Consumers of PlacementAmongFloats weren't handling margins properly.
They were assuming that they would either get a positive adjustment,
or zero for no-op.
However, just like the regular clearance triggered by 'clear', the
clearance added onto blocks that establish an independent FC can be
zero or negative, and the effect is different than having no clearance.
* Add initial support for css-text-3 whitespace handling
This adds initial support for whitespace handling from the CSS
specification for Layout 2020. In general, the basics are covered. Since
test output is very sensitive to whitespace handling, this change
incorporates several fixes:
1. Whitespace is collapsed according to the Phase 1 rules of the
specification, though language-specific unbreaking rules are not
handled properly yet.
2. Whitespace is mostly trimmed and positioned according to the Phase 2
rules, but full support for removing whitespace at the end of lines
is pending on a temporary data structure to hold lines under
construction.
3. Completely empty box fragments left over immediately after line
breaks are now trimmed from the fragment tree.
4. This change tries to detect when an inline formatting context
collapses through.
Fixes#29994.
Co-authored-by: Mukilan Thiyagarajan <me@mukilan.in>
Co-authored-by: Martin Robinson <mrobinson@igalia.com>
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
* Update test results
---------
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Mukilan Thiyagarajan <me@mukilan.in>
Co-authored-by: Martin Robinson <mrobinson@igalia.com>
* Place replaced and non-auto inline size independent FCs next to floats
The CSS2 specification says that replaced content and independent
formatting contexts should be placed next to floats. This change adds
support for that, but punts on support for independent formatting
contexts that have an auto inline size. With an auto inline size, we
which requires a much more complex layout algorithm.
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
* Fix issue with where last band was taken into account for inline size
* adjustment_from_floats should prevent margin collapse
* Properly handle elements with 0 height
---------
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
To collapse margins through, CSS2 requires "zero or auto computed height"
and "zero computed min-height" (the latter should also also include auto,
which was introduced in CSS3 as the new initial value).
Similarly, "auto computed height" is required to collapse the bottom margin
with the bottom margin of the contents.
Therefore this patch stops collapsing when the used height is clamped
to zero by max-height, but the computed value is not zero. Same for
non-zero percentages that are indefinite or that resolve to 0px.
Note that 0% and calc(0% + 0px) are still considered to be zero (so they
allow margin collapse), this may a bit inconsistent but matches Firefox
(for the collapsing through case).
This also matches the heuristics in find_block_margin_collapsing_with_parent().
We could change the heuristics instead, but then they would have to track
block sizes in order to be able to resolve percentages.
The change makes margin-collapse-through-percentage-height-block.html fail,
that test is only passing on Blink, which did a different interpretation
of the spec. To be fair, various places of CSS2 loosely consider that
indefinite percentages compute to auto, and even Firefox does so when
determining whether to collapse the top margin with the contents.
Since the spec isn't particularly clear and interoperability is lacking,
I filed https://github.com/w3c/csswg-drafts/issues/8919.
Layout 2020: Properly calculate clearance
<!-- Please describe your changes on the following line: -->
calculate_clearance() was not taking into account that adding clearance prevents top margin from collapsing with earlier margins.
---
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- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix#29885 and #29919
- [X] There are tests for these changes
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layout_2020: Do linebreak for atomic inline-level elements
<!-- Please describe your changes on the following line: -->
---
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix#29591 (GitHub issue number if applicable)
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Margins should be able to collapse through floats when collapsing with
parent blocks (the containing block). To properly place floats in this
situation, we need to look at these subsequent floats to find out how
much of the margin will collapse with the parent.
This initial implementation is very basic and the second step would be
to cache this in order to avoid having to constantly recalculate it.
Fixes#29915.
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
