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a457a5cfbb
The scroll snap spec defines the concepts [1]. There are three type of scroll operations. 1) intended end position, 2) intended direction and end position and 3) intended direction. Basically our existing ScrollUnits types correspond; 1) DEVICE_PIXELS, WHOLE => intended end position 2) PAGES => intended direction and end position 3) LINES => intended direction There are two exceptions in the `intended direction and end position` case, scrollBy() and fling gestures (on Linux). They were defined as scroll operations with DEVICE_PIXELS unit, but the spec cleary says they are `intended direction and end position` operations. Note that we will also use this information for scroll-snap-stop property since the properly will only have effects on both 2) and 3) cases. [1] https://drafts.csswg.org/css-scroll-snap/#scroll-types Depends on D145190 Differential Revision: https://phabricator.services.mozilla.com/D145191
73 lines
2.7 KiB
C++
73 lines
2.7 KiB
C++
/* 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 mozilla_ScrollTypes_h
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#define mozilla_ScrollTypes_h
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#include "mozilla/TypedEnumBits.h"
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// Types used in main-thread scrolling interfaces such as nsIScrollableFrame.
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namespace mozilla {
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/**
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* Scroll modes for main-thread scroll operations. These are mostly used
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* by nsIScrollableFrame methods.
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*
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* When a scroll operation is requested, we ask for instant, smooth,
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* smooth msd, or normal scrolling.
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*
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* |Smooth| scrolls have a symmetrical acceleration and deceleration curve
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* modeled with a set of splines that guarantee that the destination will be
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* reached over a fixed time interval. |Smooth| will only be smooth if smooth
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* scrolling is actually enabled. This behavior is utilized by keyboard and
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* mouse wheel scrolling events.
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*
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* |SmoothMsd| implements a physically based model that approximates the
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* behavior of a mass-spring-damper system. |SmoothMsd| scrolls have a
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* non-symmetrical acceleration and deceleration curve, can potentially
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* overshoot the destination on intermediate frames, and complete over a
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* variable time interval. |SmoothMsd| will only be smooth if cssom-view
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* smooth-scrolling is enabled.
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*
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* |Instant| is always synchronous, |Normal| can be asynchronous.
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*
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* If an |Instant| scroll request happens while a |Smooth| or async scroll is
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* already in progress, the async scroll is interrupted and we instantly
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* scroll to the destination.
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*
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* If an |Instant| or |Smooth| scroll request happens while a |SmoothMsd|
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* scroll is already in progress, the |SmoothMsd| scroll is interrupted without
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* first scrolling to the destination.
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*/
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enum class ScrollMode { Instant, Smooth, SmoothMsd, Normal };
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/**
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* When scrolling by a relative amount, we can choose various units.
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*/
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enum class ScrollUnit { DEVICE_PIXELS, LINES, PAGES, WHOLE };
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/**
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* Representing whether there's an on-going animation in APZC and it was
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* triggered by script or by user input.
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*/
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enum class APZScrollAnimationType {
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No, // No animation.
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TriggeredByScript, // Animation triggered by script.
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TriggeredByUserInput // Animation triggered by user input.
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};
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enum class ScrollSnapFlags : uint8_t {
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Disabled = 0,
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// https://drafts.csswg.org/css-scroll-snap/#intended-end-position
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IntendedEndPosition = 1 << 0,
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// https://drafts.csswg.org/css-scroll-snap/#intended-direction
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IntendedDirection = 1 << 1
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};
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MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(ScrollSnapFlags);
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} // namespace mozilla
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#endif // mozilla_ScrollTypes_h
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