Hi!

I'm experiencing problems with exr data windows. I would really appreciate
to have your advice...

I'm using the IlmImf library to read and write exr files. I did a lot of
testing with the images t01.exr -- t16.exr from your download section and
everything is working as expected. I'm also handling every other exr files
from that download section. I can modify the data window and the display
window of those exr files and the results are as expected when, for
instance, I look at the resulting image in Nuke by reading a file
previously written by my software. I can crop an image and I still get the
expected result. So, until that point, everything is working perfectly...

My problems arise when I try to manipulate cropped exr files that was
generated by Nuke using their own crop transformation. If I understand
correctly what Nuke is doing, it only crops the data window and it keeps
the display window as it is. This behavior makes total sense to me. My big
problem is when I'm trying to read those cropped exr files generated by
Nuke and write those back to file using my software. It seems to me that
data is not aligned correctly in the resulting file. To write back the
images correctly to file, I need to add an offset (when inserting slices in
FrameBuffer) that depends on the size of the display window. This is not
making any sense to me. My understanding is that the display window is not
playing a role when writing a file, just when displaying it. Am I right?

So, in brief, I implemented a library that works perfectly with every exr
file generated by your organization and by my own software. I do have
problems with cropped files produced by Nuke (and by other software as
well). Is there something I'm missing here? Maybe I'm not extracting all
the information I need from the headers? Is there a data alignment I need
to consider? Have you ever heard about any issues with cropped exr files
generated by Nuke?

I hope I gave you enough details about my problem.

Thank you so much for your time,
Julie
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