Bug 443349

Summary:	Pictures in "Presentation" oversharpened
Product:	[Applications] digikam	Reporter:	harald.aust
Component:	Plugin-Generic-Presentation	Assignee:	Digikam Developers <digikam-bugs-null>
Status:	RESOLVED FIXED
Severity:	normal	CC:	caulier.gilles, metzpinguin
Priority:	NOR
Version First Reported In:	7.3.0
Target Milestone:	---
Platform:	Microsoft Windows
OS:	Microsoft Windows
Latest Commit:		Version Fixed/Implemented In:	7.4.0
Sentry Crash Report:
Attachments:	view-compare.png

Description harald.aust 2021-10-05 13:06:32 UTC

SUMMARY

It is difficult to be absolutely sure about this since I can't get a screenshot from a Presentation for direct comparison, but it is my very distinct impression that images in Presentation are severely oversharpened compared to digiKam's own "Slideshow" or external picture viewers. The issue seems to particularly conspicuous when pictures are scaled down a lot -- in my case, from 4320px image height to 1200px monitor height.


STEPS TO REPRODUCE
1. Select a picture with fine detail and a resolution >> monitor resolution.
2. Start Presentation.
3. Compare result visually to digiKam's "Slideshow", or other image viewers like Irfanview.

OBSERVED RESULT
Picture in Presentation seems over-sharpened and/or over-contrasty.


EXPECTED RESULT
Pictures in Presentation, Slideshow, and other viewers are displayed +/- the same way.


SOFTWARE/OS VERSIONS
Windows: Win10 20H2
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION
This may actually be intended behavior, but I personally don't like it...

Comment 1 caulier.gilles 2021-10-05 13:29:00 UTC

Check your "Preview" settings from config dialog. Presentation use this settings to handle image quality version available.

Gilles Caulier

Comment 2 Maik Qualmann 2021-10-05 16:37:24 UTC

I don't see any difference between the slide show and the presentation in terms of the sharpness of the images. Do you use the OpenGL mode in the presentation? If so, under extended there is an option for OpenGL to use the full screen resolution.

Maik

Comment 3 harald.aust 2021-10-07 15:53:50 UTC

@Gilles: I don't find "preview" settings in "configure dgiKam" dialog. Where exactly?

@Maik: Do you mean Advanced / OpenGL effects / Use full screen resolution? It is checked.

Is there any way I can get a screenshot when Presentation is running?

Comment 4 harald.aust 2021-10-07 15:59:50 UTC

I tried to supply a sample image but they are all above the 4MB limit.

Comment 5 Maik Qualmann 2021-10-07 16:41:39 UTC

Created attachment 142239 [details]
view-compare.png

Here is a screenshot excerpt from a 24 megapixel image on a screen with 1920x1200. On the left is the slide show and on the right the presentation (without OpenGL). I don't see any difference.

Maik

Comment 6 harald.aust 2021-11-02 16:54:53 UTC

Sorry for the delay; I were away from home for some time.
I was confident that I could see a significant difference in very fine structures like foliage or rock patterns but can't reproduce. Maybe something was wrong with my graphics adapter that day.
Sorry for the bother; issue can be closed.

Comment 7 caulier.gilles 2021-11-02 16:58:20 UTC

Thanks for the feedback

Gilles Caulier