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DEC line drawing character set
The DEC Special Graphics character set (activated via
ESC ( 0) maps ASCII characters to box-drawing glyphs. Key mappings: j=\u2518 (bottom-right corner), k=\u2510 (top-right corner), l=\u250C (top-left corner), m=\u2514 (bottom-left corner), q=\u2500 (horizontal line), x=\u2502 (vertical line). These six characters form the basis for drawing boxes and borders in non-Unicode environments. Legacy applications like dialog, mc, and ncurses-based programs rely on this mapping.How this is testedautomated
Send
Send
\x1b(0jklmqx\x1b(B, verify all six characters rendered as box-drawing glyphs (none are the literal ASCII characters j, k, l, m, q, x).The same probe runs against headless backends (via Termless) and real terminal apps (via a daemon launched in each terminal). This lets us distinguish parser correctness from rendering correctness.
Analysis2026-04-06
Supported by all 12 tested terminals — universal adoption. Part of the Core TUI baseline.
Supported by 13 of 14 backends (93%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ✓ yes | |
| Ghostty | 1.3.1 | ✓ yes | |
| VS Code | ✓ yes | ||
| Warp | ✓ yes | ||
| Cursor | ✓ yes | ||
| Terminal.app | ✓ yes |