CSS Fonts level 4 renames font-stretch to font-width, with font-stretch
being left as a legacy alias. Unfortunately the other specs have not yet
been updated, so both terms are used in different places.
When a property is a "legacy name alias", any time it is used in CSS or
via the CSSOM its aliased name is used instead.
(See https://drafts.csswg.org/css-cascade-5/#legacy-name-alias)
This means we only care about the alias when parsing a string as a
PropertyID - and we can just return the PropertyID it is an alias for.
No need for a distinct PropertyID for it, and no need for LibWeb to
care about it at all.
Previously, we had a bunch of these properties, which misused our code
for "logical aliases", some of which I've discovered were not even
fully implemented. But with this change, all that code can go away, and
making a legacy alias is just a case of putting it in the JSON. This
also shrinks `StyleProperties` as it doesn't need to contain data for
these aliases, and removes a whole load of `-webkit-*` spam from the
style inspector.
Logging a parse error when the attribute is not present, is not useful,
but does fill the debug log with errors that hide any real parsing
errors. This patch introduces an early-out in this situation to prevent
this spam.
The following spec algorithms had changed since we implemented them:
- "parse a sizes attribute"
- "update the source set"
- "create a source set"
This commit brings them up to date, as well as adding some additional
logging when parsing the sizes attribute fails in some way.
According to https://www.w3.org/TR/css-grid-2/#placement-shorthands
when setting the 'grid-row' and 'grid-column' shorthand property to a
single <custom-ident> value, both 'grid-row-start'/'grid-column-start'
and 'grid-row-end'/'grid-column-end' should be set to that
<custom_ident>.
Instead of CSSColorValue holding a Gfx::Color, make it an abstract class
with subclasses for each different color function, to match the Typed-OM
spec. This means moving the color calculations from the parsing code to
the `to_color()` method on the style value.
This lets us have calc() inside a color function, instead of having to
fully resolve the color at parse time. The canvas fillStyle tests have
been updated to reflect this.
The other test change is Screenshot/css-color-functions.html: previously
we produced slightly different colors for an alpha of 0.5 and one of
50%, and this incorrect behavior was baked into the test. So now it's
more correct. :^)
"Parse a style value for <foo>", where we don't care if it's a literal
<foo> or a calculated one, is a really common thing that we previously
didn't have methods for.
A couple of methods we had have been extended to parse calc(), and the
others have been filled in.
The method for parsing the `flex` property's value is renamed
`parse_flex_shorthand_value()` as it conflicted.
For simplicity in user code, the `parse_foo_value()` methods should
parse anything that is a `<foo>`. In these cases, that means a
number/integer or calculation that resolves to them.
These uses in parse_css_value_for_properties() specifically only want a
literal IntegerStyleValue/NumberStyleValue, as calc-parsing is done
elsewhere. So, do the parsing for them locally.
Parsing a `Gfx::Color` no longer makes sense, as CSS has many ways of
defining a color, often in a dynamic way where the color value isn't
known until later. This is a small preparatory change before a much
larger color rewrite.
Soon, CSSColorValue will be an abstract class, and we'll instead create
a CSSRGB, CSSHSL, or other specific color type from the Typed-OM spec.
However, it's still useful to have an easy "just give me a style value
for this color" method. So change the name to distinguish this from the
usual StyleValue::create() methods.
We previously had 4 single-instance StyleValues for these keywords.
CSS-Typed-OM expects them keywords to be exposed as CSSKeywordValue, so
it's simpler to treat them the same. The single-instance behaviour is
kept by having StyleValue::create() use a cached instance for each of
these.
For a long time, we've used two terms, inconsistently:
- "Identifier" is a spec term, but refers to a sequence of alphanumeric
characters, which may or may not be a keyword. (Keywords are a
subset of all identifiers.)
- "ValueID" is entirely non-spec, and is directly called a "keyword" in
the CSS specs.
So to avoid confusion as much as possible, let's align with the spec
terminology. I've attempted to change variable names as well, but
obviously we use Keywords in a lot of places in LibWeb and so I may
have missed some.
One exception is that I've not renamed "valid-identifiers" in
Properties.json... I'd like to combine that and the "valid-types" array
together eventually, so there's no benefit to doing an extra rename
now.
These have a few rules that we didn't follow in most cases:
- CSS-wide keywords are not allowed. (inherit, initial, etc)
- `default` is not allowed.
- The above and any other disallowed identifiers must be tested
case-insensitively.
This introduces a `parse_custom_ident_value()` method, which takes a
list of disallowed identifier names, and handles the above rules.
This is `counter(name, style?)` or `counters(name, link, style?)`. The
difference being, `counter()` matches only the nearest level (eg, "1"),
and `counters()` combines all the levels in the tree (eg, "3.4.1").
These control the state of CSS counters.
Parsing code for `reversed(counter-name)` is implemented, but disabled
for now until we are able to resolve values for those.
The new method is Parser::parse_all_as_single_none_value(), which has a
few advantages:
1. There's no need for user code to manually create a StyleValue.
2. It consumes tokens so that doesn't have to be done manually.
3. Whitespace before or after the `none` is consumed correctly.
It does mean we create and then discard a `none` StyleValue in a couple
of places, namely parsing for `grid-*` properties. We may or may not
want to migrate those to returning the IdentifierStyleValue instead.
We already have a FlyString of its value from parsing, and most users
also want a FlyString from it, so let's use that instead of converting
backwards and forwards.
The two users that did want a String are:
- Quotes, which make sense as FlyString instead, so I've converted that.
- Animation names, which should probably be FlyString too, but the code
currently also allows for other kinds of StyleValue, and I don't want
to dive into this right now to figure out if that's needed or not.
