Raster graphics in xterm?

Question

No, not ASCII graphics, see the screenshot here:

http://en.wikipedia.org/wiki/W3m

How is that even possible?

I checked the source and it only prints character sequences. However, I am unable to find any reference to graphic drawing or image embedding escape sequences in xterm documentation or elsewhere.

w3m also seems to be the only software doing this.

There are vector graphics in Tektronix emulation, but this is done in VT mode.

Maybe I am looking for the wrong thing?

Any idea?

Answer 1

It's a cheat.

Note that this feature works only in "supported terminals" -- and by that it meant xterm, and rendering directly on the xterm window via xv.

Or not! Just checked the sources, the file that interests us is here. It's still a hack -- via X11 and GTK!

Answer 2

There is MLTerm, which supports Sixel format (not ReGis commands). It's available for both Linux and Windows.

Otherwise, according to man xterm on Ubuntu 12.04, xterm supports Tektronix graphics, which (the man page does tell) use ReGIS commands or Sixel bitmap format, depending on compilation options (I believe it's Sixel for the XTerm in the Ubuntu package repository).

One thing to know, is that ReGIS is an instruction set, while Sixel is a bitmap format.

As a side note, there exists a Python package to use Sixel aware terminal emulators: PySixel.

I'm interested in the topic too, and may update this answer in the future, with other relevant terminal emulators entries.

Answer 3

Higher-end models of Dec VT terminals support ReGis and Sixel graphics commands. If the xterm emulation is good enough, maybe that's how it was done?

Answer 4

Xterm supports the sixel and ReGIS protocols which allow rendering graphics directly in the terminal using escape sequences. However, Unicode interferes with 8 bit escape sequences, so you may need to convert them to 7bit sequences.

https://en.wikipedia.org/wiki/Sixel

https://en.wikipedia.org/wiki/ReGIS