ScrollOrigin.h - mozsearch

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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_