This one is a bit fun because it can be `add(<integer>)` or `auto-add`,
but children have to inherit the computed value not the specified one.
We also have to compute it before computing the font-size, because of
`font-size: math` which will be implemented later.
Resolving typed `attr()` functions is going to involve using more
internal Parser methods, so this is the simplest solution for that.
Also... resolving these is basically parsing them, so it makes more
sense for that process to live here.
This is just moving code, with minimal changes so it still works.
This means StyleComputer::resolve_unresolved_style_value() always
returns a value, so we can change its return type.
However, it does still return an UnresolvedStyleValue sometimes, so we
can't remove those checks from the user code.
User styles are applied after the UserAgent's built-in styles, and
before the Author styles that are part of the web page.
Because they're neither part of the page, but can still be modified
while the page is open, caching is a little tricky. The approach here
is to piggy-back on the StyleComputer's rule caches, which already get
rebuilt whenever the styles change. This is not the smartest approach,
since it means re-parsing the style sheet more often than is necessary,
but it's simple and works. :^)
This effectively makes it per-Document, but we hang it off of
StyleComputer since that's what it's used for.
The purpose of this is to prevent downloaded fonts from escaping the
context that loaded them. There's probably a more elegant solution where
we still share caching of system fonts, but let's start here.
Instead, perform the filtering for each rule as we go. This avoids
creating a separate list of rules, which was ~5% of runtime when
mousing around on the Discord web interface.
This is a universal value like `initial` and `inherit` and works by
reverting the current value to whatever we had at the start of the
current cascade origin.
The implementation is somewhat inefficient as we make a copy of all
current values at the start of each origin. I'm sure we can come up with
a way to make this faster eventually.
This commit makes the StyleComputer avoid restarting finished animations
(e.g. animations with finite iteration counts that have run to
completion).
As a bonus, it also disables the animation timer when all animations
have finished running.
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>
The resolved property sets are stored with the element in a
per-pseudo-element array (same as for pseudo element layout nodes).
Longer term, we should stop storing this with elements entirely and make
it temporary state in StyleComputer somehow, so we don't waste memory
keeping all the resolved properties around.
This makes various gradients show up on https://shopify.com/ :^)
The root element font metrics were getting queried again and again
during style computation. Before this change we would do some work to
recalculate them each time.
This patch simply caches them in a StyleComputer member. Since style
updates always start with the root element, we know that it'll be
up-to-date by the time we look at any other element.
Before this change, we were spending ~5% of CPU time on Google Groups
in root_element_font_metrics().
Before this patch, we would build full computed style for these pseudo
elements, for every DOM element, even if no ::before/::after selector
actually matched.
This was a colossal waste of time, and we can also just not do that.
Instead, just abort pseudo element style resolution early if no relevant
selectors matched. :^)
Instead of putting every rule that matches a pseudo element in the
same bucket, let them go in the best ID/class/tag name bucket instead.
Then, add a flag to MatchingRule that says whether it contains a
pseudo element in the rightmost compound selector.
When deciding which selectors to run for an element, we can now simply
filter in/out pseudo element selectors as appropriate depending on what
we're trying to match.
This fixes an issue where pages using Font Awesome had 1700+ rules in the
pseudo-element rule cache. (This meant all those rules had to run
against every element twice or more while instantiating pseudo elements.)
We were already sorting the author style selectors into buckets.
Now we do it for the built-in UA style as well.
This means less work for the selector engine everywhere :^)
This class had slightly confusing semantics and the added weirdness
doesn't seem worth it just so we can say "." instead of "->" when
iterating over a vector of NNRPs.
This patch replaces NonnullRefPtrVector<T> with Vector<NNRP<T>>.
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.
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 :^)
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.
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. :^)
