terminfo.tail

ncurses-5.4

This turns out to be essential for the Ann Arbor 4080.)
.PP
A final example is the \s-1LSI ADM\s0-3a, which uses row and column
offset by a blank character, thus \*(lqcup=\eE=%p1%' '%+%c%p2%' '%+%c\*(rq.
After sending `\eE=', this pushes the first parameter, pushes the
ASCII value for a space (32), adds them (pushing the sum on the stack
in place of the two previous values) and outputs that value as a character.
Then the same is done for the second parameter.
More complex arithmetic is possible using the stack.
.PP
.SS Cursor Motions
.PP
If the terminal has a fast way to home the cursor
(to very upper left corner of screen) then this can be given as
\fBhome\fR; similarly a fast way of getting to the lower left-hand corner
can be given as \fBll\fR; this may involve going up with \fBcuu1\fR
from the home position,
but a program should never do this itself (unless \fBll\fR does) because it
can make no assumption about the effect of moving up from the home position.
Note that the home position is the same as addressing to (0,0):
to the top left corner of the screen, not of memory.
(Thus, the \eEH sequence on HP terminals cannot be used for
.BR home .)
.PP
If the terminal has row or column absolute cursor addressing,
these can be given as single parameter capabilities
.B hpa
(horizontal position absolute)
and
.B vpa
(vertical position absolute).
Sometimes these are shorter than the more general two parameter
sequence (as with the hp2645) and can be used in preference to
.BR cup .
If there are parameterized local motions (e.g., move
.I n
spaces to the right) these can be given as
.BR cud ,
.BR cub ,
.BR cuf ,
and
.BR cuu
with a single parameter indicating how many spaces to move.
These are primarily useful if the terminal does not have
.BR cup ,
such as the \s-1TEKTRONIX\s+1 4025.
.PP
If the terminal needs to be in a special mode when running
a program that uses these capabilities,
the codes to enter and exit this mode can be given as \fBsmcup\fR and \fBrmcup\fR.
This arises, for example, from terminals like the Concept with more than
one page of memory.
If the terminal has only memory relative cursor addressing and not screen
relative cursor addressing, a one screen-sized window must be fixed into
the terminal for cursor addressing to work properly.
This is also used for the \s-1TEKTRONIX\s+1 4025,
where
.B smcup
sets the command character to be the one used by terminfo.
If the \fBsmcup\fP sequence will not restore the screen after an
\fBrmcup\fP sequence is output (to the state prior to outputting
\fBrmcup\fP), specify \fBnrrmc\fP.
.PP
.SS Area Clears
.PP
If the terminal can clear from the current position to the end of the
line, leaving the cursor where it is, this should be given as \fBel\fR.
If the terminal can clear from the beginning of the line to the current
position inclusive, leaving
the cursor where it is, this should be given as \fBel1\fP.
If the terminal can clear from the current position to the end of the
display, then this should be given as \fBed\fR.
\fBEd\fR is only defined from the first column of a line.
(Thus, it can be simulated by a request to delete a large number of lines,
if a true
.B ed
is not available.)
.PP
.SS Insert/delete line and vertical motions
.PP
If the terminal can open a new blank line before the line where the cursor
is, this should be given as \fBil1\fR; this is done only from the first
position of a line.
The cursor must then appear on the newly blank line.
If the terminal can delete the line which the cursor is on, then this
should be given as \fBdl1\fR; this is done only from the first position on
the line to be deleted.
Versions of
.B il1
and
.B dl1
which take a single parameter and insert or delete that many lines can
be given as
.B il
and
.BR dl .
.PP
If the terminal has a settable scrolling region (like the vt100)
the command to set this can be described with the
.B csr
capability, which takes two parameters:
the top and bottom lines of the scrolling region.
The cursor position is, alas, undefined after using this command.
.PP
It is possible to get the effect of insert or delete line using
.B csr
on a properly chosen region; the
.B sc
and
.B rc
(save and restore cursor) commands may be useful for ensuring that
your synthesized insert/delete string does not move the cursor.
(Note that the \fBncurses\fR(3X) library does this synthesis
automatically, so you need not compose insert/delete strings for
an entry with \fBcsr\fR).
.PP
Yet another way to construct insert and delete might be to use a combination of
index with the memory-lock feature found on some terminals (like the HP-700/90
series, which however also has insert/delete).
.PP
Inserting lines at the top or bottom of the screen can also be
done using
.B ri
or
.B ind
on many terminals without a true insert/delete line,
and is often faster even on terminals with those features.
.PP
The boolean \fBnon_dest_scroll_region\fR should be set if each scrolling
window is effectively a view port on a screen-sized canvas.
To test for
this capability, create a scrolling region in the middle of the screen,
write something to the bottom line, move the cursor to the top of the region,
and do \fBri\fR followed by \fBdl1\fR or \fBind\fR.
