Hi there I have the issue, that the conversion from PPT(X) to PDF with Libreoffice Headless.
The conversion from PowerPoint from PDF destroys the color space and brilliance as it seems.
It i very spectacular with color gradient backgrounds.
Resulting PDF File:
Command:
libreoffice --headless --convert-to pdf gradient_test.pptx
How can I prevent this?
You can find the sample file here:
TestGradient.pptx (35.4 KB)
I opened your PPTX in LibreOffice and then saved it as an ODP. When I export as PDF using the normal export function in LibreOffice, I can’t see any difference.
Thank you very much for your contribution! Honestly it is not as worse as my conversion, but I can see a difference in the gradient’s progress and I can see a difference between ODP and PPTX
Microsoft Powerpoint 2010 does export a smoother gradient but it also displays an angle set at 45 degrees to something like 30 degrees. Maybe it does that to smooth the gradient or maybe it assumes 45 degrees is corner to corner.
There might be some blurring introduced to smooth the colours when a gradient is displayed in PowerPoint to overcome the limitations of sRGB screens or narrower gamut.
You could report an enhancement bug, How to Report Bugs in LibreOffice - The Document Foundation Wiki
Hey @EarnestAl thank you very much for the explanation on the angles!
But honestly I am more concerned about the color change itself. Do you have any insights on how I can maybe define the color space for the conversion target ?
It was an observation about the angle rather than an explanation.
There isn’t colour management or support for colour profiles in LibreOffice although it does use sRGB.icc for pdf export (72146 – CMYK conversion incorrect? RGB does not match. Missing color profile?)
You might get better advice from a bug report.
You can find the PowerPoint view here as comparison (I could only embed one media file per post somehow):
Reported this as a bug now as @EarnestAl suggested:
https://bugs.documentfoundation.org/show_bug.cgi?id=160960
Will keep this thread postet for future users with the same issue.
