[okular] [Bug 377493] New: Music staff notation is often impossible to read due to object placement and line spacing

[Tom]

https://bugs.kde.org/show_bug.cgi?id=377493

Bug ID: 377493
Summary: Music staff notation is often impossible to read due
to object placement and line spacing
Product: okular
Version: unspecified
Platform: Other
OS: Linux
Status: UNCONFIRMED
Severity: normal
Priority: NOR
Component: PDF backend
Assignee: okular-***@kde.org
Reporter: tho7maspenguin+***@gmail.com
Target Milestone: ---

Created attachment 104505
--> https://bugs.kde.org/attachment.cgi?id=104505&action=edit
Tar of some examples and the source PDF

I use Okular to read scores a lot, but have noticed a couple of problems which
cause misreadings.

1) Note heads have ambiguous placements as shown in '100 percent.png' and 'step
up.png'. If they aren't either on the line or in the middle of two lines, they
are very confusing to read.

2) When zoomed out, the lines have uneven distances, making some patterns hard
to read. Maybe this could be sorted with dithering?

This seems to be a problem in PDFs exported from multiple notation programs.
Attached is a MuseScore example. Google document viewer seems to handle scores
better but not perfectly.

[Jaime Torres]

https://bugs.kde.org/show_bug.cgi?id=377493

--- Comment #1 from Jaime Torres <***@gmail.com> ---
Created attachment 116369
--> https://bugs.kde.org/attachment.cgi?id=116369&action=edit
screenshots of the same places as before

[Jaime Torres]

https://bugs.kde.org/show_bug.cgi?id=377493

Jaime Torres <***@gmail.com> changed:

What |Removed |Added
----------------------------------------------------------------------------
CC| |***@gmail.com
Resolution|--- |FIXED
Status|REPORTED |RESOLVED
Keywords| |triaged

--- Comment #2 from Jaime Torres <***@gmail.com> ---
With okular 1.6.70 and KDE Frameworks 5.53.0, Qt 5.11.2 and xcb I get render
shown in the screenshots.

[Yuri Chornoivan]

https://bugs.kde.org/show_bug.cgi?id=377493

Yuri Chornoivan <***@ukr.net> changed:

What |Removed |Added
----------------------------------------------------------------------------
CC| |***@ukr.net

--- Comment #3 from Yuri Chornoivan <***@ukr.net> ---
It can also depend on PDF backend configuration. It is worth to try all three
options of rendering to choose the one which works the best for you.

https://docs.kde.org/trunk5/en/kdegraphics/okular/config-pdf.html

[Tom]

https://bugs.kde.org/show_bug.cgi?id=377493

Tom <tho7maspenguin+***@gmail.com> changed:

What |Removed |Added
----------------------------------------------------------------------------
CC| |tho7maspenguin+***@gmail.co
| |m

--- Comment #4 from Tom <tho7maspenguin+***@gmail.com> ---
Created attachment 116410
--> https://bugs.kde.org/attachment.cgi?id=116410&action=edit
.tar.gz of some KolourPaint-scaled .pngs for comparison

The new screenshots do look different, but the problems are still there to
varying extents.

I can't try out other back-ends or make detailed examples just yet as I don't
have a properly functional desktop system installed right now, but will try to
do that soon.

‘100 percent_fixed.png’ is no longer ambiguous, but all the notes look a little
bit too high up on the staff. Something that could be adjusted to, but it's
still not quite right.

‘line spacing_fixed.png’ has much better spacing, but the first ledger line
looks very odd due to the double thickness.

In ‘step up_fixed.png’, the placement has become even more ambiguous — 3 out of
5 notes would now be misread due to being shown a step higher.

I've screenshotted the file as displayed at 400% zoom, and used KolourPaint to
smooth scale it to the sizes in the examples. This scaling may be inaccurate as
I'm on an older version of Okular. This type of scaling results in more
readable scores, but then the dithered lines look very odd.

Could I suggest marking this as unresolved? I'll try to get some proper
examples posted soon.

[Yuri Chornoivan]

https://bugs.kde.org/show_bug.cgi?id=377493

Yuri Chornoivan <***@ukr.net> changed:

What |Removed |Added
----------------------------------------------------------------------------
Resolution|FIXED |---
Status|RESOLVED |REPORTED

[Jaime Torres]

https://bugs.kde.org/show_bug.cgi?id=377493

--- Comment #5 from Jaime Torres <***@gmail.com> ---
Created attachment 116412
--> https://bugs.kde.org/attachment.cgi?id=116412&action=edit
As another reference. The same pdf as rendered by chrome pdfjs viewer

[Jaime Torres]

https://bugs.kde.org/show_bug.cgi?id=377493

Jaime Torres <***@gmail.com> changed:

What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Status|REPORTED |CONFIRMED

--- Comment #6 from Jaime Torres <***@gmail.com> ---
Oh, I can see now that the problem is still there (two different notes on the
same vertical space), specially when the zoom is lower than 100% (I didn't saw
it last time, I need new glasses).