If the data scrolled
off the bottom of the region by the \fBri\fR re-appears, then scrolling
is non-destructive.
System V and XSI Curses expect that \fBind\fR, \fBri\fR,
\fBindn\fR, and \fBrin\fR will simulate destructive scrolling; their
documentation cautions you not to define \fBcsr\fR unless this is true.
This \fBcurses\fR implementation is more liberal and will do explicit erases
after scrolling if \fBndstr\fR is defined.
.PP
If the terminal has the ability to define a window as part of
memory, which all commands affect,
it should be given as the parameterized string
.BR wind .
The four parameters are the starting and ending lines in memory
and the starting and ending columns in memory, in that order.
.PP
If the terminal can retain display memory above, then the
\fBda\fR capability should be given; if display memory can be retained
below, then \fBdb\fR should be given.
These indicate
that deleting a line or scrolling may bring non-blank lines up from below
or that scrolling back with \fBri\fR may bring down non-blank lines.
.PP
.SS Insert/Delete Character
.PP
There are two basic kinds of intelligent terminals with respect to
insert/delete character which can be described using
.I terminfo.
The most common insert/delete character operations affect only the characters
on the current line and shift characters off the end of the line rigidly.
Other terminals, such as the Concept 100 and the Perkin Elmer Owl, make
a distinction between typed and untyped blanks on the screen, shifting
upon an insert or delete only to an untyped blank on the screen which is
either eliminated, or expanded to two untyped blanks.
You can determine the
kind of terminal you have by clearing the screen and then typing
text separated by cursor motions.
Type \*(lqabc\ \ \ \ def\*(rq using local
cursor motions (not spaces) between the \*(lqabc\*(rq and the \*(lqdef\*(rq.
Then position the cursor before the \*(lqabc\*(rq and put the terminal in insert
mode.
If typing characters causes the rest of the line to shift
rigidly and characters to fall off the end, then your terminal does
not distinguish between blanks and untyped positions.
If the \*(lqabc\*(rq
shifts over to the \*(lqdef\*(rq which then move together around the end of the
current line and onto the next as you insert, you have the second type of
terminal, and should give the capability \fBin\fR, which stands for
\*(lqinsert null\*(rq.
While these are two logically separate attributes (one line versus multi-line
insert mode, and special treatment of untyped spaces) we have seen no
terminals whose insert mode cannot be described with the single attribute.
.PP
Terminfo can describe both terminals which have an insert mode, and terminals
which send a simple sequence to open a blank position on the current line.
Give as \fBsmir\fR the sequence to get into insert mode.
Give as \fBrmir\fR the sequence to leave insert mode.
Now give as \fBich1\fR any sequence needed to be sent just before sending
the character to be inserted.
Most terminals with a true insert mode
will not give \fBich1\fR; terminals which send a sequence to open a screen
position should give it here.
.PP
If your terminal has both, insert mode is usually preferable to \fBich1\fR.
Technically, you should not give both unless the terminal actually requires
both to be used in combination.
Accordingly, some non-curses applications get
confused if both are present; the symptom is doubled characters in an update
using insert.
This requirement is now rare; most \fBich\fR sequences do not
require previous smir, and most smir insert modes do not require \fBich1\fR
before each character.
Therefore, the new \fBcurses\fR actually assumes this
is the case and uses either \fBrmir\fR/\fBsmir\fR or \fBich\fR/\fBich1\fR as
appropriate (but not both).
If you have to write an entry to be used under
new curses for a terminal old enough to need both, include the
\fBrmir\fR/\fBsmir\fR sequences in \fBich1\fR.
.PP
If post insert padding is needed, give this as a number of milliseconds
in \fBip\fR (a string option).
Any other sequence which may need to be
sent after an insert of a single character may also be given in \fBip\fR.
If your terminal needs both to be placed into an `insert mode' and
a special code to precede each inserted character, then both
.BR smir / rmir
and
.B ich1
can be given, and both will be used.
The
.B ich
capability, with one parameter,
.IR n ,
will repeat the effects of
.B ich1
.I n
times.
.PP
If padding is necessary between characters typed while not
in insert mode, give this as a number of milliseconds padding in \fBrmp\fP.
.PP
It is occasionally necessary to move around while in insert mode
to delete characters on the same line (e.g., if there is a tab after
the insertion position).
If your terminal allows motion while in
insert mode you can give the capability \fBmir\fR to speed up inserting
in this case.
Omitting \fBmir\fR will affect only speed.
Some terminals
(notably Datamedia's) must not have \fBmir\fR because of the way their
insert mode works.
.PP
Finally, you can specify
.B dch1
to delete a single character,
.B dch
with one parameter,
.IR n ,
to delete
.I n characters,
and delete mode by giving \fBsmdc\fR and \fBrmdc\fR
to enter and exit delete mode (any mode the terminal needs to be placed
in for
.B dch1
to work).
