libpng warning: Incorrect bKGD chunk length

Bug reports and questions about running Virtual Radar Server on Linux
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vezza
Posts: 5
Joined: Thu Dec 27, 2012 3:13 pm

libpng warning: Incorrect bKGD chunk length

Post by vezza » Thu Dec 27, 2012 4:38 pm

Hi!

when I try to start VRS on Linux I get the following error:

$ mono VirtualRadar.exe
libpng warning: Incorrect bKGD chunk length
libpng warning: Incorrect bKGD chunk length

and then i get back to the shell. My system is a Fedora 17 x86_64. I have both libpng.i686 and libpng.x86_64 installed. Any idea how to by-pass the problem and start VRS on Linux? Thanks!

agw
Posts: 2241
Joined: Fri Feb 17, 2012 3:20 am

Re: libpng warning: Incorrect bKGD chunk length

Post by agw » Fri Dec 28, 2012 6:12 pm

Sorry for the delay in replying - the two warnings that you're getting are probably not the reason why VRS isn't starting, they seem to come up as a matter of course. I think the library is just complaining about a couple of images that I'm using, I need to track down which ones are causing it and fix them.

Have you ever managed to start VRS on Fedora 17 or has it never managed to start up for you?

vezza
Posts: 5
Joined: Thu Dec 27, 2012 3:13 pm

Re: libpng warning: Incorrect bKGD chunk length

Post by vezza » Sat Dec 29, 2012 3:38 pm

agw wrote:Sorry for the delay in replying - the two warnings that you're getting are probably not the reason why VRS isn't starting, they seem to come up as a matter of course. I think the library is just complaining about a couple of images that I'm using, I need to track down which ones are causing it and fix them.

Have you ever managed to start VRS on Fedora 17 or has it never managed to start up for you?
It is the 1st time that I try to start VRS... never used before... I'm planning to buy an USB DVB-T receiver and connect VRS to it... Can I help you to track down which images are causing problems?

vezza
Posts: 5
Joined: Thu Dec 27, 2012 3:13 pm

Re: libpng warning: Incorrect bKGD chunk length

Post by vezza » Sat Dec 29, 2012 4:00 pm

By the way I attach a report generated with Gendarme (maybe it will help a bit)...
Gendarme_report.html.zip
(37.77 KiB) Downloaded 291 times
I never used Gendarme so It is possible I have generated an unusable report...

agw
Posts: 2241
Joined: Fri Feb 17, 2012 3:20 am

Re: libpng warning: Incorrect bKGD chunk length

Post by agw » Sun Dec 30, 2012 12:47 am

The PNG images aren't going to be the problem, it'll be something more fundamental. I've just installed x86_64 Fedora 17 on a VM and started VRS without a problem (aside from the usual warnings about those two PNGs). Which mono packages did you install?

EDIT: Regarding the gendarme report, all but 3 of the complaints are in DLLs that are either compiler-generated, come from Flight Simulator X or come from SQLite.org. The first two aren't called when VRS runs under mono, they're only shipped so that the mono runtime will load VirtualRadar.Library (it has hard links to them). The SQLite library is called but that'll be going when I do the work to get VRS running under Ubuntu 10. The remaining three complaints are about my code - one of the complaints is erroneous, i.e. gendarme is mistaken, and the other two are trivial and won't have a bearing on whether VRS will run under mono or not.

