Am 11.06.2011 19:35, schrieb Albrecht Dreß:
> Am 07.06.11 21:11 schrieb(en) Oliver Eichler:
>> Am 07.06.2011 20:55, schrieb Albrecht Dreß:
>>> There is only one little problem - in my big endian boxes,
>>> gdal_translate downloads proper images e.g. for the Bavarian server,
>>> but when I open the xml with file->open, the colours are shifted.
>>> Probably an endianess issue - before digging through the sources:
>>> Oliver, where is the input processed, so I can try to fix this?
>>
>> Imho this is less an endian problem more a version problem between
>> GDAL 1.6.x. and 1.7.x The have changed the enumeration for colors. But
>> have a look on your own:
>
> It actually *is* an endianess problem - I saw the issue on OS X Intel
> (works) vs. PPC (doesn't, same on Linux/PPC), and all use the same gdal
> version (1.8.0).

Ah, ok, I thought you are using an old version for the big endian machine.

>
> I think your code basically assumes that the 4-byte RGBA value
> (uint32_t) has a certain byte order when the four uint8_t band values
> are written directly to the memory region (the offsets aren't documented
> by Qt, btw.). Apparently, the underlying Qt code interprets them as
> uint32_t, though, which explains the observation.

Ok, always thought this is byte oriented stuff. Failed in all my 
assumptions, eh? :)

>
> The attached trivial fix solves the WMS issue for me, no idea if it has
> other harmful effects. The *really* clean (but *really* slow) way is
> probably to read all four bands and to construct qrgba() pixels.
>

Right, I always have a bad feeling when accessing the bitmap buffer this 
way. But it's the only fast way.

I multiplied the patch for the other raster image objects and have 
committed it to svn.

Oliver

------------------------------------------------------------------------------
EditLive Enterprise is the world's most technically advanced content
authoring tool. Experience the power of Track Changes, Inline Image
Editing and ensure content is compliant with Accessibility Checking.
http://p.sf.net/sfu/ephox-dev2dev
_______________________________________________
Qlandkartegt-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/qlandkartegt-users

Reply via email to