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diff --git a/lib/termcap/grot/termcap.info-2 b/lib/termcap/grot/termcap.info-2 deleted file mode 100644 index 6098d62..0000000 --- a/lib/termcap/grot/termcap.info-2 +++ /dev/null @@ -1,974 +0,0 @@ -This is Info file ./termcap.info, produced by Makeinfo-1.55 from the -input file ./termcap.texi. - - This file documents the termcap library of the GNU system. - - Copyright (C) 1988 Free Software Foundation, Inc. - - Permission is granted to make and distribute verbatim copies of this -manual provided the copyright notice and this permission notice are -preserved on all copies. - - Permission is granted to copy and distribute modified versions of -this manual under the conditions for verbatim copying, provided that -the entire resulting derived work is distributed under the terms of a -permission notice identical to this one. - - Permission is granted to copy and distribute translations of this -manual into another language, under the above conditions for modified -versions, except that this permission notice may be stated in a -translation approved by the Foundation. - - -File: termcap.info, Node: Naming, Next: Inheriting, Prev: Capability Format, Up: Data Base - -Terminal Type Name Conventions -============================== - - There are conventions for choosing names of terminal types. For one -thing, all letters should be in lower case. The terminal type for a -terminal in its most usual or most fundamental mode of operation should -not have a hyphen in it. - - If the same terminal has other modes of operation which require -different terminal descriptions, these variant descriptions are given -names made by adding suffixes with hyphens. Such alternate descriptions -are used for two reasons: - - * When the terminal has a switch that changes its behavior. Since - the computer cannot tell how the switch is set, the user must tell - the computer by choosing the appropriate terminal type name. - - For example, the VT-100 has a setup flag that controls whether the - cursor wraps at the right margin. If this flag is set to "wrap", - you must use the terminal type `vt100-am'. Otherwise you must use - `vt100-nam'. Plain `vt100' is defined as a synonym for either - `vt100-am' or `vt100-nam' depending on the preferences of the - local site. - - The standard suffix `-am' stands for "automatic margins". - - * To give the user a choice in how to use the terminal. This is done - when the terminal has a switch that the computer normally controls. - - For example, the Ann Arbor Ambassador can be configured with many - screen sizes ranging from 20 to 60 lines. Fewer lines make bigger - characters but more lines let you see more of what you are editing. - As a result, users have different preferences. Therefore, termcap - provides terminal types for many screen sizes. If you choose type - `aaa-30', the terminal will be configured to use 30 lines; if you - choose `aaa-48', 48 lines will be used, and so on. - - Here is a list of standard suffixes and their conventional meanings: - -`-w' - Short for "wide". This is a mode that gives the terminal more - columns than usual. This is normally a user option. - -`-am' - "Automatic margins". This is an alternate description for use when - the terminal's margin-wrap switch is on; it contains the `am' - flag. The implication is that normally the switch is off and the - usual description for the terminal says that the switch is off. - -`-nam' - "No automatic margins". The opposite of `-am', this names an - alternative description which lacks the `am' flag. This implies - that the terminal is normally operated with the margin-wrap switch - turned on, and the normal description of the terminal says so. - -`-na' - "No arrows". This terminal description initializes the terminal to - keep its arrow keys in local mode. This is a user option. - -`-rv' - "Reverse video". This terminal description causes text output for - normal video to appear as reverse, and text output for reverse - video to come out as normal. Often this description differs from - the usual one by interchanging the two strings which turn reverse - video on and off. - - This is a user option; you can choose either the "reverse video" - variant terminal type or the normal terminal type, and termcap will - obey. - -`-s' - "Status". Says to enable use of a status line which ordinary - output does not touch (*note Status Line::.). - - Some terminals have a special line that is used only as a status - line. For these terminals, there is no need for an `-s' variant; - the status line commands should be defined by default. On other - terminals, enabling a status line means removing one screen line - from ordinary use and reducing the effective screen height. For - these terminals, the user can choose the `-s' variant type to - request use of a status line. - -`-NLINES' - Says to operate with NLINES lines on the screen, for terminals - such as the Ambassador which provide this as an option. Normally - this is a user option; by choosing the terminal type, you control - how many lines termcap will use. - -`-NPAGESp' - Says that the terminal has NPAGES pages worth of screen memory, - for terminals where this is a hardware option. - -`-unk' - Says that description is not for direct use, but only for - reference in `tc' capabilities. Such a description is a