wheel mouse does not scroll screen at uniform speed

[p.stansell@…]

Sometimes, when trying to scroll down in a long document with many figures and
tables, the wheel-mouse scrolling become interminably slow (scrolling at about 1
text line per 10 "rotation clicks" of the mouse wheal). I have tried setting
"Lyx: preferences: scrolling: wheel mouse scroll" to very high values but it
seems to have no effect.

[Georg Baum]

Do youse the qt frontend? It does not use the preferences setting (#783). I
just fixed #2175, that means that the qt wide scroll wheel setting should
now be used, and the wheel mouse scrolling should be better now. Please apply
the patch I posted in #2175) if you built LyX from sources, and report if it
fixes the problem.

[p.stansell@…]

Yes, I use the qt frontend. I tried your fix and it was an
improvement in that it increased the scroll speed. However, setting
"preferences: scrolling: wheel mouse scroll" to values from 5 to 100
still has no effect on the scroll speed. Also, the scrolling is still
very inconsistent: sometimes a single wheel mouse "rotation-click"
scrolls by a whole page (normally it scrolls by just two
lines or so).

[Georg Baum]

As I wrote in comment 1: LyX uses the global scroll wheel setting of qt with
the patch for #2175. That means that you can change that with the qtconfig
program (the default is 3 lines). The setting in LyX has never had an effect
for the qt frontend (#783, only xforms used it). We will remove that setting
in the qt fronetend completely in the future, because LyX should behave like
all other qt apps.
It would be nice if you could attach an example document to this report that
shows the one-page scroll.

[p.stansell@…]

Example lyx file showing wheelmouse scrolling problem.

[p.stansell@…]

Thanks for helping with this (I didn't know that about qtconfig).

Attached is a tar file containing an example lyx and eps file which
shows the problem when using version of lyx-1.4.0 which has had the
patch for #2175 applied . If you unpack the tar file and open the
lyx document ./wheelMouseBug/wheelMouseBug.lyx. Scroll to the bottom
of the document and place the cursor at the end of the last line.
Then use the mouse to scroll backwards in the document. When I do
this a single "scroll click" of the mouse wheel scrolls a whole page
just after the figure.

[p.stansell@…]

I just tried version 1.4.1 of lyx on the example lyx file I provided in
comment #4, and it still shows the same scrolling bug. Please try to fix it.
Thanks.

[p.stansell@…]

I just tried version 1.4.3 of lyx on the example lyx file provided in
comment #4, and it still shows the same scrolling bug. I'm still
using lyx-1.3.7 to avoid this bug, but I'd really like to move to
lyx-1.4.3 for its new functionality, etc.

Can anyone give me any hints as to what is wrong or how I may try to
fix or diagnose the bug myself?

Thanks very much.

[muzzle@…]

try scrolling around chapter 4.3.1 and 4.3.2 of the User Guide (you can find it
in the Help menu).
You should find tht if you collapse and expand some of the table and image
floats, after a while the scrolling will become very skippy, expecially when
more than one float is expanded. Sometimes the cursor skips more that a whole
page aroundthe Units-for-image table, when it is opened.
Hope this helps,

Emme

[Georg Baum]

Paul,

nothing has changed regarding scrolling in 1.4.3. The code that sets the
scrollbar parameters is in BufferView::Pimpl::updateScrollbar(), file
src/BufferView_pimpl.C. It is not easy to get it right in all cases. Please
search the developer mailing list archives, we have discussed this problem
several times, and Martin Vermeer has explained the current code there. See
e.g. this thread:
​http://marc.theaimsgroup.com/?l=lyx-devel&m=113179000603409&w=2
Ask on the developers list if something is unclear. It would be very nice if
you had an idea how to make scrolling better.

[p.stansell@…]

As far as I can tell, I would say that smooth scrolling is broken in lyx-1.4.x
for both qt and xforms versions, but works fine in lyx-1.3.7 for both qt and
xforms version. Why might that be? Does it offer any clues?

[p.stansell@…]

Georg Baum said of the scrolling problem in lyx-1.4.x:

It has nothing to do with qt, but with the way the line height is calculated.
LyX 1.4.x uses a two-step drawing approach, where the total document
height is not known. LyX 1.3.x uses a single-step approach that had
several problems, therefore it was replaced by the two-step approach.
(Others can probably explain this better than I can.)

So, as I never noticed in scrolling problems with the one-step approach, my
question is: would it be possible to re-incorporate the one-step approach in
lyx 1.4.x?

[Georg Baum]

No, this is not possible. As I wrote: The one-step approach was replaced by the
two-step approach because it had some bigger problems than smooth scrolling.
Paul, I repeat myself: please ask further questions on the developers list.
They will not be seen here.

[younes]

Add target.

[hofbauer@…]

At least on the Mac this is still an issue in 1.5.4.

Especially when there are large tables etc. wheel mouse scrolling is
inpredictable, and in general too fast.

Also note that for the Mac there exists no QtConfig where one could change the
scroll speed.

[sts@…]

I implemented a preference option to set a wheel speed multiplier. At the moment it's set to 1 by default.
Personally I have set it to 0.1! Yes, ten times slower. Please check out 1.6 and try this. We can set a more
sensible default then on Mac.

[Juergen Spitzmueller]

LyX 1.6.0 is released.