DeprecatedFlyString relies heavily on DeprecatedString's StringImpl, so
let's rename it to A) match the name of DeprecatedString, B) write a new
FlyString class that is tied to String.
Previously when resolving an attr or var-defined property
with a 'not-set' value like this `property: var(--ValueNotSet)`,
we left the property unchanged (as an unresolved) and
added it to the computed-style of the element.
We still don't change the property but rather we now also don't set
unresolved properties in the computed-style.
This is an intended behavior.
The specification suggests that, on resolving an attr or var property
(custom properties) we have an invalid property when neither the
variable inside the var, nor the backup value could be resolved.
An invalid property must be inherited or defaulted depending on it's
type. We already do this with every 'untouched'
(as in m_property_values contains no entry for it) value.
So not setting the property results in an inherited (or initial)
value by a later-called function.
This also fixes another problem, where
`text-decoration: var(--NotSet)`
wouldn't be inherited because the computed-style of the
parent element hasn't set `text-decoration` but rather
all it's long-versions like `text-decoration-line` and so on.
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 :^)
When mixing calc() and var(), we're forced to delay resolving them until
we're in StyleComputer. Previously we'd just skip over them.
This patch handles calc() in the same pass as attr(). We reparse the
calc() value after var() expansion, and then try to resolve it to a
constant value if possible. If it's not possible, we leave the calc()
where it is, and maybe layout can figure it out later.
Note that I've only implemented resolution to integer and percentage in
this commit. There are more things a calc() could resolve to, and we
should implement those as well.
We always create a Layout::InitialContainingBlock for the ICB, but in a
future where we always honor the CSS::Display everywhere, we need to
make sure everyone has the right display values.
URL had properly named replacements for protocol(), set_protocol() and
create_with_file_protocol() already. This patch removes these function
and updates all call sites to use the functions named according to the
specification.
See https://url.spec.whatwg.org/#concept-url-scheme
Instead of asking Gfx::FontDatabase for the "default font" and the
"default fixed-width font", we now proxy those requests out via
the Platform::FontPlugin. This will allow Ladybird to use other default
fonts as fallback.
This patch improves @font-face loading when there are multiple src
values in two ways:
- Invalid/empty URLs are ignored
- Fonts with unsupported file extensions are ignored
This makes us load and display the emblem font on modern Reddit,
which is pretty neat! :^)
Let's make 16px the default font size instead of 10px. This makes our
layout results match those of other engines in many more cases.
Also make the h1-h6 element styles use relative (em) font sizes, also
matching other browsers.
Instead of hard-coding the names of system fonts to use for the CSS
generic fonts (like "sans-serif", "monospace", etc.) we now call out
to a Platform::FontPlugin and ask for the generic names.
Previously, `inline-flex` would blockify to `block` since blockification
didn't take the inner display type into account. This is still not
perfect, but it fixes a lot of situations where inline-level flex
containers would be demoted to regular block containers.
Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).
No functional changes.
By the time that property() gets called, we've already given every
single property a value, so we can just return it. This simplifies a
lot of places that were manually handling a lack of value
unnecessarily.
This means deviating a little from the spec, so that we create a
complete Block in one go instead of creating an empty one and then
poking at its internals.
The goal here is to move the parser-internal classes into this namespace
so they can have more convenient names without causing collisions. The
Parser itself won't collide, and would be more convenient to just
remain `CSS::Parser`, but having a namespace and a class with the same
name makes C++ unhappy.
Previously, we would create a new Gfx::ScaledFont whenever we needed one
for an element's computed style. This worked fine on Acid3 since the use
of web fonts was extremely limited.
In the wild, web fonts obviously get used a lot more, so let's have a
per-point-size font cache for them.
Previously, we were running the "load fonts if needed" machine at the
start of every style computation. That was a lot of unnecessary work,
especially on sites with lots of style rules, since we had to traverse
every style sheet to see if any @font-face rules needed loading.
With this patch, we now load fonts once per sheet, right after adding
it to a document's style sheet list.
"Component value" is the term used in the spec, and it doesn't conflict
with any other types, so let's use the shorter name. :^)
Also, this doesn't need to be friends with the Parser any more.
CSS Values and Units Module Level 5 defines attr as:
`attr(<q-name> <attr-type>?, <declaration-value>?)`
This implementation does not contain support for the type argument,
effectively supporting `attr(<q-name>, <declaration-value>?)`
When encountering a @font-face rule, StyleComputer will now fire off
a resource request and download the first source URL specified.
