This partially implements CSS-Animations-1 (though there are references
to CSS-Animations-2).
Current limitations:
- Multi-selector keyframes are not supported.
- Most animation properties are ignored.
- Timing functions are not applied.
- Non-absolute values are not interpolated unless the target is also of
the same non-absolute type (e.g. 10% -> 25%, but not 10% -> 20px).
- The JavaScript interface is left as an exercise for the next poor soul
looking at this code.
With those said, this commit implements:
- Interpolation for most common types
- Proper keyframe resolution (including the synthetic from-keyframe
containing the initial state)
- Properly driven animations, and proper style invalidation
Co-Authored-By: Andreas Kling <kling@serenityos.org>
Both of these are supposed to be set when the CSSRule is created. The
spec is silent on setting it when a CSSRule is added to a parent. So,
this is a bit ad-hoc.
The parent rule gets set whenever a rule is added to a new parent. The
parent stylesheet gets set whenever the rule or one of its ancestors is
added to a different stylesheet. There may be some nuance there that
I'm missing, but I'm sure we'll find out quickly once we have WPT
running!
We already had the CSSRule::Type enum, but the values were not aligned
with the CSSOM spec. This patch takes care of that, and then exposes
the type of a CSSRule to JavaScript via the "type" attribute.
There are a handful of FIXME's here, but this seems generally good.
Note that CSS *values* don't get serialized in a spec-compliant way
since we currently rely on StyleValue::to_string() which is ad-hoc.
This patch makes both of these classes inherit from RefCounted and
Bindings::Wrappable, plus some minimal rejigging to allow us to keep
using them internally while also exposing them to web content.
