brace

rpic extension, inspired by PSTricks’ \psbrace. brace is a native object that annotates the span between two points with a curly brace and an optional label on its cusp.

.PS
A: box "parse" fit
move right 0.4
B: box "render" fit
brace from A.nw + (0,0.12) to B.ne + (0,0.12) up "pipeline"
.PE

Attributes

Syntax	Example	Meaning
`from` / `to`	`from A.sw to B.se`	the annotated span
`up` `down` `left` `right`	`down`	which side the brace opens toward
`wid` expr	`wid 0.25`	brace depth (default 0.18)
`bracepos` expr	`bracepos 0.3`	cusp position along the span, 0–1 (default 0.5)
`labeloffset` expr	`labeloffset 0.1`	extra gap between cusp and label

Ordinary line styling applies — thick, dashed, outlined, invis:

.PS
box wid 1.6 ht 0.5 "three phases"
brace from last box.sw to last box.se down "setup" wid 0.15 bracepos 0.2 outlined "seagreen" thick 1.6
.PE

Rules

brace is contextual — brace = 1 stays an ordinary assignment.
last brace.start/.end anchor like other open objects; .c resolves to the cusp.
Leave whitespace between brace and content with plain coordinate arithmetic (from A.nw + (0, gap)), as in the first example.

Design notes: docs/pstricks.md.