Re: modeline face under a tty

[Eli Zaretskii]

On Sat, 3 Nov 2001, Richard Stallman wrote:


>     What will we do if only one mode-line color is specified?
> 
> The idea I have in mind is that the colors will ALWAYS be specified
> (after face merging), in that they will never be `unspecified', but
> they might be unspecified-fg or unspecified-bg.

This is so already.  We never have `unspecified' for a color on a tty,
only "unspecified-fg" and "unspecified-bg".

What I meant by ``only one mode-line color is specified'' was this
situation: one color is "unspecified-?g", the other one is a color
name that is not "unspecified-?g".

Note that we must make sure that "unspecified-fg" _always_ stands for
the same color (namely, the unknown foreground color the terminal used
before Emacs started).  We cannot allow each face have a different
color called "unspecified-fg", because we have no other means but the
"op" capability to set the "unspecified-?g" colors.  The same goes for
"unspecified-bg".

> In such cases, the way to select that combination is to reset the
> terminal to the default mode, perhaps apply standout mode, then maybe
> specify one color.
> 
> For instance, for foreground=unspecified-bg and background=red,
> you reset to the default modes, apply standout mode, then specify
> red background.

One problem with this is that some terminals don't like stand-out and
color together.  The current code avoids tripping over this.

Another, related, issue is what do you store in the face structure
itself, and what do you want face-attribute to return for the
foreground and background color attributes, including in those cases
where some of the colors are not explicitly specified.