man > ppmtosixel(1)

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⚡ TLDR: ppmtosixel (tldr-pages)

Convert a PPM image to DEC sixel format.

Convert a PPM image to DEC sixel format
ppmtosixel {{path/to/file.ppm}} > {{path/to/file.sixel}}
Produce an uncompressed SIXEL file that is much slower to print
ppmtosixel {{-r|-raw}} {{path/to/file.ppm}} > {{path/to/file.sixel}}
Add a left margin of 1.5 inches
ppmtosixel {{-m|-margin}} {{path/to/file.ppm}} > {{path/to/file.sixel}}
Encode control codes in a more portable (although less space-efficient) way
ppmtosixel -7bit {{path/to/file.ppm}} > {{path/to/file.sixel}}

Ppmtosixel User Manual(1) General Commands Manual Ppmtosixel User Manual(1)

NAME
ppmtosixel - convert a PPM image to DEC sixel format

SYNOPSIS
ppmtosixel

[-raw]

[-margin]

[-7bit]

[ppmfile]

DESCRIPTION
This program is part of Netpbm(1).

ppmtosixel reads a PPM image as input and produces sixel commands (SIX) as output. The out‐
put is formatted for color printing (e.g. for a DEC LJ250 color inkjet printer) or for color
display on DEC VT terminals and terminal emulators (VT240 and beyond).

If RGB values from the PPM file do not have maxval=100, ppmtosixel rescales them to maxval
100. A printer control header and a color assignment table begin the SIX file. Image data
is in a compressed format by default. A printer control footer ends the image file.

OPTIONS
In addition to the options common to all programs based on libnetpbm (most notably -quiet,
see ]8;;index.html#commonoptions\ Common Options]8;;\ ), ppmtosixel recognizes the following command line options:

-raw If you specify this, each pixel will be explicitly described in the image file. If
-raw is not specified, output will default to compressed format in which identical ad‐
jacent pixels are replaced by "repeat pixel" commands. A raw file is often an order
of magnitude larger than a compressed file and prints much slower.

-margin
If you don't specify -margin, the image will start at the left margin (of the window,
paper, or whatever). If you do specify -margin, a 1.5 inch left margin will offset
the image.

-7bit If you don't specify -7bit, each control code will be expressed as a single, 8-bit
"C1" character. If you do specify -7bit, each control code will be expressed using
two, 7-bit "C0" characters. (See ]8;;https://en.wikipedia.org/wiki/C0_and_C1_control_codes\C0 and C1 control codes]8;;\ for more information.) In
other words, -7bit produces more portable sixel files, and its absence produces
smaller sixel files.

This option was new in Netpbm 11.04 (September 2023).

PRINTING
Generally, sixel files must reach the printer unfiltered. Use the lpr -x option or cat file‐
name > /dev/tty0?.

LIMITATIONS
Upon rescaling, truncation of the least significant bits of RGB values may result in poor
color conversion. If the original PPM maxval was greater than 100, rescaling also reduces
the image depth. While the actual RGB values from the ppm file are more or less retained,
the color palette of the LJ250 may not match the colors on your screen. This seems to be a
printer limitation.