ANN: xterm-369

[Thomas Dickey]

On Wed, Sep 22, 2021 at 09:41:41PM -0600, Grant Taylor wrote:
> On 9/22/21 5:48 PM, Thomas Dickey wrote:
> > it does.
> 
> Good.
> 
> > The problem is that when I inverted the sense of the sixelScrolling
> > feature to address this:
> > 
> >       * invert the sense of DECSDM, to correspond with VT382 manuals (lsix
> >         #41).
> 
> Hum....

More information is provided on the linked pages:

https://invisible-island.net/xterm/xterm.log.html
https://github.com/hackerb9/lsix/issues/41

The basic issue is that DECSDM was not documented properly in the VT340
manual (which was used for developing SIXEL and ReGIS features).

As a general rule, DEC terminal features are documented by indicating
the feature which will be enabled in a control sequence.  In this special
case, the control sequence for "setting" the mode actually disables the
feature.

Someone noticed that the (available) documentation for the Thai and Kanji
models of the VT382 gave some hints which disagreed with the VT340 manual.
Two of the three manuals have dates (one of the VT382 manuals does not).

The lsix developer investigated further and reported that the VT340
behaves consistently with the documentation for the VT382.

Since it is a minor feature, I changed the interpretation of the "set"
mode for DECSDM to agree, but overlooked changing the default value of
the resource.

Before/after the change, the resource value matches the sense of set/unset
for this mode.  But since the interpretation changed, the initial value
should be changed.  In the DEC manuals, this initial value is configured
by a persistent setup-screen, and the state where the scrolling is enabled
is documented as the default.

> > I overlooked changing the compiled-in default value for the resource.
> > 
> > You should be able to make it work (works for me) by adding this
> > resource setting:
> > 
> > 	*sixelScrolling:false
> 
> I had sixelScrolling set to true in my ~/.Xdefaults file.  I changed it to
> false, recompiled xterm-369, tested, and it worked.
> 
> What I'm surprised by is the meaning of sixelScrolling.
> 
> Per the man page, the sixelScrolling resource tells XTerm whether to scroll
> the terminal up one line at a time when Sixels would be written past the
> bottom line on the window.
> 
> I would think that's the behavior I want.  Very much akin to feed the paper
> on a continuous feed terminal when printing additional lines.  -- It's
> working, and I don't /need/ to understand the logic of it, much less DEC's
> when defining things years ago.
> 
> Do you have any thoughts on the similar symptoms for ReGIS?
> 
> Thank you for your efforts Thomas.
> 
> 
> 
> -- 
> Grant. . . .
> unix || die
> 



-- 
Thomas E. Dickey <dickey at invisible-island.net>
https://invisible-island.net
ftp://ftp.invisible-island.net