herdr/vendor/libghostty-vt
Gabriel 4eceb75d8a
fix: kitty graphics streams freeze on partial updates and leak host images (#948)
* fix: request a render on kitty graphics writes

pty output containing a kitty graphics sequence only scheduled the
deferred settle render. that render's wake-up notifies the render loop
only when the dirty flag was not already set, so under a continuous
stream of image updates the notify can be dropped and the pane keeps
showing an old frame until something else forces a full render.

request an immediate render like any other output. the dirty flag and
the minimum render interval still coalesce chunked writes, and the
settle render stays as a backstop.

refs #947

* fix: fingerprint kitty images exactly across retransmissions

the image fingerprint hashed only the first, middle, and last 4096
bytes of pixel data. a program that streams updates by retransmitting
one image id keeps the length and dimensions constant, so a frame whose
changed pixels all fall outside those three windows gets the same
fingerprint as the frame before it. the encoder then treats the image
as already uploaded, emits no graphics bytes, and the frame is dropped
as identical to the previous render. the pane stays stuck on the last
uploaded image until a resize resets the graphics surface.

hash the full payload instead. to keep that off the render hot path,
cache the fingerprint per image id and recompute it only when the
image's transmit time changes. libghostty-vt already refreshes the
transmit time on every transmission; vendor patch 0002 exposes it
through a new GHOSTTY_KITTY_IMAGE_DATA_TRANSMIT_TIME_NS accessor. a
static image costs one map lookup per render and a streaming image one
hash per transmitted frame.

refs #947

* fix: delete superseded host kitty images

host image ids derive from image content, so a pane image whose pixels
change maps to a new host id on every update. nothing deleted the host
image it replaced, and a streaming pane left one full-size image behind
in the host terminal per changed frame until the graphics surface was
reset. track which host image backs each pane image and delete the
replaced one once no source references it.

refs #947

* fix: prune stale kitty graphics source entries

a source entry whose pane closed or whose placement disappeared stayed
in the cache forever. through the shared-reference check it could keep
an old host image alive that nothing visible used anymore, and the
entries themselves accumulated without bound. prune sources against
the visible set at the start of every encode pass.

refs #947

* docs: link issue and upstream discussion for vendor patch 0002

the transmit time accessor now has a removal path: the ghostty
discussion proposing it upstream is linked in the patch ledger.

refs #947

---------

Co-authored-by: Can Celik <ogulcancelik@gmail.com>
2026-07-04 02:49:15 +03:00
..
.agents feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
.github chore: update libghostty vendor 2026-06-01 23:05:51 +03:00
dist/cmake build: update libghostty-vt vendor 2026-05-07 18:29:21 +03:00
include fix: kitty graphics streams freeze on partial updates and leak host images (#948) 2026-07-04 02:49:15 +03:00
nix chore: update libghostty vendor 2026-06-01 23:05:51 +03:00
pkg chore: update libghostty vendor 2026-06-01 23:05:51 +03:00
src fix: kitty graphics streams freeze on partial updates and leak host images (#948) 2026-07-04 02:49:15 +03:00
.clang-format feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
.editorconfig feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
.envrc feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
.gitattributes feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
.gitignore feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
.gitmodules feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
.mailmap feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
.prettierignore build: update libghostty-vt vendor 2026-05-07 18:29:21 +03:00
.shellcheckrc feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
.swiftlint.yml feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
AGENTS.md build: update libghostty-vt vendor 2026-05-07 18:29:21 +03:00
AI_POLICY.md feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
CLAUDE.md chore: update libghostty vendor 2026-06-01 23:05:51 +03:00
CMakeLists.txt build: update libghostty-vt vendor 2026-05-07 18:29:21 +03:00
CODEOWNERS chore: update libghostty vendor 2026-06-01 23:05:51 +03:00
CONTRIBUTING.md build: update libghostty-vt vendor 2026-05-07 18:29:21 +03:00
Doxyfile feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
DoxygenLayout.xml feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
HACKING.md build: update libghostty-vt vendor 2026-05-07 18:29:21 +03:00
LICENSE feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
Makefile feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
PACKAGING.md feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
README.md build: update libghostty-vt vendor 2026-05-07 18:29:21 +03:00
VERSION chore: update libghostty vendor 2026-06-01 23:05:51 +03:00
build.zig build: update libghostty-vt vendor 2026-05-07 18:29:21 +03:00
build.zig.zon chore: update libghostty vendor 2026-06-01 23:05:51 +03:00
build.zig.zon.json chore: update libghostty vendor 2026-06-01 23:05:51 +03:00
build.zig.zon.nix chore: update libghostty vendor 2026-06-01 23:05:51 +03:00
build.zig.zon.txt chore: update libghostty vendor 2026-06-01 23:05:51 +03:00
default.nix feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
flake.lock build: update libghostty-vt vendor 2026-05-07 18:29:21 +03:00
flake.nix build: update libghostty-vt vendor 2026-05-07 18:29:21 +03:00
shell.nix feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00
typos.toml build: update libghostty-vt vendor 2026-05-07 18:29:21 +03:00
valgrind.supp feat: finish ghostty pane backend integration 2026-04-05 01:23:06 +03:00

