Re: [png-mng-misc] libpng 1.6 upgrade

[Glenn Randers-P. <gl...@gm...>]

The "nm-signal-100.png" that was uploaded to the list has the "too far back"
error:


 | pngcrush 1.7.56
 |    Copyright (C) 1998-2002, 2006-2013 Glenn Randers-Pehrson
 |    Portions copyright (C) 2005       Greg Roelofs
 | This is a free, open-source program.  Permission is irrevocably
 | granted to everyone to use this version of pngcrush without
 | payment of any fee.
 | Executable name is pngcrush
 | It was built with libpng version 1.6.1, and is
 | running with  libpng version 1.6.1 - March 28, 2013

 |    Copyright (C) 1998-2004, 2006-2013 Glenn Randers-Pehrson,
 |    Copyright (C) 1996, 1997 Andreas Dilger,
 |    Copyright (C) 1995, Guy Eric Schalnat, Group 42 Inc.,
 | and zlib version 1.2.7.1, Copyright (C) 1995 (or later),
 |    Jean-loup Gailly and Mark Adler.
 | It was compiled with gcc version 4.6.3.

Opening file nm-signal-100.png for length measurement
Allocating read structure
Allocating read_info,  end_info structures
Reading IHDR chunk, length = 13.
Reading bKGD chunk, length = 6.
Reading pHYs chunk, length = 9.
Reading tIME chunk, length = 7.
Reading tEXt chunk, length = 29.
Reading IDAT chunk, length = 253.
Reading IEND chunk, length = 0.
Destroying data structs
   Recompressing nm-signal-100.png
   Total length of data found in critical chunks =      310


ENTERING MAIN LOOP OVER 200 METHODS
Allocating read and write structures
Allocating read_info, write_info, end_info structures
Initializing input and output streams
 Check the palette
Reading info struct
Transferring info struct
   IHDR chunk data:
      Width=22, height=22
      Bit depth =8
      Color type=6
      Interlace =0
   Setting IHDR
Handling 1 tEXt/zTXt chunks before IDAT
0  Comment: Created with The GIMP
Found 0 unknown chunks
Finished handling ancillary chunks after IDAT

Begin interlace pass 0
While reading nm-signal-100.png:
  pngcrush caught libpng error:
   IDAT: invalid distance too far back


Old versions of pngcrush were able to fix the error but current
ones built with zlib-1.2.7 and later cannot.

Previously I reported that "download.png" was OK but
gmail must have fixed it during the transfer; I had used
"view; save as" instead of "download" to retrieve it.

Glenn


On Fri, Apr 5, 2013 at 7:23 PM, Glenn Randers-Pehrson <gl...@gm...>wrote:

>
> On Fri, Apr 5, 2013 at 6:13 PM, Armin K. <kr...@em...> wrote:
>
>> On 04/06/2013 12:01 AM, Armin K. wrote:
>> > On 04/05/2013 11:41 PM, Glenn Randers-Pehrson wrote:
>> >> Not an unusual image, except that it has an sBIT chunk:
>> >>
>> >>     chunk IHDR at offset 0x0000c, length 13
>> >>       22 x 22 image, 32-bit RGB+alpha, non-interlaced
>> >>     chunk sBIT at offset 0x00025, length 4
>> >>       red = 8 = 0x08, green = 8 = 0x08, blue = 8 = 0x08, alpha = 8 =
>> 0x08
>> >>     chunk bKGD at offset 0x00035, length 6
>> >>       red = 0x00ff, green = 0x00ff, blue = 0x00ff
>> >>     chunk IDAT at offset 0x00047, length 295
>> >>       zlib: deflated, 2K window, default compression
>> >>     chunk IEND at offset 0x0017a, length 0
>> >> No errors detected in download.png (5 chunks, 80.1% compression).
>> >>
>> >> Neither pngcrush nor imagemagick built with libpng-1.6.1 has
>> >> any complaint about it.
>> >>
>> >> About all I can think of is maybe your app was built with the
>> >> wrong header files (such as pnglibconf.h from libpng-1.5).
>> >>
>> >> Glenn
>> >>
>> >
>> > It could be possible. I thought it uses Gdk Pixbuf for image loading
>> > which was built against libpng 1.6.1, but I could be wrong. Binary
>> > doesn't show any implicit dependency on libpng15.so.15. I'll try and
>> > give it a rebuild.
>> >
>>
>> No, still the same. Have you used png's from tarball I linked to or the
>> ones that someone attached here? Also, which imagemagick command(s) (and
>> how) did you use to verify the file?
>>
>>
> I used
>
> pngcrush -n -v
> pngcrush download.png download_pc.png
> pngcheck -v
> pngcheck -v -v
> convert download.png download_im.png
>
> pngcrush and imagemagick (convert) were built with libpng-1.6.1 and
> zlib-1.2.7.1
> pngcheck was built with zlib-1.2.3.3 and run with zlib-1.2.3.4.
>
> pngcrush is version 1.7.56
> imagemagick is version 6.8.4-6
> pngcheck is some old version that I have lying around:
> PNGcheck, version 2.3.0 of 7 July 2007
>
> I used the "download.png" that was attached here.
> Feel free to send another copy if you don't trust that one, either
> to the list or directly to me.  Sorry I'm not going back to ftp.gnome.org
> and weed through hundreds of MB of tar files to find it.
>
> Glenn
>
>
>>
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>
>