This keyword is de-facto required for web compatibility, Firefox is also
enabling it (https://bugzil.la/1988938).
This patch just aliases it to `stretch`.
Stylo PR: https://github.com/servo/stylo/pull/243
Testing: Various tests pass
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
Taffy treats static and sticky positionings as relative. So the inset
properties shifted the element in the relpos way, which was no good.
It's better to just treat them as `auto` instead.
Testing: 3 existing tests pass, and adding a new one.
Fixes: #39399
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
This patch refactors the logic for propagating overflow to the viewport,
fixing various issues:
- Now we won't propagate from the root element if it has no box. Note
the fix isn't observable in Servo because we lack scrollbars.
- If the first `<body>` element has no box, we won't keep searching for
other `<body>` elements. This deviates from the spec, but aligns us with
other browsers.
- We won't propagate from the `<body>` if it has no box. We were already
handling `display: none` but not `display: contents`. This deviates from
the spec, but aligns us with other browsers.
Also, when we flag the root or `<body>` as having propagated `overflow`
to the viewport, we retrieve the `LayoutBoxBase`. Therefore, now we get
the computed style from the `LayoutBoxBase` in a single operation,
instead of first retrieving the style from the DOM element and then
getting the `LayoutBoxBase` from the box.
Testing: Adding more tests. We were only failing one of them, but it's
hard to test the fixes given that we don't show scrollbars. The tests
that were already passing are useful too, e.g. Firefox fails one of
them.
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
They only had the writing mode, now they will have the entire computed
style.
This is needed for #39230.
Testing: Not needed, no behavior change
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
A LayoutBox typically has one LayoutBoxBase, or none in the case of
`LayoutBox::DisplayContents`. However, `LayoutBox::InlineLevel` can
contain multiple inline items, each one with its base. But since things
like the style or the fragment flags should be the same for all of them,
getting the first base is sometimes enough.
Testing: not needed, no change in behavior.
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
The `overflow-*` values of either the root element or the `<body>` get
propagated to the viewport. However, we were missing this part:
> The element from which the value is propagated must then have a used
`overflow` value of `visible`.
See https://drafts.csswg.org/css-overflow/#overflow-propagation
Testing:
- `css/cssom-view/scrolling-quirks-vs-nonquirks.html`
- `css/css-overflow/overflow-body-propagation-007.html`
- `css/css-overflow/overflow-body-propagation-008.html`
- `css/css-overflow/overflow-body-propagation-009.html`
- `css/css-overflow/scrollable-overflow-with-nested-elements-001.html`
- `css/css-overflow/scrollable-overflow-with-nested-elements-002.html`
- `css/css-overflow/scrollable-overflow-with-nested-elements-003.html`
- `css/css-overflow/scrollable-overflow-with-nested-elements-004.html`
- `css/css-overflow/scrollbar-gutter-scroll-into-view.html`
Failures:
- `css/css-overflow/overflow-body-propagation-010.html`
Failing because of missing support for `contain: paint`.
- `css/css-overflow/scrollable-overflow-with-nested-elements-005.html`
Failing because of wrong `data-expected-height`, but correct
`data-expected-scroll-height` which is core of this PR.
`data-expected-height` can be dealt separately.
Fixes: #38248
---------
Signed-off-by: Shubham Gupta <shubham13297@gmail.com>
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
Use `ServoThreadSafeLayoutNode` in more places in layout rather than
`ServoLayoutNode`. The former is meant to be used during layout, but
layout 2020 was written against the latter. In general, this reduces the
amount of conversion to the thread-safe version in many places in
layout.
In addition, an unused iterator from the `script` crate
`ServoThreadSafeLayoutNodeChildrenIterator` is replaced with the child
iterator from `layout`. The `layout` version must be directly in
`script` now as it uses the dangerous variants of `next_sibling` and
`first_child`, which allow encapsulating the unsafe bits into one
module.
This will ultimately be useful for storing the layout data of
pseudo-element children of pseudo-elements properly.
