Re: [PATCH v2] Support 24-bit terminal colors.

[Rami Ylimäki]

2017-02-12 22:47 GMT+02:00 Eli Zaretskii <address@hidden>:

 . Please prepare a NEWS entry for this feature.
 . It seems like you dropped the code to support the --color=
   command-line argument, which was part of your original submission?
   All the other color TTY modes support --color=NUM, so I think we
   should also support --color=16777216, and perhaps also --color-24bit.

I'll write the NEWS entry but I'm afraid that fixing the --color=NUM option would require too much effort right now.

The manual is too optimistic when it states that "Emacs might be able to turn on a color mode for 8, 16, 88, or 256 as the value of NUM". In reality, only -1, 0 and 8 are supported. The 16, 88, and 256 color modes can only be enabled based on current terminal capabilities and this is now true for the 16M color mode as well.

The problems of handling --color=NUM can be seen when colors are downgraded, because color and face pixel values aren't updated. For example, "M-x list-faces-display" produces different results with "TERM=xterm emacs -Q -nw --color=8" and "TERM=xterm-256color emacs -Q -nw --color=8". This is why I'd like to treat the --color option as a separate issue.