1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/dom/events/WheelHandlingHelper.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,160 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* vim: set ts=2 sw=2 et tw=80: */
1.6 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#ifndef mozilla_WheelHandlingHelper_h_
1.11 +#define mozilla_WheelHandlingHelper_h_
1.12 +
1.13 +#include "mozilla/Attributes.h"
1.14 +#include "mozilla/EventForwards.h"
1.15 +#include "nsCoord.h"
1.16 +#include "nsIFrame.h"
1.17 +
1.18 +class nsIScrollableFrame;
1.19 +class nsITimer;
1.20 +
1.21 +struct nsIntPoint;
1.22 +
1.23 +namespace mozilla {
1.24 +
1.25 +class EventStateManager;
1.26 +
1.27 +/**
1.28 + * DeltaValues stores two delta values which are along X and Y axis. This is
1.29 + * useful for arguments and results of some methods.
1.30 + */
1.31 +
1.32 +struct DeltaValues
1.33 +{
1.34 + DeltaValues()
1.35 + : deltaX(0.0)
1.36 + , deltaY(0.0)
1.37 + {
1.38 + }
1.39 +
1.40 + DeltaValues(double aDeltaX, double aDeltaY)
1.41 + : deltaX(aDeltaX)
1.42 + , deltaY(aDeltaY)
1.43 + {
1.44 + }
1.45 +
1.46 + explicit DeltaValues(WidgetWheelEvent* aEvent);
1.47 +
1.48 + double deltaX;
1.49 + double deltaY;
1.50 +};
1.51 +
1.52 +/**
1.53 + * WheelHandlingUtils provides some static methods which are useful at handling
1.54 + * wheel events.
1.55 + */
1.56 +
1.57 +class WheelHandlingUtils
1.58 +{
1.59 +public:
1.60 + /**
1.61 + * Returns true if the scrollable frame can be scrolled to either aDirectionX
1.62 + * or aDirectionY along each axis. Otherwise, false.
1.63 + */
1.64 + static bool CanScrollOn(nsIScrollableFrame* aScrollFrame,
1.65 + double aDirectionX, double aDirectionY);
1.66 +
1.67 +private:
1.68 + static bool CanScrollInRange(nscoord aMin, nscoord aValue, nscoord aMax,
1.69 + double aDirection);
1.70 +};
1.71 +
1.72 +/**
1.73 + * ScrollbarsForWheel manages scrollbars state during wheel operation.
1.74 + * E.g., on some platforms, scrollbars should show only while user attempts to
1.75 + * scroll. At that time, scrollbars which may be possible to scroll by
1.76 + * operation of wheel at the point should show temporarily.
1.77 + */
1.78 +
1.79 +class ScrollbarsForWheel
1.80 +{
1.81 +public:
1.82 + static void PrepareToScrollText(EventStateManager* aESM,
1.83 + nsIFrame* aTargetFrame,
1.84 + WidgetWheelEvent* aEvent);
1.85 + static void SetActiveScrollTarget(nsIScrollableFrame* aScrollTarget);
1.86 + // Hide all scrollbars (both mActiveOwner's and mActivatedScrollTargets')
1.87 + static void MayInactivate();
1.88 + static void Inactivate();
1.89 + static bool IsActive();
1.90 + static void OwnWheelTransaction(bool aOwn);
1.91 +
1.92 +protected:
1.93 + static const size_t kNumberOfTargets = 4;
1.94 + static const DeltaValues directions[kNumberOfTargets];
1.95 + static nsWeakFrame sActiveOwner;
1.96 + static nsWeakFrame sActivatedScrollTargets[kNumberOfTargets];
1.97 + static bool sHadWheelStart;
1.98 + static bool sOwnWheelTransaction;
1.99 +
1.100 +
1.101 + /**
1.102 + * These two methods are called upon NS_WHEEL_START/NS_WHEEL_STOP events
1.103 + * to show/hide the right scrollbars.
1.104 + */
1.105 + static void TemporarilyActivateAllPossibleScrollTargets(
1.106 + EventStateManager* aESM,
1.107 + nsIFrame* aTargetFrame,
1.108 + WidgetWheelEvent* aEvent);
1.109 + static void DeactivateAllTemporarilyActivatedScrollTargets();
1.110 +};
1.111 +
1.112 +/**
1.113 + * WheelTransaction manages a series of wheel events as a transaction.
1.114 + * While in a transaction, every wheel event should scroll the same scrollable
1.115 + * element even if a different scrollable element is under the mouse cursor.
1.116 + *
1.117 + * Additionally, this class also manages wheel scroll speed acceleration.
1.118 + */
1.119 +
1.120 +class WheelTransaction
1.121 +{
1.122 +public:
1.123 + static nsIFrame* GetTargetFrame() { return sTargetFrame; }
1.124 + static void BeginTransaction(nsIFrame* aTargetFrame,
1.125 + WidgetWheelEvent* aEvent);
1.126 + // Be careful, UpdateTransaction may fire a DOM event, therefore, the target
1.127 + // frame might be destroyed in the event handler.
1.128 + static bool UpdateTransaction(WidgetWheelEvent* aEvent);
1.129 + static void MayEndTransaction();
1.130 + static void EndTransaction();
1.131 + static void OnEvent(WidgetEvent* aEvent);
1.132 + static void Shutdown();
1.133 + static uint32_t GetTimeoutTime();
1.134 +
1.135 + static void OwnScrollbars(bool aOwn);
1.136 +
1.137 + static DeltaValues AccelerateWheelDelta(WidgetWheelEvent* aEvent,
1.138 + bool aAllowScrollSpeedOverride);
1.139 +
1.140 +protected:
1.141 + static const uint32_t kScrollSeriesTimeout = 80; // in milliseconds
1.142 + static nsIntPoint GetScreenPoint(WidgetGUIEvent* aEvent);
1.143 + static void OnFailToScrollTarget();
1.144 + static void OnTimeout(nsITimer* aTimer, void* aClosure);
1.145 + static void SetTimeout();
1.146 + static uint32_t GetIgnoreMoveDelayTime();
1.147 + static int32_t GetAccelerationStart();
1.148 + static int32_t GetAccelerationFactor();
1.149 + static DeltaValues OverrideSystemScrollSpeed(WidgetWheelEvent* aEvent);
1.150 + static double ComputeAcceleratedWheelDelta(double aDelta, int32_t aFactor);
1.151 + static bool OutOfTime(uint32_t aBaseTime, uint32_t aThreshold);
1.152 +
1.153 + static nsWeakFrame sTargetFrame;
1.154 + static uint32_t sTime; // in milliseconds
1.155 + static uint32_t sMouseMoved; // in milliseconds
1.156 + static nsITimer* sTimer;
1.157 + static int32_t sScrollSeriesCounter;
1.158 + static bool sOwnScrollbars;
1.159 +};
1.160 +
1.161 +} // namespace mozilla
1.162 +
1.163 +#endif // mozilla_WheelHandlingHelper_h_
