[okular] [Bug 410723] Freehand annotation jagged lines with stylus

[Rene]

https://bugs.kde.org/show_bug.cgi?id=410723

--- Comment #11 from Rene <rene.vanpaassen at gmail.com> ---
Could it be that somehow the path is created by both the xinput device and
the input fed to X's core pointer? That could explain sets of close points?

On Wed, 25 Sep 2019 at 01:10, <bugzilla_noreply at kde.org> wrote:

> https://bugs.kde.org/show_bug.cgi?id=410723
>
> --- Comment #10 from blackdovahbear at gmail.com ---
> (In reply to Oliver Sander from comment #9)
> > Created attachment 122832 [details]
> > Plot of the points of the spiky path
> >
> > I extracted the points of the problematic path from the pdf document, and
> > plotted them using gnuplot.  This gets us one step closer to an
> explanation:
> > As can be seen from the attached picture, each point is actually a pair
> of
> > points, a small distance apart. Together with a MiterJoin line style this
> > explains the jaggedness of the resulting path.
> >
> > [Currently I simply assume that MiterJoin line drawing is used, but I
> didn't
> > check. For a 'normal' set of points on a path you wouldn't see the
> > difference.]
> >
> > So the remaining task is to find out where these double points come
> from. My
> > system (which is a bleeding edge Okular on Debian Buster) doesn't produce
> > them. I am tempted to conjecture that the problem is somewhere in the
> lower
> > layers of the tablet input stack, and not in Okular itself.
>
> Thank you, Oliver. By the sounds of it, I do think you're correct about the
> origin of the error. It would make sense why the path would appear jagged
> and
> spiky because of the pair of joints. I'm not well-versed in these things
> and my
> understanding of it is lacking. So take my opinion with a grain of salt.
>
> However, I don't believe that the error is caused by the tablet itself. My
> drawing pad seems to work fine in other applications that are more geared
> towards drawing/art (Rene stated that it works fine for him in GIMP). This
> could happen because it uses a different method for tracking paths or could
> lead to an inconclusive idea that it is a problem with Okular.
>
> I would also like to mention that my drawing pad is of the same brand as
> Rene's
> but is a different model. I don't know how relevant that information is. I
> suppose it's possible that this is a bug that occurs with only Wacom
> tablets. I
> don't know how likely that would be.
>
> Drawing in Okular before I upgraded from Ubuntu 18.04 to Ubuntu 19.04, I
> had no
> issues. The error only came to be after upgrading my OS. This leaves me to
> believe (though I may be incorrect) that this isn't an issue with the
> drawing
> tablets but something else. I would also like to reiterate that this only
> occurred after upgrading my OS (the same thing happened in Rene's case). I
> don't know why that is but I do think that it's quite strange and could
> have
> something to do with the bug.
>
> --
> You are receiving this mail because:
> You reported the bug.

-- 
You are receiving this mail because:
You are the assignee for the bug.