rpterm

A graphical typewriter.

Very much in pre-alpha state, currently.

Setup

• make
• make run (or make debug)
• make install installs it in /opt/rpterm (weird location because there's no packaging yet)

Escape Codes

rpterm understands most escape codes that xterm understands (and in fact, identifies as a TERM=xterm-256color so that termcap programs don't freak out).

Additionally supported are:

[NOT IMPLEMENTED YET] iterm2 embed OSC 1337

OSC 1337 ; FILESPEC BEL (OSC is ESC ])

• iterm2's embedding code - for an explanation of what to put in for FILESPEC, see https://iterm2.com/images.html
• rpterm only supports embedding images with this escape code (but see OSC 1338 below) - on iterm2 you can also embed PDFs with OSC 1337.
• rpterm does not support downloading files via this escape code.
• rpterm also understands the somewhat more usual terminating ST (ESC 0x5c) instead of the BEL - it's unclear if iterm2 does, too.

rpterm embed OSC 1338

OSC 1338 ; MIMETYPE ; URL BEL (and OSC 1338 ; MIMETYPE ; URL ST)

• MIMETYPE can be the specific mime type (image/gif) or you can leave out the second part (just image). No wildcards are supported.
• URL is the URL of the thing you want to embed. Explicitly supported are:
  • data:$MIMETYPE;$ENCODING,$DATA where $MIMETYPE is the mime type (again), $ENCODING is something like base64 and $DATA is the encoded data.
  • file://$ABSOLUTE_PATH where $ABSOLUTE_PATH this is (local) path to the file to embed
  • http:// and https:// URLs
  • Other schemas (ftp:// and so on) will probably work, too. But sticking to the above leaves at least a glimmer of hope that this escape code can be implemented by something smaller than a full web browser engine.
• Not all mime types are supported but there's currently no list about what is supported (the goal is certainly to support as many as possible).

Wrappers

rpterm ships with wrappers for some common unix programs that automatically insert above embedding escape codes.

Examples

• directly in rpterm: curl -s https://http.cat/200 (this uses a curl wrapper)
• in your own scripts you can do something like printf '\033]1338;image;data:image;base64,'; curl -s https://http.cat/200 | base64; printf '\033\\'

Not Bugs

• There is no direct way for programs to write HTML for the terminal to display because the author hopes to get rid of the HTML/browser implementation eventually.

Bugs

• scrolling with embedded HTML is almost completely broken
• pasting into the terminal doesn't seem to work at all
• xterm compatible mouse support is implemented (by xterm.js) but doesn't work here for some weird reason (see also https://github.com/f/atom-term2/issues/195).
• The shell to execute is hard-coded to /bin/bash -i.
• Using a web browser to display a shell is ridiculous.
• I can't figure out how to make this abomination display a misc-fixed font.
• It should be possible to stream OSC 1337/1338 data, but it isn't:

# doesn't work, but should
$ curl -s https://http.cat/303 > /tmp/cat.jpg
$ printf '\033]1338;image/jpeg;data:image/jpeg;base64,'; \
    cat /tmp/cat.jpg | base64 | head -c 100; \
    sleep 3; \
    cat /tmp/cat.jpg | base64 | tail -c +101; \
    printf '\033\\'`

Known Design Problems

• The untyped nature of byte streams in unix makes interpreting them a fiddly, and ultimately buggy, balancing act.
• It's unclear whether inline UI code (via escape codes) is a good idea at all.
• The graphical escape codes always use, in cursor-addressing terms, a full row (with "one character" in it). Because of that, it is tricky to combine them with cursor-addressing escape codes (though one could call that a feature). These "graphical" rows also don't interact with other escape codes (bold, colors, etc.), though that could be fixed where it makes sense.
• While this can be made to be just as powerful as "real" GUIs output-wise, the input side of things is pretty much missing here.

Author and License

Copyright 2016 by Richard Wossal richard@r-wos.org

Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation. No representations are made about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty.

Parts of this based on https://github.com/atom/electron-quick-start, (CC0/Public Domain)

and the xterm.js demo at https://github.com/sourcelair/xterm.js/tree/master/demo, Copyright (c) 2014-2016, SourceLair, Private Company (www.sourcelair.com) (MIT License) Copyright (c) 2012-2013, Christopher Jeffrey (MIT License)

Credits

Thanks to iterm2 (http://iterm2.com/) for inspiration and for ESC ] 1337.

This program has pretty much nothing in common with it, but if you're interested in how one would do similar things properly, have a look at Plan 9's draw device (http://plan9.bell-labs.com/magic/man2html/3/draw) and rio (http://plan9.bell-labs.com/magic/man2html/1/rio9) and drawterm (http://plan9.bell-labs.com/magic/man2html/8/drawterm).