kind of - subroutine, because it describes the common characteristics of - several variant descriptions that would use other suffixes in - place of `-unk'. - - -File: termcap.info, Node: Inheriting, Next: Changing, Prev: Naming, Up: Data Base - -Inheriting from Related Descriptions -==================================== - - When two terminal descriptions are similar, their identical parts do -not need to be given twice. Instead, one of the two can be defined in -terms of the other, using the `tc' capability. We say that one -description "refers to" the other, or "inherits from" the other. - - The `tc' capability must be the last one in the terminal description, -and its value is a string which is the name of another terminal type -which is referred to. For example, - - N9|aaa|ambassador|aaa-30|ann arbor ambassador/30 lines:\ - :ti=\E[2J\E[30;0;0;30p:\ - :te=\E[60;0;0;30p\E[30;1H\E[J:\ - :li#30:tc=aaa-unk: - -defines the terminal type `aaa-30' (also known as plain `aaa') in terms -of `aaa-unk', which defines everything about the Ambassador that is -independent of screen height. The types `aaa-36', `aaa-48' and so on -for other screen heights are likewise defined to inherit from `aaa-unk'. - - The capabilities overridden by `aaa-30' include `li', which says how -many lines there are, and `ti' and `te', which configure the terminal -to use that many lines. - - The effective terminal description for type `aaa' consists of the -text shown above followed by the text of the description of `aaa-unk'. -The `tc' capability is handled automatically by `tgetent', which finds -the description thus referenced and combines the two descriptions -(*note Find::.). Therefore, only the implementor of the terminal -descriptions needs to think about using `tc'. Users and application -programmers do not need to be concerned with it. - - Since the reference terminal description is used last, capabilities -specified in the referring description override any specifications of -the same capabilities in the reference description. - - The referring description can cancel out a capability without -specifying any new value for it by means of a special trick. Write the -capability in the referring description, with the character `@' after -the capability name, as follows: - - NZ|aaa-30-nam|ann arbor ambassador/30 lines/no automatic-margins:\ - :am@:tc=aaa-30: - - -File: termcap.info, Node: Changing, Prev: Inheriting, Up: Data Base - -When Changes in the Data Base Take Effect -========================================= - - Each application program must read the terminal description from the -data base, so a change in the data base is effective for all jobs -started after the change is made. - - The change will usually have no effect on a job that have been in -existence since before the change. The program probably read the -terminal description once, when it was started, and is continuing to -use what it read then. If the program does not have a feature for -reexamining the data base, then you will need to run it again (probably -killing the old job). - - If the description in use is coming from the `TERMCAP' environment -variable, then the data base file is effectively overridden, and -changes in it will have no effect until you change the `TERMCAP' -variable as well. For example, some users' `.login' files -automatically copy the terminal description into `TERMCAP' to speed -startup of applications. If you have done this, you will need to -change the `TERMCAP' variable to make the changed data base take effect. - - -File: termcap.info, Node: Capabilities, Next: Summary, Prev: Data Base, Up: Top - -Definitions of the Terminal Capabilities -**************************************** - - This section is divided into many subsections, each for one aspect of -use of display terminals. For writing a display program, you usually -need only check the subsections for the operations you want to use. -For writing a terminal description, you must read each subsection and -fill in the capabilities described there. - - String capabilities that are display commands may require numeric -parameters (*note Parameters::.). Most such capabilities do not use -parameters. When a capability requires parameters, this is explicitly -stated at the beginning of its definition. In simple cases, the first -or second sentence of the definition mentions all the parameters, in -the order they should be given, using a name in upper case for each -one. For example, the `rp' capability is a command that requires two -parameters; its definition begins as follows: - - String of commands to output a graphic character C, repeated N - times. - - In complex cases or when there are many parameters, they are -described explicitly. - - When a capability is described as obsolete, this means that programs -should not be written to look for it, but terminal descriptions should -still be written to provide it. - - When a capability is described as very obsolete, this means that it -should be omitted from terminal descriptions as well. - -* Menu: - -* Basic:: Basic characteristics. -* Screen Size:: Screen size, and what happens when it changes. -* Cursor Motion:: Various ways to move the cursor. -* Wrapping:: What happens if you write a character in the last column. -* Scrolling:: Pushing text up and down on the screen. -* Windows:: Limiting the part of the