations will be updated and mActiveTargets will
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* be cleared. It also returns the shallowest depth of elements from active
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* observations or UINT32_MAX if there is no any active observations.
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*/
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uint32_t BroadcastActiveObservations();
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protected:
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~ResizeObserver()
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{
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mObservationList.clear();
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}
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nsCOMPtr<nsPIDOMWindowInner> mOwner;
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RefPtr<ResizeObserverCallback> mCallback;
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nsTArray<RefPtr<ResizeObservation>> mActiveTargets;
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bool mHasSkippedTargets;
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// Combination of HashTable and LinkedList so we can iterate through
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// the elements of HashTable in order of insertion time.
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// Will be nice if we have our own data structure for this in the future.
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nsRefPtrHashtable<nsPtrHashKey<Element>, ResizeObservation> mObservationMap;
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LinkedList<ResizeObservation> mObservationList;
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};
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/**
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* ResizeObserverEntry is the entry that contains the information for observed
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* elements. This object is the one that visible to JavaScript in callback
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* function that is fired by ResizeObserver.
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*/
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class ResizeObserverEntry final
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: public nsISupports
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, public nsWrapperCache
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{
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public:
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NS_DECL_CYCLE_COLLECTING_ISUPPORTS
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NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(ResizeObserverEntry)
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ResizeObserverEntry(nsISupports* aOwner, Element* aTarget)
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: mOwner(aOwner)
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, mTarget(aTarget)
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{
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MOZ_ASSERT(mOwner, "Need a non-null owner");
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MOZ_ASSERT(mTarget, "Need a non-null target element");
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}
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static already_AddRefed<ResizeObserverEntry>
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Constructor(const GlobalObject& aGlobal,
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Element* aTarget,
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ErrorResult& aRv);
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JSObject* WrapObject(JSContext* aCx,
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JS::Handle<JSObject*> aGivenProto) override
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{
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return ResizeObserverEntryBinding::Wrap(aCx, this,
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aGivenProto);
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}
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nsISupports* GetParentObject() const
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{
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return mOwner;
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}
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Element* Target() const
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{
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return mTarget;
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}
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/*
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* Returns the DOMRectReadOnly of target's content rect so it can be
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* accessed from JavaScript in callback function of ResizeObserver.
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*/
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DOMRectReadOnly* GetContentRect() const
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{
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return mContentRect;
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}
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void SetContentRect(nsRect aRect);
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protected:
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~ResizeObserverEntry();
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nsCOMPtr<nsISupports> mOwner;
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nsCOMPtr<Element> mTarget;
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RefPtr<DOMRectReadOnly> mContentRect;
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};
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/**
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* We use ResizeObservation to store and sync the size information of one
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* observed element so we can decide whether an observation should be fired
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* or not.
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*/
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class ResizeObservation final
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: public nsISupports
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, public nsWrapperCache
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, public LinkedListElement<ResizeObservation>
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{
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public:
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NS_DECL_CYCLE_COLLECTING_ISUPPORTS
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NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(ResizeObservation)
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ResizeObservation(nsISupports* aOwner, Element* aTarget)
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: mOwner(aOwner)
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, mTarget(aTarget)
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, mBroadcastWidth(0)
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, mBroadcastHeight(0)
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{
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MOZ_ASSERT(mOwner, "Need a non-null owner");
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MOZ_ASSERT(mTarget, "Need a non-null target element");
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}
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static already_AddRefed<ResizeObservation>
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Constructor(const GlobalObject& aGlobal,
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Element* aTarget,
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ErrorResult& aRv);
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JSObject* WrapObject(JSContext* aCx,
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JS::Handle<JSObject*> aGivenProto) override
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{
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return ResizeObservationBinding::Wrap(aCx, this, aGivenProto);
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}
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nsISupports* GetParentObject() const
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{
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return mOwner;
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}
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Element* Target() const
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{
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return mTarget;
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}
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nscoord BroadcastWidth() const
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{
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return mBroadcastWidth;
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}
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nscoord BroadcastHeight() const
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{
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return mBroadcastHeight;
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}
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/*
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* Returns whether the observed target element size differs from current
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* BroadcastWidth and BroadcastHeight
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*/
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bool IsActive() const;
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/*
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* Update current BroadcastWidth and BroadcastHeight with size from aRect.
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*/
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void UpdateBroadcastSize(nsRect aRect);
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/*
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* Returns the target's rect in the form of nsRect.
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* If the target is SVG, width and height are determined from bounding box.
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*/
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nsRect GetTargetRect() const;
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protected:
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~ResizeObservation();
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nsCOMPtr<nsISupports> mOwner;
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nsCOMPtr<Element> mTarget;
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// Broadcast width and broadcast height are the latest recorded size
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// of observed target.
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nscoord mBroadcastWidth;
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nscoord mBroadcastHeight;
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};
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} // namespace dom
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} // namespace mozilla
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#endif // mozilla_dom_ResizeObserver_h
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