The Micro-Term ACT-IV needs the current row and column sent preceded by a ^T, with the row and column simply encoded in binary, ‘‘cup=^T%p1%c%p2%c’’. Devices that use ‘‘%c’’ need to be able to backspace the cursor (cub1), and to move the cursor up one line on the screen (cuu1). This is necessary because it is not always safe to transmit \n, ^D, and \r, as the system may change or discard them. (The library routines dealing with terminfo set tty modes so that tabs are never expanded, so \t is safe to send. This turns out to be essential for the Ann Arbor 4080.)

A final example is the LSI ADM-3a, which uses row and column offset by a blank character, thus ‘‘cup=\E=%p1%’\s’%+%c%p2%’\s’%+%c’’. After sending ‘‘\E=’’, 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.

Section 1-3: Cursor Motions

If the device has row or column absolute-cursor addressing, these can be given as single parameter capabilities hpa (horizontal position absolute) and vpa (vertical position absolute). Sometimes these are shorter than the more general two-parameter sequence (as with the Hewlett-Packard 2645) and can be used in preference to cup. If there are parameterized local motions (for example, move n spaces to the right) these can be given as cud, cub, cuf, and cuu with a single parameter indicating how many spaces to move. These are primarily useful if the device does not have cup, such as the Tektronix 4025.

If the device 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 smcup and rmcup. This arises, for example, from terminals, such as the Concept, with more than one page of memory. If the device has only memory relative cursor addressing and not screen relative cursor addressing, a one screen-sized window must be fixed into the device for cursor addressing to work properly. This is also used for the Tektronix 4025, where smcup sets the command character to be the one used by terminfo. If the smcup sequence will not restore the screen after an rmcup sequence is output (to the state prior to outputting rmcup), specify nrrmc.

Section 1-4: Area Clears

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 el. 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 el1. If the terminal can clear from the current position to the end of the display, then this should be given as ed. ed 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 ed is not available.)

Section 1-5: Insert/Delete Line

If the terminal can open a new blank line before the line where the cursor is, this should be given as il1; 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 dl1; this is done only from the first position on the line to be deleted. Versions of il1 and dl1 which take a single parameter and insert or delete that many lines can be given as il and dl.

If the terminal has a settable destructive scrolling region (like the VT100) the command to set this can be described with the 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. It is possible to get the effect of insert or delete line using this command -- the sc and rc (save and restore cursor) commands are also useful. Inserting lines at the top or bottom of the screen can also be done using ri or ind on many terminals without a true insert/delete line, and is often faster even on terminals with those features.

To determine whether a terminal has destructive scrolling regions or non-destructive scrolling regions, create a scrolling region in the middle of the screen, place data on the bottom line of the scrolling region, move the cursor to the top line of the scrolling region, and do a reverse index (ri) followed by a delete line (dl1) or index (ind). If the data that was originally on the bottom line of the scrolling region was restored into the scrolling region by the dl1 or ind, then the terminal has non-destructive scrolling regions. Otherwise, it has destructive scrolling regions. Do not specify csr if the terminal has non-destructive scrolling regions, unless ind, ri, indn, rin, dl, and dl1 all simulate destructive scrolling.

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 wind. The four parameters are the starting and ending lines in memory and the starting and ending columns in memory, in that order.

If the terminal can retain display memory above, then the da capability should be given; if display memory can be retained below, then db should be given. These indicate that deleting a line or scrolling a full screen may bring non-blank lines up from below or that scrolling back with ri may bring down non-blank lines.

Section 1-6: Insert/Delete Character

There are two basic kinds of intelligent terminals with respect to insert/delete character operations which can be described using 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 ‘‘abc    def’’ using local cursor motions (not spaces) between the abc and the def. Then position the cursor before the abc 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 abc shifts over to the def 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 in, which stands for ‘‘insert null.’’ While these are two logically separate attributes (one line versus multiline insert mode, and special treatment of untyped spaces) we have seen no terminals whose insert mode cannot be described with the single attribute.

terminfo can describe both terminals that have an insert mode and terminals which send a simple sequence to open a blank position on the current line. Give as smir the sequence to get into insert mode. Give as rmir the sequence to leave insert mode. Now give as ich1 any sequence needed to be sent just before sending the character to be inserted. Most terminals with a true insert mode will not give ich1; terminals that send a sequence to open a screen position should give it here. (If your terminal has both, insert mode is usually preferable to ich1. Do not give both unless the terminal actually requires both to be used in combination.) If post-insert padding is needed, give this as a number of milliseconds padding in ip (a string option). Any other sequence which may need to be sent after an insert of a single character may also be given in ip. If your terminal needs both to be placed into an ‘insert mode’ and a special code to precede each inserted character, then both smir/rmir and ich1 can be given, and both will be used. The ich capability, with one parameter, n, will insert n blanks.

If padding is necessary between characters typed while not in insert mode, give this as a number of milliseconds padding in rmp.

It is occasionally necessary to move around while in insert mode to delete characters on the same line (for example, if there is a tab after the insertion position). If your terminal allows motion while in insert mode you can give the capability mir to speed up inserting in this case. Omitting mir will affect only speed. Some terminals (notably Datamedia’s) must not have mir because of the way their insert mode works.

Finally, you can specify dch1 to delete a single character, dch with one parameter, n, to delete n characters, and delete mode by giving smdc and rmdc to enter and exit delete mode (any mode the terminal needs to be placed in for dch1 to work).

A command to erase n characters (equivalent to outputting n blanks without moving the cursor) can be given as ech with one parameter.

