Instead of a blocking a layout thread on the generation of WebRender
`FontKey`s and `FontInstanceKey`s, generate the keys ahead of time and
send the font data to WebRender asynchronously. This has the benefit of
allowing use of the font much more quickly in layout, though blocking
display list sending itself on the font data upload.
In order to make this work for web fonts, `FontContext` now asks the
`SystemFontService` for a `FontKey`s and `FontInstanceKey`s for new web
fonts. This should happen much more quickly as the `SystemFontService`
is only blocking in order to load system fonts into memory now. In
practice this still drops layout thread blocking to fractions of a
millisecond instead of multiple milliseconds as before.
In addition, ensure that we don't send font data or generate keys for
fonts that are used in layout but never added to display lists. This
should help to reduce memory usage and increase performance.
Performance of this change was verified by putting a microbenchmark
around `FontContext::create_font` which is what triggered font key
generation.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
This is done by no longer forwarding compositor-bound messages through
SystemFontService and making `FontContext` non-generic:
- Messages from the `FontContext` to the `Compositor` no longer need to be
forwarded through the `SystemFontService`. Instead send these messages
directly through the script IPC channel to the `Compositor`.
- Instead of adding a mock `SystemFontServiceProxy`, simply implement a
mock `SystemFontService` on the other side of an IPC channel in the
`font_context` unit test. This allows making `FontContext`
non-generic, greatly simplifying the code. The extra complexity moves
into the unit test.
These changes necessitate adding a new kind of `FontIdentifier`,
`FontIdentifier::Mock` due to the fact that local fonts have
platform-specific identifiers. This avoids having to pretend like the
system font service can have web fonts -- which was always a bit of a
hack.
These two changes are combined into one PR because they both require
extensive and similar chages in the font_context unit test which
dependended on the details of both of them.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
This makes the determination of whether or not to use fast shaping
platform independent. Previously it was less stringent for Windows,
leading to using it in cases where a font had a GSUB or GPOS table --
which broke proper shaping.
In addition, the test is made platform independent and expanded to be
more complete.
Finally, comments are added indicating that "fast shaping" will be
removed.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
This changes modifes the way that font data is sent over IPC channels.
Instead of serializing the data or sending it via IPC byte senders, font
data is copied into shared memory and a copy of the handle is sent over
the channel.
There is also the idea of sending the file handle of the on disk data of
system fonts. This could be implemented as a further followup once there
is an abstraction in `ipc-channel` over file handles.
To accomplish this, a `FontData` abstraction is added, which also allows
caching an in-memory shared `Arc<Vec<u8>>` version of the data (neeeded
by some APIs). This could also be a place for caching font tables in the
future.
Finally, the `FontCacheThread` is renamed to the `SystemFontService`
while the proxy for this is now named `SystemFontServiceProxy`.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Mukilan Thiyagarajan <mukilan@igalia.com>
There were various cases like `text-wrap-mode: nowrap` and
`white-space-collapse: break-spaces` that weren't handled well.
Fixes#33335
flexbox_flex-formatting-interop.html fails now because we don't support
`table-layout: fixed`.
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
Up until now, Servo was using a very old version of time to get a
cross-process monotonic timestamp (using `time::precise_time_ns()`).
This change replaces the usage of old time with a new serializable
monotonic time called `CrossProcessInstant` and uses it where `u64`
timestamps were stored before. The standard library doesn't provide this
functionality because it isn't something you can do reliably on all
platforms. The idea is that we do our best and then fall back
gracefully.
This is a big change, because Servo was using `u64` timestamps all over
the place some as raw values taken from `time::precise_time_ns()` and
some as relative offsets from the "navigation start," which is a concept
similar to DOM's `timeOrigin` (but not exactly the same). It's very
difficult to fix this situation without fixing it everywhere as the
`Instant` concept is supposed to be opaque. The good thing is that this
change clears up all ambiguity when passing times as a `time::Duration`
is unit agnostic and a `CrossProcessInstant` represents an absolute
moment in time.
The `time` version of `Duration` is used because it can both be negative
and is also serializable.
Good things:
- No need too pass around `time` and `time_precise` any longer.
`CrossProcessInstant` is also precise and monotonic.
- The distinction between a time that is unset or at `0` (at some kind
of timer epoch) is now gone.
There still a lot of work to do to clean up timing, but this is the
first step. In general, I've tried to preserve existing behavior, even
when not spec compliant, as much as possible. I plan to submit followup
PRs fixing some of the issues I've noticed.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Previously if a font didn't have a space advance and it was needed to
make advances for tabs, Servo would try to read the advance from the
font. If the font didn't have a space glyph, Servo would panic. This
fixes that issue by making the space advance part of the `FontMetrics`
of a font (like Gecko) and falling back properly if that glyph doesn't
exist. The rendered glyph is still the "space" glyph, but we make
sure to select a font that supports that glyph explicitly.
This prevents a crash, but tabs still aren't handled properly. In
reality, tab stops should be calculated in layout and the size of
the space character of the current font shouldn't come into play.
The addition of the space advance metric will make this easier.
Fixes#32970.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Do font selection using Servo's font backend, which is shared with the
rest of layout. In addition, delay the creation of the `font-kit` font
until just before rendering with `raqote`. The idea is that when
`raqote` is no longer used, we can drop the `font-kit` dependency.
This change has the side-effect of fixing text rendering in canvas,
adding support for font fallback in canvas, and also correcting a bug in
font selection with size overrides.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Mukilan Thiyagarajan <mukilan@igalia.com>
This adds support for generic font families in Servo and allows for
configuration of them as well as their default font sizes. One
interesting fix here is that now monospace default to 13px, like it does
in other browsers.
In addition to that, this exposes a new interface in Stylo which allows
setting a default style. This is quite useful for fonts, but also for
other kinds of default style settings -- like text zoom.
Fixes#8371.
Fixes#14773.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Mukilan Thiyagarajan <mukilan@igalia.com>
This crate only takes care of fonts now as graphics related things are
split into other crates. In addition, this exposes data structures at
the top of the crate, hiding the implementation details and making it
simpler to import them.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Mukilan Thiyagarajan <mukilan@igalia.com>
