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445d9cf0b8
This adds a new scroll origin, None, which is used as the initial value for mLastScrollOrigin. Unlike Other, this scroll origin can be clobbered by any other scroll origin, including notably Relative. This means that on a brand-new scrollframe, if the first scroll call comes in with an origin of Relative, it will be preserved as a relative scroll instead of getting converted to a non-relative scroll. This in turn fixes a latent bug in the code that was exposed by the test_relative_update.html APZ mochitest when run with apz.allow_zooming=true. Note also that we should never be passing eNone to functions like ScrollToImpl; for those scenarios we continue using Unknown if we don't have a more specific scroll origin to use. In other words, None is a sort of sentinel value to be used for class fields, and is not to be used for actual scrollto-type calls. Differential Revision: https://phabricator.services.mozilla.com/D78439
64 lines
2.5 KiB
C++
64 lines
2.5 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 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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