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...
Check your "Preview" settings from config dialog. Presentation use this settings to handle image quality version available. Gilles Caulier
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
@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?
I tried to supply a sample image but they are all above the 4MB limit.
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
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.
Thanks for the feedback Gilles Caulier