Re: Invisible form fields w/ ncurses-5.7 on Fedora

[Thomas Dickey]

On Fri, 12 Aug 2011, Grant Edwards wrote:

> I'm sure it's something I'm doing wrong in my application, but I can't
> figure out what it might be.
>
> I've got an app that's worked fine for 10 years, but a customer using
> Fedora Linux reports that starting about a year ago the form fields
> disappeared (other text written on the same panel is there, but the
> form's data fields are invisible).  I'm actually not sure whether the
> form fields are invisible, inactive, or completely absent.  The cursor
> doesn't seem to navigate between fields, so it could be that the
> fields are completely missing or inactive.
>
> I reproduced the problem on Fedora 14[1] using gnome terminal 2.32.0
> and ncurses 5.7.  Changing the gnome terminal's foreground/background
> colors didn't help.
>
> The same application built on Gentoo with ncurses 5.7 works fine with
> gnome terminal 2.32.1 (and about a half-dozen other terminals with
> various foreground/background settings).
>
> What could I be doing wrong that would have caused form fields to go
> invisible/missing on Fedora but not other distros?

Offhand - I've done occasional bug-fixes for forms, but as usual most of 
the attention's on the base ncurses library.  "5.7" could (in most 
distributions) be any development snapshot between 5.7 release and 5.8 
release (5.9 recommended...).  As I recall it, most of the distributions 
are exercising various configure options that I've provided, not making 
patches to the code.  Knowing the patch level is a good start.

I have virtual machines for Fedora 14 and 15 (which I usually use via ssh 
to run uxterm...).  Gentoo's too much involvement, iirc. So I might be 
able to reproduce the problem.  The cause of the problem might be visible 
in an ncurses trace for instance, but tracing generally isn't configured 
in the distributions.

The "cursor doesn't navigate" comment doesn't seem to reflect on
whether it's gnome-terminal (which has a number of display defects
in every release) or some other terminal type.  If the cursor's not
being hidden, you should be able to see it move around.  But you seem
to be commenting on the problem reproducing only in gnome-terminal.

So... is it possible for me to test your application (or is that not 
feasible for whatever reason)?

A quick way to check it without direct access to the application would be 
to run the application in "script", capturing the typescript.  I can test 
the typescript by playing it back, to see what's on the screen - and how 
the cursor moves around in your test.  (There's a copy of slowcat in my
ftp area for ncurses - basically the typescript could be replayed on a
comparable terminal with the same screensize).

> [1] I initially tried to duplicate the problem using Fedora 15 but
>    found the new desktop to be so unusable I gave up.  There's
>    probably a way to install Fedora 15 w/ LXDE or XFCE, but I know
>    the customer reporting the problem is running Gnome.

Sadly, the worst desktop that I've heard of recently won't run in the
virtual machine that I set aside for it.  It's preventing me from
viewing some interesting bugs ;-)

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