The solution we had before worked in most cases but there were some
which caused problems still. This is what HarfBuzz's CoreText shaper
backend does, it uses a CTTypesetter with the forced embedding level
attribute. This fixes the failure case I found that was causing non-
monotonic outputs which can have all sorts of unexpected results, and
causes a crash in Debug modes because we assert the monotonicity while
rendering.
Reduce potential allocation while processing glyphs by ensuring capacity
in the buffer ahead of time and also using CTRunGet*Ptr functions first
and only allocating for those if that didn't work (it should almost
always work in practice.)
Hi there, this is just a low-hanging fruit and it also prepares the way
for the future 0.15, which removes addStaticLibrary.
Please, let me know what to do on the `// TODO` comments.
This is in preparation to move constraint off the GPU to simplify our
shaders, instead we only need to constrain once at raster time and never
again.
This also significantly reworks the freetype renderGlyph function to be
generally much cleaner and more straightforward.
This commit doesn't actually apply the constraints to anything yet, that
will be in following commits.
This commit is very large, representing about a month of work with many
interdependent changes that don't separate cleanly in to atomic commits.
The main change here is unifying the renderer logic to a single generic
renderer, implemented on top of an abstraction layer over OpenGL/Metal.
I'll write a more complete summary of the changes in the description of
the PR.
This fixes an issue where Ghostty would not build against the macOS 15.5 SDK.
What was happening was that Zig was adding its embedded libc paths to
the clang command line, which included old headers that were
incompatible with the latest (macOS 15.5) SDK. Ghostty was adding the
newer paths but they were being overridden by the embedded libc paths.
The reason this was happening is because Zig was using its own logic to
find the libc paths and this was colliding with the paths we were
setting manually. To fix this, we now use a `libc.txt` file that
explicitly tells Zig where to find libc, and we base this on our own SDK
search logic.
Fixes#6727
The major change in this commit is to consolidate all the C imports in
a single decl in main.zig. This is required for Zig 0.14. Without it,
the problem in #6727 will happen. I was never able to minimize why this
happens in order to open a Zig bug.
Beyond this, I fixed the build.zig and build.zig.zon to work with Zig
0.14 so that we can test building `pkg/macos` in isolation. There are no
downstream impacting changes in the build.zig files.
This commit is quite large because it's fairly interconnected and can't
be split up in a logical way. The main part of this commit is that alpha
blending is now always done in the Display P3 color space, and depending
on the configured `window-colorspace` colors will be converted from sRGB
or assumed to already be Display P3 colors. In addition, a config option
`text-blending` has been added which allows the user to configure linear
blending (AKA "gamma correction"). Linear alpha blending also applies to
images and makes custom shaders receive linear colors rather than sRGB.
In addition, an experimental option has been added which corrects linear
blending's tendency to make dark text look too thin and bright text look
too thick. Essentially it's a correction curve on the alpha channel that
depends on the luminance of the glyph being drawn.
Variable font init used to just select the first available predefined
instance, if there were any, which is often not desirable- using
createFontDescriptorFromData instead of createFontDescritorsFromData
ensures that the default variation config is selected. In the future we
should probably allow selection of predefined instances, but for now
this is the correct behavior.
I found this bug when adding the metrics calculation test case for
CoreText, hence why fixing it is part of the same commit.
Fixes#2499
We rely on CoreText's font discovery to find the best font for a
fallback by using the character set attribute. It appears that for some
codepoints, the character set attribute is not enough to find a font
that supports the codepoint.
In this case, we use CTFontCreateForString to find the font that
CoreText would use. The one subtlety here is we need to ignore the
last resort font, which just has replacement glyphs for all codepoints.
We already had a function to do this for CJK characters (#1637)
thankfully so we can just reuse that!
This also fixes a bug where CTFontCreateForString range param expects
the range length to be utf16 code units, not utf32.
Some CoreFoundation objects, such as those produced by CoreText, have
expensive callbacks that run when they are released. By offloading the
CFRelease calls to another thread, we can avoid important threads being
blocked by unexpectedly expensive callbacks.
This commit also changes the way that the coretext shaper's run iterator
builds its string. Rather than using a CFMutableString, an ArrayList of
unichars is built which is passed to CFStringCreateWithCharactersNoCopy,
which is a lot more efficient since it avoids all the CoreFoundation
overhead.
Related to #1768 but doesn't fix it properly.
This is a temporary hack to avoid some issues with fonts that have mixed
color/non-color glyphs. If there are mixed presentations and the font
does not have emoji codepoints, then we assume it is text. This fixes
the typical scenarios.
This is not a long term solution. A proper long term solution is to
detect this scenario and on a per-glyph basis handle colorization (or
the lack thereof) correctly. It looks like to do this we'll have to
parse some font tables which is considerably more work so I wanted to do
this first.
This gets `zig build -Dtarget=aarch64-ios` working. By "working" I mean
it produces an object file without compiler errors. However, the object
file certainly isn't useful since it uses a number of features that will
not work in the iOS sandbox.
This is just an experiment more than anything to see how hard it would be to
get libghostty working within iOS to render a terminal. Note iOS doesn't
support ptys so this wouldn't be a true on-device terminal. The
challenge right now is to just get a terminal rendering (not usable).
Mitchell Hashimoto