The changes in #30740, fixed an issue where certain characters should
prevent line break opportunity after atomics. This change extends that
to also apply to before atomics, which is what the specification says
should happen.
We previously sent a " " to the linebreaker in order to ensure that the
next text had a soft wrap opportunity at the start. Calling `next(" ")`
without waiting until the returned index was 1, violated some
invariants of linebreaker ultimately causing a panic.
Instead of using the linebreaker for this, simply keep a flag in the
IFC layout state, which avoids the problem entirely.
Fixes#30703.
Earlier versions of inline layout in the new layout system did not
properly support line breaking when unbreakable segments spanned
multiple inline boxes. This change updates inline layout to add support
for that. Now items are added to an unbreakable segment before being
committed to a line.
Co-authored-by: Mukilan Thiyagarajan <mukilan@igalia.com>
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
Flattening the LineItem tree into a token stream will allow for handling
the case where an unbreakable line segment spans multiple inline boxes
which might have different hierarchies. This change also fixes the
handling of the second anonymous fragment of a block-in-inline-split.
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
Co-authored-by: Mukilan Thiyagarajan <mukilan@igalia.com>
After placing a float, FloatBox's layout_into_line_items() was calling
place_line_among_floats() with ifc.current_line.inline_position as the
width of needed by the contents of the line.
The problem is that this amount includes the trailing whitespace advance
and thus it could seem that the in-flow contents wouldn't fit next to
the float.
That's not the case, since collapsible whitespace at the end of the line
is removed, and preserved whitespace hangs.
So this patch subtracts ifc.current_line.trailing_whitespace_advance
when calling place_line_among_floats(), like it was already happening
when computing the available_inline_size.
Fixes#30561
In legacy layout, anonymous text wrappers were inheriting the `overflow`
and `text-overflow` properties. This results in the creation of extra
clipping for these anonymous wrappers which could clip away floats. We
will likely implement `text-overflow` differently in non-legacy layout.
This change marks all legacy layout pseudo elements as "legacy" and also
adds a new pseudo element for non-legacy layout that does not inherit
`overflow`.
Fixes#30562.
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
Improve the calculation of the block size of line boxes and all their
component elements. Even empty spans can increase the size of the line
based on their font-size. Elements that have a line-height should
increase the block size of the line, but that setting should not effect
their own size.
In addition to the new passes there are some new failures
Failing because a progression exposes the real issue these tests are
testing:
- css/css-color/t32-opacity-offscreen-multiple-boxes-1-c.xht
- css/css-color/t32-opacity-offscreen-multiple-boxes-2-c.xht
Likely failing because of vertical-align and another sizing issue:
- css/css-transforms/perspective-untransformable-no-stacking-context.html
Failing because a progression reveals another failure:
- html/rendering/non-replaced-elements/hidden-elements.html
Co-authored-by: Mukilan Thiyagarajan <mukilan@igalia.com>
When a box has overflow, any floats placed in that box will lower the
float ceiling into the overflow. If no float is placed in the box
though, the ceiling should be the block position where the overflow
starts. We already know where this is, because we might be passing a
negative value for the new block position after processing a box
(content_size - actual_size would be negative). This negative value
never raises the ceiling though since a maximum is used.
In the case that there is overflow, this change allows raising the
ceiling, but never passed the lowest float. This necessitates keeping
two values for the ceiling: one for floats and one for non-floats.
Fixes#30304.
* Take forced line breaks into account for intrinsic size
Fixes#30350.
* Don't linebreak on collapsible whitespace
This whitespace can hang off the end of the line, because it will be
trimmed LineItem layout.
* Update float placement after line breakage
Also don't ever line break for collapsible whitespace.
* Fix a few more test cases and clean up
* Renaming according to review comments
This makes the names of flow relative geometry consistent with what is
used in the style crate and removes them from a module. With this change
it's more obvious what makes these types different from the ones in
`euclid`.
This makes the nesting architecture of inline layout a lot simpler. Now
PartialInlineBoxFragment and InlineNestingLevelState are replaced by
two structs:
- InlineContainerState
- InlineBoxContainerState
InlineContainerState holds state for the root of the inline formatting
context, while InlineBoxContainerState holds state for inline boxes.
