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>
- Better detect situations where emoji is necessary by looking ahead one
character while laying out. This allow processing Unicode presentation
selectors. When detecting emoji, put emoji fonts at the front of
fallback lists for all platforms.
This enables monochrome emoji on Windows. Full-color emoji on Windows
probably needs full support for processing the COLR table and drawing
separate glyph color layers.
- Improve the font fallback list on FreeType platforms. Ideally, Servo
would be able to look through the entire font list to find the best
font for a certain character, but until that time we can make sure the
font list contains the "Noto Sans" fonts which cover most situations.
Fixes#31664.
Fixes#12944.
This allows sharing font templates, fonts, and platform fonts across
layout threads. It's the first step toward storing web fonts in the
layout versus the shared `FontCacheThread`. Now fonts and font groups
have some locking (especially on FreeType), which will probably affect
performance. On the other hand, we measured memory usage and this saves
roughly 40 megabytes of memory when loading servo.org based on data from
the memory profiler.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Mukilan Thiyagarajan <mukilan@igalia.com>
* feat: Support font-relative `ch` and `ic` units
After #31966, which made it possible for the first time to resolve
font-relative CSS units, this change adds support for the `ch` and
`ic` units.
One difference with the `ex` unit that was added in that PR is that
these units must reflect the advance width of a character (the zero
digit in the case of `ch`, and the CJK water radical for `ic`) as it
would be rendered by the current font group. This means that the size
of these units don't only depend on the first available font, in the
case where that font does not contain a glyph for that character.
This is implemented by adding the advance width for these two
characters as optional fields of `FontMetrics`, so the advance width
computation happens in advance. Then, when the font metrics are
queried as part of unit resolution, the font group is searched for the
first font containing that character.
This change only implements support for these units in upright
typesetting modes, since Servo does not yet have support for vertical
writing modes. This means that many of the WPT tests that test for the
behavior of these units with vertical writing modes do not pass.
This change also makes a number of WPT tests pass, which relied on the
`ch` and `ic` units. It, however, also makes the test
`/css/css-text/white-space/text-wrap-balance-overflow-002.html` fail,
since it tests `text-wrap: balance`, which Servo does not yet
implement, and it was only previously passing by chance due to the
previous behavior of these units.
* Revert Python 3.10-related changes to wss
* Fix formatting
* Remove test expectation
There are a couple major changes here:
1. Support is added for the `weight`, `style`, `stretch` and
`unicode-range` declarations in `@font-face`.
2. Font matching in the font cache can return templates and
`FontGroupFamily` can own mulitple templates. This is due to needing
support for "composite fonts". These are `@font-face` declarations
that only differ in their `unicode-range` definition.
This fixes a lot of non-determinism in font selection especially when
dealing with pages that define "composite faces." A notable example of
such a page is servo.org, which now consistently displays the correct
web font.
One test starts to fail due to an uncovered bug, but this will be fixed
in a followup change.
Fixes#20686.
Fixes#20684.
Co-authored-by: Mukilan Thiyagarajan <mukilan@igalia.com>
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 fixes two issues that were preventing emojis from being properly
selected from fonts on macOS.
1. `CTFont::get_glyphs_for_characters` takes the input characters as
UniChar which are UTF-16 encoded characters. We need to encode the
input `char` as UTF-16 before passing it to CoreText.
2. The font fallback list is updated with the latest logic from Gecko,
which importantly adds "Apple Color Emoji" to the list of fallback
fonts. Sorry for the big change, but this is just a direct port of
the code from Gecko.
With these two changes, emojis display but in grayscale. 😅 To fix this,
another part of the font stack will need to detect when the font
supports color and pass that information to WebRender when creating the
font instance. We will likely do this in platform independent way later
that will depend on some more preliminary changes.
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes are part of #17267.
- [x] There are tests for these changes, but the macOS CI does not
currently run WPT so we cannot observe the updated results.
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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>
* Simplify `FontHandle` and rename it to `PlatformFont`
Rename it to `PlatformFont` and move the `FontTemplate` member to
`Font`, because it's shared by all platforms.
* Update components/gfx/platform/freetype/font.rs
Co-authored-by: Mukilan Thiyagarajan <mukilanthiagarajan@gmail.com>
* Fix build for MacOS and Windows
---------
Co-authored-by: Mukilan Thiyagarajan <mukilanthiagarajan@gmail.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.
Since the original version of the CoreText font code, it has scaled the
metrics from CoreText by an unusual scale:
```
let scale = px_to_pt(self.ctfont.pt_size()) / (ascent + descent);
```
It's unclear what this scale was trying to accomplish. Note that it's
passing the return value of `pt_size()` to `px_to_pt` which seems
backward. This scale seems bogus, but perhaps it's based on a
misconception about what its returned from CoreText. Unlike the return
values of `CGFont` methods, which are returned in font units, the ones
from `CTFont` are "scaled according to the point size and matrix of the
font reference."
Indeed, when just interpreting these values as pixel values, the results
more or less match Firefox and Chrome. This becomes much more obvious
now that we have support for `ex` units. Even when not using `ex`, you
can sometimes see the top parts of glyphs cut off due to this scaling.
This change removes the scaling and simply interpets the return values
of `CTFont` methods as pixels. It addresses all of the issues mentioned
above. Note that this path will eventually just be a fallback path and
metrics will come from sfnt tables in the future.
There is now platform-specific way to get metrics for `line-through` on
MacOS and currently striking through simply does not work. The correct
approach here is likely to first search for these metrics in font tables
and then falling back to deriving them. Searching the font tables is a
larger change, so this change adds the fallback mechanism first. This at
least makes sure that strike through renders at all on Mac.
In a followup change we can add support for getting metrics via HarfBuzz
in a platform-independent way, which is what Gecko does.
Fixes#942.
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.
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.
This is a step towards fixing #17267. To fix that, we need to be able to
try various different fallback fonts in turn, which would become
unweildy with the prior eager-loading strategy.
Prior to this change, FontGroup loaded up all Font instances, including
the fallback font, before any of them were checked for the presence of
the glyphs we're trying to render.
So for the following CSS:
font-family: Helvetica, Arial;
The FontGroup would contain a Font instance for Helvetica, and a Font
instance for Arial, and a Font instance for the fallback font.
It may be that Helvetica contains glyphs for every character in the
document, and therefore Arial and the fallback font are not needed at
all.
This change makes the strategy lazy, so that we'll only create a Font
for Arial if we cannot find a glyph within Helvetica. I've also
substantially refactored the existing code in the process and added
some documentation along the way.
to 400, not 500.
CSS `normal` font-weight is specified as 400, while Mac "Regular" font
weight is reported as 0.0. On the Mac, we need to center the two ranges
on the same value to avoid choosing "Light" fonts where "Regular" would
have been more appropriate.
Closes#9487.
fix for mac
