terminal emulator

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Superlogical – Mitchell Hashimoto
2 months ago
- Mitchell Hashimoto announced his new company Superlogical, building on his terminal emulator experience.
- After leaving his previous company in 2023, he focused on fatherhood, philanthropy, and building software for passion.
- He developed Ghostty, a terminal emulator that grew into a widely used open-source project, now donated to a non-profit.
- Ghostty will remain non-commercial and is governed by a non-profit organization with a team of maintainers.
- Superlogical will initially ship a terminal multiplexer, leveraging the libghostty library as a public building block.
- The company aims to solve deeper problems around terminal usage, with a focus on well-crafted software.
Building a serial and VGA "everything console"
2 months ago
- The project converts an IBM 7316-TF3 rack-mount LCD/keyboard unit into a portable terminal console using a VT100 terminal emulator box.
- The original IBM keyboard with UltraNav was incompatible with the terminal box's USB controller, so a Perixx slimline keyboard ($20) was substituted.
- The keyboard tray was modified using silane glue, metal braces, and Velcro to secure the replacement keyboard.
- Two manual USB/VGA switchboxes were added to toggle between the terminal box and external device connections.
- A power strip with USB ports was installed for powering the terminal box and monitor, along with cable management using Velcro ties.
- The keyboard initially contacted the screen when closed due to added Velcro thickness; this was fixed with Z-brackets and shims to lower the keyboard.
- The finished unit functions as a console for a POWER9 Raptor Blackbird (via VGA-to-HDMI) and as a serial console for an AT&T 3B2/310.
- Future improvements include adding a latch and handle for better portability.
Ghostty Devlog 001
2 months ago
- Ghostty is a GPU-accelerated terminal emulator written in Zig, supporting macOS and Linux, with Windows support planned.
- Its tech stack includes libxev event loop, OpenGL/Metal graphics, SwiftUI/GTK/GLFW frontends, and custom font rendering via FreeType, Harfbuzz, and CoreText.
- Automatic shell integration injection (#191) enables features like complex prompt redrawing on resize, working directory reporting, and safe terminal closing without confirmation.
- A bug fix (#179) ensures that missing glyphs in a given font style first try the regular style before falling back to other fonts, preventing ugly proportional font rendering.
- Ghostty now programmatically skews regular fonts to create fake italics when a font lacks italic faces, using a 15-degree skew transformation.
Ghostty Devlog 002
2 months ago
- Ghostty's non-tech updates include a public talk by Mitchell Hashimoto and community efforts to build a website, Discord, and beta waitlist.
- Ghostty will be free and open source, likely under GPLv3, with beta testers contributing to the license decision.
- Non-native fullscreen on macOS was implemented by Thorsten Ball, requiring a switch from SwiftUI to AppKit for window lifecycle management, improving the framework for future features.
- Blurry fonts and artifacts on Linux were traced to a padding calculation error involving float-to-int conversion, fixed by using integers for sizes and flooring padding values to ensure pixel-perfect rendering.
- The bug fix led to a codebase audit, revealing another rounding error, and emphasized using appropriate data types to prevent anti-aliasing issues.
Ghostty Devlog 003
2 months ago
- Ghostty now has a public Discord server for community discussions and beta program expansion.
- A talk on Ghostty's implementation will be given at Zig Showtime on September 5th.
- Keyboard input handling is complex due to non-standard layouts, dead keys, and Unicode sequences; Ghostty now supports these cross-platform.
- Ghostty implements the Kitty Keyboard Protocol and xterm modified keys, enabling more keybindings in terminal programs.
- Linux/GTK improvements include single instance mode, primary clipboard support, automatic shell integration, and better keyboard layout handling.
- Ghostty is now a top-tier GTK Linux terminal, though still behind macOS, with thanks to beta testers for feedback.
Talk: Introducing Ghostty and Some Useful Zig Patterns
2 months ago
- Ghostty is a new terminal emulator written in Zig, aiming to combine speed, feature richness, and native platform integration.
- The talk highlights Zig patterns used in Ghostty, including comptime interfaces, data tables, and type generation for zero-cost abstractions.
- Ghostty is currently in closed beta with source access, planned for free and open-source release under GPL (likely) in 2024.
- On macOS, Ghostty uses Swift for native UI (AppKit, SwiftUI), while Linux uses GTK, with the core logic in Zig.
- Key features: fast rendering (480-500 FPS in stress test), multiple font styles, splits, true color, Kitty graphics protocol, and native error messages.
- Future work includes GUI settings, iCloud sync, performance improvements, memory optimization, fuzzing, and expanding the beta program.
- The project aims to innovate terminal capabilities beyond traditional emulators, such as progress bars, drag-and-drop, and security features.
Ghostty Devlog 004
2 months ago
- Ghostty's closed beta expanded from 30 to ~100 users, with larger waves of 15-20 now due to increased stability.
- Significant GUI progress on Linux (headerbar menu, wide tabs, Wayland support) and macOS (forced dark/light mode, faded unfocused splits) for native platform feel.
