This algorithm is used by Typed-OM for producing a list of internal
style values from a single one, for properties that take a list. We
will probably need to implement this for more StyleValues later.
Now that we don't remove whitespace when parsing, we don't need to
artificially insert it back in again when serializing. We do now need
to trim leading and trailing whitespace from UnresolvedStyleValues, as
this previously was done as part of the whitespace insertion.
This makes our serialization of UnresolvedStyleValues more correct and
gets us a few WPT passes for each property in the Typed OM tests.
We don't need all this specific logic for parsing the `transition`
property - we also now maintain `none` as such until use time which
gains us a couple extra tests
Converting to CSSPixels caused us to lose precision and the sign of
signed zeroes.
The values we resolve against in Length::ResolutionContext are still
themselves rounded too early but this is in the right direction.
Since we now have access to the `AbstractElement` through the
`ComputationContext` we can just set the flag that this element relies
on tree counting functions directly, no need to pass this struct around.
Passing the `AbstractElement` rather than the
`TreeCountingFunctionResolutionContext` allows us to only compute the
resolution context when necessary (i.e. when we actually need to resolve
a tree counting function)
There are some non-math functions (such as tree counting functions)
which we should allow within `calc()`s . This commit implements the
initial infrastructure for this.
We don't yet parse any of these non-math functions in
`parse_a_calculation` so there is no functional change.
Adds support for `sibling-index()` and `sibling-count()` when parsing
`<number>` and `<integer>`. This is achieved by a new
`TreeCountingFunctionStyleValue` class which is converted within
`absolutized` to `NumberStyleValue` and `IntegerStyleValue` respectively
There are still a few kinks to work out in order to support these
everywhere, namely:
- There are some `StyleValue`s which aren't absolutized (i.e. those
which are stored within another `StyleValue` without an
`absolutize()` method.
- We don't have a way to represent this new `StyleValue` within
`{Number,Integer}OrCalculated`. This would be fixed if we were to
instead just use the `StyleValue` classes until style computation at
which time they would be absolutized into their respective
primitives (double, i64, etc) bypassing the need for *OrCalculated
entirely.
Tree counting functions should be resolved at style computation time -
to do this we will need to know the element's sibling count and index.
This commit computes that information and propagates it to the various
`StyleValue::to_computed_value` methods.
This excludes `step-end` and `step-start` which are expected to be
converted to the equivalent function at parse time.
We are expected to serialize these as the explicit keywords - previously
we would parse as `EasingStyleValue` and serialize equivalent functions
as the keywords. This caused issues as we would incorrectly serialize
even explicit functions as the keyword.
This also allows us to move the magic easing functions to
`EasingFunction` rather than `EasingStyleValue` which is a bit tidier
Previously we were doing this ad-hoc later in the process but we now
have the `calc` clamping system which can simplify things.
This reveals some false-positives in that we don't handle relative
lengths within these `calc`s but these are fixed in the next commit
Canonicalization can require information that is only known after
compute time (i.e. resolved relative lengths within calcs).
This also allows us to get rid of the `had_explicit_input` flag and just
rely on whether Optional has a value
We have this code duplicated in multiple places, and we'll want to
handle registered custom properties too at some point, so wrap it in a
reusable `CalculationContext::for_property()` method.
Noticed while doing this that ValueParsingContext will eventually need
to take a PropertyNameAndID, not a PropertyID, so I've added a FIXME.
This struct will in the future hold information other than a length
resolution context (e.g. context for tree counting functions) and a
single struct is easier to work with than multiple parameters.
When setting style to a CSSStyleValue we need to convert it to a
StyleValue. If we already have one, we might as well use it avoid the
work of serialization and re-parsing.
I realised I misunderstood what "constructed from a USVString" means, so
I've adjusted based on that. It does raise a question on what the source
USVString is if that string resulted in multiple CSSStyleValues being
created - see the linked issue.