Section 1-7: Highlighting, Underlining, and Visible Bells

Your device may have one or more kinds of display attributes that allow you to highlight selected characters when they appear on the screen. The following display modes (shown with the names by which they are set) may be available: a blinking screen (blink), bold or extra-bright characters (bold), dim or half-bright characters (dim), blanking or invisible text (invis), protected text (prot), a reverse-video screen (rev), and an alternate character set (smacs to enter this mode and rmacs to exit it). (If a command is necessary before you can enter alternate character set mode, give the sequence in enacs or "enable alternate-character-set" mode.) Turning on any of these modes singly may or may not turn off other modes.

sgr0 should be used to turn off all video enhancement capabilities. It should always be specified because it represents the only way to turn off some capabilities, such as dim or blink.

You should choose one display method as standout mode and use it to highlight error messages and other kinds of text to which you want to draw attention. Choose a form of display that provides strong contrast but that is easy on the eyes. (We recommend reverse-video plus half-bright or reverse-video alone.) The sequences to enter and exit standout mode are given as smso and rmso, 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 xmc should be given to tell how many spaces are left.

Sequences to begin underlining and end underlining can be specified as smul and rmul , respectively. If the device has a sequence to underline the current character and to move the cursor one space to the right (such as the Micro-Term MIME), this sequence can be specified as uc.

Terminals with the ‘‘magic cookie’’ glitch (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 Hewlett-Packard 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 msgr capability, asserting that it is safe to move in standout mode, is present.

If the terminal has a way of flashing the screen to indicate an error quietly (a bell replacement), then this can be given as flash; it must not move the cursor. A good flash can be done by changing the screen into reverse video, pad for 200 ms, then return the screen to normal video.

If the cursor needs to be made more visible than normal when it is not on the bottom line (to make, for example, a non-blinking underline into an easier to find block or blinking underline) give this sequence as cvvis. The boolean chts should also be given. If there is a way to make the cursor completely invisible, give that as civis. The capability cnorm should be given which undoes the effects of either of these modes.

If your terminal generates underlined characters by using the underline character (with no special sequences needed) even though it does not otherwise overstrike characters, then you should specify the capability ul. For devices on which a character overstriking another leaves both characters on the screen, specify the capability os. If overstrikes are erasable with a blank, then this should be indicated by specifying eo.

If there is a sequence to set arbitrary combinations of modes, this should be given as sgr (set attributes), taking nine parameters. Each parameter is either 0 or non-zero, as the corresponding attribute is on or off. The nine parameters are, in order: standout, underline, reverse, blink, dim, bold, blank, protect, alternate character set. Not all modes need to be supported by sgr; only those for which corresponding separate attribute commands exist should be supported. For example, let’s assume that the terminal in question needs the following escape sequences to turn on various modes.

tparm
parameter    attribute    escape sequence

    none    \E[0m
p1    standout    \E[0;4;7m
p2    underline    \E[0;3m
p3    reverse    \E[0;4m
p4    blink    \E[0;5m
p5    dim    \E[0;7m
p6    bold    \E[0;3;4m
p7    invis    \E[0;8m
p8    protect    not available
p9    altcharset    ^O (off) ^N (on)

Note that each escape sequence requires a 0 to turn off other modes before turning on its own mode. Also note that, as suggested above, standout is set up to be the combination of reverse and dim. Also, because this terminal has no bold mode, bold is set up as the combination of reverse and underline. In addition, to allow combinations, such as underline+blink, the sequence to use would be \E[0;3;5m. The terminal doesn’t have protect mode, either, but that cannot be simulated in any way, so p8 is ignored. The altcharset mode is different in that it is either ^O or ^N, depending on whether it is off or on. If all modes were to be turned on, the sequence would be \E[0;3;4;5;7;8m^N.

Now look at when different sequences are output. For example, ;3 is output when either p2 or p6 is true, that is, if either underline or bold modes are turned on.
Writing out the above sequences, along with their dependencies, gives the following:

sequence    when to output    terminfo translation

\E[0    always    \E[0
;3    if p2 or p6    %?%p2%p6%|%t;3%;
;4    if p1 or p3 or p6    %?%p1%p3%|%p6%|%t;4%;
;5    if p4    %?%p4%t;5%;
;7    if p1 or p5    %?%p1%p5%|%t;7%;
;8    if p7    %?%p7%t;8%;
m    always    m
^N or ^O    if p9 ^N, else ^O    %?%p9%t^N%e^O%;

Putting this all together into the sgr sequence gives:

sgr=\E[0%?%p2%p6%|%t;3%;%?%p1%p3%|%p6%
|%t;4%;%?%p5%t;5%;%?%p1%p5%
|%t;7%;%?%p7%t;8%;m%?%p9%t^N%e^O%;,

Remember that sgr and sgr0 must always be specified.

Section 1-8: Keypad

The sequences sent by the left arrow, right arrow, up arrow, down arrow, and home keys can be given as kcub1, kcuf1, kcuu1, kcud1, and khome, respectively. If there are function keys such as f0, f1, ..., f63, the sequences they send can be specified as kf0, kf1, ..., kf63. If the first 11 keys have labels other than the default f0 through f10, the labels can be given as lf0, lf1, ..., lf10. The codes transmitted by certain other special keys can be given: kll (home down), kbs (backspace), ktbc (clear all tabs), kctab (clear the tab stop in this column), kclr (clear screen or erase key), kdch1 (delete character), kdl1 (delete line), krmir (exit insert mode), kel (clear to end of line), ked (clear to end of screen), kich1 (insert character or enter insert mode), kil1 (insert line), knp (next page), kpp (previous page), kind (scroll forward/down), kri (scroll backward/up), khts (set a tab stop in this column). In addition, if the keypad has a 3 by 3 array of keys including the four arrow keys, the other five keys can be given as ka1, ka3, kb2, kc1, and kc3. These keys are useful when the effects of a 3 by 3 directional pad are needed. Further keys are defined above in the capabilities list.

