[Mono-dev] Problem with PNG transparancy on current Debian Unstable

Benjamin Schieder benjamin at anderdonau.de
Tue Jun 9 14:08:48 UTC 2015 

I'm pretty much happy that I got a usable workaround.

Also, those bugs don't actually exist so it'd be difficult for someone 
with literally zero knowledge about the internal workings of libgdiplus 
or mono to do either.

https://bugzilla.xamarin.com/show_bug.cgi?id=324503
https://bugzilla.xamarin.com/show_bug.cgi?id=426305


Am 2015-06-09 15:59, schrieb Andres G. Aragoneses:
> Good job, now you should file the bug in http://bugzilla.xamarin.com/
> and find a way to fix the bug in a way in which it doesn't make bug
> 426305 or 324503 reappear.
> 
> On 09/06/15 13:09, Benjamin Schieder wrote:
>> I have found the bad commit (and learned how to use git bisect in the
>> process):
>> 
>> [01:04:04][blindcoder at flora:~/Downloads/libgdiplus]$ git bisect bad
>> 59ca17e56adb8555e9b4e0960b771f2849f6366f is the first bad commit
>> commit 59ca17e56adb8555e9b4e0960b771f2849f6366f
>> Author: Dick Porter <dick at acm.org>
>> Date:   Thu Mar 31 16:02:19 2011 +0100
>> 
>>      Don't premultiply PNG images on loading, no other format does 
>> this.
>> 
>>      When drawing images, except when drawing onto a memory bitmap,
>> premultiply
>>      if needed.
>> 
>>      Fixes bug 426305, without breaking bug 324503.
>> 
>> :040000 040000 bc4a7075f87afdb5dc6e67c859cd82b06876d29e
>> cf1cea632be730ad978409f224766097ba1382ea M    src
>> [git:(59ca17e...)|BISECTING][A:0][D:0][M:1][?:5]
>> 
>> If I check out 059ca56800ccca8249260fac5e9e8b45291b8237, the
>> transparency is fine.
>> When I update to 59ca17e56adb8555e9b4e0960b771f2849f6366f, the
>> transparency is incorrect.
>> 
>> Kind regards,
>> Benjamin
>> 
>> Am 2015-06-09 12:45, schrieb Alexander Köplinger:
>> 
>>> There aren't that many commits for pngcodec.c in the last 4 years
>>> (which is when 2.10 was tagged), so it's probably one of those:
>>> https://github.com/mono/libgdiplus/commits/master/src/pngcodec.c .
>>> Shouldn't be too hard to figure out which one broke your scenario.
>>> 
>>> -- Alex
>>> 
>>> > To: knocte at gmail.com
>>> > Date: Tue, 9 Jun 2015 12:31:43 +0200
>>> > From: benjamin at anderdonau.de
>>> > CC: mono-devel-list at lists.ximian.com
>>> > Subject: Re: [Mono-dev] Problem with PNG transparancy on current
>>> Debian Unstable
>>> >
>>> > Alright, I compiled libgdiplus 2.10 and put it into /opt/libgdiplus2.10/
>>> > I then did the following:
>>> > LD_LIBRARY_PATH=/opt/libgdiplus2.10/lib/
>>> > export LD_LIBRARY_PATH
>>> > ./transparancy.exe
>>> >
>>> > And it works fine. So I guess there is a regression somewhere in
>>> > libgdiplus between 2.10 and today.
>>> >
>>> >
>>> > Am 2015-06-09 12:17, schrieb Benjamin Schieder:
>>> > > I have this version on squeeze:
>>> > > ii libgdiplus 2.10-3+b1
>>> > > armel interface library for System.Drawing of Mono
>>> > >
>>> > > And this version on unstable:
>>> > > ii libgdiplus
>>> > > 3.12-0xamarin1+jpeg62.1 amd64 interface library
>>> > > for System.Drawing of Mono
>>> > >
>>> > > I'll try to compile a 2.10 version of libgdiplus, but that's a lot of
>>> > > difference and probably way above my head to bisect correctly.
>>> > >
>>> > > Am 2015-06-09 11:50, schrieb Andres G. Aragoneses:
>>> > >> You could check what version of
>>> > >> libgdiplus(https://github.com/mono/libgdiplus) did Debian Squeeze
>>> > >> include, and try to run a custom new mono built from sources, with an
>>> > >> older libgdiplus, to confirm that it is a libgdiplus regression.
>>> If it
>>> > >> is, then after that you could try to bisect the commit that
>>> caused it.
>>> > >>
>>> > >> On 09/06/15 11:40, Benjamin Schieder wrote:
>>> > >>> Hello Alex.
>>> > >>>
>>> > >>> I have followed those instructions and done a dist-upgrade, but
>>> after
>>> > >>> re-compiling with mcs the problem persists unchanged. I have the
>>> > >>> following versions now:
>>> > >>>
>>> > >>> [11:38:29][blindcoder at flora:~/Downloads/PZ/MapMap]$ mcs --version
>>> > >>> Mono C# compiler version 4.0.1.0
>>> > >>> [11:38:34][blindcoder at flora:~/Downloads/PZ/MapMap]$ mono --version
>>> > >>> Mono JIT compiler version 4.0.1 (tarball Thu May 28 09:08:28 UTC
>>> > >>> 2015)
>>> > >>> Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors.
>>> > >>> www.mono-project.com
>>> > >>> TLS: __thread
>>> > >>> SIGSEGV: altstack
>>> > >>> Notifications: epoll
>>> > >>> Architecture: amd64
