ansi-escape-codes

name	ansi-escape-codes
description	Use when working on TaTUÍ's ANSI backend or event parser: SGR styling, cursor movement, raw mode, alt screen, mouse capture, or decoding input escape sequences. Triggers: ANSI, escape sequence, SGR, CSI, termios, raw mode, alt screen, cursor move, color degradation, mouse, bracketed paste.

ANSI escape codes

Only src/tatui/backend/ and the event reader emit/decode escape sequences.

Output (backend)

• Style via SGR (CSI ... m). Reset with CSI 0 m only when needed; track current style to avoid redundant sequences.
• Move the cursor with absolute positioning (CSI row ; col H) only when the next changed cell is not adjacent; otherwise let natural advance handle it. Minimize total bytes.
• Color degradation: truecolor (38;2;r;g;b) → 256 (38;5;n) → 16, chosen by backend capability (ADR-0012).
• Lifecycle: enter raw mode (termios) + alt screen (CSI ? 1049 h) + optional mouse capture on init; restore all on teardown via defer/destructor, even on panic (ADR-0008).

Input (event reader)

• Decode CSI/SS3 sequences into key/mouse/resize/paste events (ADR-0007).
• The parser must be total: malformed or partial sequences yield a best-effort event or are buffered, never crash. Fuzzed by tests/fuzz/ansi_parser_smoke.nim.

References

Trimmed ECMA-48 SGR table and xterm ctlseqs subset live in docs/reference/terminal/.