This lets us not care about non-absolute Length units when resolving
gradient data, as they'll already have been converted to px.
We can also use Angle::from_style_value() safely on absolutized angles,
which reduces some boilerplate code.
A few things fall out of this:
- We no longer need to templatize our color-stop list types.
- A bit more code is required to resolve gradient data.
This results in a slightly different rendering for a couple of the test
gradients, with a larger difference between macOS and Linux. I've
expanded the fuzziness factor to cover for it.
This reverts 0e3487b9ab.
Back when I made that change, I thought we could make our StyleValue
classes match the typed-om definitions directly. However, they have
different requirements. Typed-om types need to be mutable and GCed,
whereas StyleValues are immutable and ideally wouldn't require a JS VM.
While I was already making such a cataclysmic change, I've moved it into
the StyleValues directory, because it *not* being there has bothered me
for a long time. 😅
PaintContext dates back to a time when display lists didn't exist and it
truly represented "paint context". Renaming it to better align with its
current role.
None of the code here actually needs a NodeWithStyleAndBoxModelMetrics,
and we'll need to be able to resolve images from inside
NodeWithStyle::apply_style().
We previously only invalidated the cached color-stop data when the
painted area's size changed. However, multiple elements can use the
same gradient and be the same size, but have different parameters that
affect the gradient stop positions, for example if a stop has an em
position. This can also change for the same element over time.
The new cache instead uses these parameters as the cache key. So we
recompute the cache if lengths would resolve differently, or the area's
size is different.
The included test fails without this change.
The Web::CSS::Parser's GradientParsing ignores color-stops if
it is only a single one. This change allows to have color-stops
with double positions against a single color.
Further, also allows for `linear-gradient(black)` and similar
other gradient functions
