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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 */
#ifndef mozilla_dom_VisualViewport_h
#define mozilla_dom_VisualViewport_h
#include "mozilla/DOMEventTargetHelper.h"
#include "mozilla/WeakPtr.h"
#include "mozilla/dom/VisualViewportBinding.h"
#include "Units.h"
class nsPresContext;
namespace mozilla {
class PresShell;
namespace dom {
/* Visual Viewport API spec:
class VisualViewport final : public mozilla::DOMEventTargetHelper {
explicit VisualViewport(nsPIDOMWindowInner* aWindow);
double OffsetLeft() const;
double OffsetTop() const;
double PageLeft() const;
double PageTop() const;
MOZ_CAN_RUN_SCRIPT double Width() const;
MOZ_CAN_RUN_SCRIPT double Height() const;
double Scale() const;
virtual JSObject* WrapObject(JSContext* aCx,
JS::Handle<JSObject*> aGivenProto) override;
void GetEventTargetParent(EventChainPreVisitor& aVisitor) override;
void PostResizeEvent();
void PostScrollEvent(const nsPoint& aPrevVisualOffset,
const nsPoint& aPrevLayoutOffset);
// These two events are modelled after the ScrollEvent class in
// nsGfxScrollFrame.h.
class VisualViewportResizeEvent : public Runnable {
VisualViewportResizeEvent(VisualViewport* aViewport,
nsPresContext* aPresContext);
bool HasPresContext(nsPresContext* aContext) const;
void Revoke();
VisualViewport* mViewport;
WeakPtr<nsPresContext> mPresContext;
class VisualViewportScrollEvent : public Runnable {
VisualViewportScrollEvent(VisualViewport* aViewport,
nsPresContext* aPresContext,
const nsPoint& aPrevVisualOffset,
const nsPoint& aPrevLayoutOffset);
bool HasPresContext(nsPresContext* aContext) const;
void Revoke();
nsPoint PrevVisualOffset() const { return mPrevVisualOffset; }
nsPoint PrevLayoutOffset() const { return mPrevLayoutOffset; }
VisualViewport* mViewport;
WeakPtr<nsPresContext> mPresContext;
// The VisualViewport "scroll" event is supposed to be fired only when the
// *relative* offset between visual and layout viewport changes. The two
// viewports are updated independently from each other, though, so the only
// thing we can do is note the fact that one of the inputs into the relative
// visual viewport offset changed and then check the offset again at the
// next refresh driver tick, just before the event is going to fire.
// Hopefully, at this point both visual and layout viewport positions have
// been updated, so that we're able to tell whether the relative offset did
// in fact change or not.
const nsPoint mPrevVisualOffset;
const nsPoint mPrevLayoutOffset;
virtual ~VisualViewport();
MOZ_CAN_RUN_SCRIPT CSSSize VisualViewportSize() const;
CSSPoint VisualViewportOffset() const;
CSSPoint LayoutViewportOffset() const;
Document* GetDocument() const;
PresShell* GetPresShell() const;
nsPresContext* GetPresContext() const;
MOZ_CAN_RUN_SCRIPT void FireResizeEvent();
MOZ_CAN_RUN_SCRIPT void FireScrollEvent();
RefPtr<VisualViewportResizeEvent> mResizeEvent;
RefPtr<VisualViewportScrollEvent> mScrollEvent;
} // namespace dom
} // namespace mozilla
#endif // mozilla_dom_VisualViewport_h