[conspire] PNG troubles

[Ruben Safir]

On Tue, Jul 31, 2018 at 10:21:42PM -0700, Rick Moen wrote:
> Quoting Ruben Safir (ruben at mrbrklyn.com):
> 
> > It seems that the gimp mangles PNG files again
> 
> Were you going to relate the rest of this?  As stated, this claim is
> impossible to examine or say anything but 'oh', about.  So:  Oh.
> OTOH, if you just wanted an expression of sympathy without people having
> any understanding of what you're talking about, please consider it granted!
> 
> 

There has been a history that the PNG libraries have broken image
rendering of the previous libraries.  Ten years ago or so this happened
because a bug was developed in the Free Software libpng and when they
closed the bug, a great portion of my images stopped rendering and
became useless, especially the early NYLXS and Linux World Expo images,
and 911 images I had converted to png format.

Now this seems to have happened again.  the GIMP and libpng can't render
images, such as the one I posted, with the latest libraries.  So now
a large number of my images that I took in 2007 of my family and
Brooklyn as it was transforming has stopped rendering.  I a few months
they won't work anywhere.

They had aa couple of tools called optpng and few others that were
suppoded to fix these broken images.  Those tools failed to work on a
large number of the images.

I then proceded to attempt to right a program to fix them myself in C++.
I never really finished it.  It was an assignment for school where I was
trying to use the new C++ threads.  I had trouble getting the shared
memory to be accessable to multiple threads, but I did get low access to
the files.  
... but that is an aside.

There continues to be a core problem with the PNG format.  You can't
depend on it for archival purposes.  What works today might well not
work tomorrow, and that is a huge problem for one of the core free
software projects.  Picutres need to render now, and in a 100 years from
now, or they are worthless.

If you look at http://images.mrbrklyn.com

You will see a bunch of blank images.  Every one of those images are
being misrendered by the software.  That gallery uses imagmaik to
convert them on the fly to multiple sizes and thumnails.  I opened the
original images in the gimp, and they likewise don't render.

If you look at them in firefox though, they work.  But that is likely
just a matter of time before the new libaries cascade into the ecosystem

For example:

http://images.mrbrklyn.com/brooklyn/ornimental_building_kent_st_2006_00557.png?width=640

This broken image 

http://images.mrbrklyn.com/brooklyn/.cache/640x480-ornimental_building_kent_st_2006_00557.png

is rendered from this original image

http://www.mrbrklyn.com/brooklyn/images/ornimental_building_kent_st_2006_00557.png

and the original  shows up in a browser

But if you try to open it up in the gimp, it doesn't render.  Nor does
it render in viewnoir or xv.  Some core and common library has to be
broken.  When the apache software tries to rescale it on the fly, it
can't renber it either.  And this is what happened last time.

Over time these images will become completely useless.

You can only conclude at this jucnture that PNG files are wholely
undependable and not a usable format.



> _______________________________________________
> conspire mailing list
> conspire at linuxmafia.com
> http://linuxmafia.com/mailman/listinfo/conspire

-- 
So many immigrant groups have swept through our town
that Brooklyn, like Atlantis, reaches mythological
proportions in the mind of the world - RI Safir 1998
http://www.mrbrklyn.com 

DRM is THEFT - We are the STAKEHOLDERS - RI Safir 2002
http://www.nylxs.com - Leadership Development in Free Software
http://www2.mrbrklyn.com/resources - Unpublished Archive 
http://www.coinhangout.com - coins!
http://www.brooklyn-living.com 

Being so tracked is for FARM ANIMALS and and extermination camps, 
but incompatible with living as a free human being. -RI Safir 2013