Move the inline dom_node() method to Viewport.cpp so the header no
longer needs the full Document definition. Add explicit includes to
files that relied on the transitive dependency.
Instead, compute them on demand. This affects ReplacedBox and its
subclasses.
This commit is centered around a new Box::auto_content_box_size
method. It returns a SizeWithAspectRatio representing the natural
size of a replaced element, or the size derived from attributes
for text input and textarea. These values are used when the
corresponding axis is auto or indefinite.
Although introducing this API choke-point for sizing replaced and
replaced-like elements was the main goal, it's notable that layout
becomes more robust in the face of dynamic changes due to reduced
potential for stale size values (at the cost of extra calculations
and allocations).
The quirks mode percentage height calculation quirk was incorrectly
applied to anonymous boxes (like the internal flex wrapper inside
buttons), causing buttons to collapse to zero height.
Per the quirks spec, the percentage height quirk:
- Only applies to DOM elements, not anonymous boxes
- Does not apply to flex/grid items (they resolve against their
container)
- Does not apply to table-related display types
This patch:
1. Excludes anonymous boxes and flex/grid items from the quirk in
should_treat_height_as_auto()
2. Adds quirks mode percentage height walk-up in
calculate_inner_height() for inline-level boxes
3. Removes the incorrect flex/grid container exclusion from
BlockFormattingContext (the quirk applies to containers, not items)
Per CSS 2.1 Section 10.5, percentage heights should only resolve when
the containing block's height is "specified explicitly". This means a
containing block with `height: auto` and `min-height: 50px` does NOT
provide a definite height for percentage resolution - the child's
`height: 100%` should be treated as `auto`.
Previously, we checked `available_space.height.is_indefinite()` to
determine if percentage heights should become auto. However, this
conflated "available layout space" with "containing block height for
percentage resolution" - these are distinct concepts.
Now we check the containing block's `has_definite_height()` flag, which
correctly reflects whether the containing block has an explicit height
property. This handles:
- Anonymous wrapper blocks (skip them to find real containing block)
- Quirks mode (has special percentage height handling)
- Absolutely positioned elements (excluded, different rules apply)
Also update `calculate_inner_height()` to use the containing block's
actual used height when resolving percentages with indefinite available
space, which fixes inline-block and similar cases.
Compute inline-block baselines by traversing into nested block children
to find the last in-flow line box, using correct offsets relative to the
margin box edge.
Also ensure inline-flex and inline-grid containers always derive their
baseline from content (per CSS Align), and add special handling for
<input> elements which have `overflow: clip` in the UA stylesheet but
should still align adjacent text with their internal content.
CSS allows inline elements with `position: relative` (or other
containing-block-establishing properties) to serve as the containing
block for their absolutely positioned descendants. However, our layout
system stores containing blocks as `Box*`, which cannot represent
inline elements (they are `InlineNode`, not `Box`).
This patch adds a workaround: when computing containing blocks, we
also check if there's an inline element between the abspos element
and its Box containing block that should actually be the CSS
containing block. If found, we store it in a new member called
`m_inline_containing_block_if_applicable` and use it during abspos
layout to:
1. Compute the inline's fragment bounding box as the containing
block rectangle (including padding, per CSS spec)
2. Resolve percentage-based insets against the inline's dimensions
3. Position the abspos element relative to the inline's location
Some details to be aware of:
- The inline containing block search happens in the function
`recompute_containing_block()` by walking DOM ancestors (not layout
tree ancestors, since the layout tree restructures blocks inside
inlines as siblings)
- For pseudo-elements like `::after`, we start the search from the
generating element itself, since it may be the inline containing
block
- Fragment offsets are relative to their block container, so we
translate the computed rect to the abspos element's containing
block coordinate system by accumulating offsets up the ancestor
chain
- When the abspos element uses static position (auto insets), we
don't apply the inline rect translation since static position is
already computed in the correct coordinate system
Long term, we want to refactor our "containing block" concept to
map more cleanly to the spec concept. That means turning it into
a rectangle instead of the box this rectangle was derived from.
