lynx-dev Fun with character attributes in xterm (was: UTF-8 display questions)

[Klaus Weide]

On 13 Jun 2000, Sergei Pokrovsky wrote:

> >>>>> Klaus Weide writes:
> 
>   Klaus> On 12 Jun 2000, Sergei Pokrovsky wrote:
> ...
>   Klaus> Hmm, and since you are using slang, you may want to
>   Klaus> experiment with the '-blink' flag to lynx.
> 
> I observe that everything becomes bold.  Not bad, but in fact that is
> not very good, because my bold face is a bit less rich than the meager
> one (e.g. it lacks quantifiers, logical connectors etc).

Yes, same difference between the fonts here.

I think you can coerce xterm to use overstriking of the non-bold font,
rather than a separate bold font, for 'bold'.  Of course the results
would look less pretty.

There is even the possibility that xterm would fall back to overstriking
automatically, only for those characters that are not present in the
bold font.  I've seen some dicussion of this somewhere, I am not sure
whether it is implemented (and if yes, in which version, and how to
turn it on if that's necessary).  Maybe Tom can help us out here.

Now all this may not be relevant here anyway, since we are now talking
about the 'blink' attribute and not the 'bold' attribute...
For this, I find in
   Linkname: XTERM - Change Log
        URL: http://dickey.his.com/xterm/xterm.log.html
the following:
     * add support for blinking text.
          + This does not actually cause the text to flash, but text with
            the blink attribute can be displayed in color, using new
            resources colorBL and colorBLMode.
          + If colors are not used, the blinking text will be displayed
            as before (just like bold). The main purpose of this is to
            make applications work properly when they assume the emulator
            supports blinking text.

I don't know according to which logic text with 'blink' attribute ends
up being displayed with the bold _font_, but apparently that's what
is happening.  The above quote, and the man page, don't seem to
indicate this.

(I have verified that it isn't lynx which somehow converts 'blink'
to 'bold' - strace says that "\e[5m" gets written to the tty.)

> But this gives me an idea: by inverting the convention and defining

Congratulations!  

> COLOR:0:gray:white
> COLOR:4:black:white
> 
> I obtain the bold face for the main text, and the meager face for the
> emphasized (and my math happens to be emphasized).  That gives a
> better way to distinguish among emphasis (by the heaviness, and that
> in a non-unusual way, as italics often are lighter than the plain
> face), and the anchors (which are distinguished with the color). 

I take it that this is without the '-blink'?  (With it, I see both
COLORs 0 and 4 as the same - except for underlining if I don't use
'-nounderline'.)

Now, if I change the "white" in your COLORs 0 and 4 to "lightgray",
I get your effect whether I use '-blink' or not...

(-blink affects only COLORs where the specified background is
from the second half of the list.)

Of course, your trick is only useful as long as the "math happens to
be emphasized".  It dosn't work well for <http://
www.esperanto.mv.ru/KompLeks/UTF8/UNIKP.html>, for example.
So it would still be useful to figure out how to make xterm use
character from the non-bold font for 'bold'ing.

>   Klaus> And see what happens after you "LYNXCFG://reload".  (Just
>   Klaus> trying to make sure that your inexhaustible source won't dry
>   Klaus> up soon...)
> 
> I do not see anything special.  OK, your idea really was a source of
> innocent merriment, but probably in a different way than you
> expected.

Reloading the COLOR settings "forgets" the additional underlining of
COLORs 4 and 5...  So if you didn't know about -nounderline (or if
you hadn't read my mind when I wrote something else when I meant
"-underline" :) ), you could use LYNXCFG://reload as a startpage...

>   >> - emphasis is sometimes rendered with the color only (which I'd
>   >> prefer), or is combined with underline (which I'd rather turn
>   >> off, but don't know how to do it).
> 
>   Klaus> lynx -nocolor suppresses that.
> 
> Probably you mean -nounderline

Indeed.

>   Klaus> (cont'd in another message)
> 
> Yes, see there about the horrible effects of your imprudent
> misadvice ...

Oh, more fun...

  Klaus


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