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