This combines `style()`, `boldness()`, `stretchiness()` into a
`descriptor()` method which is used when creating `FontTemplate`s for
web fonts. Eventually this method will simply read font tables using
skrifa. This is the first step.
In addition, `family_name()` and `face_name()` are removed. They were
only used for debugging and the `FontIdentifier` serves for that. On
Windows, this was adding another way in which font loading could fail,
without buying us very much. The path or URL to the font is more
important when debugging than the names in the font tables.
Closes#15103.
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This change reworks the way that platform fonts are created and
descriptor data is on `FontTemplate` is initialized.
The main change here is that platform fonts for local font faces are
always initialized using the font data loaded into memory from disk.
This means that there is now only a single path for creating platform
fonts.
In addition, the font list is now responsible for getting the
`FontTemplateDescriptor` for local `FontTemplate`s. Before the font had
to be loaded into memory to get the weight, style, and width used for
the descriptor. This is what fonts lists are for though, so for every
platform we have that information before needing to load the font. In
the future, hopefully this will allow discarding fonts before needing to
load them into memory. Web fonts still get the descriptor from the
platform handle, but hopefully that can be done with skrifa in the
future.
Thsese two fixes together allow properly loading indexed font variations
on Linux machines. Before only the first variation could be
instantiated.
Fixes https://github.com/servo/servo/issues/13317.
Fixes https://github.com/servo/servo/issues/24554.
Co-authored-by: Martin Robinson <mrobinson@igalia.com>
----
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix#13317 and #24554
- [x] There are tests for these changes
---------
Co-authored-by: Martin Robinson <mrobinson@igalia.com>
Now that `FontTemplateData` is more or less the same on all platforms,
it can be removed. This is a preparatory change for a full refactor of
the font system on Servo. The major changes here are:
- Remove `FontTemplateData` and move its members into `FontTemplate`
- Make `FontTemplate` have full interior mutability instead of only
the `FontTemplateData` member. This is preparation for having these
data types `Send` and `Sync` with locking.
- Remove the strong/weak reference concept for font data. In practice,
all font data references were strong, so this was never fully
complete. Instead of using this approach, the new font system will
use a central font data cache with references associated to layouts.
- The `CTFont` cache is now a global cache, so `CTFont`s can be shared
between threads. The cache is cleared when clearing font caches.
A benefit of this change (apart from `CTFont` sharing) is that font data
loading is platform-independent now.
The `FontContextHandle` was really only used on FreeType platforms to
store the `FT_Library` handle to use for creating faces. Each
`FontContext` and `FontCacheThread` would create its own
`FontContextHandle`. This change removes this data structure in favor of
a mutex-protected shared `FontContextHandle` for an entire Servo
process. The handle is initialized using a `OnceLock` to ensure that it
only happens once and also that it stays alive for the entire process
lifetime.
In addition to greatly simplifying the code, this will make it possible
for different threads to share platform-specific `FontHandle`s, avoiding
multiple allocations for a single font.
The only downside to all of this is that memory usage of FreeType fonts
isn't measured (though the mechanism is still there). This is because
the `FontCacheThread` currently doesn't do any memory measurement.
Eventually this *will* happen though, during the font system redesign.
In exchange, this should reduce the memory usage since there is only a
single FreeType library loaded into memory now.
This is part of #32033.
Instead of using a simple `Atom` to identify a local font, use a data
structure. This allows us to carry more information necessary to
identify a local font (such as a path on MacOS). We need this for the
new version of WebRender, as fonts on MacOS now require a path.
This has a lot of benefits:
1. We can avoid loading fonts without paths on MacOS, which should
avoid a lot of problems with flakiness and ensure we always load the
same font for a given identifier.
2. This clarifies the difference between web fonts and local fonts,
though there is more work to do here.
3. This avoid a *lot* of font shenanigans, such as trying to work
backwards from the name of the font to the path of the font we
actually matched. In general, we can remove a lot of code trying to
accomplish these shenanigans.
4. Getting the font bytes always returns an `Arc` now avoiding an extra
full font copy in the case of Canvas.
* clippy: fix warnings in components/gfx
* refactor: switched the order of impl so that its intent is clearer
* fix: add font context default in other platforms
Prior to this change, if none of the fonts specified in CSS contained a
glyph for a codepoint, we tried only one fallback font. If that font
didn't contain the glyph, we'd give up.
With this change, we try multiple fonts in turn. The font names we try
differ across each platform, and based on the codepoint we're trying to
match. The current implementation is heavily inspired by the analogous
code in Gecko, but I've used to ucd lib to make it more readable,
whereas Gecko matches raw unicode ranges.
This fixes some of the issues reported in #17267, although colour emoji
support is not implemented.
== Notes on changes to WPT metadata ==
=== css/css-text/i18n/css3-text-line-break-opclns-* ===
A bunch of these have started failing on macos when they previously
passed.
These tests check that the browser automatically inserts line breaks
near certain characters that are classified as "opening and closing
punctuation". The idea is that if we have e.g. an opening parenthesis,
it does not make sense for it to appear at the end of a line box; it
should "stick" to the next character and go into the next line box.
Before this change, a lot of these codepoints rendered as a missing
glyph on Mac and Linux. In some cases, that meant that the test was
passing.
After this change, a bunch of these codepoints are now rendering glyphs
on Mac (but not Linux). In some cases, the test should continue to pass
where it previously did when rendering with the missing glyph.
However, it seems this has also exposed a layout bug. The "ref" div in
these tests contains a <br> element, and it seems that this, combined
with these punctuation characters, makes the spacing between glyphs ever
so slightly different to the "test" div. (Speculation: might be
something to do with shaping?)
Therefore I've had to mark a bunch of these tests failing on mac.
=== css/css-text/i18n/css3-text-line-break-baspglwj-* ===
Some of these previously passed on Mac due to a missing glyph. Now that
we're rendering the correct glyph, they are failing.
=== css/css-text/word-break/word-break-normal-bo-000.html ===
The characters now render correctly on Mac, and the test is passing. But
we do not find a suitable fallback font on Linux, so it is still failing
on that platform.
=== css/css-text/word-break/word-break-break-all-007.html ===
This was previously passing on Mac, but only because missing character
glyphs were rendered. Now that a fallback font is able to be found, it
(correctly) fails.
=== mozilla/tests/css/font_fallback_* ===
These are new tests added in this commit. 01 and 02 are marked failing
on Linux because the builders don't have the appropriate fonts installed
(that will be a follow-up).
Fix build errors from rebase
FontTemplateDescriptor can no longer just derive(Hash). We need to
implement it on each component part, because the components now
generally wrap floats, which do not impl Hash because of NaN. However in
this case we know that we won't have a NaN, so it is safe to manually
impl Hash.
Issue #17321. Under Linux, using "font-family: sans-serif" previously
caused Servo to select the "UltraLight" face (of DejaVu Sans). There
were two reasons for this:
1. Font weight was only retrieved from the OS/2 table for bold faces.
This neglected to retrieve the weight information for "lighter than
normal" weight faces. This meant that the UltraLight face appeared as
normal weight, and was selected.
2. Retrieval of font stretch information from the OS/2 table was not
implemented at all.
