TESI v0.1

Started: 2006-05-04 Updated: 2006-11-11
Progress: 70%
Language: C
OS: Linux
License: GPL

Since May I've been making progress on a library I affectionately call TESI. It is a combination of a "Terminal Escape Sequence Interpreter" and the Terminfo definition for the terminal it interprets. It aims to be a more well-rounded alternative to iterm and ROTE.

The Point

There are many areas of computing that need improvement, and I see terminals being one of them. Software terminals still closely emulate the hardware terminals of 20+ years ago. This means terminals aren't as efficient or simple as they should be.

Also, Knox needs something simpler than iterm and more usable than ROTE. If a programmer wants to create their own terminal (like xterm, Konsole, etc) he shouldn't have to worry about all the details of emulating a terminal. He should only have to worry about drawing to the screen and adding snazzy UI-related features.

TESI is Unique

iterm is a "framework for making an Internationalized Virtual Terminal Emulator" and it is also a type of terminal, which libiterm emulates. TESI is similar, except that a TESI terminal is not reminiscent of VT100, VT102, VT202 or Xterm terminals. TESI doesn't yet have internationalization capabilities but it is a high priority.

ROTE assumes you'll be using nCurses to display your output. TESI doesn't assume this and tries to make it easy to use something like GTK.

Achieved Milestones

Minimized escape sequence set means interpretation code is simpler and the sequences are easier for humans to debug
Can be used to run VIM!
Terminals have their own controlling PTY
Attributes (bold, inverse)
Insert line, delete line
Insert char
Normal character printing

Remaining Milestones

Support for advanced applications that make use of alternate drawing character sets (apps that utilize solid-line borders)
Unicode support
Finalize colors
Ensure correct handling of large terminals

Somewhat Technical Details

TESI merely processes escape sequences received from the child process (such as a shell) and invokes the appropriate callback functions (which are implemented by the programmer). This means the method for drawing characters to the screen is up to you. Output can be performed using any library or GUI API that you want, or none at all.

API

newTESIObject(): Returns a pointer to a new TESI object.
tesi_handleInput(tesiObject*): Handles the escape sequences awaiting a TESI object.
deleteTESIObject(tesiObject*): Delete a TESI object.

The following are callbacks that should be set by the coder wishing to utilize TESI. This leaves it up to the coder to perform the actual drawing on the screen with a library such as GTK or DirectFB.

callback_clear(void*): Clear canvas
callback_printCharacter(void*, char): Print character at current cursor position
callback_printString(void*, char*, int): Print string of length at current cursor position
callback_insertCharacter(void*, char): Insert character at current cursor position
callback_insertLine(void*): Insert line after current line
callback_eraseLine(void*): Erase line at current cursor position
callback_eraseCharacter(void*): Erase character at specified cursor position
callback_printString(void*, char): Print string at current cursor position
callback_moveCursor(void*, int, int): Move cursor to X, Y.
callback_attributes(void*, short, short, short, short, short, short, short): Set attributes (bold, blink, inverse, underline, foreground, background, charset)
callback_scrollRegion(void*,int,int): Set scroll region from line A to line B.
callback_scrollUp(void*): Scroll contents up 1 line.
callback_scrollDown(void*): Scroll contents down 1 line.
callback_bell(void*): Perform a bell command