As mentioned in jwilm/alacritty#931, it can be troublesome if a font has
an underline symbol outside of the glyph's bounding box. This can lead
to the underline disappearing at the bottom of the terminal.
As a solution a symbol from the private use area was used as the
character code for the underline symbol. Whenever this symbol is
encountered, instead of rendering it, a custom block is rendered.
In this implementation the block has the full character as width and
sits flush with the bottom of the glyph's bounding box. The height is
half the distance between the baseline and the bottom of the bounding
box.
The source of the leak was loading up multiple copies of the FT_face
even when not necessary. Fonts are now appropriately cached for
FreeType when going through the `Rasterize::load_font` API.
Additionally, textures in the glyph cache are now reused.
The result of this is that resizing to already loaded fonts is free
from a memory consumption perspective.
To allow FontConfig to work with Bitmap font, we shall pass the size
we are interested in, and account for the size returned in the font
matching process. This is, because we cannot scale those fonts.
FontConfig will return the closest match, and we take its returned
pixel size back when we are rendering the glyphs.
There's an oddity when call set_char_size in TrueType - we need to
behave as if the DPI is 72. It is due to the following macro:
#define FT_REQUEST_HEIGHT( req ) \
( (req)->vertResolution \
? ( (req)->height * (FT_Pos)(req)->vertResolution + 36 ) / 72 \
: (req)->height )
Further work can allow for integer scaling of the largest bitmap
font variant.
Tested with Terminus PCF-type font under Linux.
This addresses issue #582 .
The FreeType rasterizer now reads settings like antialias, rgba,
lcdfilter, and hintstyle and chooses FreeType settings accordingly. The
result is that Alacritty fonts should look similar to the rest of the
system.
The hash map of key -> face was previouly cloned every time a glyph was
rasterized. This refactored the rasterization path to be more borrowck
friendly.
Sadly, this implementation is not *that* clean, but once NLLs land, much
of this can be cleaned up.
The fontconfig `FcPattern` type is wrapped as `fc::Pattern` and
`fc::Pattern` ref. All methods for accessing data on the pattern now
return an `Iterator`. This API turns out to be much more ergonomic than
providing an integer index. We also override the default `nth`
implementation of `Iterator` on these accessors to allow random
(incremental only) access.
For instance, accessing `family` attributes from a pattern:
let families = pattern.family();
let second = pattern.nth(1);
Or printing available styles
for style in pattern.style() {
println!("style={}", style);
}
As it turns out, FreeType does not always provide glyph data in LCD mode
as we requested. We now correctly handle several common modes returned
from FreeType including Lcd, Mono, and Gray.
Note that we don't check number of grays at this time since it's
1. Almost always 256, according to FreeType docs
2. Not available in the Rust FreeType bindings being used
Resolves#515Resolves#185Resolves#482
The font metrics function was using freetype metrics in an ineffective
way, improve the use of those metrics and remove the now unnecessary
separate default values for font offset in linux.
This is done in order to help prevent us from loading the same
font face over and over again under separate keys. We still incur
the performance hit of doing the fontconfig search each new glyph,
but that's unavoidable without more extensive refactoring.
Makes thin stroke rendering for darwin configurable by a new toplevel
key under `font:` in the config file. Defaults to false, has no impact
on non macos.
This work started because we wanted to be able to simply say "monospace"
on Linux and have it give us some sort of font. The config format for
fonts changed to accomodate this new paradigm. As a result, italic and
bold can have different families from the normal (roman) face.
The fontconfig based font resolution probably works a lot better than
the CoreText version at this point. With CoreText, we simply iterate
over fonts and check it they match the requested properties. What's
worse is that the CoreText version requires a valid family. With
fontconfig, it will just provide the closest matching thing and use it
(unless a specific style is requested).
There's now a proper wrapper in place for working with the FontConfig
library. This should help significantly with error handling with font
loading; at least, the FontConfig code shouldn't panic. The FreeType
rasterizer still needs to be updated to handle missing fonts, and a more
sensible default font should be specified.
Ref tests use a recording of the terminal protocol and a serialization
of the grid state to check that the parsing and action handling systems
produce the correct result. Ref tests may be recorded by running
alacritty with `--ref-test` and closing the terminal by using the window
"X" button. At that point, the recording is fully written to disk, and a
serialization of important state is recorded. Those files should be
moved to an appropriate folder in the `tests/ref/` tree, and the
`ref_test!` macro invocation should be updated accordingly.
A couple of changes were necessary to make this work:
* Ref tests shouldn't create a pty; the pty was refactored out of the
`Term` type.
* Repeatable lines/cols were needed; on startup, the terminal is resized
* by default to 80x24 though that may be changed by passing
`--dimensions w h`.
* Calculating window size based on desired rows/columns and font metrics
required making load_font callable multiple times.
* Refactor types into library crate so they may be imported in an
integration test.
* A whole bunch of types needed symmetric serialization and
deserialization. Mostly this was just adding derives, but the custom
deserialization of Rgb had to change to a deserialize_with function.
This initially adds one ref test as a sanity check, and more will be
added in subsequent commits. This initial ref tests just starts the
terminal and runs `ll`.
The FreeType font Rasterizer API is updated to match the CoreText
Rasterizer. This enabled bold/italic fonts since the rest of the
codebase has already been updated.
Alacritty now runs on macOS using CoreText for font rendering.
The font rendering subsystems were moved into a separate crate called
`font`. The font crate provides a unified (albeit limited) API which
wraps CoreText on macOS and FreeType/FontConfig on other platforms. The
unified API differed slightly from what the original Rasterizer for
freetype implemented, and it was updated accordingly.
The cell separation properties (sep_x and sep_y) are now premultiplied
into the cell width and height. They were previously passed through as
uniforms to the shaders; removing them prevents a lot of redundant work.
`libc` has some differences between Linux and macOS. `__errno_location`
is not available on macOS, and the `errno` crate was brought in to
provide a cross-platform API for dealing with errno.
Differences in `openpty` were handled by implementing a macOS specific
version. It would be worth investigating a way to unify the
implementations at some point.
A type mismatch with TIOCSCTTY was resolved with a cast.
Differences in libc::passwd struct fields were resolved by using
std::mem::uninitialized instead of zeroing the struct ourselves. This
has the benefit of being much cleaner.
The thread setup had to be changed to support both macOS and Linux.
macOS requires that events from the window be handled on the main
thread. Failure to do so will prevent the glutin window from even
showing up! For this reason, the renderer and parser were moved to their
own thread, and the input is received on the main thread. This is
essentially reverse the setup prior to this commit. Renderer
initialization (and thus font cache initialization) had to be moved to
the rendering thread as well since there's no way to make_context(null)
with glx on Linux. Trying to just call make_context a second time on the
rendering thread had resulted in a panic!.
Christian Duerr
Martin Lindhe
Joe Wilm
Dan Aloni
Jack O'Connor
Joe Wilm
Aaron Williamson
Harlan Lieberman-Berg
Lukas Lueg
Tom Crayford