[arch-general] Help needed to find a system/graphics related bug in my Music Notation Editor. (Little time and effort for you)

[Nils]

Thank you very very much for that information! 
This problem is the last piece before I can do my first (alpha) release.
With xrandr --fbmm I could reproduce the error on the first try so I can do further tests myself now.

And it really is a font issue. The lines in the display are correct but my fonts are not, not even the menu fonts.

I will contact the PyQt or Qt community now to find out how to fix that.
One already contacted me and notified me of a commandline parameter "-graphicssystem raster" which I have not tried yet. But the person also told me that this is a only workaround.

I am excited to finally find a solution for this longstanding problem.

Nils





On Thu, 19 Jan 2012 20:30:19 +0100
Thomas Jost <schnouki at schnouki.net> wrote:

> On Thu, 19 Jan 2012 20:12:28 +0100, Thomas Jost <schnouki at schnouki.net> wrote:
> > On Thu, 19 Jan 2012 19:35:59 +0100, Nils <list at nilsgey.de> wrote:
> > > Hello list!
> > > 
> > > I hope this is not offtopic and I hope to find help here because Archlinux has python3 as default python. 
> > > 
> > > I have a software, a Music Notation Editor,  here that can start in a one-liner and I need to find a bug that only occurs on some systems.
> > > 
> > > git clone git://github.com/nilsgey/Laborejo.git && cd Laborejo && ./laborejo-qt.sh
> > > 
> > > This will download and run my software Laborejo as normal user without installing anything. The only modifications to your system are new dir .laborejo in your home directory and the downloaded files via git. The only dependency is pyqt and git to download it 
> > > 
> > > You will see 5 lines and a symbol. The symbol must be perfectly alingned within the five lines (one pixel above can be tolerated). It should look like this: http://www.wargsang.de/pyqt-bug-report.jpg
> > > Do you see that symbol shifted up or down or is it correct?
> > > 
> > > Could you please answer me with the following information attached: Your graphic driver (type ("ati, nvidia, intel" etc. and closed or open source?) and desktop enviroment/window manager (Gnome, KDE, xfce, i3 etc.). If you want to add more information like qt version or X-Server it would be nice as well. Everything display related helps:
> > > I believe closed nvidia drivers will shift the symbol. I tested it myself on ati and intel graphics, both 32 and 64 bit and it looked good, both on Linux and Windows. Other users with ati and intel GPU's had no problem. But two persons with an nvidia card had the wrong display. 
> > > 
> > > It would be very nice to hear from you!
> > > 
> > > Nils
> > > http://www.laborejo.org
> > > 
> > > *The only modifications to your system are new dir .laborejo in your home directory and the downloaded files via git.
> > 
> > Hi Nils,
> > 
> > First, your program looks really good :) A few years ago I tried using
> > Lilypond but since I knew nothing about TeX/LaTeX/whatever at that time
> > I found it very difficult.
> > 
> > So here's a screenshot of how it looks like on my machine:
> Non-text part: image/png
> > 
> > Python 3.2.2, Qt 4.8.0, pyqt 4.9. Using the proprietary nvidia driver
> > (290.10), no desktop environment (Awesome WM), xorg-server 1.11.3.
> > 
> > If that can help I could try using the "nouveau" driver too.
> > 
> > Maybe I'm completely wrong, but that could be a screen resolution issue.
> > 
> > AFAIK, most Xorg drivers can detect the screen resolution (in dots per
> > inch) correctly. However they then "lie" about it and report 96x96 dpi,
> > whatever the real value is. (They do this to mimick Windows behaviour,
> > which always consider any screen to be 96x96 dpi so that developers who
> > don't understand resolution can still get something to work -- more
> > details on https://bugs.freedesktop.org/show_bug.cgi?id=23705).
> > 
> > However, the proprietary nvidia driver does *not* do this: it only
> > reports the *real* resolution, and not 96x96. For example right now on
> > my laptop:
> > 
> >   $ xdpyinfo | grep resolution
> >     resolution:    129x127 dots per inch
> > 
> > (I discovered this when switching to the "nouveau" driver, which also
> > lies about the real resolution -- my fonts looked weird until I added a
> > call to xrandr in my .xinitrc to "fix" the reported resolution...)
> > 
> > So if you're using pixel-based placement for a part of your UI and
> > point-based placement for other parts (hence depending on the
> > resolution), you may very well end with errors like the one I just
> > experienced.
> > 
> > You may try playing with "xrandr --fbmm" to change the reported
> > resolution of your screen if that can help. Unfortunately it doesn't
> > work with the nvidia driver, but again, if you want (and if my
> > hypothesis sound reasonable to you) I can try with the "nouveau" driver
> > and see if it changes anything.
> > 
> > Hope that helps :)
> > 
> > Regards
> > 
> > -- 
> > Thomas/Schnouki
> 
> Hi again :)
> 
> Did some more testing using the nouveau driver and playing with "xrandr
> --fbmm" to change the Xorg resolution.
> 
> 129x129 (autodetected) in laborejo-129x129.png, 213x267 (random values
> :)) in laborejo-213x267.png, 96x96 in laborejo-96x96.png. Now I'm pretty
> sure that's the issue :)
> 
> Good luck to solve that!
> 
> Best regards,
> 
> -- 
> Thomas/Schnouki