Once downloaded, we try to parse it as a TrueType font file, and if it
works, it's added to a cache in StyleComputer. This effectively makes
fonts per-document since every document has its own StyleComputer.
This is very unoptimized and could definitely use some caching, etc.
But it does work on Acid3. :^)
Our font database uses point sizes for fonts, and we were passing it
px sizes. This caused all fonts to be 1.333x larger than they should
be on the web. Of course it wasn't always noticeable with bitmap fonts,
but noticeable everywhere with scalable fonts.
Relative font-sizes like "2em" were previously resolved against the
fallback value (10px) which led to incorrect layouts in many places.
Fix this by resolving relative font-sizes against the absolutized
font-size of the parent or root element as appropriate.
Let's make it very clear that these are *computed* values, and not at
all the specified values. The specified values are currently discarded
by the CSS cascade algorithm.
Get rid of the old, roundabout way of invalidating the rule cache by
incrementing the StyleSheetList "generation".
Instead, when something wants to invalidate the rule cache, just have it
directly invalidate the rule cache. This makes it much easier to see
what's happening anyway.
Style computation always happens *before* layout, so we can't rely on
things having (or not having) layout nodes, as that information will
always be one step behind.
Instead, we have to use the DOM to find all the information we need.
Previously we were making a copy of the full set of custom properties
that applied to a DOM element. This was very costly and dominated the
profile when mousing around on GitHub.
Note that this may break custom properties on pseudo elements a little
bit, and that's something we'll have to look into.
Previously this queried the root layout-node's font, which was both
wrong and could crash if the layout wasn't ready yet. Now, it's just
wrong. But at least all the font-related wrongness is grouped together
in StyleComputer. :^)
Build the final custom property map right away instead of first making
a temporary pointer-only map. We also precompute the final needed
capacity for the map to avoid incremental rehashing.
Let's have one function that determines the type of transformation
needed, and another to actually perform the transformation.
This makes it much easier to read, and we don't have to duplicate the
logic for doing the transformation.
Instead of awkwardly visiting and mutating lengths inside StyleValues,
we now simply create a new StyleValue instead.
This fixes an issue where inherited relative lengths could get
absolutized using a parent as reference, and then not having the correct
values when used in a child context.
Use the new Gfx::Font::AllowInexactSizeMatch parameter when doing CSS
font lookups. This fixes a long-standing issue where text with e.g text
with "font-size:12px" would be larger than "font-size:13px" since there
was an exact match for 12, but none for 13 (so we'd fall back to 10).
This works a little differently from the other caches - ALL rules
containing a pseudo-element are in this bucket. This lets us only look
at this bucket when finding styles for a pseudo-element, and ignore it
if we're not.
Since each selector can only have zero or one pseudo-element, we match
against it as a separate step, before matching the rest of the
selector. This should be faster, but mostly I did this because I could
not figure out how else to stop selectors without a pseudo-element from
matching the pseudo-element, eg so `.foo` styles don't affect
`.foo::before`.
"5em" means 5*font-size, but by forcing "em" to mean the presentation
size of the bitmap font actually used, we broke a bunch of layouts that
depended on a correct interpretation of "em".
This means that "em" units will no longer be relative to the exact
size of the bitmap font in use, but I think that's a compromise we'll
have to make, since accurate layouts are more important.
This yields a visual progression on both ACID2 and ACID3. :^)
The ICB (initial containing block) gets its style from StyleComputer's
create_document_style(). It's basically a generic style for the root of
the layout tree.
With this patch, we now assign the width and height of the viewport rect
as two CSS "px" lengths to the "width" and "height" properties of the
ICB style. (Previously they were just defaulting to "auto" and we
assigned override dimensions during layout.)
This fixes an issue where position:absolute elements with relative width
and/or height were not dimensioned correctly, since the values were
relative to the width and/or height of the ICB style.
After style computation, every StyleProperties has a value for every
PropertyID. Given this, it's simpler, faster and less memory-heavy to
use an Array instead of a HashMap. :^)
This patch introduces the StyleComputer::RuleCache, which divides all of
our (author) CSS rules into buckets.
Currently, there are two buckets:
- Rules where a specific class must be present.
- All other rules.
This allows us to check a significantly smaller set of rules for each
element, since we can skip over any rule that requires a class attribute
not present on the element.
This takes the typical numer of rules tested per element on Discord from
~16000 to ~550. :^)
We can definitely improve the cache invalidation. It currently happens
too often due to media queries. And we also need to make sure we
invalidate when mutating style through CSSOM APIs.
