Re: Why is it that png files are not dependable over the long haul

convert -list format|grep PNG

[ruben@flatbush ~]$ convert -list format|grep PNG
      JNG* PNG       rw-   JPEG Network Graphics
      MNG* PNG       rw+   Multiple-image Network Graphics (libpng 1.6.34)
      PNG* PNG       rw-   Portable Network Graphics (libpng 1.6.34)
           See http://www.libpng.org/ for details about the PNG format.
    PNG00* PNG       rw-   PNG inheriting bit-depth, color-type from original, if possible
    PNG24* PNG       rw-   opaque or binary transparent 24-bit RGB (zlib 1.2.11)
    PNG32* PNG       rw-   opaque or transparent 32-bit RGBA
    PNG48* PNG       rw-   opaque or binary transparent 48-bit RGB
    PNG64* PNG       rw-   opaque or transparent 64-bit RGBA
     PNG8* PNG       rw-   8-bit indexed with optional binary transparency

The problem is almost certainly in libpng



On 08/01/2018 03:15 PM, J Decker wrote:
> shows in chrome too... 1.7.0b89 fails
> (errors from error callback)
> IDAT: invalid distance too far back
> Too many calls to png_read_row
> 
> (lots of too many calls to png_read_row)
> 
> and fails in 1.6.34 (infinte reports of)  (chrome is also on 1.6.34,zlib
> 1.2.11 )
> IDAT: invalid distance too far back
> 
> (I have patches so simple things like 'invalid sRGB profile' doesn't cause
> my program to abort)
> 
> fixing the infinite loop doesn't result in a valid image though.
> 
> still cloning the repo - don't know if there are custom patches applied...
> otherwise there must be some setup option for reading that must not be right
> 
> or maybe in pngconf options...
> https://github.com/chromium/chromium/blob/master/third_party/libpng/pnglibconf.h#L140
> 
> 
> 
> 
> On Wed, Aug 1, 2018 at 12:21 AM Ruben Safir <ruben-v1XHP5QhJixWk0Htik3J/[email protected]> wrote:
> 
>> When PNG was created I enthusiatically preserved the majority of my
>> family pictures as PNG files and they were lost because of bugs in the
>> PNG libraries that were fixed.  I wrote aps to try to fix them as the
>> stock optpng etc all could not fix them.
>>
>> Now this month we lost a whole new set of precious images to some change
>> int he PNG libraries.
>>
>> Images like this:
>>
>>
>> http://www.mrbrklyn.com/brooklyn/images/wall_art_river_and_metropolitian_avenue_williamsburg_2006_00578.png
>>
>> which is completely mangles in the gimp and imagemagik but viewaable in
>> firefox?!?
>>
>> What are you guys doing.  I am going to have no choice but to abandon
>> PNG.
>>
>> --
>> 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
>>
>>
>>
>> ------------------------------------------------------------------------------
>> Check out the vibrant tech community on one of the world's most
>> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
>> _______________________________________________
>> png-mng-implement mailing list
>> png-mng-implement-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
>> https://lists.sourceforge.net/lists/listinfo/png-mng-implement
>>
> 
> 
> 
> ------------------------------------------------------------------------------
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> 
> 
> 
> _______________________________________________
> png-mng-implement mailing list
> png-mng-implement-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
> https://lists.sourceforge.net/lists/listinfo/png-mng-implement
> 


-- 
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://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

------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot