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e33d1e93e3
The `PanGestureInput`, the argument of the new function named CanTriggerSwipe,
is generated by `theEvent`, the `PanGesgureInput.mPanDisplacement.{x,y}` are
calculated by `theEvent.scrollingDelta{X,Y}` * `BackingScaleFactor()`, so both
inequalities are equivalent.
[1] https://searchfox.org/mozilla-central/rev/07c3bd159f79f81f86050d5e002a14ed741f34f7/widget/cocoa/nsChildView.mm#3394-3395,3408
Differential Revision: https://phabricator.services.mozilla.com/D134368
111 lines
3.9 KiB
C++
111 lines
3.9 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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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
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef SwipeTracker_h
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#define SwipeTracker_h
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#include "EventForwards.h"
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#include "mozilla/layers/AxisPhysicsMSDModel.h"
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#include "mozilla/RefPtr.h"
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#include "mozilla/TimeStamp.h"
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#include "nsRefreshObservers.h"
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#include "Units.h"
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class nsIWidget;
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class nsRefreshDriver;
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namespace mozilla {
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class PanGestureInput;
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/**
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* SwipeTracker turns PanGestureInput events into swipe events
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* (WidgetSimpleGestureEvent) and dispatches them into Gecko.
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* The swiping behavior mirrors the behavior of the Cocoa API
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* -[NSEvent
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* trackSwipeEventWithOptions:dampenAmountThresholdMin:max:usingHandler:].
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* The advantage of using this class over the Cocoa API is that this class
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* properly supports submitting queued up events to it, and that it hopefully
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* doesn't intermittently break scrolling the way the Cocoa API does (bug
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* 927702).
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*
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* The swipe direction is either left or right. It is determined before the
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* SwipeTracker is created and stays fixed during the swipe.
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* During the swipe, the swipe has a current "value" which is between 0 and the
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* target value. The target value is either 1 (swiping left) or -1 (swiping
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* right) - see SwipeSuccessTargetValue().
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* A swipe can either succeed or fail. If it succeeds, the swipe animation
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* animates towards the success target value; if it fails, it animates back to
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* a value of 0. A swipe can only succeed if the user is swiping in an allowed
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* direction. (Since both the allowed directions and the swipe direction are
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* known at swipe start time, it's clear from the beginning whether a swipe is
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* doomed to fail. In that case, the purpose of the SwipeTracker is to simulate
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* a bounce-back animation.)
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*/
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class SwipeTracker final : public nsARefreshObserver {
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public:
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NS_INLINE_DECL_REFCOUNTING(SwipeTracker, override)
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SwipeTracker(nsIWidget& aWidget, const PanGestureInput& aSwipeStartEvent,
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uint32_t aAllowedDirections, uint32_t aSwipeDirection);
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void Destroy();
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nsEventStatus ProcessEvent(const PanGestureInput& aEvent);
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void CancelSwipe(const TimeStamp& aTimeStamp);
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static WidgetSimpleGestureEvent CreateSwipeGestureEvent(
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EventMessage aMsg, nsIWidget* aWidget,
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const LayoutDeviceIntPoint& aPosition, const TimeStamp& aTimeStamp);
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// nsARefreshObserver
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void WillRefresh(mozilla::TimeStamp aTime) override;
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static bool CanTriggerSwipe(const PanGestureInput& aPanInput);
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protected:
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~SwipeTracker();
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bool SwipingInAllowedDirection() const {
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return mAllowedDirections & mSwipeDirection;
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}
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double SwipeSuccessTargetValue() const;
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double ClampToAllowedRange(double aGestureAmount) const;
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bool ComputeSwipeSuccess() const;
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void StartAnimating(double aTargetValue);
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void SwipeFinished(const TimeStamp& aTimeStamp);
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void UnregisterFromRefreshDriver();
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bool SendSwipeEvent(EventMessage aMsg, uint32_t aDirection, double aDelta,
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const TimeStamp& aTimeStamp);
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nsIWidget& mWidget;
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RefPtr<nsRefreshDriver> mRefreshDriver;
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layers::AxisPhysicsMSDModel mAxis;
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const LayoutDeviceIntPoint mEventPosition;
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TimeStamp mLastEventTimeStamp;
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TimeStamp mLastAnimationFrameTime;
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const uint32_t mAllowedDirections;
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const uint32_t mSwipeDirection;
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double mGestureAmount;
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double mCurrentVelocity;
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bool mEventsAreControllingSwipe;
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bool mEventsHaveStartedNewGesture;
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bool mRegisteredWithRefreshDriver;
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};
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struct SwipeEventQueue {
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SwipeEventQueue(uint32_t aAllowedDirections, uint64_t aInputBlockId)
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: allowedDirections(aAllowedDirections), inputBlockId(aInputBlockId) {}
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nsTArray<PanGestureInput> queuedEvents;
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uint32_t allowedDirections;
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uint64_t inputBlockId;
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};
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} // namespace mozilla
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#endif // SwipeTracker_h
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