>>> > >>> Disabled: none
>>> > >>> Misc: softdebug
>>> > >>> LLVM: supported, not enabled.
>>> > >>> GC: sgen
>>> > >>> [11:38:37][blindcoder at flora:~/Downloads/PZ/MapMap]$ cli --version
>>> > >>> Mono JIT compiler version 4.0.1 (tarball Thu May 28 09:08:28 UTC
>>> > >>> 2015)
>>> > >>> Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors.
>>> > >>> www.mono-project.com
>>> > >>> TLS: __thread
>>> > >>> SIGSEGV: altstack
>>> > >>> Notifications: epoll
>>> > >>> Architecture: amd64
>>> > >>> Disabled: none
>>> > >>> Misc: softdebug
>>> > >>> LLVM: supported, not enabled.
>>> > >>> GC: sgen
>>> > >>>
>>> > >>> Kind regards,
>>> > >>> Benjamin
>>> > >>>
>>> > >>> Am 2015-06-09 11:07, schrieb Alexander Köplinger:
>>> > >>>
>>> > >>>> It works fine here with latest Mono 4.0.1.44 on Ubuntu. Can you try
>>> > >>>> upgrading to latest Mono from Xamarin by following
>>> > >>>>
>>> http://www.mono-project.com/docs/getting-started/install/linux/#debian-ubuntu-and-derivatives
>>> 
>>> > >>>> ?
>>> > >>>>
>>> > >>>> I suspect this has something to do with libgdiplus (the native
>>> > >>>> library
>>> > >>>> most of the System.Drawing code calls into).
>>> > >>>>
>>> > >>>> -- Alex
>>> > >>>>
>>> > >>>> > To: mono-devel-list at lists.ximian.com
>>> > >>>> > Date: Tue, 9 Jun 2015 10:15:02 +0200
>>> > >>>> > From: benjamin at anderdonau.de
>>> > >>>> > Subject: [Mono-dev] Problem with PNG transparancy on current
>>> Debian
>>> > >>>> Unstable
>>> > >>>> >
>>> > >>>> > Hello.
>>> > >>>> >
>>> > >>>> > I have a problem with PNG transparancy in mono on current Debian
>>> > >>>> > Unstable.
>>> > >>>> > I created a small example (4 kB download) with minimal code
>>> and two
>>> > >>>> > example images:
>>> > >>>> > https://oc.anderdonau.de/index.php/s/VwTAlcjETG6j3XP
>>> > >>>> >
>>> > >>>> > Running this example on a current Debian Unstable results in
>>> this - bad
>>> > >>>> > - image:
>>> > >>>> > https://oc.anderdonau.de/index.php/s/AtVtba0tpSk4bn8
>>> > >>>> >
>>> > >>>> > Running the same code on an old Debian Squeeze (on armel)
>>> results in
>>> > >>>> > this - correct - image:
>>> > >>>> > https://oc.anderdonau.de/index.php/s/eqhmXh9qpBbg0WW
>>> > >>>> >
>>> > >>>> > Can someone help me with this issue?
>>> > >>>> >
>>> > >>>> >
>>> > >>>> > Kind regards,
>>> > >>>> > Benjamin
>>> > >>>> > --
>>> > >>>> > Jabber: blindcoder at jabber.ccc.de
>>> > >>>> > Twitter: https://twitter.com/blind_coder
>>> > >>>> > Web: http://www.benjamin-schieder.de/
>>> > >>>> > _______________________________________________
>>> > >>>> > Mono-devel-list mailing list
>>> > >>>> > Mono-devel-list at lists.ximian.com
>>> > >>>> > http://lists.ximian.com/mailman/listinfo/mono-devel-list
>>> > >>>
>>> > >>> Jabber: blindcoder at jabber.ccc.de <mailto:blindcoder at jabber.ccc.de>
>>> > >>> Twitter: https://twitter.com/blind_coder
>>> > >>> Web: http://www.benjamin-schieder.de/
>>> > >>>
>>> > >>>
>>> > >>> _______________________________________________
>>> > >>> Mono-devel-list mailing list
>>> > >>> Mono-devel-list at lists.ximian.com
>>> > >>> http://lists.ximian.com/mailman/listinfo/mono-devel-list
>>> > >>>
>>> > >>
>>> > >>
>>> > >> _______________________________________________
>>> > >> Mono-devel-list mailing list
>>> > >> Mono-devel-list at lists.ximian.com
>>> > >> http://lists.ximian.com/mailman/listinfo/mono-devel-list
>>> >
>>> > --
>>> > Jabber: blindcoder at jabber.ccc.de
>>> > Twitter: https://twitter.com/blind_coder
>>> > Web: http://www.benjamin-schieder.de/
>>> > _______________________________________________
>>> > Mono-devel-list mailing list
>>> > Mono-devel-list at lists.ximian.com
>>> > http://lists.ximian.com/mailman/listinfo/mono-devel-list
>> 
>> Jabber: blindcoder at jabber.ccc.de <mailto:blindcoder at jabber.ccc.de>
>> Twitter: https://twitter.com/blind_coder
>> Web: http://www.benjamin-schieder.de/
>> 
>> 
>> _______________________________________________
>> Mono-devel-list mailing list
>> Mono-devel-list at lists.ximian.com
>> http://lists.ximian.com/mailman/listinfo/mono-devel-list
>> 
> 
> 
> _______________________________________________
> Mono-devel-list mailing list
> Mono-devel-list at lists.ximian.com
> http://lists.ximian.com/mailman/listinfo/mono-devel-list

-- 
Jabber: blindcoder at jabber.ccc.de
Twitter: https://twitter.com/blind_coder
Web: http://www.benjamin-schieder.de/

More information about the Mono-devel-list mailing list