There are a bunch of situations where we need to treat cross axis
max-size properties as "none", notably percentage values when the
reference containing block size is an intrinsic sizing constraint.
This fixes an issue where flex items with definite width would get
shrunk to 0px by "max-width: 100%" in case the item itself is an
SVG with no natural width or height.
For consistency, we now use the should_treat_max_width/height_as_none
helpers throughout FFC.
This makes the search/account/cart icons show up in the top right
on https://twinings.co.uk :^)
Before this change, we used the wrong insertion point for flex items
in reverse layouts with `justify-content: normal`. This caused flex
items to overflow the flex containers "backwards" from the start edge.
CSSPixels should not be wrapped into CSS::Length before being passed
to resolved() to end up resolving percentages without losing
precision.
Fixes thrashing layout when 33.3333% width is used together with
"box-sizing: border-box".
We were incorrectly offsetting the static position of abspos children of
flex containers by the padding twice. This was a misguided attempt to
adjust to the abspos containing block being the padding box, not the
content box.
Fixes#21344.
There's a particularly awkward case where the static position of an
abspos child of a flex container is dependent on its height. This can
happen when `align-items: center` is in effect, as we have to adjust
the abspos child's Y position by half of its height.
This patch solves the issue by reordering operations in the abspos
height resolution algorithm, to make sure that height is resolved
before the static position is calculated.
Before this change, we were creating a new anonymous flex item for every
inline-level child of a flex container, even when we had a sequence of
inline-level children.
The fix here is to simply keep putting things in the last child of the
flex container, if that child is already an anonymous flex item.
CSS-ALIGN-3 tells us that `normal` behavior inside flex containers is
simply to behave as `stretch` so this patch makes them behave the same
inside FFC.
Furthermore, we change the `align-items` initial value to `normal`,
matching other engines.
This stuff is pretty hairy since the specifications don't give any
guidance on which widths to use when calculating the intrinsic height of
flex items in a column layout.
However, our old behavior of "treat anything indefinite as fit-content"
was definitely not good enough, so this patch improves the situation by
considering values like `min-content`, `max-content` and `fit-content`
separately from `auto`, and making the whole flex layout pipeline aware
of them (in the cross axis context).
Properties like min-width, max-width, etc, should be ignored while we're
trying to determine the intrinsic size of a flex container.
This fixes an infinite recursion when using an intrinsic size keyword as
the max-width of a flex column container.
Note that this behavior is marked as AD-HOC in code comments because
specs don't tell us how to achieve intrinsic sizing.
We can now load product pages on the Twinings site, such as
https://twinings.co.uk/products/earl-grey-100-tea-bags :^)
This change makes tree builder omit elements with "display: contents"
from the layout tree during construction. Their child elements are
instead directly appended to the parent element in layout tree.
Auto margins used together with justify-content would previously
result in children being positioned outside their parent. This was
solved by letting auto margins take precedence when they are used,
which was already implemented to some extent before, but not
fully.
After switching to fixed-point arithmetic in CSSPixels, it no longer
supports representing infinite values, which was previously the case
for remaining_free_space in FFC. Using Optional that is not empty only
when value is finite to store remaining_free_space ensures that
infinity is avoided in layout calculations.
Once we've resolved the used flex item width & height, we should allow
percentage flex item sizes to resolve against them instead of forcing
flex items to always treat percentages as auto while doing intrinsic
sizing layout.
Regressed in 8dd489da61.
We do this by piggybacking on FormattingContext helpers instead of
reinventing the wheel in FlexFormattingContext.
This fixes an issue where `min-width: fit-content` (and other
layout-dependent values) were treated as 0 on flex items.
This makes the cookie banners look okay on https://microsoft.com/ :^)
The tests still pass, but opening the files in Ladybird and Safari or
Firefox shows clearly where the layouting in Ladybird is incorrect
for some absolute positioned elements. The previous 1px border was
subtly hiding some issues.
When sizing under a max-content constraint, we allow flex lines to have
an infinite amount of "remaining space", but we shouldn't let infinity
leak into the geometry of items. So treat it as zero in arithmetic.
This fixes an issue where inline SVGs with natural aspect ratio (from
viewBox) but no natural width or height could get an infinite size as
flex items.
The part in FFC where we ask the parent formatting context to size the
flex container midway through layout is really weird, but let's at least
be consistently weird for BFC and IFC. Since IFC always works within its
parent BFC, it can simply forward these requests to the BFC.
This fixes an issue where inline-flex containers incorrectly had main
axis margins subtracted from their content size.
We were incorrectly returning a "specified size suggestion" for flex
items with a definite main size where that main size was also automatic.
This led to us incorrectly choosing 0 as the automatic minimum size for
that flex item, instead of its min-content size.
If a flex item's main size is a CSS calc() value that resolves to a
length and contains a percentage, we can only resolve it when we have
the corresponding reference size for the containing block.
If the flex container is being sized under a max-content main size
constraint, there is effectively infinite space available for flex
items. Thus, flex lines should be allowed to be infinitely long.
This is a little awkward, because the spec doesn't mention specifics
about how to resolve flexible lengths during intrninsic sizing.
I've marked the spec deviations with big "AD-HOC" comments.
We were not taking reverse flex directions into account when choosing
the initial offset for flex item placement if justify-content were
either space-around or space-between.
1. Propagate calc() values from StyleProperties to ComputedValues.
2. Actually resolve calc() values when determining the used flex basis.
This makes the "support" section on https://shopify.com/ show up
correctly as a 2x2 grid (instead of 1x4). :^)
If there are min or max size constraints in the cross axis for a flex
item that has a desired aspect ratio, we may need to adjust the main
size *after* applying the cross size constraints.
All the steps to achieving this aren't mentioned in the spec, but it
seems that all other browsers behave this way, so we should too.
If the parent BFC can come up with a nice stretch-fit width for the flex
container, it will have already done so *before* even entering flex
layout. There's no need to do it again, midway through the flex layout
algorithm.
This wasn't just unnecessary, but we were also doing it incorrectly and
not taking margins into account when calculating the amount of available
space for stretch-fit. This led to oversized flex containers in the
presence of negative margins.
Fixes#18614
Although the spec doesn't mention it, if a flex item has box-sizing:
border-box, and the specified size suggestion is a definite size, we
have to subtract the borders and padding from the size before using it.
This fixes an issue seen in "This Week in Ladybird #4" where the
screenshots ended up in one long vertical stack instead of paired up
2 by 2.
When sizing a flex container with flex-direction:column under a
max-content height constraint, we were incorrectly truncating the
infinite available height to 0 when collecting flex items into lines.
This caused us to put every flex item in its own flex line, which is the
complete opposite of what we want during max-content intrinsic sizing,
as the layout would grow wide but not tall.
This isn't actually part of CSS-FLEXBOX-1, but all major engines honor
these properties in flex layout, and it's widely used on the web.
There's a bug open against the flexbox spec where fantasai says the
algorithm will be updated in CSS-FLEXBOX-2:
https://github.com/w3c/csswg-drafts/issues/2336
I've added comments to all the places where we adjust calculations for
gaps with "CSS-FLEXBOX-2" so we can find them easily. When that spec
becomes available, we can add proper spec links.
