Zutty

Zutty, the "Zero-cost Unicode Teletype", is a terminal emulator for the X Window System written in C++ by Tom Szilagyi. It renders the character grid entirely on the GPU with an OpenGL ES 3.1 compute shader, targeting low-cost ARM single-board computers whose graphics cores support OpenGL ES but not desktop OpenGL. It suits people who want a small, xterm-like terminal with accurate VT emulation, often paired with tmux.

There is no config file of its own. Every option has a command-line flag and an X resource key, so persistent settings go in ~/.Xresources as Zutty.<option> lines (for example Zutty.font or Zutty.saveLines) and are loaded with xrdb -merge ~/.Xresources. The -name option or RESOURCE_NAME selects a different resource prefix for separate profiles. zutty -help lists the options and zutty -listres lists the extra resources that have no command-line flag. Documentation is the README, user guide and FAQ bundled with the source and published on the project site.

Zutty emulates the commonly used parts of the VT52 through VT520 protocols plus xterm additions such as modifyOtherKeys and mouse reporting, and an automated VTTEST setup checks screen output against approved images. It supports true colour, bitmap and scalable fonts that it loads itself from a font search path, a separate double-width font for CJK, xterm-style primary and clipboard selection, and rectangular selection toggled with Space while dragging.

The FAQ is explicit about what Zutty will not do: run on macOS or Windows, transparent backgrounds, scrollbars, menus or interactive configuration, ligatures, right-to-left text, curly underlines, or Sixel and ReGIS images. It also lacks characters above U+FFFF, composing characters, double-height lines and blinking text, and there are no tabs or splits. It is developed on Linux and OpenBSD, also builds on FreeBSD and NetBSD, and is written against Xlib, though users report it works under XWayland. It is a hobby project that takes contributions by email and accepts no donations.