Re: lynx-dev Re: size_change code

[Webmaster Jim]

On Wed, Mar 10, 1999 at 09:09:28AM -0600, Klaus Weide wrote:
> On Tue, 9 Mar 1999 address@hidden wrote:
> > In a recent note, Webmaster Jim said:
> > > Date: Tue, 9 Mar 1999 11:54:24 -0500
> > > Complete success would mean the full page as resized looks like it would
> > > if Lynx started at that size. I have tried combos of ^R, ^W, ^L without
> > > being able to get a usable screen after resize. The main symptom is
> > > that moving from link to link will land the cursor in the wrong place,
> > > redrawing text in the wrong position during the move.
> > I don't experience even a "partial" success; more like an incomplete
> > failure on either Solaris or OS/390.  After I resize the screen,
> > ^R and ^L simply allow me to alternate between two different
> > versions of garbled screen.
> Do these failures also occur when making the screen smaller, or only
> when making it larger than the initial size?

Both. I clipped some screen shots of a single page being resized; they
can be seen on: http://jim.spath.com/lynx/resize.html

> > And this is complicated even more because on startup Lynx (or perhaps
> > curses) fully respects the settings of environment variables LINES
> > and COLUMNS.  I find COLUMNS particularly useful when I want to format
> > a document to fit a particular printer; I'd dislike to see its
> > effectiveness eroded.
> On the other hand, for me on linux setting LINES or COLUMNS environment
> variables doesn't do anything.  Nor should it: that's what `stty rows NN'
> or `stty cols NN' are for, in case I really want to fake the screen size.
> I'd dislike to see *this* eroded, only to recognize some (on this system)
> unnecessary environment variables...

Unsetting LINES and COLUMNS allows lynx to resize after a couple ^L and
^R's. Some possible problem with the title being right flush, but a
lot better behaved. I don't think I've seen this technique in the Lynx
manual or help anywhere.

> I can't see any place where the lynx code checks for LINES or COLUMNS in
> the environment.  So it must be either the curses library code that
> checks them, or setting them could have the size effect of changing
> the termios (or equivalent) size info (a shell could do that, but I
> don't know of any that does).
> 
> > So, how should SIGWINCH interact with
> > LINES and COLUMNS?  Should catching SIGWINCH override and reset
> > the settings of LINES and COLUMNS on entry?  Should SIGWINCH be
> > honored only if LINES and COLUMNS were unset on entry?  Are there
> > useful intermediate alternatives?

If lynx is not using them, how can they be masked without user
intervention?
 
> The most useful behavior for me is if lynx continues to act as it does
> for me on linux with ncurses 4 - ignore the environment, they just
> duplicate information that can be gotten by system calls.

That would be fine if we can get this to work as built on other OS
flavors as well.
 
> Maybe the solution for those folks where resizing does not work is
> to *unset* LINES and COLUMNS before lynx starts.  As long as
> HAVE_SIZECHANGE is defined, lynx should (eventually) figure out the 
> screen dimensions.

see above.

++++++++++++++++++++++++++++
Marvin the Paranoid Android.