.PP
A command to erase
.I n
characters (equivalent to outputting
.I n
blanks without moving the cursor)
can be given as
.B ech
with one parameter.
.PP
.SS "Highlighting, Underlining, and Visible Bells"
.PP
If your terminal has one or more kinds of display attributes,
these can be represented in a number of different ways.
You should choose one display form as
\f2standout mode\fR,
representing a good, high contrast, easy-on-the-eyes,
format for highlighting error messages and other attention getters.
(If you have a choice, reverse video plus half-bright is good,
or reverse video alone.)
The sequences to enter and exit standout mode
are given as \fBsmso\fR and \fBrmso\fR, respectively.
If the code to change into or out of standout
mode leaves one or even two blank spaces on the screen,
as the TVI 912 and Teleray 1061 do,
then \fBxmc\fR should be given to tell how many spaces are left.
.PP
Codes to begin underlining and end underlining can be given as \fBsmul\fR
and \fBrmul\fR respectively.
If the terminal has a code to underline the current character and move
the cursor one space to the right,
such as the Microterm Mime,
this can be given as \fBuc\fR.
.PP
Other capabilities to enter various highlighting modes include
.B blink
(blinking)
.B bold
(bold or extra bright)
.B dim
(dim or half-bright)
.B invis
(blanking or invisible text)
.B prot
(protected)
.B rev
(reverse video)
.B sgr0
(turn off
.I all
attribute modes)
.B smacs
(enter alternate character set mode)
and
.B rmacs
(exit alternate character set mode).
Turning on any of these modes singly may or may not turn off other modes.
.PP
If there is a sequence to set arbitrary combinations of modes,
this should be given as
.B sgr
(set attributes),
taking 9 parameters.
Each parameter is either 0 or nonzero, as the corresponding attribute is on or off.
The 9 parameters are, in order:
standout, underline, reverse, blink, dim, bold, blank, protect, alternate
character set.
Not all modes need be supported by
.BR sgr ,
only those for which corresponding separate attribute commands exist.
.PP
For example, the DEC vt220 supports most of the modes:
.PP
.TS
center;
l c c
l c c
lw28 lw6 lw2 lw20.
\fBtparm parameter	attribute	escape sequence\fP

none	none	\\E[0m
p1	standout	\\E[0;1;7m
p2	underline	\\E[0;4m
p3	reverse	\\E[0;7m
p4	blink	\\E[0;5m
p5	dim	not available
p6	bold	\\E[0;1m
p7	invis	\\E[0;8m
p8	protect	not used
p9	altcharset	^O (off) ^N (on)
.TE
.PP
We begin each escape sequence by turning off any existing modes, since
there is no quick way to determine whether they are active.
Standout is set up to be the combination of reverse and bold.
The vt220 terminal has a protect mode,
though it is not commonly used in sgr
because it protects characters on the screen from the host's erasures.
The altcharset mode also is different in that it is either ^O or ^N,
depending on whether it is off or on.
If all modes are turned on, the resulting sequence is \\E[0;1;4;5;7;8m^N.
.PP
Some sequences are common to different modes.
For example, ;7 is output when either p1 or p3 is true, that is, if
either standout or reverse modes are turned on.
.PP
Writing out the above sequences, along with their dependencies yields
.PP
.TS
center;
l c c
l c c
lw28 lw6 lw2 lw20.
\fBsequence	when to output	terminfo translation\fP

\\E[0	always	\\E[0
;1	if p1 or p6	%?%p1%p6%|%t;1%;
;4	if p2	%?%p2%|%t;4%;
;5	if p4	%?%p4%|%t;5%;
;7	if p1 or p3	%?%p1%p3%|%t;7%;
;8	if p7	%?%p7%|%t;8%;
m	always	m
^N or ^O	if p9 ^N, else ^O	%?%p9%t^N%e^O%;
.TE
.PP
Putting this all together into the sgr sequence gives:
.PP
.nf
    sgr=\\E[0%?%p1%p6%|%t;1%;%?%p2%t;4%;%?%p1%p3%|%t;7%;
        %?%p4%t;5%;%?%p7%t;8%;m%?%p9%t\\016%e\\017%;,
.fi
.PP
Remember that if you specify sgr, you must also specify sgr0.
.PP
Terminals with the ``magic cookie'' glitch
.RB ( xmc )
deposit special ``cookies'' when they receive mode-setting sequences,
which affect the display algorithm rather than having extra bits for
each character.
Some terminals, such as the HP 2621, automatically leave standout
mode when they move to a new line or the cursor is addressed.
Programs using standout mode should exit standout mode before
moving the cursor or sending a newline,
unless the
.B msgr
capability, asserting that it is safe to move in standout mode, is present.
.PP
If the terminal has
a way of flashing the screen to indicate an error quietly (a bell replacement)
then this can be given as \fBflash\fR; it must not move the cursor.
.PP
If the cursor needs to be made more visible than normal when it is