Exporting to PDF a single layer transparency enabled drawing does not work anymore.
GIMP version: 2.10.12
Operating System: Ubuntu 19.04 x86_64
Package: Vanilla gimp installed thru apt-get install from Ubuntu repos.
Description of the bug
I am trying to stamp a PDF document with a "Confidential" stamp. For this I use pdftk (and pdfchain) to do the actual stamping. I create the "confidential" stamp using gimp as a pdf with no background, 70% transparent stamp. This works perfectly under Ubuntu 16.04 and gimp version v2.8.16. But the stamp.pdf generated using gimp 2.10.12 using same steps does not work. I am attaching resulting stamped doc showing what I mean by "does not work".
- Generate the stamp design as a 70% opaque pdf and no background and export to stamp.pdf in gimp.
- Use this command line to stamp the document: pdftk ./DocToStamp.pdf stamp ./Stamp.pdf output ./Result.pdf
- Check the Result.pdf.
Expected result: The document should get stamped as if an actual rubber stamp was used to stamp the document.
Actual result: The stamp.pdf generated using gimp 2.10.12 does not work. The original doc is white-washed, and then the stamp is applied. This is equivalent to stamping a white page with the stamp. In stamp.pdf generated using gimp v2.8.16 (from Ubuntu 16.04) works. Attached are the stamp files generated using (good case) v.2.8.16 and (bad case) v2.10.12. I am also attaching the corresponding xcf and png files and also the stamped documents.
If you have a backtrace for a crash or a warning, paste it here. Stamp_working_gimp_v2.8.16.pdf