InlineBoxContainerState has an InlineContainerState as the first
element, thus "extends" it.
Now the inline iterators are stack variables directly in the `layout()`
method. They are no longer stored in the state. This avoids the weird
nesting of state and instead relies on a normal vector to hold the
stack of state.
Co-authored-by: Mukilan Thiyagarajan <mukilan@igalia.com>
PlacementAmongFloats would stop iterating when current_bands would be
empty, even if next_band wasn't at infinity.
Then the BFC root or replaced block was placed after all the floats,
even if it could fit next to some of them.
This patch moves the next_band into current_bands so that the loop
keeps considering bands.
This implements the rest of the bulk of float support. Now inline
element flow around floats and floats can be pushed down by inline
elements before them.
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
PlacementAmongFloats was assuming that there would always be a FloatBand
at a position smaller than or equal to the given ceiling, but this was
not the case for negative ceilings.
The reason is that the FloatContext initialized the FloatBandTree with
a band at 0, and another at +∞.
This patch changes the initial bands to −∞ and +∞. This seems more
consistent and matches the expectation of PlacementAmongFloats.
When layout was split into two phases, floats were laid out as direct
children of the inline formatting context. This meant that they were
positioned properly, but not properly made children of their inline
ancestors' stacking contexts. This change maintains the proper
positioning of floats, but positions them relatively to their inline
ancestors.
The big change here is that `text-align` needs to be taken into account
before actually laying out LineItems. This has the added benefit of
setting inline layout for the implementation of `text-align: full`. Now
all line items are laid out at the real final position and we can adjust
the `start_corner` property of float `BoxFragments` when their ancestors
are laid out.
In the first phase, we gather LineItems and then when we have enough to
form a line we turn them into Fragments. This will make it possible to
more simply implement `vertical-align` and `text-align: justify` because
we need to measure the different aspects of the candidate line and then
produce a Fragments.
This is a general refactor of the way that inline layout works, so comes
with some progressions. In addition there are some new failures.
New failures:
Some tests are now failing because only the test or reference is getting
proper line height when it wasn't before. These should be fixed in a
followup change that properly calculate line-height in more cases:
- /_mozilla/css/list_style_position_a.html
- /css/CSS2/floats/float-no-content-beside-001.html
- /css/css-content/pseudo-element-inline-box.html
- /css/css-flexbox/flexbox_flex-none-wrappable-content.html
Some tests are now failing because floats are now placed properly, but
are no longer in their inline box stacking contexts. These will be fixed
by a followup change which properly parents them:
- /css/filter-effects/filtered-inline-applies-to-float.html.ini
- /css/css-color/inline-opacity-float-child.html.ini
One test is failing due to floating point precision errors:
- /css/CSS2/floats-clear/floats-141.xht.ini
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Mukilan Thiyagarajan <mukilan@igalia.com>
Avoid solve_containing_block_padding_border_and_margin_for_in_flow_box()
for a block-level box that establishes an independent formatting context
(or is replaced) in the presence of floats, since the margins and inline
size could then be incorrect.
No actual change in behavior: this patch still resolves the margins
incorrectly with solve_block_margins_for_in_flow_block_level(),
and also keeps the old logic for width:auto.
However, this refactoring prepares the terrain to address these issues
in #30072 and #30057.
- Add explanatory comments.
- Rename some methods.
- Store the ceiling instead of relying on the first band, this allows
calling place() when current_bands is empty.
- Make current_bands_height() work when current_bands is empty.
- Add add_one_band() helper method.
- Make place() return a Rect. Follow-up patches will need to know the
size of the area shrunk by floats.
This will be useful for #30057 and #30050.
Co-authored-by: Martin Robinson <mrobinson@igalia.com>
With direction:ltr (and we don't support direction:rtl yet), the rules
from https://drafts.csswg.org/css2/#blockwidth imply that margin-left
shouldn't resolve auto to a negative amount.
