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DECSACE — Select Attribute Change Extent (`CSI Ps * x`)

Toggle whether DECCARA / DECRARA treat their rectangle as a literal cell block (default) or as a stream from start-position to end-position. The content-side rect ops (DECCRA / DECFRA / DECERA / DECSERA) are unaffected.

Byte forms

Every common string-literal form so you can paste-and-search either direction.

\\x1b[\x1b[<Ps>*x
\\033[\033[0*x / \033[1*x / \033[2*x
\\e[\e[0*x / \e[1*x / \e[2*x
ESC [ESC [ Ps * x
hex1b 5b 30 2a 78 / 1b 5b 31 2a 78 / 1b 5b 32 2a 78

Description

DECSACE is the one-byte parameter that decides what 'a rectangle' means to DECCARA ($r) and DECRARA ($t). The content-side ops — DECCRA ($v), DECFRA ($x), DECERA ($z), DECSERA (${) — always use block semantics regardless of DECSACE (see dec-rect-ops).

Parameters - Ps = 0 (default) or Ps = 1 — block / rectangle mode. Coordinates name the corners of a strict cell rectangle. Pt;Pl is the top-left, Pb;Pr is the bottom-right; the affected cells form a literal rectangle of (Pb−Pt+1) × (Pr−Pl+1) cells. - Ps = 2 — stream mode. Coordinates name two positions in text-flow order. Pt;Pl is the stream-start, Pb;Pr is the stream-end; the affected cells are every cell on or after start through the end, following normal text wrap. A 'paragraph' highlighter — e.g. bold the prose from (3,1) through (7,40) ignoring column boundaries.

Query: DECSACE is reported via DECRQM with private mode ?92 (\x1b[?92$p reply: \x1b[?92;<Ps>$y where Ps is the active extent — 2 means stream, anything else means block). Some emulators report 1 for the default rather than 0.

Persistence: the value is part of terminal state — saved by DECRQTSR / DECSC and restored by DECRSTS / DECRC. DECSTR (soft reset) resets DECSACE to block (Ps = 0). RIS (hard reset) does the same.

Practical use: the block default is what TUIs and screen renderers want — a rectangle attribute change is a rectangle. Stream mode is what *editors* want when re-attributing a selection that may span line wraps without preserving column structure — VS Code-style 'underline this prose span'. The mode is sticky, so toggle to stream, do the rect-attr ops, toggle back to block. Don't leave it in stream mode — later code that assumes block semantics will mis-paint.

Coverage: xterm = full (definitive). Konsole + gnome-terminal + mlterm + WezTerm + Ghostty = full. iTerm2 = partial (DECRQM ?92 reports correctly, but stream-mode DECRARA mis-paints when the rectangle straddles a wrapped line). Kitty = partial (mode is parsed and stored, but DECCARA / DECRARA themselves are partial — see their entry). Alacritty + Windows Terminal + cmd / ConPTY + Linux console + macOS Terminal = no-op (DECCARA / DECRARA also no-op, so DECSACE has nothing to switch).

Spec citation: DEC VT510 RM (DECSACE) / xterm-ctlseqs (CSI Ps * x)

Parameters

Ps = 0 or 1Block (rectangle) mode — DECCARA / DECRARA treat coords as rect corners. Default.
Ps = 2Stream mode — DECCARA / DECRARA treat coords as start / end positions in text flow.

Examples

bash
# Enter stream mode, bold a prose span from (3,1) to (7,40), restore block.\nprintf '\\033[2*x'                  # DECSACE = stream\nprintf '\\033[3;1;7;40;1$r'         # DECCARA bold\nprintf '\\033[0*x'                  # DECSACE = block (cleanup)
python
import sys\nsys.stdout.write('\\x1b[?92$p')   # DECRQM probe — what's the current extent?\nsys.stdout.flush()\n# Reply on stdin: '\\x1b[?92;0$y' = block, ';2$y' = stream.
go
// Always restore block mode before exiting a TUI subroutine.\ndefer fmt.Print(\"\\x1b[0*x\")\nfmt.Print(\"\\x1b[2*x\")  // stream for the duration\n// ... rect-attr work ...
javascript
// Highlight a wrap-aware selection: positions 12,5 -> 18,40 as one stream.\nprocess.stdout.write('\\x1b[2*x\\x1b[12;5;18;40;7$r\\x1b[0*x');
c
/* Toggle stream mode briefly; assume xterm or konsole. */\nprintf(\"\\x1b[2*x\");\nprintf(\"\\x1b[%d;%d;%d;%d;1;4$r\", t, l, b, r);  /* bold + underline */\nprintf(\"\\x1b[0*x\");

Terminal support

xterm
yes
Linux console (fbcon)
no
macOS Terminal.app
no
iTerm2
partial
Windows Terminal
no
cmd.exe / ConPTY
no
kitty
partial
alacritty
no
WezTerm
yes
Ghostty
yes
GNOME Terminal
yes
Konsole
yes
tmux
yes
GNU screen
yes

Related sequences