michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim: set ts=2 sw=2 et tw=80: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef mozilla_WheelHandlingHelper_h_
michael@0: #define mozilla_WheelHandlingHelper_h_
michael@0: 
michael@0: #include "mozilla/Attributes.h"
michael@0: #include "mozilla/EventForwards.h"
michael@0: #include "nsCoord.h"
michael@0: #include "nsIFrame.h"
michael@0: 
michael@0: class nsIScrollableFrame;
michael@0: class nsITimer;
michael@0: 
michael@0: struct nsIntPoint;
michael@0: 
michael@0: namespace mozilla {
michael@0: 
michael@0: class EventStateManager;
michael@0: 
michael@0: /**
michael@0:  * DeltaValues stores two delta values which are along X and Y axis.  This is
michael@0:  * useful for arguments and results of some methods.
michael@0:  */
michael@0: 
michael@0: struct DeltaValues
michael@0: {
michael@0:   DeltaValues()
michael@0:     : deltaX(0.0)
michael@0:     , deltaY(0.0)
michael@0:   {
michael@0:   }
michael@0: 
michael@0:   DeltaValues(double aDeltaX, double aDeltaY)
michael@0:     : deltaX(aDeltaX)
michael@0:     , deltaY(aDeltaY)
michael@0:   {
michael@0:   }
michael@0: 
michael@0:   explicit DeltaValues(WidgetWheelEvent* aEvent);
michael@0: 
michael@0:   double deltaX;
michael@0:   double deltaY;
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * WheelHandlingUtils provides some static methods which are useful at handling
michael@0:  * wheel events.
michael@0:  */
michael@0: 
michael@0: class WheelHandlingUtils
michael@0: {
michael@0: public:
michael@0:   /**
michael@0:    * Returns true if the scrollable frame can be scrolled to either aDirectionX
michael@0:    * or aDirectionY along each axis.  Otherwise, false.
michael@0:    */
michael@0:   static bool CanScrollOn(nsIScrollableFrame* aScrollFrame,
michael@0:                           double aDirectionX, double aDirectionY);
michael@0: 
michael@0: private:
michael@0:   static bool CanScrollInRange(nscoord aMin, nscoord aValue, nscoord aMax,
michael@0:                                double aDirection);
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * ScrollbarsForWheel manages scrollbars state during wheel operation.
michael@0:  * E.g., on some platforms, scrollbars should show only while user attempts to
michael@0:  * scroll.  At that time, scrollbars which may be possible to scroll by
michael@0:  * operation of wheel at the point should show temporarily.
michael@0:  */
michael@0: 
michael@0: class ScrollbarsForWheel
michael@0: {
michael@0: public:
michael@0:   static void PrepareToScrollText(EventStateManager* aESM,
michael@0:                                   nsIFrame* aTargetFrame,
michael@0:                                   WidgetWheelEvent* aEvent);
michael@0:   static void SetActiveScrollTarget(nsIScrollableFrame* aScrollTarget);
michael@0:   // Hide all scrollbars (both mActiveOwner's and mActivatedScrollTargets')
michael@0:   static void MayInactivate();
michael@0:   static void Inactivate();
michael@0:   static bool IsActive();
michael@0:   static void OwnWheelTransaction(bool aOwn);
michael@0: 
michael@0: protected:
michael@0:   static const size_t kNumberOfTargets = 4;
michael@0:   static const DeltaValues directions[kNumberOfTargets];
michael@0:   static nsWeakFrame sActiveOwner;
michael@0:   static nsWeakFrame sActivatedScrollTargets[kNumberOfTargets];
michael@0:   static bool sHadWheelStart;
michael@0:   static bool sOwnWheelTransaction;
michael@0: 
michael@0: 
michael@0:   /**
michael@0:    * These two methods are called upon NS_WHEEL_START/NS_WHEEL_STOP events
michael@0:    * to show/hide the right scrollbars.
michael@0:    */
michael@0:   static void TemporarilyActivateAllPossibleScrollTargets(
michael@0:                 EventStateManager* aESM,
michael@0:                 nsIFrame* aTargetFrame,
michael@0:                 WidgetWheelEvent* aEvent);
michael@0:   static void DeactivateAllTemporarilyActivatedScrollTargets();
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * WheelTransaction manages a series of wheel events as a transaction.
michael@0:  * While in a transaction, every wheel event should scroll the same scrollable
michael@0:  * element even if a different scrollable element is under the mouse cursor.
michael@0:  *
michael@0:  * Additionally, this class also manages wheel scroll speed acceleration.
michael@0:  */
michael@0: 
michael@0: class WheelTransaction
michael@0: {
michael@0: public:
michael@0:   static nsIFrame* GetTargetFrame() { return sTargetFrame; }
michael@0:   static void BeginTransaction(nsIFrame* aTargetFrame,
michael@0:                                WidgetWheelEvent* aEvent);
michael@0:   // Be careful, UpdateTransaction may fire a DOM event, therefore, the target
michael@0:   // frame might be destroyed in the event handler.
michael@0:   static bool UpdateTransaction(WidgetWheelEvent* aEvent);
michael@0:   static void MayEndTransaction();
michael@0:   static void EndTransaction();
michael@0:   static void OnEvent(WidgetEvent* aEvent);
michael@0:   static void Shutdown();
michael@0:   static uint32_t GetTimeoutTime();
michael@0: 
michael@0:   static void OwnScrollbars(bool aOwn);
michael@0: 
michael@0:   static DeltaValues AccelerateWheelDelta(WidgetWheelEvent* aEvent,
michael@0:                                           bool aAllowScrollSpeedOverride);
michael@0: 
michael@0: protected:
michael@0:   static const uint32_t kScrollSeriesTimeout = 80; // in milliseconds
michael@0:   static nsIntPoint GetScreenPoint(WidgetGUIEvent* aEvent);
michael@0:   static void OnFailToScrollTarget();
michael@0:   static void OnTimeout(nsITimer* aTimer, void* aClosure);
michael@0:   static void SetTimeout();
michael@0:   static uint32_t GetIgnoreMoveDelayTime();
michael@0:   static int32_t GetAccelerationStart();
michael@0:   static int32_t GetAccelerationFactor();
michael@0:   static DeltaValues OverrideSystemScrollSpeed(WidgetWheelEvent* aEvent);
michael@0:   static double ComputeAcceleratedWheelDelta(double aDelta, int32_t aFactor);
michael@0:   static bool OutOfTime(uint32_t aBaseTime, uint32_t aThreshold);
michael@0: 
michael@0:   static nsWeakFrame sTargetFrame;
michael@0:   static uint32_t sTime; // in milliseconds
michael@0:   static uint32_t sMouseMoved; // in milliseconds
michael@0:   static nsITimer* sTimer;
michael@0:   static int32_t sScrollSeriesCounter;
michael@0:   static bool sOwnScrollbars;
michael@0: };
michael@0: 
michael@0: } // namespace mozilla
michael@0: 
michael@0: #endif // mozilla_WheelHandlingHelper_h_