Testing: This should not change any behavior and thus is covered by
existing tests.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
Moves `Size`, `SizeConstraint`, `Sizes` and `LazySizeData`.
Testing: Not needed, no change in behavior.
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
### Changes made
This implements named grid lines (line names in `grid-template-*`),
named grid areas (`grid-template-areas`), and the ability to target
those using `grid-{row,column}-{start,end}`. It also includes a bunch of
miscelaneous fixes for `repeat(auto-fill | auto-fit, ...)` syntax as
that interacts with the specification of line names.
The actual layout implementation is in Taffy. The bulk of this PR is
updating Servo to translate (CSS Grid-related) Stylo types into Taffy
types using a new iterator-based API which uses iterators and lazy
translation for efficiency (which is more important now that we're
dealing with string data, even though they're `Atom`s).
### Testing
This functionality has lots of WPT tests. It fixes some seemingly random
CSS Grid tests that use named lines/areas even though that's not what
they're testing.
### Screenshots
wikipedia.org
<img width="1624" height="1056" alt="Screenshot 2025-07-27 at 20 03 16"
src="https://github.com/user-attachments/assets/2c50b96f-ae36-4405-ac48-b771bfdcb515"
/>
bbc.co.uk:
<img width="1624" height="1056" alt="Screenshot 2025-07-27 at 20 32 57"
src="https://github.com/user-attachments/assets/ba84e211-65d2-4411-95fb-7b9b91bea31c"
/>
theguardian.com:
<img width="1624" height="1056" alt="Screenshot 2025-07-27 at 20 33 29"
src="https://github.com/user-attachments/assets/e85daaa6-5fb0-45d4-b9ec-b22b38b087ec"
/>
---------
Signed-off-by: Nico Burns <nico@nicoburns.com>
This makes grid layout make use of Servo's layout caching system.
Testing: No behavior change. Existing WPT coverage
---------
Signed-off-by: Nico Burns <nico@nicoburns.com>
The logic was wrong, sometimes we weren't setting it to true on flex
containers that needed it, and then as a workaround we were setting it
to to true on flex items that didn't need it.
For example, this testcase had 5 cache misses when stretching the items,
now we will avoid laying them out again:
```html
<div style="display: flex">
<div></div> <div></div> <div></div> <div></div> <div></div>
</div>
```
Also, the workaround wasn't always working, e.g. it failed to stretch
the green element here:
```html
<div style="display: flex; min-height: 200px">
<div>
<div style="display: flex; height: 100%; background-color: red">
<div style="width: 200px; background-color: green;"></div>
</div>
</div>
</div>
```
Testing: Adding new test
Fixes: #38023
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
Laying out a grid item will now use the same logic regardless of whether
it's replaced or not.
This reduces the amount of code, and should have no observable effect
(but hard to say since and I don't understand Taffy).
Testing: Unneeded (no behavior change)
This part of #37942
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
When laying out a grid item, the tentative block size that is used to
determine the intrinsic inline sizes was different than the one used in
the containing block for the contents. The latter is now used for both
cases.
Testing: A test is now passing.
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
With the work to unify the layout logic for replaced and non-replaced
boxes (#37942), I think the `IndependentNonReplacedContents` enum does
no longer make much sense.
Therefore, this removes `IndependentNonReplacedContents`, merging its
values into `IndependentFormattingContextContents`.
The methods defined on `IndependentFormattingContextContents` can now be
on `IndependentFormattingContext`, in particular this implies that the
layout results of a replaced box will now be cached.
Testing: Unneeded (no behavior change)
This part of #37942
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
When a style change does not chang the structure of the box tree, it is
possible to skip box tree rebuilding for an element. This change adds
support for reusing old box trees when no element has that type of
damage. In order to make this happen, there needs to be a type of
"empty" `LayoutDamage` that just indicates that a fragment tree layout
is necessary.
This is the first step toward incremental fragment tree layout.