That's an invasive change for another day though.
Boxes with no layout children have no content, so their intrinsic
content size is zero by definition. This lets us skip creating a
throwaway layout state and running a formatting context just to
arrive at the same answer.
This occured because the abspos containing block is in-between the
containing blocks of two regular ancestors in this case, so it was
being skipped. (The containing block of a table cell is the table
itself, not the table row.)
In several content calculation methods in FormattingContext, we assumed
that if create_independent_formatting_context_if_needed() fails the
input Layout::Box is a BlockContainer; however, the web platform test
css/css-pseudo/parsing/marker-supported-properties-in-animation.html is
one scenario where the input is a Layout::ListItemMarkerBox instead and
there is no FormattingContext supported for it yet.
This function can really only be called with a box and its containing
block, otherwise the results are not meaningful. Instead of passing
these two dependent values separatly, reduce it down to a single
parameter to not make the function appear more general than it is.
If there are multiple nested `position: fixed` or `position: absolute`
elements that are positioned based on their static position due to not
specifying any insets, we sum up all their ancestor offsets to calculate
said static position.
However, these offsets represent the offset to the containing block. So
summing up all the ancestor blocks will count elements multiple times
for cases where the containing block is not based on the closest element
capable of forming a containing block (i.e. absolute and fixed position
elements) when multiple such elements are nested.
With this change we only iterate over ancestors forming containing
blocks instead of over all ancestors boxes. To sum up everything between
the box currently being positioned and its containing block, we start
the iteration on the parent box of the current box.
This fixes 3 WPT tests that I could find. But these tests are not
intended to test the error cases fixed here, they just incidentally rely
on the correct behavior. As such, I have added dedicated tests myself.
Note that two of the tests already pass on master, but they seemed like
a good cases to have anyway.
The CSS spec says the baseline of an inline-block should be the bottom
margin when either the overflow property is not 'visible' or there are
no in-flow line boxes. Previously, only the latter case was checked.
This fixes 1 WPT test:
https://wpt.live/css/css-align/baseline-of-scrollable-1a.html
These functions are trivial, and we were actually bleeding a lot of time
in profiles to just function entry/exit.
By marking Length::make_px() as [[nodiscard]], we also exposed some
places that were creating a Length and not using it for anything.
This means that we now calculate the inner width correctly for `display:
inline-block` nodes when we have `box-sizing: border-box` and
`min-width`, as we would previously assume these dimensions were all `0`
Not every user of this requires an `auto` state, but most do.
This has quite a big diff but most of that is mechanical:
LengthPercentageOrAuto has `resolved_or_auto()` instead of `resolved()`,
and `to_px_or_zero()` instead of `to_px()`, to make their output
clearer.
For button layouts, we were overriding the computed `width` value with
`fit-content` in `TreeBuilder::wrap_in_button_layout_if_needed()`. But
the spec asks us to set the _used value_ instead, so we now actually
calculate the fit-content width and set the box' content width to it.
Fixes#2516.
CSS grid specification states that for grid items with a replaced
element and a percentage preferred size or maximum size, the percentage
should be resolved against 0 during content-based minimum size
calculation. This makes sense, as it prevents replaced items from
overshooting their grid track while intrinsic track sizes are
calculated, and allows later track size resolution steps to scale
replaced items to fit their grid track.
This behavior is part of the cyclic percentage contribution logic from
CSS-SIZING-3 which explicitly only applies to non-replaced boxes.
This fixes an issue on Discord where buttons in the settings UI were
cropped to a narrower width than intended.
Fixes#3572
The specification [1] indicates that the tentative used width and height
should be computed first, and if they exceed the `max-width` or
`max-height`, the rules should be applied again using the computed
values of `max-width` and `max-height`.
The only required change to follow the spec is to remove the early
`return` statements, in both `compute_width_for_replaced_element`
and `compute_height_for_replaced_element`.
Fixes#5100.
