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From the spec [1]; Using the scroll-snap-type property on the relevant scroll container, the author can request a particular bias for the scrollport to land on a snap position after scrolling operations (including programmatic scrolls such as the scrollTo() method). The target here are functions exposed in web contents other than Element.scrollIntoView which will be changed in the next commit. [1] https://drafts.csswg.org/css-scroll-snap-1/#overview Depends on D21624 Differential Revision: https://phabricator.services.mozilla.com/D21625 --HG-- extra : moz-landing-system : lando
91 lines
3.5 KiB
C++
91 lines
3.5 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 nsIScrollbarMediator_h___
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#define nsIScrollbarMediator_h___
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#include "nsQueryFrame.h"
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#include "nsCoord.h"
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class nsScrollbarFrame;
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class nsIFrame;
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class nsIScrollbarMediator : public nsQueryFrame {
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public:
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NS_DECL_QUERYFRAME_TARGET(nsIScrollbarMediator)
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/**
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* The aScrollbar argument denotes the scrollbar that's firing the
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* notification. aScrollbar is never null. aDirection is either -1, 0, or 1.
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*/
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/**
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* When set to ENABLE_SNAP, additional scrolling will be performed after the
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* scroll operation to maintain the constraints set by CSS Scroll snapping.
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* The additional scrolling may include asynchronous smooth scrolls that
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* continue to animate after the initial scroll position has been set.
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* In case of DEFAULT, it means ENABLE_SNAP for CSS scroll snap v1,
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* DISABLE_SNAP for the old scroll snap.
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*/
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enum ScrollSnapMode { DEFAULT, DISABLE_SNAP, ENABLE_SNAP };
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/**
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* One of the following three methods is called when the scrollbar's button is
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* clicked.
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* @note These methods might destroy the frame, pres shell, and other objects.
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*/
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virtual void ScrollByPage(nsScrollbarFrame* aScrollbar, int32_t aDirection,
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ScrollSnapMode aSnap = DISABLE_SNAP) = 0;
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virtual void ScrollByWhole(nsScrollbarFrame* aScrollbar, int32_t aDirection,
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ScrollSnapMode aSnap = DISABLE_SNAP) = 0;
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virtual void ScrollByLine(nsScrollbarFrame* aScrollbar, int32_t aDirection,
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ScrollSnapMode aSnap = DISABLE_SNAP) = 0;
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/**
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* RepeatButtonScroll is called when the scrollbar's button is held down. When
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* the button is first clicked the increment is set; RepeatButtonScroll adds
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* this increment to the current position.
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* @note This method might destroy the frame, pres shell, and other objects.
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*/
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virtual void RepeatButtonScroll(nsScrollbarFrame* aScrollbar) = 0;
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/**
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* aOldPos and aNewPos are scroll positions.
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* The scroll positions start with zero at the left edge; implementors that
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* want zero at the right edge for RTL content will need to adjust
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* accordingly. (See ScrollFrameHelper::ThumbMoved in nsGfxScrollFrame.cpp.)
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* @note This method might destroy the frame, pres shell, and other objects.
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*/
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virtual void ThumbMoved(nsScrollbarFrame* aScrollbar, nscoord aOldPos,
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nscoord aNewPos) = 0;
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/**
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* Called when the scroll bar thumb, slider, or any other component is
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* released.
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*/
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virtual void ScrollbarReleased(nsScrollbarFrame* aScrollbar) = 0;
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virtual void VisibilityChanged(bool aVisible) = 0;
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/**
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* Obtain the frame for the horizontal or vertical scrollbar, or null
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* if there is no such box.
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*/
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virtual nsIFrame* GetScrollbarBox(bool aVertical) = 0;
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/**
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* Show or hide scrollbars on 2 fingers touch.
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* Subclasses should call their ScrollbarActivity's corresponding methods.
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*/
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virtual void ScrollbarActivityStarted() const = 0;
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virtual void ScrollbarActivityStopped() const = 0;
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virtual bool IsScrollbarOnRight() const = 0;
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/**
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* Returns true if the mediator is asking the scrollbar to suppress
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* repainting itself on changes.
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*/
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virtual bool ShouldSuppressScrollbarRepaints() const = 0;
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};
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#endif
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