Strings to program function keys can be specified as pfkey, pfloc, and pfx. A string to program screen labels should be specified as pln. Each of these strings takes two parameters: a function key identifier and a string to program it with. pfkey causes pressing the given key to be the same as the user typing the given string; pfloc causes the string to be executed by the terminal in local mode; and pfx causes the string to be transmitted to the computer. The capabilities nlab, lw and lh define the number of programmable screen labels and their width and height. If there are commands to turn the labels on and off, give them in smln and rmln. smln is normally output after one or more pln sequences to make sure that the change becomes visible.

Section 1-9: Tabs and Initialization

If the device has hardware tabs, the command to advance to the next tab stop can be given as ht (usually control I). A ‘‘backtab’’ command that moves leftward to the next tab stop can be given as cbt. By convention, if tty modes show that tabs are being expanded by the computer rather than being sent to the device, programs should not use ht or cbt (even if they are present) because the user may not have the tab stops properly set. If the device has hardware tabs that are initially set every n spaces when the device is powered up, the numeric parameter it is given, showing the number of spaces the tabs are set to. This is normally used by tput init (see tput(1) ) to determine whether to set the mode for hardware tab expansion and whether to set the tab stops. If the device has tab stops that can be saved in nonvolatile memory, the terminfo description can assume that they are properly set. If there are commands to set and clear tab stops, they can be given as tbc (clear all tab stops) and hts (set a tab stop in the current column of every row).

Other capabilities include: is1, is2, and is3, initialization strings for the device; iprog, the path name of a program to be run to initialize the device; and if, the name of a file containing long initialization strings. These strings are expected to set the device into modes consistent with the rest of the terminfo description. They must be sent to the device each time the user logs in and be output in the following order: run the program iprog; output is1; output is2; set the margins using mgc, smgl and smgr; set the tabs using tbc and hts; print the file if; and finally output is3. This is usually done using the init option of tput.

Most initialization is done with is2. Special device modes can be set up without duplicating strings by putting the common sequences in is2 and special cases in is1 and is3. Sequences that do a reset from a totally unknown state can be given as rs1, rs2, rf, and rs3, analogous to is1, is2, is3, and if. (The method using files, if and rf, is used for a few terminals, from /usr/share/lib/tabset/*; however, the recommended method is to use the initialization and reset strings.) These strings are output by tput reset, which is used when the terminal gets into a wedged state. Commands are normally placed in rs1, rs2, rs3, and rf only if they produce annoying effects on the screen and are not necessary when logging in. For example, the command to set a terminal into 80-column mode would normally be part of is2, but on some terminals it causes an annoying glitch on the screen and is not normally needed because the terminal is usually already in 80-column mode.

If a more complex sequence is needed to set the tabs than can be described by using tbc and hts, the sequence can be placed in is2 or if.

Any margin can be cleared with mgc. (For instructions on how to specify commands to set and clear margins, see "Margins" below under "PRINTER CAPABILITIES.")

Section 1-10: Delays

Section 1-11: Status Lines

If escape sequences and other special commands, such as tab, work while in the status line, the flag eslok can be given. A string which turns off the status line (or otherwise erases its contents) should be given as dsl. If the terminal has commands to save and restore the position of the cursor, give them as sc and rc. The status line is normally assumed to be the same width as the rest of the screen, for example, cols. If the status line is a different width (possibly because the terminal does not allow an entire line to be loaded) the width, in columns, can be indicated with the numeric parameter wsl.

Section 1-12: Line Graphics

        vt100+
glyph name      character

arrow pointing right    +
arrow pointing left     ,
arrow pointing down     .
solid square block      0
lantern symbol  I
arrow pointing up       -
diamond ‘
checker board (stipple) a
degree symbol   f
plus/minus      g
board of squares        h
lower right corner      j
upper right corner      k
upper left corner       l
lower left corner       m
plus    n
scan line 1     o
horizontal line q
scan line 9     s
left tee (z|-) t
right tee (-|)  u
bottom tee (o’_|’)   v
top tee (o’rn|’)      w
vertical line   x
bullet  ~

The best way to describe a new device’s line graphics set is to add a third column to the above table with the characters for the new device that produce the appropriate glyph when the device is in the alternate character set mode. For example,

vt100+    new    tty
glyph name    char    char

upper left corner    l    R
lower left corner    m    F
upper right corner    k    T
lower right corner    j    G
horizontal line    q    ,
vertical line    x    .

Now write down the characters left to right, as in ‘‘acsc=lRmFkTjGq\,x.’’.

In addition, terminfo allows you to define multiple character sets. See Section 2-5 for details.

Section 1-13: Color Manipulation

The numeric variables colors and pairs define the number of colors and color-pairs that can be displayed on the screen at the same time. If a terminal can change the definition of a color (for example, the Tektronix 4100 and 4200 series terminals), this should be specified with ccc (can change color). To change the definition of a color (Tektronix 4200 method), use initc (initialize color). It requires four arguments: color number (ranging from 0 to colors-1) and three RGB (red, green, and blue) values or three HLS colors (Hue, Lightness, Saturation). Ranges of RGB and HLS values are terminal dependent.

Tektronix 4100 series terminals only use HLS color notation. For such terminals (or dual-mode terminals to be operated in HLS mode) one must define a boolean variable hls; that would instruct the curses init_color routine to convert its RGB arguments to HLS before sending them to the terminal. The last three arguments to the initc string would then be HLS values.

If a terminal can change the definitions of colors, but uses a color notation different from RGB and HLS, a mapping to either RGB or HLS must be developed.

To set current foreground or background to a given color, use setaf (set ANSI foreground) and setab (set ANSI background). They require one parameter: the number of the color. To initialize a color-pair (HP method), use initp (initialize pair). It requires seven parameters: the number of a color-pair (range=0 to pairs-1), and six RGB values: three for the foreground followed by three for the background. (Each of these groups of three should be in the order RGB.) When initc or initp are used, RGB or HLS arguments should be in the order "red, green, blue" or "hue, lightness, saturation"), respectively. To make a color-pair current, use scp (set color-pair). It takes one parameter, the number of a color-pair.

