Now that all platforms know whether the system fallbacks
covered the requested glyph range, it is reasonable to
restore the configuration error window to advise the user
if they are missing fonts for the text they want to display.
refs: https://github.com/wez/wezterm/issues/671
Previously, we would add a list of ~100 or so fallback fonts to
the shaper's fallback list.
In pathological cases where a wide range of glyphs that have no
corresponding font are repeatedly emitted to the output, we'd
keep loading and unloading that large list of fallbacks in the
hope of finding a match.
Since that code was written, we're now able to compute the
codepoint coverage for ourselves, so teach the core text locator
how to reduce the the list of fallback fonts to just those that
contain the missing glyphs.
Furthermore, we restrict that list to just the normal/regular
weight/stretch/style fonts.
refs: https://github.com/wez/wezterm/issues/671
The intent is to reveal more context on what's happening in
https://github.com/wez/wezterm/issues/671
As a nice side benefit, this avoids the potential inability
to open paths that are not utf8 or representable as c-strings
on Windows.
And on top of that: this enables memory mapped file IO as well,
which wasn't enabled previously. This should help to reduce
extraneous copies of the font in memory, have fewer open files
and minimize the chances of racing with O_CLOEXEC.
When we process the system fallback list, we can produce a long list
of fonts to be speculatively processed by the shaper.
Until this commit, the shaper would always keep the associated
freetype face open forever, which increases the number of open
files and the amount of allocated memory.
This commit allows the shaper to release a font if it has never
produced any valid shaper results, which keeps the list down
to just the fonts that are in use.
This commit allows the x11 window implementation to detect changes
in the DPI that occur after a window is created.
These can occur when changing desktop resolution or when changing
the accessibility option for "Large Text" in gnome.
In order to avoid continually polling for the value on every resize,
we look for the `_GTK_EDGE_CONSTRAINTS` atom in our property change
notifications. This seems to be sent at least as often as the
dpi/scaling changes.
It's also worth noting that some dpi changes don't generate resize
events, so we can't just read the dpi value on every resize, because
we'd miss some of those changes.
Part of this commit changes the font scaling logic: previously
we'd keep a notion of "dpi scale" to apply. That dates from an
earlier time in wezterm where we didn't think that we knew an
actual dpi value.
The way that worked was that we'd compare our current guestimate
of the DPI against what we though the baseline OS dpi should be to
produce a scaling factor.
On X11 that dpi value is global and we'd effectively always produce
a revised scaling factor of 1 after we'd set up the initial window.
This commit changes that logic to just pass down the actual DPI value
to the font code. That DPI value already accounts for HiDPI scaling
so this is hopefully a NOP change for the other systems.
refs: https://github.com/wez/wezterm/issues/667
Replaces the last usage of ttf-parser with calling into freetype.
This removes a source of inconsistency, as ttf-parser doesn't support
all of the things that freetype does.
Notably, this prevents a weird error from blowing up codepoint coverage
calculations on a system where I have helvetica.bdf in my font dir for
long-forgotten reasons.
```
WEZTERM_LOG=wezterm_font=trace,info wezterm
```
will list fonts found in font_dirs and the builtin fonts.
It can't show all fonts found via the system locator, because
that only has an interface for finding fonts by matching name,
not listing all of them.
With this configuration:
```lua
local wezterm = require 'wezterm'
return {
font_dirs = {"/Users/wez/Downloads/Inconsolata"},
font = wezterm.font("Inconsolata"),
font_locator = "ConfigDirsOnly"
}
```
wezterm is now able to see the 74 variations that are available
in the single inconsolata ttf.
Running `WEZTERM_LOG=wezterm_font=trace wezterm` will log the
variations.
refs: https://github.com/wez/wezterm/issues/655
If shaping can't resolve some glyphs, queue the font locator
fallback resolution to another thread; meanwhile, a last resort
glyph is used.
That thread can trigger an invalidation once the fallback resolve
is complete, the window is invalidated and the last resort glyph
is replaced by the resolve glyph.
refs: https://github.com/wez/wezterm/issues/559
refs: https://github.com/wez/wezterm/issues/508
