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DEC Special Graphics

Category: charsets · Baseline: core · Tags: VT100 · Specification ↗

The DEC Special Graphics character set provides box-drawing characters. Activate with ESC ( 0 (designate G0 as Special Graphics), deactivate with ESC ( B (restore ASCII). When active, ASCII characters like j k l m q x render as box-drawing glyphs (corners, horizontal/vertical lines). Used by legacy TUI applications (dialog, mc, ncurses programs) to draw borders and frames. Modern applications typically use Unicode box-drawing characters (U+2500 block) instead, but DEC Special Graphics remains relevant for environments where UTF-8 is not available.
How this is testedautomated
Send \x1b(0 to designate DEC Special Graphics, write "q", send \x1b(B to restore ASCII. Verify the cell does not contain literal "q" (should be box-drawing U+2500).

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

TerminalVersionSupportNotes
iTerm23.6.9✓ yes
Ghostty1.3.1✓ yes
VS Code✓ yes
Warp✓ yes
Cursor✓ yes
Terminal.app✓ yes

Headless Backends

Parser correctness only — a means the parser accepts the sequence.

BackendVersionSupportNotes
Alacritty0.26.0✓ yes
Kitty0.40.0✓ yes
vt100.js0.2.1✓ yes
vterm0.2.0✓ yes
WezTerm0.1.0-fork.5✓ yes
xterm.js5.5.0✓ yes