[1] https://www.w3.org/TR/CSS22/visudet.html#min-max-widths
For `vertical-align: middle` and `vertical-align: text-bottom`, we used
just the content height of the inline box to determine its alignment
position. This caused incorrect positioning when padding is applied.
This fixes the button alignment on our GitHub page.
Fixes#290.
We were already always doing this, but through an unusual mechanism:
SVG layout creates a BFC on the stack when laying out foreignObject
subtrees.
This change makes the rest of the layout system aware of this, and
also allows it to be reflected in layout dumps.
By the time we calculate the min-content height, the width is already
known, so we can use it to calculate the height based on the natural
aspect ratio.
Instead, use the generic create_independent_formatting_context_if_needed
so that unusual situations like image-as-table-caption don't crash.
This logic clearly needs more work, but let's at least do better than
crashing. This gives us 26 new subtest passes on WPT.
We were incorrectly deciding that abspos elements shouldn't treat many
max-width and max-height values as `none`. My best understanding is that
this was a hack in 2023 for an issue that has been solved since then.
By removing the incorrect short-circuit, we stop at least one WPT test
from crashing due to infinite recursion and get ourselves +34 passes.
When determining the content/margin box rects within their ancestor's
coordinate space, we were returning early if the passed in values
already belonged to the requested ancestor. Unfortunately, we had
already applied the used values' offset to the rect, which is the offset
to the ancestor's ancestor.
This simplifies the logic to always apply the rect offset after checking
if we've reached the ancestor. Fixes determining float intrusions inside
block elements with `margin: auto` set.
Fixes#4083.
It's safe to remove this pointer because intrinsic layout should never
look up a box's state beyond its containing block.
This change affects the expectations of two layout tests, but both
already differ slightly from other browsers, and the difference between
expectations is less than 5px.
...boxes with non-auto height.
We know for sure that by the time we layout abspos boxes, their
containing block has definite height, so it's possible to resolve
non-auto heights and mark it as definite before doing inner layout.
Big step towards having reasonable performance on
https://demo.immich.app/photos because now we avoid a bunch of work
initiated by mistakenly invoked intersection observer callbacks.
Co-Authored-By: Andreas Kling <andreas@ladybird.org>
positioned element is a descendant of inline-block
Sets inline block offsets in InlineFormattingContext.cpp, but this is
not enough. When static position rect is calculated during layout,
not all ancestors of abspos box may have their offsets calculated yet
(more info here: https://github.com/LadybirdBrowser/ladybird/pull/2583#issuecomment-2507140272).
So now static position rect is calculated relative to static containing
block during layout and calculation relative to actual containing block
is done later in
FormattingContext::layout_absolutely_positioned_element.
Fixes wpt/css/CSS2/abspos/static-inside-inline-block.html
12c6ac78e2 with fixed mistake when cache
slot is copied instead of being referenced:
```cpp
auto cache =
box.cached_intrinsic_sizes().min_content_height.ensure(width);
```
while it should've been:
```cpp
auto& cache =
box.cached_intrinsic_sizes().min_content_height.ensure(width);
```
This change moves intrinsic sizes cache from
LayoutState, which is local to current layout run,
to layout nodes, so it could be reused between
layout runs. This optimization is possible because
we can guarantee that these measurements will
remain unchanged unless the style of the element
or any of its descendants changes.
For now, invalidation is implemented simply by
resetting cache on whole ancestors chain once we
figured that element needs layout update.
The case when layout is invalidated by DOM's
structural changes is covered by layout tree
invalidation that drops intrinsic sizes cache
along with layout nodes.
I measured improvement on couple websites:
- Mail list on GMail 28ms -> 6ms
- GitHub large code page 47ms -> 36ms
- Discord chat history 15ms -> 8ms
(Time does not include `commit()`)
By the time we're measuring the height of a BFC root, we've already
collapsed all relevant margins for the root and its descendants.
Given this, we should simply use 0 (relative to the BFC root) as the
lowest block axis coordinate (i.e Y value) for the margin edges.
This fixes a long-standing issue where BFC roots were sometimes not tall
enough to contain their children due to margins.
