gecko-dev/layout/generic/ScrollbarActivity.h

146 lines
4.7 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 http://mozilla.org/MPL/2.0/. */
#ifndef ScrollbarActivity_h___
#define ScrollbarActivity_h___
#include "mozilla/Attributes.h"
#include "nsCOMPtr.h"
#include "nsIDOMEventListener.h"
#include "mozilla/TimeStamp.h"
#include "nsRefreshDriver.h"
class nsIContent;
class nsIScrollbarOwner;
class nsITimer;
class nsIAtom;
namespace mozilla {
namespace layout {
/**
* ScrollbarActivity
*
* This class manages scrollbar behavior that imitates the native Mac OS X
* Lion overlay scrollbar behavior: Scrollbars are only shown while "scrollbar
* activity" occurs, and they're hidden with a fade animation after a short
* delay.
*
* Scrollbar activity has these states:
* - inactive:
* Scrollbars are hidden.
* - ongoing activity:
* Scrollbars are visible and being operated on in some way, for example
* because they're hovered or pressed.
* - active, but waiting for fade out
* Scrollbars are still completely visible but are about to fade away.
* - fading out
* Scrollbars are subject to a fade-out animation.
*
* Initial scrollbar activity needs to be reported by the scrollbar holder that
* owns the ScrollbarActivity instance. This needs to happen via a call to
* ActivityOccurred(), for example when the current scroll position or the size
* of the scroll area changes.
*
* As soon as scrollbars are visible, the ScrollbarActivity class manages the
* rest of the activity behavior: It ensures that mouse motions inside the
* scroll area keep the scrollbars visible, and that scrollbars don't fade away
* while they're being hovered / dragged. It also sets a sticky hover attribute
* on the most recently hovered scrollbar.
*
* ScrollbarActivity falls into hibernation after the scrollbars have faded
* out. It only starts acting after the next call to ActivityOccurred() /
* ActivityStarted().
*/
class ScrollbarActivity : public nsIDOMEventListener,
public nsARefreshObserver {
public:
ScrollbarActivity(nsIScrollbarOwner* aScrollableFrame)
: mScrollableFrame(aScrollableFrame)
, mNestedActivityCounter(0)
, mIsActive(false)
, mIsFading(false)
, mListeningForEvents(false)
, mHScrollbarHovered(false)
, mVScrollbarHovered(false)
{}
NS_DECL_ISUPPORTS
NS_DECL_NSIDOMEVENTLISTENER
virtual ~ScrollbarActivity() {}
void Destroy();
void ActivityOccurred();
void ActivityStarted();
void ActivityStopped();
virtual void WillRefresh(TimeStamp aTime) MOZ_OVERRIDE;
static void FadeBeginTimerFired(nsITimer* aTimer, void* aSelf) {
reinterpret_cast<ScrollbarActivity*>(aSelf)->BeginFade();
}
static const uint32_t kScrollbarFadeBeginDelay = 450; // milliseconds
static const uint32_t kScrollbarFadeDuration = 200; // milliseconds
protected:
bool IsActivityOngoing()
{ return mNestedActivityCounter > 0; }
bool IsStillFading(TimeStamp aTime);
void HandleEventForScrollbar(const nsAString& aType,
nsIContent* aTarget,
nsIContent* aScrollbar,
bool* aStoredHoverState);
void SetIsActive(bool aNewActive);
bool SetIsFading(bool aNewFading); // returns false if 'this' was destroyed
void BeginFade();
void EndFade();
void StartFadeBeginTimer();
void CancelFadeBeginTimer();
void StartListeningForEvents();
void StartListeningForEventsOnScrollbar(nsIDOMEventTarget* aScrollbar);
void StopListeningForEvents();
void StopListeningForEventsOnScrollbar(nsIDOMEventTarget* aScrollbar);
void RegisterWithRefreshDriver();
void UnregisterFromRefreshDriver();
bool UpdateOpacity(TimeStamp aTime); // returns false if 'this' was destroyed
void HoveredScrollbar(nsIContent* aScrollbar);
nsRefreshDriver* GetRefreshDriver();
nsIContent* GetScrollbarContent(bool aVertical);
nsIContent* GetHorizontalScrollbar() { return GetScrollbarContent(false); }
nsIContent* GetVerticalScrollbar() { return GetScrollbarContent(true); }
static const TimeDuration FadeDuration() {
return TimeDuration::FromMilliseconds(kScrollbarFadeDuration);
}
nsIScrollbarOwner* mScrollableFrame;
TimeStamp mFadeBeginTime;
nsCOMPtr<nsITimer> mFadeBeginTimer;
nsCOMPtr<nsIDOMEventTarget> mHorizontalScrollbar; // null while inactive
nsCOMPtr<nsIDOMEventTarget> mVerticalScrollbar; // null while inactive
int mNestedActivityCounter;
bool mIsActive;
bool mIsFading;
bool mListeningForEvents;
bool mHScrollbarHovered;
bool mVScrollbarHovered;
};
} // namespace layout
} // namespace mozilla
#endif /* ScrollbarActivity_h___ */