Some terminals (for example, most color terminal emulators for PCs) erase areas of the screen with current background color. In such cases, bce (background color erase) should be defined. The variable op (original pair) contains a sequence for setting the foreground and the background colors to what they were at the terminal start-up time. Similarly, oc (original colors) contains a control sequence for setting all colors (for the Tektronix method) or color-pairs (for the HP method) to the values they had at the terminal start-up time.

Some color terminals substitute color for video attributes. Such video attributes should not be combined with colors. Information about these video attributes should be packed into the ncv (no color video) variable. There is a one-to-one correspondence between the nine least significant bits of that variable and the video attributes. The following table depicts this correspondence.

    Bit    Decimal
Attribute    Position    Value

A_STANDOUT    0    1
A_UNDERLINE    1    2
A_REVERSE    2    4
A_BLINK    3    8
A_DIM    4    16
A_BOLD    5    32
A_INVIS    6    64
A_PROTECT    7    128
A_ALTCHARSET    8    256

When a particular video attribute should not be used with colors, the corresponding ncv bit should be set to 1; otherwise it should be set to zero. To determine the information to pack into the ncv variable, you must add together the decimal values corresponding to those attributes that cannot coexist with colors. For example, if the terminal uses colors to simulate reverse video (bit number 2 and decimal value 4) and bold (bit number 5 and decimal value 32), the resulting value for ncv will be 36 (4 + 32).

"Section 1-14: Miscellaneous"

If the terminal can move up or down half a line, this can be indicated with hu (half-line up) and hd (half-line down). This is primarily useful for superscripts and subscripts on hardcopy terminals. If a hardcopy terminal can eject to the next page (form feed), give this as ff (usually control L).

If there is a command to repeat a given character a given number of times (to save time transmitting a large number of identical characters) this can be indicated with the parameterized string rep. The first parameter is the character to be repeated and the second is the number of times to repeat it. Thus, tparm(repeat_char, ’x’, 10) is the same as xxxxxxxxxx.

If the terminal has a settable command character, such as the Tektronix 4025, this can be indicated with cmdch. A prototype command character is chosen which is used in all capabilities. This character is given in the cmdch capability to identify it. The following convention is supported on some systems: If the environment variable CC exists, all occurrences of the prototype character are replaced with the character in CC.

Terminal descriptions that do not represent a specific kind of known terminal, such as switch, dialup, patch, and network, should include the gn (generic) capability so that programs can complain that they do not know how to talk to the terminal. (This capability does not apply to virtual terminal descriptions for which the escape sequences are known.) If the terminal is one of those supported by the system virtual terminal protocol, the terminal number can be given as vt. A line-turn-around sequence to be transmitted before doing reads should be specified in rfi.

If the device uses xon/xoff handshaking for flow control, give xon. Padding information should still be included so that routines can make better decisions about costs, but actual pad characters will not be transmitted. Sequences to turn on and off xon/xoff handshaking may be given in smxon and rmxon. If the characters used for handshaking are not ^S and ^Q, they may be specified with xonc and xoffc.

If the terminal has a ‘‘meta key’’ which acts as a shift key, setting the 8th bit of any character transmitted, this fact can be indicated with km. Otherwise, software will assume that the 8th bit is parity and it will usually be cleared. If strings exist to turn this ‘‘meta mode’’ on and off, they can be given as smm and rmm.

If the terminal has more lines of memory than will fit on the screen at once, the number of lines of memory can be indicated with lm. A value of lm#0 indicates that the number of lines is not fixed, but that there is still more memory than fits on the screen.

Media copy strings which control an auxiliary printer connected to the terminal can be given as mc0: print the contents of the screen, mc4: turn off the printer, and mc5: turn on the printer. When the printer is on, all text sent to the terminal will be sent to the printer. A variation, mc5p, takes one parameter, and leaves the printer on for as many characters as the value of the parameter, then turns the printer off. The parameter should not exceed 255. If the text is not displayed on the terminal screen when the printer is on, specify mc5i (silent printer). All text, including mc4, is transparently passed to the printer while an mc5p is in effect.

Section 1-15: Special Cases

Terminals that cannot display tilde (~) characters, such as certain Hazeltine terminals, should indicate hz.

Terminals that ignore a linefeed immediately after an am wrap, such as the Concept 100, should indicate xenl. Those terminals whose cursor remains on the right-most column until another character has been received, rather than wrapping immediately upon receiving the right-most character, such as the VT100, should also indicate xenl.

If el is required to get rid of standout (instead of writing normal text on top of it), xhp should be given.

Those Teleray terminals whose tabs turn all characters moved over to blanks, should indicate xt (destructive tabs). This capability is also taken to mean that it is not possible to position the cursor on top of a ‘‘magic cookie.’’ Therefore, to erase standout mode, it is necessary, instead, to use delete and insert line.

Those Beehive Superbee terminals which do not transmit the escape or control-C characters, should specify xsb, indicating that the f1 key is to be used for escape and the f2 key for control C.

Section 1-16: Similar Terminals

att4424-2|Teletype 4424 in display function group ii,
rev@, sgr@, smul@, use=att4424,

defines an AT&T 4424 terminal that does not have the rev, sgr, and smul capabilities, and hence cannot do highlighting. This is useful for different modes for a terminal, or for different user preferences. More than one use capability may be given.

Part 2: Printer Capabilities

Section 2-1: Rounding Values

Section 2-2: Printer Resolution

All printers are assumed to be capable of printing with a uniform horizontal and vertical resolution. The view of printing that terminfo currently presents is one of printing inside a uniform matrix: All characters are printed at fixed positions relative to each ‘‘cell’’ in the matrix; furthermore, each cell has the same size given by the smallest horizontal and vertical step sizes dictated by the resolution. (The cell size can be changed as will be seen later.)

