Re: [Lynx-dev] Color in an Emacs terminal emulator (eterm)

[Thomas Dickey]

On Fri, 14 Oct 2005, Bryan Henderson wrote:

> > ok.  The "eterm" terminfo you sent would produce the same effect on xterm
> > or linux console, since the relevant parts (cursor move, clearing, etc)
> > behave the same on both.  But with a quick check on either xterm or Linux
> > console, I don't see the problem you reported.
>
> This suggests that Emacs isn't implementing the interface it describes
> in the eterm terminfo entry, right?  Like maybe Lynx is sending some

That's one of the possibilities - though I have a nagging sense that
I've seen this symptom in lynx at some point, reading the changelog
doesn't show me a case that I've fixed since 2.8.5, and it does work
for me.

One that comes to mind is whether your terminal is handling hard tabs,
and whether ncurses has been configured to use those.

> characters that should clear the left margin and Emacs isn't clearing
> it?  If you could do that ncurses trace and tell me what capabilities
> Lynx (via Ncurses) uses to effect the blank left margin, maybe I could
> remove those from my eterm definition and force Lynx to do something
> more primitive, like write spaces?  That would help isolate the problem.

I don't even have to do that.  The strings that do erasure are
the ones beginning with 'e': ed, el, el1

If the corresponding erasure code is missing, ncurses works around that,
e.g., clearing by writing spaces.

> Specifically, in http://netpbm.sf.net/doc/pnmtojpeg.html, the option
> descriptions are indented so that the paragraph under "exif=filename",
> for example, has 10 blank positions to the left of it.  The question
> is: what made those positions blank?  (When I do it in an eterm, they
> aren't blank; they contain whatever they did when the previous page
> was displayed).

You can see this readily using 'script' to capture a typescript file
and using some program such as unmap (in my ncurses ftp directory)
to make things printable.  I just tried that, to see and the only
erasure I see is at the end of the trace.  It's possible that my
configuration differs someplace - you could make a typescript like
that, and I could tell what's happening.

> Or maybe there is an Ncurses test program that would expose capabilities
> that don't do what they're supposed to.

tack does a reasonable job - though it's not necessarily easy to find
all of the ways a program can fail.

--
Thomas E. Dickey
http://invisible-island.net
ftp://invisible-island.net