[PATCH] export correct alpha information to xlsx

Hey,

while investigating some problems around color scale export to xlsx I
came across a difference between an original excel document and our
exported version of the document. It seems that we are always missing
to export the right alpha information or I'm just not understanding
the file correctly. It seems that excel opens both versions correctly
but that makes it even more mysterious for me.

Does anyone have an idea if this patch is correct? At least the color
information looks the same between both versions.

Regards,
Markus

Attachment: 0001-export-correct-alpha-information-to-xlsx.patch
Description: Binary data