This will allow us to easily add copies of the relevant canvas drawing
state to a stack, and likewise replace the current drawing state with
an entry from that stack.
I don't know if the original author simply missed this or thought the
default color of Gfx::Color is black, but this meant that drawing on a
canvas without explicitly setting a fillStyle or strokeStyle first would
be drawn in transparent color and therefore be invisible.
In the spec this is indicated by a small comment in the IDL definition:
attribute ... strokeStyle; // (default black)
attribute ... fillStyle; // (default black)
I'm starting to question whether Gfx::Color actually *should* have a
default constructor.
This wasn't quite following what the spec says for step 2:
"If index is −1, then remove the last element in the rows collection
from its parent, or do nothing if the rows collection is empty."
It was behaving like:
"If index is −1 and the rows collection is not empty, then remove the
last element in the rows collection from its parent."
Which is not the same, as it will fall into the "Otherwise" if
`index == -1` and the rows collection is empty and try and get the -2nd
element of the rows.
Found with Domato.
Step 1 of the spec is to capture the <script> element's node document
into a local variable.
When I originally implemented this, I thought this was not necessary.
However, I realised that the script that runs can adopt the current
script element into a different document, meaning step 5.4 and 6 then
operate on the incorrect document.
Covered by this WPT: 7b0ebaccc6/html/semantics/scripting-1/the-script-element/moving-between-documents-during-evaluation.html
The "completely finish loading" algorithm (from the HTML spec) is
responsible for sending a "load" event to nested browsing context
containers (iframes).
This patch removes the old mechanism for sending "load" events, which we
had mistakenly kept around, causing two events to be sent instead of
one. :^)
This changes allows for nested browser contexts to be embedded in the
serialized JSON of their container element (like `iframe`) and enables
their inspection in the DOM Inspector.
When valid, this attribute needs to result in an IdentifierStyleValue.
Before this change we were turning it into a StringStyleValue, which
then defaulted to left alignment for all values.
For "center" and "middle", we turn it into -libweb-center. All other
values are passed verbatim to the CSS parser.
This always felt awkward to me, and required a few other hacks to make
it work. Now, the request is only started when `load_bitmap()` is
called, which we do inside `NodeWithStyle::apply_style()`.
Note our Attribute class is what the spec refers to as just "Attr". The
main differences between the existing implementation and the spec are
just that the spec defines more fields.
Attributes can contain namespace URIs and prefixes. However, note that
these are not parsed in HTML documents unless the document content-type
is XML. So for now, these are initialized to null. Web pages are able to
set the namespace via JavaScript (setAttributeNS), so these fields may
be filled in when the corresponding APIs are implemented.
The main change to be aware of is that an attribute is a node. This has
implications on how attributes are stored in the Element class. Nodes
are non-copyable and non-movable because these constructors are deleted
by the EventTarget base class. This means attributes cannot be stored in
a Vector or HashMap as these containers assume copyability / movability.
So for now, the Vector holding attributes is changed to hold RefPtrs to
attributes instead. This might change when attribute storage is
implemented according to the spec (by way of NamedNodeMap).
https://www.w3.org/TR/cssom/ is the more permanent home of the CSSOM
specification's latest version, and is up to date with the draft spec.
Also, https://drafts.csswg.org/ has been down multiple times recently
which made looking things up a pain.
This paves the way for the rejectionhandled and unhandledrejection
events.
It's also used by core-js (in browsers, at least) to check whether
Promise needs to be polyfilled, so adding it should allow more websites
to leverage LibJS's native Promise implementation :^)
There's a subtle difference here. A "block box" in the spec is a
block-level box, while a "block container" is a box whose children are
either all inline-level boxes in an IFC, or all block-level boxes
participating in a BFC.
Notably, an "inline-block" box is a "block container" but not a "block
box" since it is itself inline-level.
Until now, we've internally thought of the CSS "display" property as a
single-value property. In practice, "display" is a much more complex
property that comes in a number of configurations.
The most interesting one is the two-part format that describes the
outside and inside behavior of a box. Switching our own internal
representation towards this model will allow for much cleaner
abstractions around layout and the various formatting contexts.
Note that we don't *parse* two-part "display" yet, this is only about
changing the internal representation of the property.
Spec: https://drafts.csswg.org/css-display
Instead of doing layout synchronously whenever something changes,
we now use a basic event loop timer to defer and coalesce relayouts.
If you did something that requires a relayout of the page, make sure
to call Document::set_needs_layout() and it will get coalesced with all
the other layout updates.
There's lots of room for improvement here, but this already makes many
web pages significantly snappier. :^)
Also, note that this exposes a number of layout bugs where we have been
relying on multiple relayouts to calculate the correct dimensions for
things. Now that we only do a single layout in many cases, these kind of
problems are much more noticeable. That should also make them easier to
figure out and fix. :^)
This patch adds the "has a rendering opportunity" concept from the spec
to BrowsingContext and uses it to filter out contexts that are unable
to render right now when doing the event loop's rendering updates.
Note that we actually consider all contexts to have a rendering
opportunity at all times right now. Coming up with reasons to avoid
rendering is left as a FIXME. :^)
We now invoke DOM timer callbacks via HTML tasks. This brings callback
sequencing closer to the spec, although there are still many
imperfections in this area.