window that output affects. -* Clearing:: Erasing one or many lines. -* Insdel Line:: Making new blank lines in mid-screen; deleting lines. -* Insdel Char:: Inserting and deleting characters within a line. -* Standout:: Highlighting some of the text. -* Underlining:: Underlining some of the text. -* Cursor Visibility:: Making the cursor more or less easy to spot. -* Bell:: Attracts user's attention; not localized on the screen. -* Keypad:: Recognizing when function keys or arrows are typed. -* Meta Key:: META acts like an extra shift key. -* Initialization:: Commands used to initialize or reset the terminal. -* Pad Specs:: Info for the kernel on how much padding is needed. -* Status Line:: A status line displays "background" information. -* Half-Line:: Moving by half-lines, for superscripts and subscripts. -* Printer:: Controlling auxiliary printers of display terminals. - - -File: termcap.info, Node: Basic, Next: Screen Size, Up: Capabilities - -Basic Characteristics -===================== - - This section documents the capabilities that describe the basic and -nature of the terminal, and also those that are relevant to the output -of graphic characters. - -`os' - Flag whose presence means that the terminal can overstrike. This - means that outputting a graphic character does not erase whatever - was present in the same character position before. The terminals - that can overstrike include printing terminals, storage tubes (all - obsolete nowadays), and many bit-map displays. - -`eo' - Flag whose presence means that outputting a space erases a - character position even if the terminal supports overstriking. If - this flag is not present and overstriking is supported, output of - a space has no effect except to move the cursor. - - (On terminals that do not support overstriking, you can always - assume that outputting a space at a position erases whatever - character was previously displayed there.) - -`gn' - Flag whose presence means that this terminal type is a generic type - which does not really describe any particular terminal. Generic - types are intended for use as the default type assigned when the - user connects to the system, with the intention that the user - should specify what type he really has. One example of a generic - type is the type `network'. - - Since the generic type cannot say how to do anything interesting - with the terminal, termcap-using programs will always find that the - terminal is too weak to be supported if the user has failed to - specify a real terminal type in place of the generic one. The - `gn' flag directs these programs to use a different error message: - "You have not specified your real terminal type", rather than - "Your terminal is not powerful enough to be used". - -`hc' - Flag whose presence means this is a hardcopy terminal. - -`rp' - String of commands to output a graphic character C, repeated N - times. The first parameter value is the ASCII code for the desired - character, and the second parameter is the number of times to - repeat the character. Often this command requires padding - proportional to the number of times the character is repeated. - This effect can be had by using parameter arithmetic with - `%'-sequences to compute the amount of padding, then generating - the result as a number at the front of the string so that `tputs' - will treat it as padding. - -`hz' - Flag whose presence means that the ASCII character `~' cannot be - output on this terminal because it is used for display commands. - - Programs handle this flag by checking all text to be output and - replacing each `~' with some other character(s). If this is not - done, the screen will be thoroughly garbled. - - The old Hazeltine terminals that required such treatment are - probably very rare today, so you might as well not bother to - support this flag. - -`CC' - String whose presence means the terminal has a settable command - character. The value of the string is the default command - character (which is usually ESC). - - All the strings of commands in the terminal description should be - written to use the default command character. If you are writing - an application program that changes the command character, use the - `CC' capability to figure out how to translate all the display - commands to work with the new command character. - - Most programs have no reason to look at the `CC' capability. - -`xb' - Flag whose presence identifies Superbee terminals which are unable - to transmit the characters ESC and `Control-C'. Programs which - support this flag are supposed to check the input for the code - sequences sent by the F1 and F2 keys, and pretend that ESC or - `Control-C' (respectively) had been read. But this flag is - obsolete, and not worth supporting. - - -File: termcap.info, Node: Screen Size, Next: Cursor Motion, Prev: Basic, Up: Capabilities - -Screen Size -=========== - - A terminal description has two capabilities, `co' and `li', that -describe the screen size in columns and lines. But there is more to -the question of screen size than this. - - On some operating systems the "screen" is really a window and the -effective width can vary. On some of these systems, `tgetnum' uses the -actual width of the window to decide what value to return for the `co' -capability, overriding what is actually written in the terminal -description. On other