[Libreoffice-bugs] [Bug 134744] New: OpenGL causes white artifacts in exported PDF - Document has bitmap background and transparency effect

[bugzilla-daemon at bugs.documentfoundation.org]

https://bugs.documentfoundation.org/show_bug.cgi?id=134744

            Bug ID: 134744
           Summary: OpenGL causes white artifacts in exported PDF -
                    Document has bitmap background and transparency effect
           Product: LibreOffice
           Version: 6.4.3.2 release
          Hardware: x86-64 (AMD64)
                OS: Windows (All)
            Status: UNCONFIRMED
          Severity: normal
          Priority: medium
         Component: Printing and PDF export
          Assignee: libreoffice-bugs at lists.freedesktop.org
          Reporter: fz1844 at gmail.com

Description:
The Covers for the books I make usually have a bitmap picture inserted via the
Page style dialog as a Background (stretch to fill).

Then, to make the Title text stand out, I use a Radial Transparency behind the
text (usually about 1/4 of the way down the cover page).

I recently noticed that this was causing stray white pixels in the exported PDF
files.

At first I didn't realize this was OpenGL-related, and I tried many earlier
versions of LO. But eventually, I realized it was caused by the OpenGL option.
If I turn that off, the PDF generates fine.

I'm using a fairly high-end Dell Precision M6800 with Core i7 M4800Q cpu, 16GB
RAM, and AMD FirePro M6100 graphics card.

I checked for a graphics driver update, and there was one, so I installed it,
but the problem only got worse (as you can see in the samples I will attach).

My workaround for now is to turn off OpenGL.

This seems to have also given one other benefit: on large documents (1000 pages
or more) my cursor movement would get "sticky" and slow when I moved around in
text using the keyboard arrow keys. Since turning off OpenGL, I no longer
notice that.



Steps to Reproduce:
1. Create a document

2. Go into the Page Style dialog, Area tab, and insert a bitmap picture, with
"stretch to fill" so it fills the whole page. Use a darker picture to see the
problem better.

3. While in the Page Style dialog, go to the Transparency tab and turn on
"Gradient" transparency with "Radial" type. Click OK to exit the dialog.

4. Probably not necessary, but add a Text Box to the page with a Title centered
over the Radial transparency.

5. Export as PDF and zoom in to view the PDF.

Actual Results:
You should see white pixels showing, in broken radial lines.

Expected Results:
It should be nice and clean, with no white pixels.


Reproducible: Always


User Profile Reset: No


OpenGL enabled: Yes

Additional Info:
As I said, with OpenGL turned off, this problem goes away.

I tried the export on an Acer laptop (Windows 10) with AMD graphics, and it
showed the same problem.

I also tried this on a Toshiba Laptop with the latest Kubuntu (20.04), using an
Intel Atom Z36/Z37 graphics and Open GL 3.0 (Mesa) and the problem did not show
up (I think...but I probably should test it again).

So it could be related to specific hardware.

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/libreoffice-bugs/attachments/20200712/f5df9f9e/attachment-0001.htm>