The display list item for a line of text has a single color assigned for
it, so text fragments with different colors cannot be merged.
There is no issue number for this, as far as I know. I found this while
trying an internal program that uses red asterisks for required text
fields.
Empty fragments may need to be layed out to draw borders, padding/background,
and insertion points. (Fragments that consist of discardable whitespace and
control characters, on the other hand, can still be discarded.)
This ends up preserving some useless empty fragments. It's possible we could
avoid this by storing some sort of flag on "important" empty fragments, so we
can discard the rest.
bottom-up pass.
Right now, the only reason that overflow calculation works is that we
rely on script inducing extra reflows that are sent for display. This
was preventing #10021 from landing.
This change regresses layout performance by about 1% in my tests.
Fixes#7797 properly.
This fixes#7846, a failure in the "quotes-036.htm" test. Servo lays out this
test correctly in its initial layout, but then messes it up in any relayout
(whether it's an incremental or full layout).
The problem is that the ResolveGeneratedContent traversal is not safe to run
more than once on the same flow. It mutates some GeneratedContent fragments
into ScannedText fragments, but leaves others unmodified (in particular,
those that generate empty content). The next time layout runs, these remaining
GeneratedContent fragments are processed *again* but with an incorrect correct
quote nesting level (because some of the surrounding GeneratedContent
fragments are gone).
This patch ensures that each GeneratedContent fragment is resolved only once.
Table border-collapse fixes
Two related fixes for border-collapse:
* Fix border collapsing across table-row-group flows
This fixes the border-end calculation for table rows whose borders are collapsed with rows in different rowgroups. The border collapsing code now uses an iterator that yields all the rows as a flat sequence, regardless of how they are grouped in rowgroups. It gets rid of `TableRowGroupFlow::preliminary_collapsed_borders` which was never correct. (It was read but never written.)
This may fix#8120 but I'm not 100% certain. (I haven't managed to reproduce the intermittent failure locally, and my reduced test case still fails but in a different way.)
* Fix confusing `push_or_mutate` API
This fixes a bug when recalculating border collapsing for an existing table row. The bug was caused by using `push_or_mutate` which has no effect if there is already a value at the specified index.
The fix switches incorrect `push_or_mutate` calls to use `push_or_set` instead. It also renames `push_or_mutate` to `get_mut_or_push` which I think is a less-confusing name for this method.
r? @pcwalton
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This fixes the border-end calculation for table rows whose borders are
collapsed with rows in different rowgroups. The border collapsing code now
uses an iterator that yields all the rows as a flat sequence, regardless of
how they are grouped in rowgroups. It gets rid of
`TableRowGroupFlow::preliminary_collapsed_borders` which was never correct.
(It was read but never written.)
This may fix#8120 but I'm not 100% certain. (I haven't managed to reproduce
the intermittent failure locally, and my reduced test case still fails but in
a different way.)
absolutely-positioned flows separately when storing overflow.
This code dates back to the time when absolutely positioned flows were
ignored by all of their ancestors up to the containing block. This
hasn't been true for at least a year.
Closes#9306.
Closes#9309.
Is a partial fix for #9308.
Also change when pipelines become active.
This makes the constellation activate a pipeline as the current frame
when it is ready to do initial reflow, rather than when it is ready
to paint.
This fixes a number of intermittent failures that could previously occur
if an iframe was not visible - which would mean it was never moved from
a pending frame in the constellation to an active frame.
(It happens that webrender exposes these intermittents as permanent failures).
Move Stylesheet loading and ownership from the layout task into HTML elements
Stylesheets for `HTMLLinkElement`s are now loaded by the resource task, triggered by the element in question. Stylesheets are owned by the elements they're associated with, which can be `HTMLStyleElement`, `HTMLLinkElement`, and `HTMLMetaElement` (for `<meta name="viewport">).
Additionally, the quirks mode stylesheet (just as the user and user agent stylesheets a couple of commits ago), is implemented as a lazy static, loaded once per process and shared between all documents.
This all has various nice consequences:
- Stylesheet loading becomes a non-blocking operation.
- Stylesheets are removed when the element they're associated with is removed from the document.
- It'll be possible to implement the CSSOM APIs that require direct access to the stylesheets (i.e., ~ all of them).
- Various subtle correctness issues are fixed.
One piece of interesting follow-up work would be to move parsing of external stylesheets to the resource task, too. Right now, it happens in the link element once loading is complete, so blocks the script task. Moving it to the resource task would probably be fairly straight-forward as it doesn't require access to any external state.
Depends on #7979 because without that loading stylesheets asynchronously breaks lots of content.
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Stylesheets for `HTMLLinkElement`s are now loaded by the resource task, triggered by the element in question. Stylesheets are owned by the elements they're associated with, which can be `HTMLStyleElement`, `HTMLLinkElement`, and `HTMLMetaElement` (for `<meta name="viewport">).
Additionally, the quirks mode stylesheet (just as the user and user agent stylesheets a couple of commits ago), is implemented as a lazy static, loaded once per process and shared between all documents.
This all has various nice consequences:
- Stylesheet loading becomes a non-blocking operation.
- Stylesheets are removed when the element they're associated with is removed from the document.
- It'll be possible to implement the CSSOM APIs that require direct access to the stylesheets (i.e., ~ all of them).
- Various subtle correctness issues are fixed.
One piece of interesting follow-up work would be to move parsing of external stylesheets to the resource task, too. Right now, it happens in the link element once loading is complete, so blocks the script task. Moving it to the resource task would probably be fairly straight-forward as it doesn't require access to any external state.
Sometimes positioned content needs to be layered on top of stacking
contexts. The layer synthesis code can do this, but the current design
prevents it because stacking contexts are stored in a separate struct
member. In order to preserve tree order, mix stacking contexts into the
positioned content list, by adding a new StackingContextClass
DisplayItem. Such items do not have a base DisplayItem.
In some ways this simplifies the code, because we no longer have to
have a separate code path in the StackingContextLayerCreator.
Fixes#7779.
Fixes#7983.
Fixes#8122.
Fixes#8310.
There is no easy way to pass position-relative-035 & also
pass both tests/ref/border_rounding_1px_invisible_issue_7184 and
tests/ref/text_decoration_underline_subpx.
https://github.com/servo/servo/pull/7161, "Snap rectangles to nearest
pixels...", did fix position-relative-035 (except
for OS X) but broke 1px borders.