systems, it is up to the application program to -check the actual window width using a system call. For example, on BSD -4.3 systems, the system call `ioctl' with code `TIOCGWINSZ' will tell -you the current screen size. - - On all window systems, termcap is powerless to advise the application -program if the user resizes the window. Application programs must deal -with this possibility in a system-dependent fashion. On some systems -the C shell handles part of the problem by detecting changes in window -size and setting the `TERMCAP' environment variable appropriately. -This takes care of application programs that are started subsequently. -It does not help application programs already running. - - On some systems, including BSD 4.3, all programs using a terminal get -a signal named `SIGWINCH' whenever the screen size changes. Programs -that use termcap should handle this signal by using `ioctl TIOCGWINSZ' -to learn the new screen size. - -`co' - Numeric value, the width of the screen in character positions. - Even hardcopy terminals normally have a `co' capability. - -`li' - Numeric value, the height of the screen in lines. - - -File: termcap.info, Node: Cursor Motion, Next: Wrapping, Prev: Screen Size, Up: Capabilities - -Cursor Motion -============= - - Termcap assumes that the terminal has a "cursor", a spot on the -screen where a visible mark is displayed, and that most display -commands take effect at the position of the cursor. It follows that -moving the cursor to a specified location is very important. - - There are many terminal capabilities for different cursor motion -operations. A terminal description should define as many as possible, -but most programs do not need to use most of them. One capability, -`cm', moves the cursor to an arbitrary place on the screen; this by -itself is sufficient for any application as long as there is no need to -support hardcopy terminals or certain old, weak displays that have only -relative motion commands. Use of other cursor motion capabilities is an -optimization, enabling the program to output fewer characters in some -common cases. - - If you plan to use the relative cursor motion commands in an -application program, you must know what the starting cursor position -is. To do this, you must keep track of the cursor position and update -the records each time anything is output to the terminal, including -graphic characters. In addition, it is necessary to know whether the -terminal wraps after writing in the rightmost column. *Note Wrapping::. - - One other motion capability needs special mention: `nw' moves the -cursor to the beginning of the following line, perhaps clearing all the -starting line after the cursor, or perhaps not clearing at all. This -capability is a least common denominator that is probably supported -even by terminals that cannot do most other things such as `cm' or `do'. -Even hardcopy terminals can support `nw'. - -`cm' - String of commands to position the cursor at line L, column C. - Both parameters are origin-zero, and are defined relative to the - screen, not relative to display memory. - - All display terminals except a few very obsolete ones support `cm', - so it is acceptable for an application program to refuse to - operate on terminals lacking `cm'. - -`ho' - String of commands to move the cursor to the upper left corner of - the screen (this position is called the "home position"). In - terminals where the upper left corner of the screen is not the - same as the beginning of display memory, this command must go to - the upper left corner of the screen, not the beginning of display - memory. - - Every display terminal supports this capability, and many - application programs refuse to operate if the `ho' capability is - missing. - -`ll' - String of commands to move the cursor to the lower left corner of - the screen. On some terminals, moving up from home position does - this, but programs should never assume that will work. Just - output the `ll' string (if it is provided); if moving to home - position and then moving up is the best way to get there, the `ll' - command will do that. - -`cr' - String of commands to move the cursor to the beginning of the line - it is on. If this capability is not specified, many programs - assume they can use the ASCII carriage return character for this. - -`le' - String of commands to move the cursor left one column. Unless the - `bw' flag capability is specified, the effect is undefined if the - cursor is at the left margin; do not use this command there. If - `bw' is present, this command may be used at the left margin, and - it wraps the cursor to the last column of the preceding line. - -`nd' - String of commands to move the cursor right one column. The - effect is undefined if the cursor is at the right margin; do not - use this command there, not even if `am' is present. - -`up' - String of commands to move the cursor vertically up one line. The - effect of sending this string when on the top line is undefined; - programs should never use it that way. - -`do' - String of commands to move the cursor vertically down one line. - The effect of sending this string when on the bottom line is - undefined; programs should never use it that way. - - Some programs do use `do' to scroll up one line if used at the - bottom line, if `sf' is not defined but `sr' is. This