Termcurses
==========

   Terminal emulation library for NuttX
   Author:  Ken Pettit
            2018-2019

The Termcurses library provides terminal emulation support for performing common
screen actions such as cursor movement, foreground / background color control
and keyboard escape sequence mapping.  The initial release supports only vt100 /
ansi terminal types, but the library architecture has an extensible interface 
to allow support for additional emulation types if needed.

The library can be used standalone or in conjunction with the apps/graphics/pdcurses
libraries.  The pdcurses libraries have been updated with a "termcurses" config 
option which fully integrates the termcurses library automatically.

Usage
=====

To use the termcurses library, the routines must be initialized by calling the 
termcurses_initterm() function.  This routine accepts a terminal type string
identifying the type of terminal emulation support requested.  If a NULL pointer
is passed, then the routine will check for a "TERM" environment variable and set
the terminal type based on that string.  If the emulation type still cannot be
determined, the routine will default to "vt100" emulation type.

Upon successful initialization, the termcurses_initterm() function will allocate
an new terminal context which must be passed with all future termcurses library
functions.  When this context is no longer needed, the termcurses_deinitterm()
routine should be called for proper freeing and terminal teardown.

Use with telnetd
================

When using termcurses with the telnet daemon, the telnet config option 
CONFIG_TELNET_SUPPORT_NAWS should be enabled.  This option adds code to the
telnet library for terminal size negotiation.  Wihout this option, the telnet
routines have no concept of the terminal size, and therefore the termcurses
routines must default to 80x24 screen mode.

Use with pdcurses
=================

When using the pdcurses termcurses support (i.e you have enabled both the
CONFIG_PDCURSES and CONFIG_TERMCURSES options),, the pdcurses input device should
be selected to be "TERMINPUT" (i.e. set CONFIG_PDCURSES_TERMINPUT=y).  This 
causes the pdcurses keyboard input logic to use termcurses_getkeycode() routine
for curses input.