Bug 134744 - OpenGL causes white artifacts in exported PDF - Document has bitmap background and transparency effect
Summary: OpenGL causes white artifacts in exported PDF - Document has bitmap backgroun...
Status: RESOLVED WONTFIX
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Printing and PDF export (show other bugs)
Version:
(earliest affected)
6.4.3.2 release
Hardware: x86-64 (AMD64) Windows (All)
: medium normal
Assignee: Not Assigned
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-07-12 07:14 UTC by Frank Zimmerman
Modified: 2020-08-28 13:06 UTC (History)
2 users (show)

See Also:
Crash report or crash signature:


Attachments
Here is a basic test ODT which already has the background pic and radial transparency to test with. (365.60 KB, application/vnd.oasis.opendocument.text)
2020-07-12 07:16 UTC, Frank Zimmerman
Details
Here is the PDF I generated from the ODT. (443.89 KB, application/pdf)
2020-07-12 07:18 UTC, Frank Zimmerman
Details
PDF generated after updating graphics driver to latest. (469.73 KB, application/pdf)
2020-07-12 07:20 UTC, Frank Zimmerman
Details
PDF generated with OpenGL turned off (462.50 KB, application/pdf)
2020-07-12 07:21 UTC, Frank Zimmerman
Details

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Description Frank Zimmerman 2020-07-12 07:14:49 UTC
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.
Comment 1 Frank Zimmerman 2020-07-12 07:16:46 UTC
Created attachment 162917 [details]
Here is a basic test ODT which already has the background pic and radial transparency to test with.

You should be able to just load this ODT, (make sure OpenGL is turned in in LO Writer), and export to PDF. Then zoom in to view the PDF around the radial transparency area.
Comment 2 Frank Zimmerman 2020-07-12 07:18:37 UTC
Created attachment 162918 [details]
Here is the PDF I generated from the ODT.

This one was using the Dell Laptop, AMD FirePro Graphics, OpenGL turned on. You can see the radial white pixels especially in the upper left part of the page.
Comment 3 Frank Zimmerman 2020-07-12 07:20:02 UTC
Created attachment 162919 [details]
PDF generated after updating graphics driver to latest.

This PDF was generated after I installed the latest driver for the AMD FirePro 6100 card. The white pixel problem is even worse.
Comment 4 Frank Zimmerman 2020-07-12 07:21:28 UTC
Created attachment 162920 [details]
PDF generated with OpenGL turned off

Here is a PDF generated from the same Dell Precision laptop, with OpenGL turned off. Looks perfect!
Comment 5 Julien Nabet 2020-07-12 20:29:36 UTC
Could you give a try to 6.4.5?
Comment 6 Frank Zimmerman 2020-07-14 04:03:11 UTC
I'll do that tonight. I assume it is okay if I use a portable version of LO 6.4.5?
Comment 7 Julien Nabet 2020-07-14 08:04:08 UTC
(In reply to Frank Zimmerman from comment #6)
> I'll do that tonight. I assume it is okay if I use a portable version of LO
> 6.4.5?

I never use portable version so can't tell. I suppose you can give it a try.
Comment 8 Frank Zimmerman 2020-07-16 17:52:55 UTC
I tested with 6.4.5 portable. Same problem on PDF Export.
Comment 9 Julien Nabet 2020-07-23 09:20:21 UTC
Ok thank you for your feedback.
I can't help here so uncc myself
Comment 10 Buovjaga 2020-08-28 13:06:05 UTC
As Skia with Vulkan will replace OpenGL UI rendering on all platforms, it does not make sense to keep OpenGL UI reports open.

Details about Skia: https://www.collaboraoffice.com/success-story/implementing-vulkan-capable-libreoffice-user-interface-using-the-skia-library/