Many printers are capable of ‘‘proportional printing,’’ where the horizontal spacing depends on the size of the character last printed. terminfo does not make use of this capability, although it does provide enough capability definitions to allow an application to simulate proportional printing.

A printer must not only be able to print characters as close together as the horizontal and vertical resolutions suggest, but also of ‘‘moving’’ to a position an integral multiple of the smallest distance away from a previous position. Thus printed characters can be spaced apart a distance that is an integral multiple of the smallest distance, up to the length or width of a single page.

Some printers can have different resolutions depending on different ‘‘modes.’’ In ‘‘normal mode,’’ the existing terminfo capabilities are assumed to work on columns and lines, just like a video terminal. Thus the old lines capability would give the length of a page in lines, and the cols capability would give the width of a page in columns. In ‘‘micro mode,’’ many terminfo capabilities work on increments of lines and columns. With some printers the micro mode may be concomitant with normal mode, so that all the capabilities work at the same time.

Section 2-3: Specifying Printer Resolution

Specification of Printer Resolution
Characteristic Number of Smallest Steps

orhi    Steps per inch horizontally
orvi    Steps per inch vertically
orc     Steps per column
orl     Steps per line

When printing in normal mode, each character printed causes movement to the next column, except in special cases described later; the distance moved is the same as the per-column resolution. Some printers cause an automatic movement to the next line when a character is printed in the rightmost position; the distance moved vertically is the same as the per-line resolution.
When printing in micro mode, these distances can be different, and may be zero for some printers.

Specification of Printer Resolution
Automatic Motion after Printing

Normal Mode:

orc     Steps moved horizontally
orl     Steps moved vertically

Micro Mode:

mcs     Steps moved horizontally
mls     Steps moved vertically

Some printers are capable of printing wide characters. The distance moved when a wide character is printed in normal mode may be different from when a regular width character is printed. The distance moved when a wide character is printed in micro mode may also be different from when a regular character is printed in micro mode, but the differences are assumed to be related: If the distance moved for a regular character is the same whether in normal mode or micro mode (mcs=orc), then the distance moved for a wide character is also the same whether in normal mode or micro mode. This doesn’t mean the normal character distance is necessarily the same as the wide character distance, just that the distances don’t change with a change in normal to micro mode. However, if the distance moved for a regular character is different in micro mode from the distance moved in normal mode (mcs<orc), the micro mode distance is assumed to be the same for a wide character printed in micro mode, as the table below shows.

Specification of Printer Resolution
Automatic Motion after Printing Wide Character

Normal Mode or Micro Mode (mcs = orc):
sp
widcs   Steps moved horizontally

Micro Mode (mcs < orc):

mcs     Steps moved horizontally

There may be control sequences to change the number of columns per inch (the character pitch) and to change the number of lines per inch (the line pitch). If these are used, the resolution of the printer changes, but the type of change depends on the printer:

Specification of Printer Resolution
Changing the Character/Line Pitches

cpi     Change character pitch
cpix    If set, cpi changes orhi, otherwise changes
orc

lpi     Change line pitch
lpix    If set, lpi changes orvi, otherwise changes
orl

chr     Change steps per column
cvr     Change steps per line

The cpi and lpi string capabilities are each used with a single argument, the pitch in columns (or characters) and lines per inch, respectively. The chr and cvr string capabilities are each used with a single argument, the number of steps per column and line, respectively.

Using any of the control sequences in these strings will imply a change in some of the values of orc, orhi, orl, and orvi. Also, the distance moved when a wide character is printed, widcs, changes in relation to orc. The distance moved when a character is printed in micro mode, mcs, changes similarly, with one exception: if the distance is 0 or 1, then no change is assumed (see items marked with † in the following table).

Programs that use cpi, lpi, chr, or cvr should recalculate the printer resolution (and should recalculate other values-- see "Effect of Changing Printing Resolution" under "Dot-Mapped Graphics").

Specification of Printer Resolution
Effects of Changing the Character/Line Pitches

Before  After

Using cpi with cpix clear:

$bold orhi ’$   orhi
$bold orc ’$    $bold orc = bold orhi over V sub italic cpi$

Using cpi with cpix set:

$bold orhi ’$   $bold orhi = bold orc cdot V sub italic cpi$
$bold orc ’$    $bold orc$

Using lpi with lpix clear:

$bold orvi ’$   $bold orvi$
$bold orl ’$    $bold orl = bold orvi over V sub italic lpi$

Using lpi with lpix set:

$bold orvi ’$   $bold orvi = bold orl cdot V sub italic lpi$
$bold orl ’$    $bold orl$

Using chr:

$bold orhi ’$   $bold orhi$
$bold orc ’$    $V sub italic chr$

Using cvr:

$bold orvi ’$   $bold orvi$
$bold orl ’$    $V sub italic cvr$

Using cpi or chr:

$bold widcs ’$  $bold widcs = bold {widcs ’} bold orc over { bold {orc ’}
}$
$bold mcs ’$    $bold mcs = bold {mcs ’} bold orc over { bold {orc ’} }$

$V sub italic cpi$, $V sub italic lpi$, $V sub italic chr$, and $V sub italic cvr$ are the arguments used with cpi, lpi, chr, and cvr, respectively. The prime marks (’) indicate the old values.

Section 2-4: Capabilities that Cause Movement

terminfo has string capabilities for control sequences that cause movement a number of full columns or lines. It also has equivalent string capabilities for control sequences that cause movement a number of smallest steps.

String Capabilities for Motion

mcub1   Move 1 step left
mcuf1   Move 1 step right
mcuu1   Move 1 step up
mcud1   Move 1 step down

mcub    Move N steps left
mcuf    Move N steps right
mcuu    Move N steps up
mcud    Move N steps down

mhpa    Move N steps from the left
mvpa    Move N steps from the top

The latter six strings are each used with a single argument, N.