is only to - compensate for certain old, incorrect terminal descriptions. (In - principle this might actually lead to incorrect behavior on other - terminals, but that seems to happen rarely if ever.) But the - proper solution is that the terminal description should define - `sf' as well as `do' if the command is suitable for scrolling. - - The original idea was that this string would not contain a newline - character and therefore could be used without disabling the - kernel's usual habit of converting of newline into a - carriage-return newline sequence. But many terminal descriptions - do use newline in the `do' string, so this is not possible; a - program which sends the `do' string must disable output conversion - in the kernel (*note Initialize::.). - -`bw' - Flag whose presence says that `le' may be used in column zero to - move to the last column of the preceding line. If this flag is - not present, `le' should not be used in column zero. - -`nw' - String of commands to move the cursor to start of next line, - possibly clearing rest of line (following the cursor) before - moving. - -`DO', `UP', `LE', `RI' - Strings of commands to move the cursor N lines down vertically, up - vertically, or N columns left or right. Do not attempt to move - past any edge of the screen with these commands; the effect of - trying that is undefined. Only a few terminal descriptions provide - these commands, and most programs do not use them. - -`CM' - String of commands to position the cursor at line L, column C, - relative to display memory. Both parameters are origin-zero. - This capability is present only in terminals where there is a - difference between screen-relative and memory-relative addressing, - and not even in all such terminals. - -`ch' - String of commands to position the cursor at column C in the same - line it is on. This is a special case of `cm' in which the - vertical position is not changed. The `ch' capability is provided - only when it is faster to output than `cm' would be in this - special case. Programs should not assume most display terminals - have `ch'. - -`cv' - String of commands to position the cursor at line L in the same - column. This is a special case of `cm' in which the horizontal - position is not changed. The `cv' capability is provided only - when it is faster to output than `cm' would be in this special - case. Programs should not assume most display terminals have `cv'. - -`sc' - String of commands to make the terminal save the current cursor - position. Only the last saved position can be used. If this - capability is present, `rc' should be provided also. Most - terminals have neither. - -`rc' - String of commands to make the terminal restore the last saved - cursor position. If this capability is present, `sc' should be - provided also. Most terminals have neither. - -`ff' - String of commands to advance to the next page, for a hardcopy - terminal. - -`ta' - String of commands to move the cursor right to the next hardware - tab stop column. Missing if the terminal does not have any kind of - hardware tabs. Do not send this command if the kernel's terminal - modes say that the kernel is expanding tabs into spaces. - -`bt' - String of commands to move the cursor left to the previous hardware - tab stop column. Missing if the terminal has no such ability; many - terminals do not. Do not send this command if the kernel's - terminal modes say that the kernel is expanding tabs into spaces. - - The following obsolete capabilities should be included in terminal -descriptions when appropriate, but should not be looked at by new -programs. - -`nc' - Flag whose presence means the terminal does not support the ASCII - carriage return character as `cr'. This flag is needed because - old programs assume, when the `cr' capability is missing, that - ASCII carriage return can be used for the purpose. We use `nc' to - tell the old programs that carriage return may not be used. - - New programs should not assume any default for `cr', so they need - not look at `nc'. However, descriptions should contain `nc' - whenever they do not contain `cr'. - -`xt' - Flag whose presence means that the ASCII tab character may not be - used for cursor motion. This flag exists because old programs - assume, when the `ta' capability is missing, that ASCII tab can be - used for the purpose. We use `xt' to tell the old programs not to - use tab. - - New programs should not assume any default for `ta', so they need - not look at `xt' in connection with cursor motion. Note that `xt' - also has implications for standout mode (*note Standout::.). It - is obsolete in regard to cursor motion but not in regard to - standout. - - In fact, `xt' means that the terminal is a Teleray 1061. - -`bc' - Very obsolete alternative name for the `le' capability. - -`bs' - Flag whose presence means that the ASCII character backspace may be - used to move the cursor left. Obsolete; look at `le' instead. - -`nl' - Obsolete capability which is a string that can either be used to - move the cursor down or to scroll. The same string must scroll - when used on the bottom line and move the cursor when used on any - other line. New programs should use `do' or `sf', and ignore `nl'. - - If there is no `nl' capability, some old programs assume they can - use the newline character for this purpose. These programs