- Transition from TERM=xterm-ghostty to TERM=ghostty is ongoing; blocked by a Vim bug (hardcoded terminal list) and upstream issues in Go's tcell library, with community fixes submitted.
- Implemented XTGETTCAP to enable remote terminfo queries via VT escape sequences, using Zig compile-time generation for fast, allocation-free performance.
- Added support for variable fonts (e.g., Inconsolata) with configurable variation axes (like weight), a rare feature among terminal emulators.
Ghostty Devlog 005
2 months ago
- Beta testing group grew from 100 to over 350 people in two months, indicating increased stability and feature completeness.
- Ghostty introduced a terminal inspector to help developers debug text-based applications, inspired by web inspectors like Firebug.
- Asian language input (Chinese, Japanese, Korean) was fixed, including multi-codepoint suggestions, edge cases, and Chinese character alignment issues.
- Linux IME input now works properly, with only a small code diff to integrate GTK and Ghostty APIs.
- Custom shaders allow users to apply visual effects like CRT or accessibility enhancements (e.g., for colorblindness) without significantly impacting performance.
- Ghostty aims to match xterm's behavior wherever possible, with ongoing audits and documentation to improve compatibility and fix bugs.
- Over 100 bug fixes and improvements were made, and nearly 50 contributors have sent code, showing strong community involvement.
Ghostty Devlog 006
2 months ago
- Focus on IO throughput speed improvements in Ghostty terminal emulator.
- SIMD optimization for plain text processing: 7.3x faster ASCII, 16.6x faster UTF-8 decode.
- Precomputed lookup tables for codepoint width: 2.8x faster ASCII, 5x faster random UTF-8.
- Optimized grapheme break detection using small lookup table, nearly 8x faster.
- CSI sequence fast-path parser improved throughput by 1.4-2x in control-heavy workloads.
- Real-world results: cat'ing large files 2-5x faster, outperforming other terminals even with grapheme clustering.
- Community contributions and future plans to further improve performance.
Ghostty 1.0 is Coming
2 months ago
- Ghostty 1.0, an open-source terminal emulator under the MIT license, will be released in December 2024 after nearly two years of private beta testing with around 2,000 testers.
- The project aims to be the best drop-in replacement for current terminal emulators on macOS and Linux, focusing on speed, feature-richness, and a platform-native GUI without forcing trade-offs.
- Key features include fast performance (achieved through optimizations like those in a 5-minute lightning talk), extensive support for xterm escape sequences, modern specifications like styled underlines and Kitty keyboard protocol, and native GUI toolkits (macOS native and GTK/libadwaita on Linux).
- The first public release is version 1.0, not a ZeroVer version, due to extensive private testing, which was motivated by family priorities and a nostalgic desire to release software when ready.
- Future plans include libghostty as a standalone library for ecosystem growth (e.g., embedded terminals, web-based terminals) and expanding terminal functionality (e.g., security, modern input methods), but Ghostty 1.0 will not have a stable libghostty API.
- The project is a non-commercial passion project funded by the creator's past successes, with long-term sustainability plans involving a not-for-profit structure.
Ghostty: Reflecting on Reaching 1.0
2 months ago
- Ghostty 1.0 is released; the author reflects on the project's journey.
- The project started as a way to learn Zig and graphics programming, not intended for public release.
- The private beta helped manage bandwidth and family time but also caused hype and frustration.
- The tech stack uses Zig for the core and platform-specific GUIs, which proved successful.
- The community formed around Ghostty is passionate about performance, design, and quality.
- Post-1.0 plans include fixing bugs and releasing a standalone libghostty for other projects.
- The author thanks the beta community, Discord moderators, and his wife for support.
Finding and Fixing Ghostty's Largest Memory Leak
2 months ago
- Ghostty had a major memory leak, causing up to 37 GB usage after 10 days of uptime.
- The leak was caused by a scrollback pruning optimization that reused non-standard pages without resizing the underlying memory allocation, leading to the memory never being freed.
- The fix never reuses non-standard pages during pruning; instead it destroys them properly and allocates a fresh standard-sized page from the pool.
- The leak was triggered by Claude Code's CLI, which produces many multi-codepoint grapheme outputs, forcing Ghostty to use non-standard pages frequently.
- The bug was identified using virtual memory tags on macOS, which made it easy to associate the leak with the PageList structure.
- Ghostty uses a PageList data structure with a memory pool for standard pages and mmap for non-standard pages; the leak occurred because the metadata incorrectly marked large pages as standard.
- A test has been added to reproduce the leak and prevent future regressions.

terminal emulator

Superlogical – Mitchell Hashimoto

Building a serial and VGA "everything console"

Ghostty Devlog 001

Ghostty Devlog 002

Ghostty Devlog 003

Talk: Introducing Ghostty and Some Useful Zig Patterns

Ghostty Devlog 004

Ghostty Devlog 005

Ghostty Devlog 006

Ghostty 1.0 is Coming

Ghostty: Reflecting on Reaching 1.0

Finding and Fixing Ghostty's Largest Memory Leak