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DECCARA — change attrs in rectangle
CSI Pt ; Pl ; Pb ; Pr ; Ps $ rDECCARA (
CSI Pt ; Pl ; Pb ; Pr ; Ps $ r) changes the SGR attributes of every cell in a rectangular region without touching the characters themselves. The Ps parameters are SGR codes (1=bold, 4=underline, 7=inverse, etc.), accumulated and applied to the rectangle. Whether DECCARA operates on a true rectangle or on the stream of cells between the corners depends on DECSACE. Used by VT420-era forms to highlight an entire input field, error message, or table cell without rewriting its contents.How this is testedautomated
Write text, send
Write text, send
\x1b[1;1;3;5;7$r (apply inverse to rows 1-3 cols 1-5), verify the sequence is consumed.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 9 tested terminals — universal adoption. Part of the Unicode baseline.
Supported by 8 of 14 backends (57%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ✓ yes | sequence consumed |
| Ghostty | 1.3.1 | ✓ yes | sequence consumed |
| VS Code | ✓ yes | ||
| Warp | ✓ yes | ||
| Cursor | ✓ yes | ||
| Terminal.app | ✓ yes |
Headless Backends
Parser correctness only — a ✓ means the parser accepts the sequence.
| Backend | Version | Support | Notes |
|---|---|---|---|
| Alacritty | 0.26.0 | ✗ no | VT420 rectangular area operations not implemented — legacy DEC features omitted by most modern terminals |
| Kitty | 0.40.0 | ✗ no | VT420 rectangular area operations not implemented — legacy DEC features omitted by most modern terminals |
| vt100.js | 0.2.1 | ✗ no | VT420 rectangular area operations not implemented — legacy DEC features omitted by most modern terminals |
| vterm | 0.2.0 | ✗ no | VT420 rectangular area operations not implemented — legacy DEC features omitted by most modern terminals |
| WezTerm | 0.1.0-fork.5 | ✗ no | VT420 rectangular area operations not implemented — legacy DEC features omitted by most modern terminals |
| xterm.js | 5.5.0 | ✗ no | VT420 rectangular area operations not implemented — legacy DEC features omitted by most modern terminals |