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# @(#)README 1.1 94/10/31 SMI; from S5R3 1.6
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1	Within the curses component, exists other conversion tools which are
	much more robust than those described below. They are called infocmp, 
	and captoinfo. The cvt files are provided here only for those possible 
	cases where a user has the terminfo component without the libcurses 
	component.
	
	The captoinfo and infocmp utilities cannot be included here, as they
	require the user to have libcurses. Although we know of no instance
	when a user would have one and not the other, we have provided the
	cvt files (described below) for those limited cases.
	


2	The files in this directory with the .ti suffix are terminfo sources.
	They should be compiled (separately or by catting them together into
	terminfo.src) with tic, placing the results in /usr/lib/terminfo.
	Please send any updates to AT&T Bell Laboratories UNIX support,
	via UNIX mail to attunix!terminfo.
	


3	The cvt files are useful tools for converting termcap to terminfo.
	They are not 100% accurate, but do most of the conversion for you.
	cvt.ex is an ex script to convert a termcap description into a
	terminfo description.  Note that it will not convert padding 
	specifications, so they must be done by hand.  Note also that typical 
	termcap entries do not give as much information as terminfo, so the 
	resulting terminfo entry is often incomplete (e.g. won't tell you the 
	terminal uses xon/xoff handshaking, or what extra function keys send).
	You are urged to read the list of terminfo capabilities and augment your
	terminfo descriptions accordingly.
	
	The cvt.h file is useful for a quick hack at converting termcap programs
	which use uppercase 2 letter names for capabilities to use terminfo.
	Since tget* are provided anyway, this is of questionable value unless
	your program barely fits on a pdp-11.
	
	The cvt.sed script is useful for actually editing the source of the same
	class of programs.  It requires a sed that understands \< and \>, the
	mod is trivial to make if you look at the corresponding code in ex or
	grep.
	


3	There are other incompatibilities at the user level between termcap and
	terminfo.  A program which creates a termcap description and then
	passes it to tgetent (e.g. vi used to do this if no TERM was set) or
	which puts such a description in the environment for a child cannot
	possibly work, since terminfo puts the parser into the compiler, not
	the user program.  If you want to give a child a smaller window, set
	up the LINES and COLUMNS environment variables or implement the JWINSIZE
	ioctl.
	


4	If you want to edit your own personal terminfo descriptions (and are not
	a super user on your system) the method is different.  Set
	TERMINFO=$HOME/term (or wherever you put the compiled tree) in your
	environment, then compile your source with tic.  Tic and user programs
	will check in $TERMINFO before looking in /usr/lib/terminfo/*/*
	


5	Philosophy in adding new terminfo capabilities:
	
	Capabilities were cheap in termcap, since no code supported them
	and they need only be documented.  In terminfo, they add size to
	the structure and the binaries, so don't add them in mass quantities.
	
	Add a capability only if there is an application that wants to use it.
	Lots of terminals have a half duplex forms editing mode, but no UNIX
	applications use it, so we don't include it.
	
	Before you add a capability, try to hold off until there are at least
	2 or 3 different terminals implementing similar features.  That way,
	you can get a better idea of the general model that the capability
	should have, rather than coming up with something that only works
	on one kind of terminal.  For example, the status line capabilities
	were added after we had seen the h19, the tvi950, and the vt100 run
	sysline.  The original program, called h19sys, only worked on an h19
	and addressed the cursor to line 25.  This model doesn't fit other
	terminals with a status line.
	
	Note that capabilities must be added at the end of ../screen/caps.
	Furthermore, if you add a private capability, you should check with
	someone to make sure your capability goes into the master file, 
	otherwise someone else will add a different capability and 
	compatibility between two systems is destroyed.  There must be one 
	master set of capabilities. This list is maintained at AT&T UNIX 
	Development. Comments should be sent to attunix!terminfo.
	


6	Current murky areas include:
	
	Color - there is demand for colors but it isn't clear what to do yet.
	Some terminals support only 2 or 4 or 8 or 16 colors, others have a
	palette of some huge selection.  What are the standard colors?  How
	does graphics fit into this (terminfo is alphanumeric oriented?)
	Curses can have another 16 bits added, or some routine set to decide
	which 9 attribute bits have meaning in any given program.  An 
	alternative is that if you just want color alphanumerics for a simple 
	application, e.g. highlighting certain fields, decide how you would 
	want your application to behave on a B/W terminal (e.g. a vt100), 
	using reverse for one thing, blinking for another, bold for another, 
	invisible for another, etc.
	(Invis may be useful for colored fields with no information in them.)
	Then make a terminfo entry with blink=xxx, bold=yyy, etc, where xxx
	and yyy are sequences to go into the colors you really want.  This way
	your application also works on B/W terminals.
	
	Graphics: Giles Billingsley at Berkeley did something called MFBCAP
	once, it was like termcap but 3 times as big and handled graphics.
	I don't think it was ever finished.  I don't know how to do graphics
	in curses, one might add it to terminfo at very high cost.
	
	Input: things that send escape sequences to your program to be decoded
	are a hard issue.  You have to somehow deal with typeahead and with
	terminals that can't do it.  This includes "request cursor position",
	for which a better solution is to immediately address the cursor to
	a known position.  (Curses also has filter mode that won't assume
	the line but will assume the column.)  Mice also fall into this
	category.  Scanf style strings (tparm is printf style) might be able
	to decode these sequences, but I have no experience with them.
	
	Alternate character set: the vt100 set seems to be becoming a defacto
	standard, although it doesn't do much.  I almost standardized on the
	Teletype 5410, which was a nice superset of the vt100, but then Teletype
	updated the 5410 to make it a vt100 duplicate, so now all I've put in
	are the vt100 line drawing characters.  HP has a more complete set,
	but it has some really weird things in it and the mappings are 
	nonstandard.
	Any extension should be able to handle both kinds of terminals, and
	handle common programs without assuming an HP (or even a vt100).
	
	------------------------------------
	

7	Additional modules:
	
		ckout		shell script, analyzes file errs for diagnostics
				and displays number of entries built
	
		Doc.sed		sed script to be run on ti files.
				prints documentation of ti files.