vezza
Posts: 5
Joined: Thu Dec 27, 2012 3:13 pm

Re: libpng warning: Incorrect bKGD chunk length

Post by vezza » Sun Dec 30, 2012 7:54 am

Thanks for the quick replies... On my system I have the followings mono packages installed:
# yum list installed mono*
  • mono-addins.x86_64 0.6.2-5.fc17 @fedora
    mono-addins-devel.x86_64 0.6.2-5.fc17 @fedora
    mono-basic.x86_64 2.10-4.fc17 @fedora
    mono-basic-devel.x86_64 2.10-4.fc17 @fedora
    mono-bouncycastle.x86_64 1.7-3.fc17 @fedora
    mono-cecil-flowanalysis.x86_64 0.1-0.17.20110512svn100264.fc17 @fedora
    mono-cecil-flowanalysis-devel.x86_64 0.1-0.17.20110512svn100264.fc17 @fedora
    mono-core.x86_64 2.10.8-2.fc17 @fedora
    mono-data.x86_64 2.10.8-2.fc17 @fedora
    mono-data-oracle.x86_64 2.10.8-2.fc17 @fedora
    mono-data-postgresql.x86_64 2.10.8-2.fc17 @fedora
    mono-data-sqlite.x86_64 2.10.8-2.fc17 @fedora
    mono-debugger.x86_64 2.10-3.fc17 @fedora
    mono-debugger-devel.x86_64 2.10-3.fc17 @fedora
    mono-devel.x86_64 2.10.8-2.fc17 @fedora
    mono-extras.x86_64 2.10.8-2.fc17 @fedora
    mono-icon-theme.noarch 1:4.9.4-1.fc17 @updates
    mono-locale-extras.x86_64 2.10.8-2.fc17 @fedora
    mono-mvc.x86_64 2.10.8-2.fc17 @fedora
    mono-mvc-devel.x86_64 2.10.8-2.fc17 @fedora
    mono-nat.x86_64 1.1.0-2.fc17 @fedora
    mono-nat-devel.x86_64 1.1.0-2.fc17 @fedora
    mono-nunit.x86_64 2.10.8-2.fc17 @fedora
    mono-nunit-devel.x86_64 2.10.8-2.fc17 @fedora
    mono-reflection.x86_64 0.1-0.4.20110613git304d1d.fc17 @fedora
    mono-reflection-devel.x86_64 0.1-0.4.20110613git304d1d.fc17 @fedora
    mono-tools.x86_64 2.10-5.fc17 @fedora
    mono-tools-devel.x86_64 2.10-5.fc17 @fedora
    mono-tools-monodoc.x86_64 2.10-5.fc17 @fedora
    mono-wcf.x86_64 2.10.8-2.fc17 @fedora
    mono-web.x86_64 2.10.8-2.fc17 @fedora
    mono-web-devel.x86_64 2.10.8-2.fc17 @fedora
    mono-winforms.x86_64 2.10.8-2.fc17 @fedora
    mono-winfx.x86_64 2.10.8-2.fc17 @fedora
    mono-zeroconf.x86_64 0.9.0-7.fc17 @fedora
    mono-zeroconf-devel.x86_64 0.9.0-7.fc17 @fedora
    monodevelop.x86_64 2.8.8.4-1.fc17 @updates
    monodevelop-debugger-gdb.x86_64 2.8.8.4-1.fc17 @updates
    monodevelop-devel.x86_64 2.8.8.4-1.fc17 @updates
    monodevelop-vala.x86_64 2.8.8.1-1.fc17 @updates
    monodoc.x86_64 2.10.8-2.fc17 @fedora

agw
Posts: 2241
Joined: Fri Feb 17, 2012 3:20 am

Re: libpng warning: Incorrect bKGD chunk length

Post by agw » Sun Dec 30, 2012 7:05 pm

What do you have for "yum list installed sqlite*"?

vezza
Posts: 5
Joined: Thu Dec 27, 2012 3:13 pm

Re: libpng warning: Incorrect bKGD chunk length

Post by vezza » Sun Dec 30, 2012 8:52 pm

# yum list installed sqlite*

sqlite.i686
sqlite.x86_64

agw
Posts: 2241
Joined: Fri Feb 17, 2012 3:20 am

Re: libpng warning: Incorrect bKGD chunk length

Post by agw » Mon Dec 31, 2012 4:36 am

If you could do mono -v VirtualRadar.exe > dump.txt and then after it fails to start PM or email me (my address is on the main site) the dump.txt file and I'll take a look, see if it gives a clue as to what's happening.

agw
Posts: 2241
Joined: Fri Feb 17, 2012 3:20 am

Re: libpng warning: Incorrect bKGD chunk length

Post by agw » Tue Jan 08, 2013 8:50 am

This turned out to be a clash on the port number being used - TomCat was listening to port 8080, which is the default port that VRS on Mono will try to listen to. I'll look at making it behave more gracefully when I come to improving Mono support, in the meantime if you find the Mono version halting with no exceptions when you start up then do this from the command line to see if anything else is listening to port 8080:

netstat -an | grep 8080

and then if you need to change the port create an InstallerConfiguration.xml as detailed here: http://www.virtualradarserver.co.uk/mono.aspx, making sure that you put the XML file into ~/.local/share/VirtualRadar.

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