Impress Slideshow pixelated images, why?

JoachimOtahal · April 25, 2025, 6:59am

The .pptx looks find and high resolution when editing. When hitting F5 the images are rendered in very low resolution. (Printing is fine BTW)
Version 25.2.2.2 x64 on Windows two screens: Laptop screen is 1366x768, but NOT USED (i.e. lid closed), only the external screen with 3840x2160 is used and visible in Windows “screen settings”.
Look when editing is fine. I hit F5 and get this, pixelated and some parts completely out-of-whack:

Original Document:
https://joumxyzptlk.de/tmp/libreoffice/libre-office-pixelated-when-hitting-f5.pptx

JoachimOtahal · April 25, 2025, 7:00am

The look when editing:

Hrbrgr · April 25, 2025, 7:40am

There is no difference in your screenshots, imho.
It’s probably mainly about the pink background and the palettes.
I saved it as the original image of the background and it then has a size of 392px x 295px. If you then stretch the image to 22.5cm x 11.0cm, nothing sensible can come of it.
I recommend that you don’t use any images, but instead recreate the roof surface and the pallets by drawing.

Here is a sample of what it could look like with shapes:

121244 HB libre-office-pixelated-when-hitting-f5.odp (336,8 KB)
The file will be much smaller without pictures.
From what I’ve seen, I’m sure you’ll get it even nicer.

If you work with LibreOffice, you should always save in the native file format.
For Impress this is ODP.

How to open files from MS-Office 2007 or 2010 (.DOCX, .XLSX,…)?

JoachimOtahal · April 25, 2025, 2:08pm

This is the first screenshot annotated, the exact picture from the opening post:

There are a lot of things visibly wrong there.
Thanks for reworking some of it into shapes! But the missing lines are still missing even in your version here when i hit F5, and other details are still pixelated. OS is Windows, LO is 25.2.2.2 here, screen is 4k. What is your OS, LO version and screen resolution? Maybe I have to use a 24.* LO version…

Hrbrgr · April 25, 2025, 2:19pm

With me:
Version: 25.2.2.2 (X86_64) / LibreOffice Community
Build ID: 7370d4be9e3cf6031a51beef54ff3bda878e3fac
CPU threads: 8; OS: Windows 10 X86_64 (10.0 build 19045); UI render: Skia/Raster; VCL: win
Locale: de-DE (de_DE); UI: de-DE
Calc: CL threaded

screen: 1920 x 1080

I don’t think it’s the LO version.
The problem will be your 4k monitor! because the lines are so thin.
You can make the lines thicker or simply increase the zoom level.
In my screenshot above, all the lines are there.

JoachimOtahal · April 25, 2025, 2:45pm

Indeed, your screenshot is a lower resolution. Technically it cannot be the monitor - when hitting “print screen” the screenshot is taken from the OS side, and not a smartphone or something similar pointing to the monitor. This is clearly hinting a possible LO bug, or a setting not visible which only activates when starting a slideshow with F5. You did start a slide show with F5 or via the menu?
The machines in question, both showing the same issue…:

Version: 25.2.2.2 (X86_64) / LibreOffice Community
Build ID: 7370d4be9e3cf6031a51beef54ff3bda878e3fac
CPU threads: 4; OS: Windows 10 X86_64 (10.0 build 20348); UI render: Skia/Vulkan; VCL: win
Locale: de-DE (de_DE); UI: en-US
Calc: CL threaded
GPU: Titan RTX
CPU: AMD Ryzen 5950x
…
Version: 24.8.6.1 (X86_64) / LibreOffice Community
Build ID: 051bf11303684a0a982c9966e8be766d0a9efbc7
CPU threads: 32; OS: Windows 11 X86_64 (10.0 build 26100); UI render: Skia/Vulkan; VCL: win
Locale: de-DE (de_DE); UI: en-US
Calc: CL threaded
GPU: Intel integrated
CPU: I5-6300U
…
I think I’ll file a bug…

Hrbrgr · April 25, 2025, 3:16pm

Yes, but only now. Then some lines are also missing.

That is a possibility, it will imho be a compatibility problem.
The lines in Draw are not lines but pictures.
You can check this yourself in the Navigator (Alt+4).
If you replace the lines with “real” lines from Draw, they will also be displayed in presentation mode.