Testing: This should not change observable behavior and thus is covered
by
existing WPT tests. Performance numbers to follow.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
Clearance only applies to block-level boxes, so it was unnecessary to
require it as a parameter. Instead, in block layout we can set it using
the new `.with_clearance()` method.
Testing: Unnecessary (no behavior change)
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
It was very easy to forget about using `.with_specific_layout_info()` to
set the specific layout info, so it's better to make it a parameter.
In fact this already happened in the past: #36993 fixed the missing
specific layout info for flex items.
This patch fixes it for floats and atomic inlines. It also propagates it
in other cases where not doing so was not a big deal because the
specific layout info was None, but that was a fragile assumption.
Testing: Various WPT improvements
Fixes: #37898
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
Layout: Continue support incremental box tree reconstruction for
flex&taffy level box
This change reuse the flex/taffy level box from old box slot if the box
slot is valid and there is no LayoutDamage to the element.
Testing: This should not change observable behavior and is thus covered
by existing WPT tests.
Signed-off-by: sharpshooter_pt <ibluegalaxy_taoj@163.com>
This applies some fixes for CSS Grid percentage sizing. These fixes are
mostly within Taffy, but there are some changes in Servo to allow it to
communicate whether an item is replaced to Taffy.
It also updates Taffy to v0.8.0. Taffy has switched to a tagged pointer
representation of length/size styles. Much of the diff here is updating
Servo's type conversion code to use the new representation.
---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by
`[X]` when the step is complete, and replace `___` with appropriate
data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] There are tests for these changes OR
---------
Signed-off-by: Nico Burns <nico@nicoburns.com>
Text decorations have a special kind of propagation. Instead of
propating these during box tree construction, move propagation to
stacking context tree construction. This will allow for using a very
easy type of incremental layout when text decorations change. For
instance, when a link changes color during hovering over it, we can skip
all of box and fragment tree construction.
In addition, propagation works a bit better now and color and style
properly move down from their originating `Fragment`s.
This introduces three new failures, because now we are drawing the
text-decoration with the correct color in more places, which exposes an
issue we have with text-decorations not being drawn in relation to the
baseline (taking into account `vertical-align`).
Testing: There are tests for these changes.
Fixes#31736.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
When making last-minute changes to the repaint-only layout pass, damage
propagation was broken, meaning that full layout was always done. This
change fixes that, meaning that times in the `blaster.html` test case
now reflect those described in the original commit message from #36978.
In addition, some style repair is now fixed:
- `InlineFormattingContext`s now keep a `SharedInlineStyles` for the
root of the IFC
which is updated during style repair.
- `BlockFormattingContext`s now properly update their style.
These changes are verified by turning on repaint only layout for more
properties
in Stylo via servo/stylo#183.
Testing: Manual performance testing via `blaster.html`.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Before this patch it wasn't possibly to simultaneously support intrinsic
min/max sizes and content alignment in the block axis. For example,
block containers only support the former, and flex containers only the
latter.
The reason is that the final block size was decided by the parent
formatting context *after* performing layout, while content alignment is
performed *during* layout.
To address the problem, this introduces the struct `LazySize`, which
contains the data to resolve the final size, except for the intrinsic
size. Thus the parent formatting context can first create a `LazySize`,
then pass it to the child layout so that (if necessary) it can compute
the final size once the intrinsic one is known, and after layout the
parent formatting context uses it to actually size the child.
This PR just provides the functionality that will be used by follow-ups,
but at this point no layout is using the `LazySize` provided by the
parent, so there shouldn't be any behavior change yet.
Testing: Unnecessary (no behavior change)
This is part of #36981 and #36982
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
This change adds the simplest kind of incremental layout. When Servo
detects that all style changes only require a repaint, only run stacking
context tree and WebRender display list generation. This means that
these kind of restyles do not need a re-layout. Instead, the existing
box and fragment trees will be used and the styles of damaged nodes will
be updated in their box and fragment tree nodes.
