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/* -*- 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 nsIScrollbarMediator_h___
#define nsIScrollbarMediator_h___
#include "nsQueryFrame.h"
#include "nsCoord.h"
class nsScrollbarFrame;
class nsIFrame;
class nsIScrollbarMediator : public nsQueryFrame
{
public:
NS_DECL_QUERYFRAME_TARGET(nsIScrollbarMediator)
/**
* The aScrollbar argument denotes the scrollbar that's firing the notification.
* aScrollbar is never null.
* aDirection is either -1, 0, or 1.
*/
/**
* When set to ENABLE_SNAP, additional scrolling will be performed after the
* scroll operation to maintain the constraints set by CSS Scroll snapping.
* The additional scrolling may include asynchronous smooth scrolls that
* continue to animate after the initial scroll position has been set.
*/
enum ScrollSnapMode { DISABLE_SNAP, ENABLE_SNAP };
/**
* One of the following three methods is called when the scrollbar's button is
* clicked.
* @note These methods might destroy the frame, pres shell, and other objects.
*/
virtual void ScrollByPage(nsScrollbarFrame* aScrollbar, int32_t aDirection,
ScrollSnapMode aSnap = DISABLE_SNAP) = 0;
virtual void ScrollByWhole(nsScrollbarFrame* aScrollbar, int32_t aDirection,
ScrollSnapMode aSnap = DISABLE_SNAP) = 0;
virtual void ScrollByLine(nsScrollbarFrame* aScrollbar, int32_t aDirection,
ScrollSnapMode aSnap = DISABLE_SNAP) = 0;
/**
* RepeatButtonScroll is called when the scrollbar's button is held down. When the
* button is first clicked the increment is set; RepeatButtonScroll adds this
* increment to the current position.
* @note This method might destroy the frame, pres shell, and other objects.
*/
virtual void RepeatButtonScroll(nsScrollbarFrame* aScrollbar) = 0;
/**
* aOldPos and aNewPos are scroll positions.
* The scroll positions start with zero at the left edge; implementors that want
* zero at the right edge for RTL content will need to adjust accordingly.
* (See ScrollFrameHelper::ThumbMoved in nsGfxScrollFrame.cpp.)
* @note This method might destroy the frame, pres shell, and other objects.
*/
virtual void ThumbMoved(nsScrollbarFrame* aScrollbar,
nscoord aOldPos,
nscoord aNewPos) = 0;
/**
* Called when the scroll bar thumb, slider, or any other component is
* released.
*/
virtual void ScrollbarReleased(nsScrollbarFrame* aScrollbar) = 0;
virtual void VisibilityChanged(bool aVisible) = 0;
/**
* Obtain the frame for the horizontal or vertical scrollbar, or null
* if there is no such box.
*/
virtual nsIFrame* GetScrollbarBox(bool aVertical) = 0;
/**
* Show or hide scrollbars on 2 fingers touch.
* Subclasses should call their ScrollbarActivity's corresponding methods.
*/
virtual void ScrollbarActivityStarted() const = 0;
virtual void ScrollbarActivityStopped() const = 0;
virtual bool IsScrollbarOnRight() const = 0;
/**
* Returns true if the mediator is asking the scrollbar to suppress
* repainting itself on changes.
*/
virtual bool ShouldSuppressScrollbarRepaints() const = 0;
};
#endif
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