Since the early dawn of Dolphin, technology has advanced rapidly: Displays have higher resolutions and 4K became a standard. Especially for media designers a quick overview of images in adequate resolution is necessary. Unfortunately, 256x256 as a maximum preview size (as given in Dolphin as to date) for thumbnails seldomly satisfies. Yes, there are image viewers (gwenview etc) that can be used to see larger thumbnails, but imagine the use case of grandma trying to sort its private picture library. She has to switch back and forth between Dolphin and Gwenview, which is highly disrupting the workflow and not quite intuitive. So, my feature request would be A) Add an option to select the maximum thumbnail zoom size OR at least scale up to 512x512 for good measure and B) Add an option to save views per folder. Meaning: Have on default view (grid layout and thumbnail size), but when browsing pictures, make Dolphin remember the higher thumbnail preview size.
nemo and caja have a dconf setting for the thumbnail size that you can customize to any size you want. IMO this is a great solution because while I sometimes want very big thumbnails, I also understand that this is probably not a desirable option to provide in the preferences, as it may lead to performance or memory issues for some users, so having it as a dconf setting makes it clear that this is not an intended use and you're making changes at your own risk. Perhaps Dolphin could use some equivalent of that?
regardless I agree that 512 is reasonable these days. Dolphin went to great lengths to be the best for managing pictures by e.g. showing thumbnails of a folder's contents directly onto the folder's icon (something no other manager can do to my knowledge), so I think allowing for very large previews would go in that continuity.
Also been wanting this feature for years. And if the Qt thumbnail spec is limited to 256x256 or whatnot, then just do some scaling/interpolation. I use desktop zoom all the time to make up for this.
Even with Breeze icons, on 6.4.4, icon size still has a maximum of 256px I agree that larger icons would be an accessibility benefit
Btw Dolphin can do 512 pixels resolution images when using an higher dpi than 1 to compensate. This is a bit of a pickle. I did this: http://gitlab.freedesktop.org/xdg/xdg-specs/-/merge_requests/40 and https://invent.kde.org/frameworks/kio/-/merge_requests/266 To achieve the aforementioned better support for Hidpi. This starts to add a lot of disk usage if we were to keep using thumbnails. Then a workaround would be to not cache the thumbnail when using 512x512 resolution but read it each time from files, which would remove the advantage of caching thumbnails for snappy file browsing. At the same time minimizing say a photo to 512 or 1024 is not harder on the CPU than to compute for 256, only in memory usage. This could be acceptable, but users would feel it, a bit like when you browse a folder whose thumbnails haven't been computed yet, except all the time depending on the zoom level. Do you think that would be reasonable ? I would consider have an opt-in option to allow to generate 512x512 preview (in logical pixel that is 1024x1024 for dpi>1).
Hi Méven, thank you very much for your suggestion. I think, that would be a good compromise. One thought though, is it really that slow to create larger thumbnails? I mean yes, HDD will get reasonably slower, when trying to create the caches, but on the other hand, modern PCs are running with PCIE SSDs. Best regards, Julius
(In reply to Julius R. from comment #6) > Hi Méven, > > thank you very much for your suggestion. I think, that would be a good > compromise. One thought though, is it really that slow to create larger > thumbnails? Creating a thumbnails 256/512 (with hidpi) should generally be as fast as a 512/1024. On disk/memory that could be twice bigger though. We use png at the moment, other new formats could be better like webp to save disk usage and that might make 1024 thumbnails more The issue is creating those thumbnails each time without the cache. > I mean yes, HDD will get reasonably slower, when trying to > create the caches, but on the other hand, modern PCs are running with PCIE > SSDs. > You can remove `~/.cache/thumbnails/` folder to simulate the state, go to a folder with lots of images in icon mode with the biggest zoom. Things changed recently we load/create thumbnails on several CPU-core now, so this feels better than it used to. Or you can use gwenview, since it doesn't use the thumbnail cache at all. HDD are still very big in term of usage, especially for large storage (video/photos), and we must at least not make too bad for them, i.e only tailor for SSD.
Dolphin has per-folder view settings which I am grateful for, but would like in addition to that to have per-folder zoom settings. I'm working on a bunch of cursors right now that size correctly at 100% but I want smallest previews outside of these cursor folders for example. Not sure if this is the wrong request to comment this on.