Re: jumpy scrolling on the Mac

I was planning of trapping the mousewheel event (SEL_MOUSEWHEEL)
and toggle between SCROLLERS_DONT_TRACK and  SCROLLERS_TRACK but
it doesn't seem to be possible, the call to SEL_MOUSEWHEEL just
gets ignored..




-----Original Message-----
From: [email protected] <[email protected]> 
Sent: Tuesday, May 21, 2024 2:19 PM
To: [email protected]
Cc: [email protected]; [email protected]
Subject: Re: [Foxgui-users] jumpy scrolling on the Mac

On 2024-05-21 12:23, John Selverian wrote:
> I passed SCROLLBAR_WHEELJUMP and it was the same and the
vertical 
> scroll disappeared.
> 
> I used SCROLLERS_DONT_TRACK and this works! It jumps by 1 line
each 
> time and there is no blurring/smearing...I assume that is what
you 
> meant.

SCROLLERS_DONT_TRACK makes the scroll area (your scrollable list,
in this
case) ignore the SEL_CHANGED messages, and only handle the
SEL_COMMAND one.  So as you're dragging scrollbars, contents stay
put until you stop moving and release the mouse button.

SCROLLBAR_WHEELJUMP affects only mouse wheel movement.  It skips
the animation part and jump-scrolls straight to the scroll
position the wheel would ultimately land on [e.g. a whole number
of wheel lines further].  The animation serves no purpose other
than user-feedback.

But the SCROLLERS_DONT_TRACK might be too much in that you won't
see interactive scrolling at all.

One note, as you're dragging the scrollbar, keep in mind that
modern mice may sometimes have very high report-rates.  I think
the logitech g300s I'm using right now can push up to 1000
updates/second.  For scrolling this may be overkill as you're
seeing only 60 changed images/second, or maybe slightly more on
high-refresh-rate monitors.  A few very high-end screens may go
to 120, or even 240, but I have not seen anything beyond that.

If you can control it [you can configure it with the g300s mouse]
you can try dropping the report rate.  Things may actually work
better at lower rates...

Note, report rates and dpi rates are not the same thing.  dpi
rates pertain to mouse accuracy, or pixels/inch movement.  Report
rate is position update transfers/second.

I have an older logitech which has only like 120/second rate and
it always felt very smooth; higher rates just cause more workload
on CPU w/o a lot of benefit; as long as you're above screen
refresh rate it works very well.




        -- JVZ