This aligns Servo with Gecko and Blink. WebKit may resolve to a negative
amount in some cases.
When descending and we have the option, don't create new
PositioningContexts just to update the static position of laid out
abspos descendants. Instead, use the new PositioningContextLength to
only update the newly added hoisted abspos boxes.
Just use clamp_between_extremums() to resolve the inline size, and then
only call solve_inline_margins_for_in_flow_block_level() once.
There should be no change in behavior.
No difference in behavior, just these changes:
- PlacementAmongFloats::new() initializes the top of the 1st band to the
ceiling, so that other methods can just refer to the former without
having to floor by the later.
- In fact, the 'ceiling' field becomes unnecessary, and is removed.
- top_of_placement_for_current_bands() is renamed to current_ceiling().
- try_place_once() is reorganized to reduce indentation.
- The condition 'len() > 0' becomes '!is_empty()'.
- The 1st band is now popped in place() instead of try_place_once(),
then it's easier to see why the loop will end.
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.
Calculating the max-content size of a block container may add the outer
max-content sizes of multiple children. The problem is that the outer
size may be negative (due to margins), producing an incorrect result.
In particular, it could happen that the max-content size was 50-25=25,
but the min-content size would just take the maximum and be 50, which
doesn't make sense.
Therefore, this patch floors the size of all children by 0. This seems
to match Blink. Firefox and WebKit don't floor in some cases, but then
the result seems suboptimal to me. Note that there is no spec for this,
see https://github.com/w3c/csswg-drafts/issues/9120 for details.
Since #29950, unit tests were only running with the legacy layout, and
there was no way to run them for layout 2020.
This patch makes './mach test-unit' run unit tests for both.
Also doing some changes so that the layout 2020 floats.rs tests compile.
* 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>
A block that establishes an independent formatting context is placed
next to previous floats, so we should add their sizes when computing
the intrinsic contribution of the parent block container.
Remove rayon_croissant and refactor the way that information about
floats in flows bubbles up. This simplifies the code a good deal and
lets us take advantage of some more optimized functions provided by
rayon. This removes 2 crates from the dependency tree.
In addition, this allows avoiding passing `contains_floats` up from
every box tree construction function. This makes things simpler, but
also opens up the possibility of passing more of these flags up in the
future (such as `contains_counters`).
calculate_inline_content_size_for_block_level_boxes was relying on
inline_content_sizes to get the size of each block-level box child.
For absolutely positioned boxes, this was 0x0.
That was no-op before #29887, but then it prevented adding the sizes
of a sequence of floats. Abspos should just be ignored instead of
treated as 0x0.
This patch removes inline_content_sizes, moves the logic into
calculate_inline_content_size_for_block_level_boxes (the only caller),
and handles abspos correctly.
* 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>
This function is already quite big and the changes necessary for
properly laying out independent formatting contexts next to floats will
make it even more unwieldy. Split the function in two and add a helper
for calculating the containing block for children and the margin. As
time goes on the independent formatting case is probably going to be
more like the replaced case anyway.
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
Every time that we would lay out a block box that could collapse its
top margin with its contents, we would do a lookahead to compute the
resulting margin in order to place floats correctly.
The problem was that this lookahead could iterate several descendants,
but then when laying these we would run the lookahead again.
This patch restricts the lookahead to boxes that either aren't collapsing
their top margin with their parent, or that have 'clear' different than
'none' (since clearance prevents collapsing margins with the parent).
Since the lookahead stops iterating when it finds a box that doesn't
collapse its top margin with its parent, or whose 'clear' isn't 'none',
this should ensure that lookahead never handles the same box twice.
Check computed (min-)block-size when determining margin collapse
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.
<!-- 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#29907
- [X] There are tests for these changes (1 test fails, see above)
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Padding percentages weren't being resolved, this function would think
that margins wouldn't collapse even if the percentage resolved to 0px.
And margin percentages were always resolved to 0px.
So now the function takes a ContainingBlock parameter that is used to
resolve these percentages properly.
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 build -d` does not report any errors
- [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
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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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- [x] There are tests for these changes OR
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