[gdal-dev] libpng and autotest

[Kurt Schwehr]

Jack,

Is there an explanation someplace with more detail as to what is wrong those png's, why older versions of libpng are okay with it and why libpng has changed its behavior?

Thanks,
-kurt



On Nov 8, 2013, at 8:02 AM, Jack Howarth <howarth at bromo.med.uc.edu> wrote:

> On Fri, Nov 08, 2013 at 10:31:08AM -0500, Jack Howarth wrote:
>> On Thu, Nov 07, 2013 at 04:34:07PM -0500, Jack Howarth wrote:
>>> The failures on x86_64-apple-darwin13 for the png.py test suite from auto
>>> test for gdal 0.10.1 are the same failures described here...
>>> 
>>> https://github.com/licq-im/licq/pull/32
>>> <https://github.com/licq-im/licq/pull/32>
>>> 
>>> The failures are completely suppressed by regenerating
>>> autotest/gdrivers/data/test.png with
>>> "optipng -nb -nc -np test.png"...
>> 
>> Just to clarify, I used optipng 0.6.3 for this. The newer optipng 0.7.4
>> release seems more problematic as none of the obvious combination of options
>> can fix the test.png file without changing the checksums and causing additional
>> failures. So you will want to use the optipng 0.6.x release series to fix
>> the bad png files in gdal.
> 
> Also, my tests here using optipng 0.7.4 to detect damaged png files indicate
> that only data/gdalicon.png in gdal-0.10.1 needs to be fixed.
> 
> optipng -nb -nc -np -fix data/gdalicon.png
> ** Processing: data/gdalicon.png
> Warning: 
> 32x32 pixels, 4x8 bits/pixel, RGB+alpha
> Recoverable errors found in input. Fixing...
> Input IDAT size = 1964 bytes
> Input file size = 2021 bytes
> 
> Trying:
>  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 240
> 
> Selecting parameters:
>  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 240
> 
> Output IDAT size = 240 bytes (1724 bytes decrease)
> Output file size = 313 bytes (1708 bytes = 84.51% decrease)
> 
> ** Status report
> 1 file(s) have been processed.
> 1 error(s) have been encountered.
> 1 erroneous file(s) have been fixed.
> 
> 
>> 
>>> 
>>> % ./png.py
>>>  TEST: png_1 ... success
>>>  TEST: png_2 ... success
>>>  TEST: png_3 ... success
>>>  TEST: png_4 ... success
>>>  TEST: png_5 ... success
>>>  TEST: png_6 ... success
>>>  TEST: png_7 ... success
>>>  TEST: png_8 ... success
>>>  TEST: png_9 ... success
>>>  TEST: png_10 ... success
>>>  TEST: png_11 ... success
>>> 
>>> Test Script: png
>>> Succeeded: 11
>>> Failed:    0 (0 blew exceptions)
>>> Skipped:   0
>>> Expected fail:0
>>> Duration:  0.08s
>>> 
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