Sparkles

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Sparkles Terminal ​

A minimal, fast terminal emulator for Linux, written in D. It pairs libghostty-vt — the terminal core that powers Ghostty — with a raylib renderer, in roughly two thousand lines of code.

bash
nix profile add github:PetarKirov/sparkles#terminal

Sparkles Terminal running Neovim with D code, true-color syntax highlighting, and italic styled text

It exists for two reasons: as a usable, no-frills terminal, and as the real-world integration test for the sparkles:ghostty bindings (D bindings for libghostty-vt, in libs/ghostty). It is deliberately small — no tabs, no splits, no config file — but the terminal itself is not a toy: the VT engine is the same one Ghostty ships.

bash
dub run :terminal                       # interactive login shell
dub run :terminal -- --font "Fira Code" --font-size 14
dub run :terminal -- -- htop            # run a command instead of a shell

Highlights ​

Correct ​

All escape-sequence parsing, terminal modes, and state live in libghostty-vt, so full-screen applications behave the way they do in Ghostty:

  • VT220-class emulation with TERM=xterm-256color, true color, and accurate responses to the capability queries (device attributes, size reports, XTVERSION) that programs like vim, tmux, and htop probe at startup.
  • Kitty Graphics Protocol — PNG images render inline, with the file, temp-file, and shared-memory transmission mediums enabled and correct z-layering around text.
  • Grapheme clusters — combining marks, ZWJ sequences, and variation selectors draw as single units instead of dropped accents.
  • OSC 8 hyperlinks and plain http(s):// URLs: hover underlines them, click opens them in your browser.

Fast where it matters ​

The steady-state frame loop is nothrow @nogc — a long-running session has no GC pauses. When nothing on screen changes, the renderer skips the redraw entirely, dropping idle CPU to near zero. Backgrounds, glyphs, cursor, and decorations all batch through a single font-atlas texture, so a full-screen redraw is a handful of draw calls.

Practical text rendering ​

  • Use any font by file path or fontconfig name (--font "Fira Code").
  • Bold, italic, and bold-italic faces of the same family are discovered automatically, so styled text uses real glyphs (e.g. cursive italics), with a synthetic fallback when a face is missing.
  • Nerd Font and regular monospace fallbacks cover glyphs the primary font lacks; anything the primary face does cover is rasterized on demand, so icon planes like Material Design Icons work without preloading ~109k glyphs.
  • --font-codepoint-map routes specific codepoint ranges to a dedicated font, mirroring Ghostty's option of the same name.

Everyday terminal ergonomics ​

Selection with rectangular (Alt) mode, clipboard copy/paste, mouse reporting for TUI apps, a hover-activated scrollbar over infinite scrollback (configurable), focus reporting, a visual bell, window-title updates, live window resizing, and Ctrl +/- font zoom. See key and mouse bindings.

Documentation ​

Limitations ​

Linux/POSIX only (it spawns the shell with forkpty). One window, one terminal: no tabs, splits, or configuration file — configuration is the command line. Font discovery shells out to fontconfig (fc-match, fc-query), which the Nix dev shell provides.