Now that LengthStyleValue never contains `auto`, IdentifierStyleValue is
the only type that can hold an identifier. This lets us remove a couple
of virtual methods from StyleValue.
I've kept `has_auto()` and `to_identifier()` for convenience, but they
are now simple non-virtual methods.
This parses the new background-position-x/y longhands and properly
hooks up them up. This requires converting PositionStyleValue to
just contain two EdgeStyleValues so that it can be easily expanded
into the longhands.
Explicitly check is_viewport() instead of looking at the corresponding
DOM node. (The viewport has the DOM document as its DOM node, but that's
not obvious from context here.)
Until now we were just creating a stacking context for the tree root,
which usually is the viewport element. This lead to weird painting
behaviour when negative z-index children of the html element that
established their own stacking context were drawn below the canvas
background.
Now we establish a stacking context for both, the root element and the
viewport.
This moves color to be the first value resolved, this ensures that
calls to .to_color() on style values for other properties will always
be able to resolve the current color.
This change fixes the `background-color: currentColor` example in
colors.html.
The name "initial containing block" was wrong for this, as it doesn't
correspond to the HTML element, and that's specifically what it's
supposed to do! :^)
Grid containers were incorrectly represented as BlockContainer before.
Furthermore, GridFormattingContext had a bogus inheritance relationship
with BlockFormattingContext.
This patch brings our architecture closer to spec by making grid
containers be plain boxes and making GFC not inherit from BFC.
This simplifies the ownership model between DOM/layout/paint nodes
immensely by deferring to the garbage collector for figuring out what's
live and what's not.
According to table fixup algorithm:
https://www.w3.org/TR/css-tables-3/#fixup-algorithm
around every table-root should be generated anonymous
box wrapper.
Also this patch implements important part of CSS 2.2
spec that is currently not present in CSS Tables 3
spec draft: https://www.w3.org/TR/CSS22/tables.html#model
that portion of computed properties should be moved
from table-root to table wrapper box. Without having
this part implemented height of absolutely positioned
table with `height: auto` won't be computed correctly.
The only difference between these two values is that `hidden` has
different behaviour for border conflict resolution for border-collapsed
tables in table layout, which we don't have yet.
This gets rid of the main border around the repository information on
the GitHub repository page.
This fixes a few sizing issues too. The page size is now correct in most
cases! \o/
We get to remove some of the `to_type<>()` shenanigans, though it
reappears in some other places.
Previously identifiers were resolved to zero length. This could be seen
when a border declaration doesn't have specified width (e.g. `border:
solid`), as the initial border width is 'medium'.
The spec doesn't specify what the identifiers should really resolve to,
but it gives us some example values and that's what I've used here. :^)
Spec link: https://www.w3.org/TR/css-backgrounds-3/#border-width
This will make it easier to support both string types at the same time
while we convert code, and tracking down remaining uses.
One big exception is Value::to_string() in LibJS, where the name is
dictated by the ToString AO.
We have a new, improved string type coming up in AK (OOM aware, no null
state), and while it's going to use UTF-8, the name UTF8String is a
mouthful - so let's free up the String name by renaming the existing
class.
Making the old one have an annoying name will hopefully also help with
quick adoption :^)
We were mistakenly creating stacking contexts for all elements with
non-static CSS position.
For `absolute` and `relative`, we should only create stacking contexts
if the `z-index` value is something other than `auto`.
This makes it possible to click the cookie on Cookie Clicker. :^)
Now that both the layout tree and browsing context are GC-allocated,
we can formalize their relationship a bit better by having layout
nodes keep a NonnullGCPtr to the browsing context.
This makes the previously-indirect link direct, removing an unpleasant
"how do we know the browsing context is alive" question when accessing
it from the layout tree.
This removes a set of complex reference cycles between DOM, layout tree
and browsing context.
It also makes lifetimes much easier to reason about, as the DOM and
layout trees are now free to keep each other alive.
Instead of storing two JS::Handles into the DOM, we can combine them
into a single one.
If the layout node is anonymous, m_dom_node points to the DOM::Document.
Otherwise, m_dom_node points to the associated DOM node.
The anonymous state is moved to an m_anonymous boolean member.
This cuts the number of JS::Handles created by the layout tree in half
(and shrinks Layout::Node by 8 bytes).
These were totally ad-hoc before, is_inline() was based on a boolean
flag on Layout::Node that we set in various situations.
Meanwhile, is_inline_block() was a combination on is_inline() plus a
type check to see if the layout node inherited from BlockContainer.
This patch replaces the above mess with simple lookups of the CSS
display value. Note that layout nodes without their own style (i.e text
nodes) are automatically assumed to be inline and non-blocks. This has
to be special-cased since layout nodes without style will consult the
style of their parent, so without short-circuiting this would break.
Let's not assume the containing block has a paintable box just because
someone is calling set_needs_display(). It can just be a no-op in that
case, and nobody gets hurt.
This patch changes the *computed* representation of the following CSS
properties to use CSS::Size:
- width, min-width, max-width
- height, min-height, max-height
A few things had to change in order for things to keep working,
but I tried to keep the diff to a minimum.
The main trouble was that `min-width` and `max-width` can't actually be
`auto`, but they *can* be `none`. We previously treated `auto` as a
valid value (and it behaved mostly like `none`).
