PySixel 0.1.3

Make SIXEL color graphics supported by some terminal emulators(DECTerm/RLogin/mlterm/tanasinn/xterm)

What is SIXEL?

SIXEL is one of image formats for terminal imaging introduced by DEC VT series. SIXEL image data scheme is represented as a terminal-friendly escape sequence. So if you want to show a SIXEL image file, all you have to do is “cat” it to your terminal.

I heared SIXEL is supported by some old terminal applications, such as SAS, WordPerfect.

Nowadays netpbm and Gnuplot support this.

Requirements

If you want to view a SIXEL image, you have to get a terminal which support sixel graphics.

Now SIXEL feature is supported by the following terminals.

• RLogin (Japanese terminal emulator)

  http://nanno.dip.jp/softlib/man/rlogin/

• tanasinn (Works with firefox)

  http://zuse.jp/tanasinn/

• mlterm

  Works on each of X, win32/cygwin, framebuffer version. http://mlterm.sourceforge.net/

• XTerm (compiled with –enable-sixel option) You should launch xterm with “-ti 340” option. the SIXEL palette is limited to a maximum of 256 colors. http://invisible-island.net/xterm/

• DECterm

• Kermit

• WRQ Reflection

• ZSTEM

Install

via github

$ git clone https://github.com/saitoha/PySixel.git
$ cd pysixel
$ python setup.py install

or via pip

$ pip install PySixel

Usage

PySixel provides a Command line tool:

$ sixelconv [options] filename

or

$ cat filename | sixelconv [options]

• Options:

  -h, --help                                            show this help message and exit
  -8, --8bit-mode                                       Generate a sixel image for 8bit terminal or printer
  -7, --7bit-mode                                       Generate a sixel image for 7bit terminal or printer
  -r, --relative-position                               Treat specified position as relative one
  -a, --absolute-position                               Treat specified position as absolute one
  -x LEFT, --left=LEFT                                  Left position in cell size, or pixel size with unit 'px'
  -y TOP, --top=TOP                                     Top position in cell size, or pixel size with unit 'px'
  -w WIDTH, --width=WIDTH                               Width in cell size, or pixel size with unit 'px'
  -e HEIGHT, --height=HEIGHT                            Height in cell size, or pixel size with unit 'px'
  -t ALPHATHRESHOLD, --alpha-threshold=ALPHATHRESHOLD   Alpha threshold for PNG-to-SIXEL image conversion
  -c, --chromakey                                       Enable auto chroma key processing
  -n NCOLOR, --ncolor=NCOLOR                            Specify number of colors

Example

View an image file:

$ sixelconv test.png

Generate sixel file from an image file:

$ sixelconv < test.png > test.six

View generated sixel file:

$ cat test.six

Show sixel in xterm

    $ curl ftp://invisible-island.net/xterm/xterm-301.tgz | tar xz
    $ cd xterm-301
    $ ./configure --enable-wide-chars --enable-sixel-graphics --enable-256-color
$ make
# make install
    $ xterm -ti vt340 -e 'sixelconv ~/testdir/test.jpg'

Code Example

import sixel
writer = sixel.SixelWriter()
writer.draw('test.png')

Dependency

• Pillow https://github.com/python-imaging/Pillow

• Python imageloader module https://pypi.python.org/pypi/imageloader

Reference

• Chris_F_Chiesa, 1990 : All About SIXELs ftp://ftp.cs.utk.edu/pub/shuford/terminal/all_about_sixels.txt

• Netpbm http://netpbm.sourceforge.net/

  It includes ppmtosixel command http://netpbm.sourceforge.net/doc/ppmtosixel.html

• vt100.net http://vt100.net/