follow - a bad practice, but because they exist, it is still desirable to - define the `nl' capability in a terminal description if the best - way to move down is *not* a newline. - - -File: termcap.info, Node: Wrapping, Next: Scrolling, Prev: Cursor Motion, Up: Capabilities - -Wrapping -======== - - "Wrapping" means moving the cursor from the right margin to the left -margin of the following line. Some terminals wrap automatically when a -graphic character is output in the last column, while others do not. -Most application programs that use termcap need to know whether the -terminal wraps. There are two special flag capabilities to describe -what the terminal does when a graphic character is output in the last -column. - -`am' - Flag whose presence means that writing a character in the last - column causes the cursor to wrap to the beginning of the next line. - - If `am' is not present, writing in the last column leaves the - cursor at the place where the character was written. - - Writing in the last column of the last line should be avoided on - terminals with `am', as it may or may not cause scrolling to occur - (*note Scrolling::.). Scrolling is surely not what you would - intend. - - If your program needs to check the `am' flag, then it also needs - to check the `xn' flag which indicates that wrapping happens in a - strange way. Many common terminals have the `xn' flag. - -`xn' - Flag whose presence means that the cursor wraps in a strange way. - At least two distinct kinds of strange behavior are known; the - termcap data base does not contain anything to distinguish the two. - - On Concept-100 terminals, output in the last column wraps the - cursor almost like an ordinary `am' terminal. But if the next - thing output is a newline, it is ignored. - - DEC VT-100 terminals (when the wrap switch is on) do a different - strange thing: the cursor wraps only if the next thing output is - another graphic character. In fact, the wrap occurs when the - following graphic character is received by the terminal, before the - character is placed on the screen. - - On both of these terminals, after writing in the last column a - following graphic character will be displayed in the first column - of the following line. But the effect of relative cursor motion - characters such as newline or backspace at such a time depends on - the terminal. The effect of erase or scrolling commands also - depends on the terminal. You can't assume anything about what - they will do on a terminal that has `xn'. So, to be safe, you - should never do these things at such a time on such a terminal. - - To be sure of reliable results on a terminal which has the `xn' - flag, output a `cm' absolute positioning command after writing in - the last column. Another safe thing to do is to output - carriage-return newline, which will leave the cursor at the - beginning of the following line. - -`LP' - Flag whose presence means that it is safe to write in the last - column of the last line without worrying about undesired - scrolling. `LP' indicates the DEC flavor of `xn' strangeness. - - -File: termcap.info, Node: Scrolling, Next: Windows, Prev: Wrapping, Up: Capabilities - -Scrolling -========= - - "Scrolling" means moving the contents of the screen up or down one or -more lines. Moving the contents up is "forward scrolling"; moving them -down is "reverse scrolling". - - Scrolling happens after each line of output during ordinary output -on most display terminals. But in an application program that uses -termcap for random-access output, scrolling happens only when -explicitly requested with the commands in this section. - - Some terminals have a "scroll region" feature. This lets you limit -the effect of scrolling to a specified range of lines. Lines outside -the range are unaffected when scrolling happens. The scroll region -feature is available if either `cs' or `cS' is present. - -`sf' - String of commands to scroll the screen one line up, assuming it is - output with the cursor at the beginning of the bottom line. - -`sr' - String of commands to scroll the screen one line down, assuming it - is output with the cursor at the beginning of the top line. - -`do' - A few programs will try to use `do' to do the work of `sf'. This - is not really correct--it is an attempt to compensate for the - absence of a `sf' command in some old terminal descriptions. - - Since these terminal descriptions do define `sr', perhaps at one - time the definition of `do' was different and it could be used for - scrolling as well. But it isn't desirable to combine these two - functions in one capability, since scrolling often requires more - padding than simply moving the cursor down. Defining `sf' and - `do' separately allows you to specify the padding properly. Also, - all sources agree that `do' should not be relied on to do - scrolling. - - So the best approach is to add `sf' capabilities to the - descriptions of these terminals, copying the definition of `do' if - that does scroll. - -`SF' - String of commands to scroll the screen N lines up, assuming it is - output with the cursor at the beginning of the bottom line. - -`SR' - String of commands to scroll the screen N lines down, assuming it - is output with the cursor at the beginning of the top line. - -`cs' - String of commands to set the scroll region. This command takes - two