Sometimes the motion is limited to less than the width or length of a page. Also, some printers don’t accept absolute motion to the left of the current position. terminfo has capabilities for specifying these limits.

Limits to Motion

mjump   Limit on use of mcub1, mcuf1, mcuu1,
mcud1
maddr   Limit on use of mhpa, mvpa

xhpa    If set, hpa and mhpa can’t move left
xvpa    If set, vpa and mvpa can’t move up

If a printer needs to be in a ‘‘micro mode’’ for the motion capabilities described above to work, there are string capabilities defined to contain the control sequence to enter and exit this mode. A boolean is available for those printers where using a carriage return causes an automatic return to normal mode.

Entering/Exiting Micro Mode

smicm   Enter micro mode
rmicm   Exit micro mode

crxm    Using cr exits micro mode

The movement made when a character is printed in the rightmost position varies among printers. Some make no movement, some move to the beginning of the next line, others move to the beginning of the same line. terminfo has boolean capabilities for describing all three cases.

What Happens After Character
Printed in Rightmost Position

sam     Automatic move to beginning of same line

Some printers can be put in a mode where the normal direction of motion is reversed. This mode can be especially useful when there are no capabilities for leftward or upward motion, because those capabilities can be built from the motion reversal capability and the rightward or downward motion capabilities. It is best to leave it up to an application to build the leftward or upward capabilities, though, and not enter them in the terminfo database. This allows several reverse motions to be strung together without intervening wasted steps that leave and reenter reverse mode.

Entering/Exiting Reverse Modes

slm     Reverse sense of horizontal motions
rlm     Restore sense of horizontal motions
sum     Reverse sense of vertical motions
rum     Restore sense of vertical motions

While sense of horizontal motions reversed:
mcub1   Move 1 step right
mcuf1   Move 1 step left
mcub    Move N steps right
mcuf    Move N steps left
cub1    Move 1 column right
cuf1    Move 1 column left
cub     Move N columns right
cuf     Move N columns left

While sense of vertical motions reversed:
mcuu1   Move 1 step down
mcud1   Move 1 step up
mcuu    Move N steps down
mcud    Move N steps up
cuu1    Move 1 line down
cud1    Move 1 line up
cuu     Move N lines down
cud     Move N lines up

The reverse motion modes should not affect the mvpa and mhpa absolute motion capabilities. The reverse vertical motion mode should, however, also reverse the action of the line ‘‘wrapping’’ that occurs when a character is printed in the right-most position. Thus printers that have the standard terminfo capability am defined should experience motion to the beginning of the previous line when a character is printed in the right-most position under reverse vertical motion mode.

The action when any other motion capabilities are used in reverse motion modes is not defined; thus, programs must exit reverse motion modes before using other motion capabilities.

Two miscellaneous capabilities complete the list of new motion capabilities. One of these is needed for printers that move the current position to the beginning of a line when certain control characters, such as ‘‘line-feed’’ or ‘‘form-feed,’’ are used. The other is used for the capability of suspending the motion that normally occurs after printing a character.

Miscellaneous Motion Strings

docr    List of control characters causing cr
zerom   Prevent auto motion after printing next single character

Margins

terminfo provides two strings for setting margins on terminals: one for the left and one for the right margin. Printers, however, have two additional margins, for the top and bottom margins of each page. Furthermore, some printers require not using motion strings to move the current position to a margin and then fixing the margin there, but require the specification of where a margin should be regardless of the current position. Therefore terminfo offers six additional strings for defining margins with printers.

Setting Margins

smgl    Set left margin at current column
smgr    Set right margin at current column
smgb    Set bottom margin at current line
smgt    Set top margin at current line
smgbp   Set bottom margin at line N
smglp   Set left margin at column N
smgrp   Set right margin at column N
smgtp   Set top margin at line N

The last four strings are used with one or more arguments that give the position of the margin or margins to set. If both of smglp and smgrp are set, each is used with a single argument, N, that gives the column number of the left and right margin, respectively. If both of smgtp and smgbp are set, each is used to set the top and bottom margin, respectively: smgtp is used with a single argument, N, the line number of the top margin; however, smgbp is used with two arguments, N and M, that give the line number of the bottom margin, the first counting from the top of the page and the second counting from the bottom. This accommodates the two styles of specifying the bottom margin in different manufacturers’ printers. When coding a terminfo entry for a printer that has a settable bottom margin, only the first or second parameter should be used, depending on the printer. When writing an application that uses smgbp to set the bottom margin, both arguments must be given.

If only one of smglp and smgrp is set, then it is used with two arguments, the column number of the left and right margins, in that order. Likewise, if only one of smgtp and smgbp is set, then it is used with two arguments that give the top and bottom margins, in that order, counting from the top of the page. Thus when coding a terminfo entry for a printer that requires setting both left and right or top and bottom margins simultaneously, only one of smglp and smgrp or smgtp and smgbp should be defined; the other should be left blank. When writing an application that uses these string capabilities, the pairs should be first checked to see if each in the pair is set or only one is set, and should then be used accordingly.

In counting lines or columns, line zero is the top line and column zero is the left-most column. A zero value for the second argument with smgbp means the bottom line of the page.

All margins can be cleared with mgc.

Shadows, Italics, Wide Characters

Five new sets of strings describe the capabilities printers have of enhancing printed text.

Enhanced Printing

sshm    Enter shadow-printing mode
rshm    Exit shadow-printing mode
sitm    Enter italicizing mode
ritm    Exit italicizing mode
swidm   Enter wide character mode
rwidm   Exit wide character mode
ssupm   Enter superscript mode
rsupm   Exit superscript mode
supcs   List of characters available as superscripts
ssubm   Enter subscript mode
rsubm   Exit subscript mode
subcs   List of characters available as subscripts

If a printer requires the sshm control sequence before every character to be shadow-printed, the rshm string is left blank. Thus programs that find a control sequence in sshm but none in rshm should use the sshm control sequence before every character to be shadow-printed; otherwise, the sshm control sequence should be used once before the set of characters to be shadow-printed, followed
by rshm. The same is also true of each of the sitm/ritm, swidm/rwidm, ssupm/rsupm, and ssubm/ rsubm pairs.

