Introducing Glyph Protocol for Terminals

The Glyph Protocol has been introduced, allowing terminal applications to directly register and render vector glyphs at runtime instead of relying on patched fonts like Nerd Font.

The core consists of two parts.

• register: The application registers glyf outlines to Unicode PUA codepoints.
• query: Check whether a specific codepoint is covered by system / session / both / free.

Transport uses APC (Application Program Command) instead of OSC, and all messages are delivered as frames prefixed with 25a1 (WHITE SQUARE). Supported formats are returned as a bitfield in the response; in v1, glyf is mandatory, with COLR v0/v1 extendable later.

The design also considers security. Registration targets are restricted to PUA, preventing phishing that would swap out characters in regular text. Up to 1024 entries can be registered per session, and when exceeded, the oldest entries are evicted FIFO.

On the terminal side, implementation is underway first in Rio, and example code for Bubble Tea, Ratatui, and Ink has also been released. Since glyphs use a TrueType glyf subset rather than SVG, existing rasterizers already included in text rendering can be reused, and the wire size is also explained to be smaller than SVG.