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/* 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 mozilla_ScrollOrigin_h_
#define mozilla_ScrollOrigin_h_
#include "mozilla/DefineEnum.h"
namespace mozilla {
// A scroll origin is a bit of a combination of "what part of the code caused
// this scroll" and "what special properties does this scroll have, in the
// context of what caused it". See specific comments below.
MOZ_DEFINE_ENUM_CLASS_WITH_BASE_AND_TOSTRING(
ScrollOrigin, uint8_t,
(
// This is used as an initial value for the "LastScrollOrigin" property
// on scrollable frames. It is not intended to be an actual scroll
// origin, but a sentinel value that indicates that there was no "last
// scroll". It is used similarly for the "LastSmoothScrollOrigin"
// property, to indicate no smooth scroll is in progress.
None,
// This is a default value that we use when we don't know of a more
// specific value that we can use.
NotSpecified,
// The scroll came from APZ code.
Apz,
// The scroll came from an attempt at restoring a scroll position saved
// in the bfcache or history.
Restore,
// The scroll came from a "relative" scroll method like ScrollBy, where
// the scroll destination is indicated by a delta from the current
// position instead of an absolute value.
Relative,
// The scroll came from an attempt by the main thread to re-clamp the
// scroll position after a reflow.
Clamp,
// The following scroll origins also are associated with prefs of the
// form
// general.smoothScroll.<origin>(.*)
// e.g. general.smoothScroll.lines indicates whether or not a scroll
// with origin Lines will be animated smoothly, and e.g. subprefs like
// general.smoothScroll.lines.durationMinMS control some of the
// animation timing behavior.
// The scroll came from some sort of input that's not one of the above
// or below values. Generally this means it came from a content-exposed
// API, like window.scrollTo, but may also be from other sources that
// don't need any particular special handling.
Other,
// The scroll was originated by pixel-scrolling input device (e.g.
// precision mouse wheel).
Pixels,
// The scroll was originated by a line-scrolling input device (e.g.
// up/down keyboard buttons).
Lines,
// The scroll was originated by a page-scrolling input device (e.g.
// pgup/ pgdn keyboard buttons).
Pages,
// The scroll was originated by a mousewheel that scrolls by lines.
MouseWheel,
// The scroll was originated by moving the scrollbars.
Scrollbars));
} // namespace mozilla
#endif // mozilla_ScrollOrigin_h_
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