parameters, START and END, which are the line numbers - (origin-zero) of the first line to include in the scroll region - and of the last line to include in it. When a scroll region is - set, scrolling is limited to the specified range of lines; lines - outside the range are not affected by scroll commands. - - Do not try to move the cursor outside the scroll region. The - region remains set until explicitly removed. To remove the scroll - region, use another `cs' command specifying the full height of the - screen. - - The cursor position is undefined after the `cs' command is set, so - position the cursor with `cm' immediately afterward. - -`cS' - String of commands to set the scroll region using parameters in - different form. The effect is the same as if `cs' were used. - Four parameters are required: - - 1. Total number of lines on the screen. - - 2. Number of lines above desired scroll region. - - 3. Number of lines below (outside of) desired scroll region. - - 4. Total number of lines on the screen, the same as the first - parameter. - - This capability is a GNU extension that was invented to allow the - Ann Arbor Ambassador's scroll-region command to be described; it - could also be done by putting non-Unix `%'-sequences into a `cs' - string, but that would have confused Unix programs that used the - `cs' capability with the Unix termcap. Currently only GNU Emacs - uses the `cS' capability. - -`ns' - Flag which means that the terminal does not normally scroll for - ordinary sequential output. For modern terminals, this means that - outputting a newline in ordinary sequential output with the cursor - on the bottom line wraps to the top line. For some obsolete - terminals, other things may happen. - - The terminal may be able to scroll even if it does not normally do - so. If the `sf' capability is provided, it can be used for - scrolling regardless of `ns'. - -`da' - Flag whose presence means that lines scrolled up off the top of the - screen may come back if scrolling down is done subsequently. - - The `da' and `db' flags do not, strictly speaking, affect how to - scroll. But programs that scroll usually need to clear the lines - scrolled onto the screen, if these flags are present. - -`db' - Flag whose presence means that lines scrolled down off the bottom - of the screen may come back if scrolling up is done subsequently. - -`lm' - Numeric value, the number of lines of display memory that the - terminal has. A value of zero means that the terminal has more - display memory than can fit on the screen, but no fixed number of - lines. (The number of lines may depend on the amount of text in - each line.) - - Any terminal description that defines `SF' should also define `sf'; -likewise for `SR' and `sr'. However, many terminals can only scroll by -one line at a time, so it is common to find `sf' and not `SF', or `sr' -without `SR'. - - Therefore, all programs that use the scrolling facilities should be -prepared to work with `sf' in the case that `SF' is absent, and -likewise with `sr'. On the other hand, an application program that -uses only `sf' and not `SF' is acceptable, though slow on some -terminals. - - When outputting a scroll command with `tputs', the NLINES argument -should be the total number of lines in the portion of the screen being -scrolled. Very often these commands require padding proportional to -this number of lines. *Note Padding::. - - -File: termcap.info, Node: Windows, Next: Clearing, Prev: Scrolling, Up: Capabilities - -Windows -======= - - A "window", in termcap, is a rectangular portion of the screen to -which all display operations are restricted. Wrapping, clearing, -scrolling, insertion and deletion all operate as if the specified -window were all the screen there was. - -`wi' - String of commands to set the terminal output screen window. This - string requires four parameters, all origin-zero: - 1. The first line to include in the window. - - 2. The last line to include in the window. - - 3. The first column to include in the window. - - 4. The last column to include in the window. - - Most terminals do not support windows. - - -File: termcap.info, Node: Clearing, Next: Insdel Line, Prev: Windows, Up: Capabilities - -Clearing Parts of the Screen -============================ - - There are several terminal capabilities for clearing parts of the -screen to blank. All display terminals support the `cl' string, and -most display terminals support all of these capabilities. - -`cl' - String of commands to clear the entire screen and position the - cursor at the upper left corner. - -`cd' - String of commands to clear the line the cursor is on, and all the - lines below it, down to the bottom of the screen. This command - string should be used only with the cursor in column zero; their - effect is undefined if the cursor is elsewhere. - -`ce' - String of commands to clear from the cursor to the end of the - current line. - -`ec' - String of commands to clear N characters, starting with the - character that the cursor is on. This command string is expected - to leave the cursor position unchanged. The parameter N should - never be large enough to reach past the right margin; the effect - of such a large parameter would be undefined. - - Clear to end of line (`ce') is extremely important in programs that -maintain an updating display. Nearly all