Note that terminfo also has a capability for printing emboldened text (bold). While shadow printing and emboldened printing are similar in that they ‘‘darken’’ the text, many printers produce these two types of print in slightly different ways. Generally, emboldened printing is done by overstriking the same character one or more times. Shadow printing likewise usually involves overstriking, but with a slight movement up and/or to the side so that the character is ‘‘fatter.’’

It is assumed that enhanced printing modes are independent modes, so that it would be possible, for instance, to shadow print italicized subscripts.

As mentioned earlier, the amount of motion automatically made after printing a wide character should be given in widcs.

If only a subset of the printable ASCII characters can be printed as superscripts or subscripts, they should be listed in supcs or subcs strings, respectively. If the ssupm or ssubm strings contain control sequences, but the corresponding supcs or subcs strings are empty, it is assumed that all printable ASCII characters are available as superscripts or subscripts.

Automatic motion made after printing a superscript or subscript is assumed to be the same as for regular characters. Thus, for example, printing any of the following three examples will result in equivalent motion:

Bi Bdi u Bui d

Note that the existing msgr boolean capability describes whether motion control sequences can be used while in ‘‘standout mode.’’ This capability is extended to cover the enhanced printing modes added here. msgr should be set for those printers that accept any motion control sequences without affecting shadow, italicized, widened, superscript, or subscript printing. Conversely, if msgr is not set, a program should end these modes before attempting any motion.

Section 2-5: Alternate Character Sets

Alternate Character Sets

scs     Select character set N

scsd    Start definition of character set N, M characters
defc    Define character A, B dots wide, descender D
rcsd    End definition of character set N
csnm    List of character set names
daisy   Printer has manually changed print-wheels

The scs, rcsd, and csnm strings are used with a single argument, N, a number from 0 to 63 that identifies the character set. The scsd string is also used with the argument N and another, M, that gives the number of characters in the set. The defc string is used with three arguments: A gives the ASCII code representation for the character, B gives the width of the character in dots, and D is zero or one depending on whether the character is a ‘‘descender’’ or not. The defc string is also followed by a string of ‘‘image-data’’ bytes that describe how the character looks (see below).

Character set 0 is the default character set present after the printer has been initialized. Not every printer has 64 character sets, of course; using scs with an argument that doesn’t select an available character set should cause a null result from tparm.

If a character set has to be defined before it can be used, the scsd control sequence is to be used before defining the character set, and the rcsd is to be used after. They should also cause a null result from tparm when used with an argument N that doesn’t apply. If a character set still has to be selected after being defined, the scs control sequence should follow the rcsd control sequence. By examining the results of using each of the scs, scsd, and rcsd strings with a character set number in a call to tparm, a program can determine which of the three are needed.

Between use of the scsd and rcsd strings, the defc string should be used to define each character. To print any character on printers covered by terminfo, the ASCII code is sent to the printer. This is true for characters in an alternate set as well as ‘‘normal’’ characters. Thus the definition of a character includes the ASCII code that represents it. In addition, the width of the character in dots is given, along with an indication of whether the character should descend below the print line (such as the lower case letter ‘‘g’’ in most character sets). The width of the character in dots also indicates the number of image-data bytes that will follow the defc string. These image-data bytes indicate where in a dot-matrix pattern ink should be applied to ‘‘draw’’ the character; the number of these bytes and their form are defined below under ‘‘Dot-Mapped Graphics.’’

It’s easiest for the creator of terminfo entries to refer to each character set by number; however, these numbers will be meaningless to the application developer. The csnm string alleviates this problem by providing names for each number.

When used with a character set number in a call to tparm, the csnm string will produce the equivalent name. These names should be used as a reference only. No naming convention is implied, although anyone who creates a terminfo entry for a printer should use names consistent with the names found in user documents for the printer. Application developers should allow a user to specify a character set by number (leaving it up to the user to examine the csnm string to determine the correct number), or by name, where the application examines the csnm string to determine the corresponding character set number.

These capabilities are likely to be used only with dot-matrix printers. If they are not available, the strings should not be defined. For printers that have manually changed print-wheels or font cartridges, the boolean daisy is set.

Section 2-6: Dot-Matrix Graphics

Dot-Matrix Graphics

npins   Number of pins, N, in print-head
spinv   Spacing of pins vertically in pins per inch
spinh   Spacing of dots horizontally in dots per inch
porder  Matches software bits to print-head pins
sbim    Start printing bit image graphics, B bits wide
rbim    End printing bit image graphics

The sbim sring is used with a single argument, B, the width of the image in dots.

The model of dot-matrix or raster-graphics that terminfo presents is similar to the technique used for most dot-matrix printers: each pass of the printer’s print-head is assumed to produce a dot-matrix that is N dots high and B dots wide. This is typically a wide, squat, rectangle of dots. The height of this rectangle in dots will vary from one printer to the next; this is given in the npins numeric capability. The size of the rectangle in fractions of an inch will also vary; it can be deduced from the spinv and spinh numeric capabilities.
With these three values an application can divide a complete raster-graphics image into several horizontal strips, perhaps interpolating to account for different dot spacing vertically and horizontally.

The sbim and rbim strings are used to start and end a dot-matrix image, respectively. The sbim string is used with a single argument that gives the width of the dot-matrix in dots. A sequence of ‘‘image-data bytes’’ are sent to the printer after the sbim string and before the rbim string. The number of bytes is a integral multiple of the width of the dot-matrix; the multiple and the form of each byte is determined by the porder string as described below.

