[Interest] iOS libpng conflicts with another lib

[maitai]

Thanks you for your replies

I will decide to compile qt on iOS when I will be retired and nothing 
else to do, too much a pain with lipo and all ;)

Better option is probably to modify my lib (gdal, btw) and to change all 
references to libpng to something else. Not too smart I admit, and will 
cause many issues later when gdal upgrade is needed.

I will try to run this in XCode/debug maybe more info later this week on 
that.

For the time being I am trying to avoid the pb by converting to tif with 
transparency so I won't need png support in gdal, but some other 
problems arose...

Basically I need to convert to a format that supports alpha channel and 
that is not png.

Philippe.

Le 06-02-2018 20:36, Konstantin Tokarev a écrit :
> 06.02.2018, 13:28, "maitai" <maitai at virtual-winds.org>:
>> Hello,
>> 
>> I have an external lib build statically into my qt app (5.9.4,
>> widget-based). That lib can optionally support internally png images. 
>> If
>> I activate this, there is no problems in other platforms (I tested
>> Android, Windows, Linux, Raspberry, MacOS), but on iOS as soon as I 
>> try
>> to open a png image with a QPixmap or a QImage it crashes. If I 
>> compile
>> my external lib without png support no more crash.
>> 
>> So it appears that libpng from Qt and the one from my lib are
>> conflicting, but only on iOS.
>> 
>> Any idea why this occurs on iOS and what I could do to avoid the 
>> crash?
>> I badly need png support in both qt and the external lib.
> 
> Also, make sure that when you build your lib it uses headers from the 
> same
> copy of libpng that it links to. (At least with cmake it's quite easy
> to get into
> such situation)
> 
>> 
>> Thanks
>> Philippe
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