DECCRA Copy Rectangular Area

Copy a rectangle of characters, with their attributes, to another place. The eight parameters are

CSI Pts ; Pls ; Pbs ; Prs ; Pps ; Ptd ; Pld ; Ppd $ v

Pts, Pls, Pbs and Prs are the top line, left column, bottom line and right column of the source, Ptd and Pld the top line and left column of the destination, and Pps and Ppd the pages of each. Left out, the source is the whole page and the destination its top-left corner. A value past the edge of the page is taken as the edge, and a source whose top is below its bottom, or whose left is right of its right, makes the whole sequence ignored. The cursor does not move.

The copy is made as if the source were read in full before anything was written, so a destination that overlaps the source still gets the source as it was. Whatever of the destination falls off the page is clipped. Origin mode makes the coordinates count from the margins; the margins do not otherwise matter.

DECCRA is a VT420 function, at level 4 in DEC STD 070. xterm, a VT420 unless told otherwise, implements it (CASE_DECCRA, xtermParseRect, ScrnCopyRectangle), ignoring the page numbers, and the cases follow xterm and esctest2’s deccra.py.

libghostty-vt, a VT220 (see DA), has no case for $ v in stream.zig, so it ignores DECCRA, and the cases are known differences.

Validation

DECCRA-1: Copy a block

AB\r\n
CD
\e[1;1;2;2;1;3;4;1$v

|AB____|
|CD____|
|___AB_|
|___CD_|
cursor 2,3

DECCRA-2: Overlapping source and destination

ABCD
\e[1;1;1;4;1;1;3;1$v

|ABABCD|

DECCRA-3: Clipped at the edge of the screen

AB\r\n
CD
\e[1;1;2;2;1;2;6;1$v

|AB____|
|CD___A|
|_____C|

DECCRA-4: The destination left out

\e[2;3H
XY
\e[2;3;2;4$v

|XY____|
|__XY__|

DECCRA-5: Counted from the margins in origin mode

\e[2;1H
AB
\e[2;3r   # region is lines 2 and 3
\e[?6h    # origin mode
\e[1;1;1;2;1;2;1$v

|______|
|AB____|
|AB____|
|______|
cursor 2,1