Re: [PLUG] Smooth Scrolling Terminals

["Alan D. Salewski via plug" <plug@lists.phillylinux.org>]

On 2024-06-28 22:25:50, "Alan D. Salewski via plug" <plug@lists.phillylinux.org> spake thus:
> On 2024-06-23 17:21:07, Casey Bralla via plug <plug@lists.phillylinux.org> spake thus:
> > Back in ancient times, Fred Flintstone and I used DEC VT-100 terminals. 
> > These terminals had gorgeous smooth scrolling where the text floated
> > upward instead of jerking line by line.
> >
> > I assume somebody has written a smooth-scrolling terminal emulator, but
> > I haven't been able to find one easily.  The docs for xterm mention
> > smooth mode, but don't explain how to set it.
>
> Here's a clunky way to enable/disable it in xterm. There's probably
> a better way, but I couldn't find the knob:
[...]

...and my wife would tell you that I could not find the knob because
it was right there in front of me. Again.

The main thing for me to realize was that "smooth scrolling" and
"jump scrolling" are opposites, and the control knobs are mostly
named with "jump" in their name (as with "jumpScroll" below) or with
mnemonics suggesting a relationship to "jumping" (e.g., the '-j' and
'+j' options noted below). I'm guessing that "smooth scrolling" was
the default back in the day, and "jump scrolling" was added later;
hence the naming.

In addition to echoing (to xterm) the raw control sequences I
mentioned in my earlier message, there are (at least) three knobs to
enable or disable the behavior.

    1. The "Enable Jump Scroll" option xterm's "VT Options" menu

    2. The xterm '-j' and '+j' command line options

    3. The 'jumpScroll' X11 resource

For (1), you can toggle back and forth between "smooth scrolling"
and "jump scrolling" from within a running xterm. The "VT Options"
(vtMenu) popup menu is accessed via CTRL+<mouse-2>, and the "Enable
Jump Scroll" option can be either checked or unchecked. (On my
setup, <mouse-2> is the middle button on my wheel mouse.)

For (2), the xterm '-j' command option enables jump scrolling, and
the '+j' option disables jump scrolling (so thereby enables smooth
scrolling).

For (3), there are various ways to set X11 resources with different
amount of specificity, but having a line such as the following in
your ~/.Xresources file should do the trick:

    XTerm*jumpScroll:  false

To have the effect of that setting take effect within the current
X11 session, you would need to:

    $ xrdb -merge ~/.Xresources

Whew! That was fun  :-)
-Al

--
a l a n   d.   s a l e w s k i
ads@salewski.email
salewski@att.net
https://github.com/salewski
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