README.md

Logo
Ghostty

Fast, native, feature-rich terminal emulator pushing modern features.
A native GUI or embeddable library via libghostty.
About · Download · Documentation · Contributing · Developing

About

Ghostty is a terminal emulator that differentiates itself by being fast, feature-rich, and native. While there are many excellent terminal emulators available, they all force you to choose between speed, features, or native UIs. Ghostty provides all three.

libghostty is a cross-platform, zero-dependency C and Zig library for building terminal emulators or utilizing terminal functionality (such as style parsing). Anyone can use libghostty to build a terminal emulator or embed a terminal into their own applications. See Ghostling for a minimal complete project example or the examples directory for smaller examples of using libghostty in C and Zig.

For more details, see About Ghostty.

Download

See the download page on the Ghostty website.

Documentation

See the documentation on the Ghostty website.

Contributing and Developing

If you have any ideas, issues, etc. regarding Ghostty, or would like to contribute to Ghostty through pull requests, please check out our "Contributing to Ghostty" document. Those who would like to get involved with Ghostty's development as well should also read the "Developing Ghostty" document for more technical details.

Roadmap and Status

Ghostty is stable and in use by millions of people and machines daily.

The high-level ambitious plan for the project, in order:

# Step Status
1 Standards-compliant terminal emulation
2 Competitive performance
3 Rich windowing features -- multi-window, tabbing, panes
4 Native Platform Experiences
5 Cross-platform libghostty for Embeddable Terminals
6 Ghostty-only Terminal Control Sequences

Additional details for each step in the big roadmap below:

Standards-Compliant Terminal Emulation

Ghostty implements all of the regularly used control sequences and can run every mainstream terminal program without issue. For legacy sequences, we've done a comprehensive xterm audit comparing Ghostty's behavior to xterm and building a set of conformance test cases.

In addition to legacy sequences (what you'd call real "terminal" emulation), Ghostty also supports more modern sequences than almost any other terminal emulator. These features include things like the Kitty graphics protocol, Kitty image protocol, clipboard sequences, synchronized rendering, light/dark mode notifications, and many, many more.

We believe Ghostty is one of the most compliant and feature-rich terminal emulators available.

Terminal behavior is partially a de jure standard (i.e. ECMA-48) but mostly a de facto standard as defined by popular terminal emulators worldwide. Ghostty takes the approach that our behavior is defined by (1) standards, if available, (2) xterm, if the feature exists, (3) other popular terminals, in that order. This defines what the Ghostty project views as a "standard."

Competitive Performance

Ghostty is generally in the same performance category as the other highest performing terminal emulators.

"The same performance category" means that Ghostty is much faster than traditional or "slow" terminals and is within an unnoticeable margin of the well-known "fast" terminals. For example, Ghostty and Alacritty are usually within a few percentage points of each other on various benchmarks, but are both something like 100x faster than Terminal.app and iTerm. However, Ghostty is much more feature rich than Alacritty and has a much more native app experience.

This performance is achieved through high-level architectural decisions and low-level optimizations. At a high-level, Ghostty has a multi-threaded architecture with a dedicated read thread, write thread, and render thread per terminal. Our renderer uses OpenGL on Linux and Metal on macOS. Our read thread has a heavily optimized terminal parser that leverages CPU-specific SIMD instructions. Etc.

