True Colour support in various terminals

[est]

You know I tried to hack to play a gif upon SSH login, /etc/issue.net does not accept ANSI chars, but /etc/motd does.

So I mkfifo /etc/motd, use some monkey patched shell commands to stream gif to /etc/motd, tried SSH login, the animation totally works, adjust the sleep you get different speeds.

I was totally satisfied with this and logged out of my VPS server. Oh wait....

Since my scripts was not in a loop, so it only feeds data into /etc/motd once, after I logout every SSH session, I can no longer login. Even local login fails because Linux would stuck forever reading the fifo /etc/motd.

I had to mount the disk into another machine and restore /etc/motd to normal.

Lessons learned, don't mkfifo /etc/motd.

[toast0]

Isn't motd only displayed on interactive login? You could probably have gotten back in if you did something like ssh foo "sudo rm /etc/motd"

[Symbiote]

I use this fairly often, when working on the image parts of our API (image caching, map tiles etc).

I tweaked the "img" script linked from the article to download and display an image, so I don't need to leave the terminal.

  img http://sipi.usc.edu/database/preview/misc/4.2.03.png

My result is this, in Konsole (KDE): http://i.imgur.com/34fjSas.png

[i336_]

Sad infodrop: the main reason this is a nonevent is because ncurses encodes fg/bg colors in an unsigned int. :(

[GTP]

I don't understand the problem, could you please elaborate?

[citrusui]

Serious question: will terminals ever support P3 color? Maybe that's too much to ask for?

https://webkit.org/blog/6682/improving-color-on-the-web/ https://webkit.org/blog-files/color-gamut/comparison.html

[nenreme]

Why P3? It is better to go directly to Rec. 2100 with HDR which is more future-proof.

[grp]

It only improves images, no?

[ziotom78]

What I think is really interesting in this is not the possibility to use 16 millions colors per se, but rather the ability to directly specify the RGB components of the color to use.

The current approach used by terminfo and ncurses is to refer to an index within a palette, which has the drawback of giving little guarantees about the final shade of the color. (Look at the color table here [1] for a comparison among different terminals; here it is stated that xterm changed the RGB components of two shades of blue from one version to another!)

Allowing true colors in terminals would make curses programming very similar to what you do in HTML and CSS, where you directly specify the color you want. It would surely be a nice improvement.

[1] https://en.m.wikipedia.org/wiki/ANSI_escape_code

[chipb]

Except you can already query/set the color palette to arbitrary RGB values with control sequences (at least with xterm, rxvt-unicode, and I imagine others).

As far as I've been able to tell, "truecolor" terminal support is about simultaneous display of a range of colors beyond what fits in a palette. Which, eh...seems a bit much for a terminal.

[octoploid]

Here is an image printing function for bash/zsh:

  function img { for image in "$@"; do convert -thumbnail $(tput cols) "$image" txt:- | awk -F '[)(,]' '!/^#/{gsub(/ /,"");printf"\033[48;2;"$8";"$9";"$10"m "}'; echo -e "\e[0;0m"; done ;}

Example: http://i.imgur.com/d5RzWAC.png

[Symbiote]

I think yours has stretched the image vertically, though it is simpler than the one linked in the article [1]. That uses "Upper Half Block" characters to give square pixels, and sets a foreground and background colour -- doing two rows at once.

With that, I see this: http://i.imgur.com/uqCHAmF.png

[1] https://git.gnome.org/browse/vte/tree/perf/img.sh?h=vte-0-36

[cooper12]

Just a note that this requires imagemagick.