The porder string is a comma separated list of pin numbers optionally followed by an numerical offset. The offset, if given, is separated from the list with a semicolon. The position of each pin number in the list corresponds to a bit in an 8-bit data byte. The pins are numbered consecutively from 1 to npins, with 1 being the top pin. Note that the term ‘‘pin’’ is used loosely here; ‘‘ink-jet’’ dot-matrix printers don’t have pins, but can be considered to have an equivalent method of applying a single dot of ink to paper. The bit positions in porder are in groups of 8, with the first position in each group the most significant bit and the last position the least significant bit. An application produces 8-bit bytes in the order of the groups in porder.

An application computes the ‘‘image-data bytes’’ from the internal image, mapping vertical dot positions in each print-head pass into 8-bit bytes, using a 1 bit where ink should be applied and 0 where no ink should be applied. This can be reversed (0 bit for ink, 1 bit for no ink) by giving a negative pin number. If a position is skipped in porder, a 0 bit is used. If a position has a lower case ‘x’ instead of a pin number, a 1 bit is used in the skipped position. For consistency, a lower case ‘o’ can be used to represent a 0 filled, skipped bit. There must be a multiple of 8 bit positions used or skipped in porder; if not, 0 bits are used to fill the last byte in the least significant bits. The offset, if given, is added to each data byte; the offset can be negative.

Some examples may help clarify the use of the porder string. The AT&T 470, AT&T 475 and C.Itoh 8510 printers provide eight pins for graphics. The pins are identified top to bottom by the 8 bits in a byte, from least significant to most. The porder strings for these printers would be 8,7,6,5,4,3,2,1. The AT&T 478 and AT&T 479 printers also provide eight pins for graphics. However, the pins are identified in the reverse order. The porder strings for these printers would be 1,2,3,4,5,6,7,8. The AT&T 5310, AT&T 5320, DEC LA100, and DEC LN03 printers provide six pins for graphics. The pins are identified top to bottom by the decimal values 1, 2, 4, 8, 16 and 32. These correspond to the low six bits in an 8-bit byte, although the decimal values are further offset by the value 63. The porder string for these printers would be ,,6,5,4,3,2,1;63, or alternately o,o,6,5,4,3,2,1;63.

Section 2-7: Effect of Changing Printing Resolution

Dot-Matrix Graphics
Changing the Character/Line Pitches

cpi     Change character pitch
cpix    If set, cpi changes spinh
lpi     Change line pitch
lpix    If set, lpi changes spinv

Programs that use cpi or lpi should recalculate the dot spacing:

Dot-Matrix Graphics
Effects of Changing the Character/Line Pitches

Before       After

Using cpi with cpix clear:

$bold spinh ’$  $bold spinh$

Using cpi with cpix set:

$bold spinh ’$  $bold spinh = bold spinh ’ cdot bold orhi over { bold
{orhi ’} }$

Using lpi with lpix clear:

$bold spinv ’$  $bold spinv$

Using lpi with lpix set:

$bold spinv ’$  $bold spinv = bold {spinv ’} cdot bold orhi over {
bold {orhi ’}}$

Using chr:

$bold spinh ’$  $bold spinh$

Using cvr:

$bold spinv ’$  $bold spinv$

orhi’ and orhi are the values of the horizontal resolution in steps per inch, before using cpi and after using cpi, respectively. Likewise, orvi’ and orvi are the values of the vertical resolution in steps per inch, before using lpi and after using lpi, respectively. Thus, the changes in the dots per inch for dot-matrix graphics follow the changes in steps per inch for printer resolution.

Section 2-8: Print Quality

Print Quality

snlq    Set near-letter quality print
snrmq   Set normal quality print
sdrfq   Set draft quality print

The capabilities are listed in decreasing levels of quality. If a printer doesn’t have all three levels, one or two of the strings should be left blank as appropriate.

Section 2-9: Printing Rate and Buffer Size

Print Rate/Buffer Size

cps     Nominal print rate in characters per second
bufsz   Buffer capacity in characters

cps is the nominal or average rate at which the printer prints characters; if this value is not given, the rate should be estimated at one-tenth the prevailing baud rate. bufsz is the maximum number of subsequent characters buffered before the guaranteed printing of an earlier character, assuming proper flow control has been used. If this value is not given it is assumed that the printer does not buffer characters, but prints them as they are received.

As an example, if a printer has a 1000-character buffer, then sending the letter ‘‘a’’ followed by 1000 additional characters is guaranteed to cause the letter ‘‘a’’ to print. If the same printer prints at the rate of 100 characters per second, then it should take 10 seconds to print all the characters in the buffer, less if the buffer is not full. By keeping track of the characters sent to a printer, and knowing the print rate and buffer size, a program can synchronize itself with the printer.

Note that most printer manufacturers advertise the maximum print rate, not the nominal print rate. A good way to get a value to put in for cps is to generate a few pages of text, count the number of printable characters, and then see how long it takes to print the text.

Applications that use these values should recognize the variability in the print rate. Straight text, in short lines, with no embedded control sequences will probably print at close to the advertised print rate and probably faster than the rate in cps. Graphics data with a lot of control sequences, or very long lines of text, will print at well below the advertised rate and below the rate in cps. If the application is using cps to decide how long it should take a printer to print a block of text, the application should pad the estimate. If the application is using cps to decide how much text has already been printed, it should shrink the estimate. The application will thus err in favor of the user, who wants, above all, to see all the output in its correct place.

Files

/usr/share/lib/terminfo/?/*

compiled terminal description database

/usr/share/lib/.COREterm/?/*

subset of compiled terminal description database

/usr/share/lib/tabset/*

tab settings for some terminals, in a format appropriate to be output to the terminal (escape sequences that set margins and tabs)

See Also

Notes