This requires a new style repair DOM traversal for nodes that have had
their style damaged. In addition, careful accounting of all the places
where we store style must happen in order ot update those styles.
Testing: This is covered by existing WPT tests as it should not change
observable behavior.
We have created a test case which shows a 50% speedup when run
in Servo, even though there still a long way to go to match the speed
of other browsers:
https://gist.github.com/mrobinson/44ec87d028c0198917a7715a06dd98a0
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
`TextRun`s use their parent style to render. Previously, these styles
were cloned and stored directly in the box tree `TextRun` and resulting
`TextFragment`s. This presents a problem for incremental layout.
Wrapping the style in another layer of shared ownership and mutability
will allow updating all `TextFragment`s during repaint-only incremental
layout by simply updating the box tree styles of the original text
parents.
This adds a new set of borrows when accessing text styles, but also
makes it so that during box tree block construction
`InlineFormattingContext`s are created lazily and now
`InlineFormattingContextBuilder::finish` consumes the builder, making
the API make a bit more sense. This should also improve performance of
box tree block construction slightly.
Testing: This should not change observable behavior and thus is covered
by existing WPT tests.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
This makes it so that layout is no longer generic on the node type,
depending directly on `script`'s `ServoLayoutNode`. In addition to
greatly simplifying layout, this is necessary because incremental layout
needs to be able to create pseudo-element styles without having a handle
on the original `impl LayoutNode`. We feel this is a reasonable
tradeoff.
Testing: No functional changes, so covered by existing WPT tests.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
`PositioningContext` held two vectors, one inside an `Option`, to
differentiate between the version used for a containing block for all
descendants (including `position: absolute` and `position: fixed`) or
only for `position: absolute` descendants. This distinction was really
hard to reason about and required a lot of bookkeeping about what kind
of `PositioningContext` a layout box's parent expected. In addition, it
led to a lot of mistakes.
This change simplifies things so that `PositioningContext` only holds a
single vector. When it comes time to lay out hoisted absolutely
positioned
fragments, the code then:
- lays out all of them (in the case of a `PositioningContext` for all
descendants), or
- only lays out the `position: absolute` descendants and preserves the
`position: fixed` descendants (in the case the `PositioningContext`
is only for `position: absolute`.), or
- lays out none of them if the `PositioningContext` was created for
box that did not establish a containing block for absolutes.
It's possible that this way of dealing with hoisted absolutes is a bit
less efficient, but, the number of these descendants is typically quite
small, so it should not be significant. In addition, this decreases the
size in memory of all `PositioningContexts` which are created in more
situations as time goes on.
Testing: There is a new WPT test with this change.
Fixes: #36696.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
As per
[w3.org/TR/filter-effects-1#FilterProperty](https://www.w3.org/TR/filter-effects-1/#FilterProperty),
`filter` shouldn't make the root element establish a containing block
for absolute and fixed positioned descendants. `will-change: filter` has
matching behavior.
This PR adds a check for if we are the root element before establishing
such a block.
To know if we are the root element, we look at the `FragmentFlags`
passed in. Previously for our function, these were dummy flags, always
constructed as empty. Thus, this PR also makes sure the correct
FragmentFlags are passed down the chain to the function
`establishes_containing_block_for_all_descendants`.
Testing:
- `/css/filter-effects/filtered-html-is-not-container.html` now passes
- `/css/css-will-change/will-change-fixedpos-cb-003.html` now passes
- Manual tests are working
Fixes: #35391
---------
Signed-off-by: haval0 <56519858+haval0@users.noreply.github.com>
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
Now that legacy layout has been removed, the name `layout_2020` doesn't
make much sense any longer, also it's 2025 now for better or worse. The
split between the "layout thread" and "layout" also doesn't make as much
sense since layout doesn't run on it's own thread. There's a possibility
that it will in the future, but that should be something that the user
of the crate controls rather than layout iself.
This is part of the larger layout interface cleanup and optimization
that
@Looriool and I are doing.
Testing: Covered by existing tests as this is just code movement.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
