$Id$

   o  Colour does not work with all backends and all terminals. I tested
      many terminal emulators and tried to summarise which combinations
      worked properly and which ones did not.

   o  I tested the following terminals:

         name             $TERM        $COLORTERM
        ------------------------------------------
         Linux console    linux
         pterm            xterm
         aterm            xterm        rxvt-xpm
         wterm            xterm        wterm-xpm
         Eterm            xterm        Eterm
         xterm            xterm
         gnome-terminal   xterm
         konsole          xterm
         mlterm           mlterm
         uxterm           xterm

   o  In most terminals, \e[3xm and \[4xm respectively set the foreground
      and background colours. x is an colour between 0 and 7 or the value
      9 for default value.

      \e[0m sets everything to normal, \e[1m sets bold, \e[5m sets blink
      and \e[7m sets inverse video.

      In ncurses, only 64 colour pairs are created, and A_BOLD (\e[1m) and
      A_BLINK (\e[5m) are used for foreground/background colour highlighting,
      hence creating 256 possible colour pairs.

      Different tests of blue on yellow:

      for invert in '' '\e[7m'; do
        for blink in '' '\e[5m'; do
          for bold in '' '\e[1m'; do
            echo -ne "$bold$blink$invert"'\e[34m\e[43m'hop'\e[0m '
            echo "($bold$blink$invert)"
          done
        done
      done

      Successfully works on:
       + Linux console
       + pterm
       + Eterm
       + aterm, wterm, rxvt

      Almost works on:
       + xterm (bright bg works for blue, but not for red or yellow)

      Fails on:
       + mlterm (no bright colours, neither fg nor bg)
       + gnome-terminal (no bright bg)
       + konsole (no bright bg, $blink really blinks)

   o  In an XTerm-compatible terminal, \e[9xm sets bright foreground and
      \e[10xm bright background colours. Unfortunately all terminals don't
      support these escape sequences. Here is a testcase:

      for fgpre in 3 9; do for fg in 0 4 2 6 1 5 3 7; do
        for bgpre in 4 10; do
          echo -ne '\e['$fgpre$fg'm'
          for bg in 0 4 2 6 1 5 3 7; do echo -ne '\e['$bgpre$bg'm# '; done
          echo -ne '\e[0m '
        done
        echo ''
      done; echo ''; done

      Successfully tested on:
       + gnome-terminal
       + konsole
       + xterm
       + pterm

      Failed (\e[9x and \e[10x don't work) on:
       + Eterm
       + aterm, wterm, rxvt
       + mlterm
       + linux

   o  S-Lang:

   o  MS-DOS: all bright colours, bright backgrounds, and bright combinations
      work using <conio.h>. No need to kludge anything.