[Mapserver-dev] Re: mapserver bug

Steve Lime steve.lime at dnr.state.mn.us
Thu Sep 18 15:40:03 EDT 2003

The "native" method uses GD as an intermediary and not libpng directly
so it doesn't suprise me that GDAL is faster. Since old versions of GD
couldn't even read a 24-bit PNG errors were caught that way. It just
slipped through the 24-bit upgrade. A 4 line test, error set and return
should fix the issue.


>>> Alan Steremberg <alans at wunderground.com> 09/18/03 01:43PM >>>

Everything works fine when I turn GDAL on, and it seems fast. For some
reason I assumed that the native methods would be better.  The PNG
is definately broken, it needs a check at the very least..


 Alan Steremberg
 415-543-5021 x 103

On Wed, 17 Sep 2003, Frank Warmerdam wrote:

> Alan Steremberg wrote:
> > Hi,
> >
> > The mapraster.c file doesn't seem to pay attention to whether the
PNGs are
> > true color, before trying to fish inside the pixel buffer (and it
> > crashes).
> >
> > Is this fixed in the CVS tree, or should I fix the implementation
> > handle loading truecolor images from gd?
> >
> > I am still not sure if I want to be in 8bit or 24bit mode
eventually.. but
> > this seems like a bug.
> Alan,
> You are referring to the drawPNG() code, right?  Yes, I imagine you
are right
> and it should be fixed or at least a clean error message produced.  I
> suggest you create a bugzilla entry for the issue, and if you are
> to create a patch for it note that in the bug report so no one else
works on it.
> I don't normally run into this myself because if GDAL is enabled it
should be
> used in preference to the drawPNG() code *I think*.  The drawGDAL()
> for PNG would handle the different modes and also extra rendering
> so it isn't worth our putting too much effort into the "legacy"
> code.  However, a clean fix in drawPNG() would be nice if you don't
> doing it.
> Best regards,
> --
> I set the clouds in motion - turn up   | Frank Warmerdam,
warmerdam at pobox.com 
> light and sound - activate the windows | http://pobox.com/~warmerdam

> and watch the world go round - Rush    | Geospatial Programmer for
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