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* What is VTE?
- You could say that VTE is something of a research project of mine, based on
the simple question: "if programs can use a termcap file (through either
libtermcap or curses or ncurses) to determine how to drive a terminal, why
can't a terminal emulator use a termcap file to determine how to behave?"
* What does VTE include?
- VTE includes a library (libvte) which implements such a terminal emulator
widget for GTK+ 2.0, and a sample application (vte) which wraps that widget
in a GTK window. Because I'm more concerned with whether or not it works,
all settings are hard-coded to whatever I needed to test the last time I
touched it. If you actually want to use the widget to get work done, you
should probably be using profterm.
* How does it work?
- The VTE library inserts terminal capability strings into a tree of tables,
and then uses it to determine if data received from a pseudo-terminal is a
control sequence or just random data. The sample program "interpret"
illustrates more or less what the widget sees after it filters incoming data.
* What's missing?
- Accessibility isn't completed yet.
- Mouse hilite tracking isn't implemented yet.
- Extending the selection using shift+click pays attention to whether or not
the existing selection was done word-at-a-time or line-at-a-time, but
probably shouldn't.
- Most control sequences are recognized, but many aren't implemented. There
are enough to run ls, vim, less, emacs and mutt, but more need to be
implemented (ff, i1, i3, is, iP, LF, LO, MC, mh, ML, mm, mo, nw, pf,
pk, pl, pf, po, pO, ps, px, r1, r2, r3, RA, RF, rp, rs, RX, SA, SX, wi,
several more from the XTerm set).
- I'm not sure the widget implementation itself is correct. There are many
changes in going from GTK+ 1.2 to 2.0, and examples of the proper way to do
things is currently scarce, so some of it's guesswork.
- An actual property interface needs to be retrofitted over the various options
which are currently hard-coded at startup-time.
* What's weird?
- Relative cursor motion is weird. When the character to the right of the
cursor is a 3-byte UTF-8 sequence for a character which occupies two
columns on the screen, three things may happen when the application sends
the "cursor left" control sequence:
* the cursor moves two columns (one character) to the left
This eliminates the possibility of moving the cursor into the middle of
a multi-column character.
* the cursor moves one column (one half-character) to the left
This makes determining where the cursor is easier, but requires the
application to emit a control sequence more than once for multi-column
characters.
* the cursor moves one "byte" to the left
This happens to work for a few locales, and is otherwise just broken.
Currently VTE follows the second convention. More on this topic:
http://czyborra.com/unicode/terminals.html
http://mail.nl.linux.org/linux-utf8/1999-10/msg00014.html
http://www.debian.org/doc/manuals/intro-i18n/ch-output.en.html
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