display terminals support this -operation, so it is acceptable for a an application program to refuse to -work if `ce' is not present. However, if you do not want this -limitation, you can accomplish clearing to end of line by outputting -spaces until you reach the right margin. In order to do this, you must -know the current horizontal position. Also, this technique assumes -that writing a space will erase. But this happens to be true on all -the display terminals that fail to support `ce'. - - -File: termcap.info, Node: Insdel Line, Next: Insdel Char, Prev: Clearing, Up: Capabilities - -Insert/Delete Line -================== - - "Inserting a line" means creating a blank line in the middle of the -screen, and pushing the existing lines of text apart. In fact, the -lines above the insertion point do not change, while the lines below -move down, and one is normally lost at the bottom of the screen. - - "Deleting a line" means causing the line to disappear from the -screen, closing up the gap by moving the lines below it upward. A new -line appears at the bottom of the screen. Usually this line is blank, -but on terminals with the `db' flag it may be a line previously moved -off the screen bottom by scrolling or line insertion. - - Insertion and deletion of lines is useful in programs that maintain -an updating display some parts of which may get longer or shorter. -They are also useful in editors for scrolling parts of the screen, and -for redisplaying after lines of text are killed or inserted. - - Many terminals provide commands to insert or delete a single line at -the cursor position. Some provide the ability to insert or delete -several lines with one command, using the number of lines to insert or -delete as a parameter. Always move the cursor to column zero before -using any of these commands. - -`al' - String of commands to insert a blank line before the line the - cursor is on. The existing line, and all lines below it, are - moved down. The last line in the screen (or in the scroll region, - if one is set) disappears and in most circumstances is discarded. - It may not be discarded if the `db' is present (*note - Scrolling::.). - - The cursor must be at the left margin before this command is used. - This command does not move the cursor. - -`dl' - String of commands to delete the line the cursor is on. The - following lines move up, and a blank line appears at the bottom of - the screen (or bottom of the scroll region). If the terminal has - the `db' flag, a nonblank line previously pushed off the screen - bottom may reappear at the bottom. - - The cursor must be at the left margin before this command is used. - This command does not move the cursor. - -`AL' - String of commands to insert N blank lines before the line that - the cursor is on. It is like `al' repeated N times, except that - it is as fast as one `al'. - -`DL' - String of commands to delete N lines starting with the line that - the cursor is on. It is like `dl' repeated N times, except that - it is as fast as one `dl'. - - Any terminal description that defines `AL' should also define `al'; -likewise for `DL' and `dl'. However, many terminals can only insert or -delete one line at a time, so it is common to find `al' and not `AL', -or `dl' without `DL'. - - Therefore, all programs that use the insert and delete facilities -should be prepared to work with `al' in the case that `AL' is absent, -and likewise with `dl'. On the other hand, it is acceptable to write -an application that uses only `al' and `dl' and does not look for `AL' -or `DL' at all. - - If a terminal does not support line insertion and deletion directly, -but does support a scroll region, the effect of insertion and deletion -can be obtained with scrolling. However, it is up to the individual -user program to check for this possibility and use the scrolling -commands to get the desired result. It is fairly important to implement -this alternate strategy, since it is the only way to get the effect of -line insertion and deletion on the popular VT100 terminal. - - Insertion and deletion of lines is affected by the scroll region on -terminals that have a settable scroll region. This is useful when it is -desirable to move any few consecutive lines up or down by a few lines. -*Note Scrolling::. - - The line pushed off the bottom of the screen is not lost if the -terminal has the `db' flag capability; instead, it is pushed into -display memory that does not appear on the screen. This is the same -thing that happens when scrolling pushes a line off the bottom of the -screen. Either reverse scrolling or deletion of a line can bring the -apparently lost line back onto the bottom of the screen. If the -terminal has the scroll region feature as well as `db', the pushed-out -line really is lost if a scroll region is in effect. - - When outputting an insert or delete command with `tputs', the NLINES -argument should be the total number of lines from the cursor to the -bottom of the screen (or scroll region). Very often these commands -require padding proportional to this number of lines. *Note Padding::. - - For `AL' and `DL' the NLINES argument should *not* depend on the -number of lines inserted or deleted; only the total number of lines -affected. This is because it is just as fast to insert two or N lines -with `AL' as to insert one line with `al'. - |