Rich Windowing Features

The Mac and Linux (build with GTK) apps support multi-window, tabbing, and splits with additional features such as tab renaming, coloring, etc. These features allow for a higher degree of organization and customization than single-window terminals.

Native Platform Experiences

Ghostty is a cross-platform terminal emulator but we don't aim for a least-common-denominator experience. There is a large, shared core written in Zig but we do a lot of platform-native things:

  • The macOS app is a true SwiftUI-based application with all the things you would expect such as real windowing, menu bars, a settings GUI, etc.
  • macOS uses a true Metal renderer with CoreText for font discovery.
  • macOS supports AppleScript, Apple Shortcuts (AppIntents), etc.
  • The Linux app is built with GTK.
  • The Linux app integrates deeply with systemd if available for things like always-on, new windows in a single instance, cgroup isolation, etc.

Our goal with Ghostty is for users of whatever platform they run Ghostty on to think that Ghostty was built for their platform first and maybe even exclusively. We want Ghostty to feel like a native app on every platform, for the best definition of "native" on each platform.

Cross-platform libghostty for Embeddable Terminals

In addition to being a standalone terminal emulator, Ghostty is a C-compatible library for embedding a fast, feature-rich terminal emulator in any 3rd party project. This library is called libghostty.

Due to the scope of this project, we're breaking libghostty down into separate libraries, starting with libghostty-vt. The goal of this project is to focus on parsing terminal sequences and maintaining terminal state. This is covered in more detail in this blog post.

libghostty-vt is already available and usable today for Zig and C and is compatible for macOS, Linux, Windows, and WebAssembly. The functionality is extremely stable (since its been proven in Ghostty GUI for a long time), but the API signatures are still in flux.

libghostty is already heavily in use. See examples for small examples of using libghostty in C and Zig or the Ghostling project for a complete example. See awesome-libghostty for a list of projects and resources related to libghostty.

We haven't tagged libghostty with a version yet and we're still working on a better docs experience, but our Doxygen website is a good resource for the C API.

Ghostty-only Terminal Control Sequences

We want and believe that terminal applications can and should be able to do so much more. We've worked hard to support a wide variety of modern sequences created by other terminal emulators towards this end, but we also want to fill the gaps by creating our own sequences.

We've been hesitant to do this up until now because we don't want to create more fragmentation in the terminal ecosystem by creating sequences that only work in Ghostty. But, we do want to balance that with the desire to push the terminal forward with stagnant standards and the slow pace of change in the terminal ecosystem.

We haven't done any of this yet.

Crash Reports

Ghostty has a built-in crash reporter that will generate and save crash reports to disk. The crash reports are saved to the $XDG_STATE_HOME/ghostty/crash directory. If $XDG_STATE_HOME is not set, the default is ~/.local/state. Crash reports are not automatically sent anywhere off your machine.

Crash reports are only generated the next time Ghostty is started after a crash. If Ghostty crashes and you want to generate a crash report, you must restart Ghostty at least once. You should see a message in the log that a crash report was generated.

[!NOTE]

Use the ghostty +crash-report CLI command to get a list of available crash reports. A future version of Ghostty will make the contents of the crash reports more easily viewable through the CLI and GUI.

Crash reports end in the .ghosttycrash extension. The crash reports are in Sentry envelope format. You can upload these to your own Sentry account to view their contents, but the format is also publicly documented so any other available tools can also be used. The ghostty +crash-report CLI command can be used to list any crash reports. A future version of Ghostty will show you the contents of the crash report directly in the terminal.

To send the crash report to the Ghostty project, you can use the following CLI command using the Sentry CLI:

SENTRY_DSN=https://e914ee84fd895c4fe324afa3e53dac76@o4507352570920960.ingest.us.sentry.io/4507850923638784 sentry-cli send-envelope --raw <path to ghostty crash>

[!WARNING]

The crash report can contain sensitive information. The report doesn't purposely contain sensitive information, but it does contain the full stack memory of each thread at the time of the crash. This information is used to rebuild the stack trace but can also contain sensitive data depending on when the crash occurred.