Perspective/custom/preset folder preview types in icon packs: what would be needed?

Nubnubbud · May 23, 2026, 8:18am

alright, so I’m a filthy windows scrub, and there is one thing from windows 7 to 10 that I fell in love with, which is really hard to get used to in other file managers:

the folder previews. they’re just so… clear and obvious and tactile.

basically, the reason they feel so nice is:

All images are full icon size, meaning you can see details at a smaller zoom.
you get multiple previews- always good,
squishing the image and skewing it allows you to see more image in a thinner space.
adjusting the skew of each successive image allows you to see even more at the top.
the human brain is VERY good at understanding things in perspective view (surprising nobody) so by squishing and skewing, we can simply see more preview per preview.
this allows you at a glance to be sure if a folder is empty, almost empty, or so on.

it’s not perfect though. if I was omnipotent and a development god (I am not, sadly) I would add:

“opening” the folder icon more than 90 degrees or making it translucent you could add more images.
adding “thickness” to it, to signify 1-10 items, 10-25, 25+ files, to see folder size at a glance
increasing the number of files shown, angling for “dense view”
flipping through the files/opening wider/images spreading out as you mouse over them
some people embrace the chaos- what if you just wanted a pile of 3-9 previews that look like a pile of files?
I’m an old hat. I know my parents would be more familiar with a rolodex- style preview to boot.

and so on.

so, I’m curious, how complicated would the additions need to be to allow Plasma to generate skewed, occluded, or transformed previews? Can it already and it’s just not exposed for basic themes? I’ve been trying to find a built in way or a hack, but no dice. maybe I’m bad at finding info.
I assume it won’t be too intense computationally, seeing as it already shows 4 tilted images at a lower resolution, and windows’ solution even requires you to load the folder’s thumbnails or refresh first.

I’m not saying a direct copy is good here, I do have some gripes, but overall, when I was shopping for a new OS, I was floored by how much of a downgrade windows 11’s file manager was from XP to 10, when it came to clarity, and then when I tried plasma, cinnamon, mac OS and so on, that most of the previews were… just not as nice.

**TL;DR
I feel that the windows 7/10 file preview style has distinct advantages that set it above others for usability.

Perspective previews, along with at least a few other folder preview styles, should be available to icon pack creators, to allow for further customization, and in this case (and my admittedly biased opinion), more readable previews. At the very least, being able to simply set a folder preview style for an icon pack or individual icons would probably get plenty of use.**

meven · May 23, 2026, 8:24am

We have it in plasma / Dolphin, enable previews for folders.

Example for folders containing source code:

Having a different style, would need a specific icon with a specific rendering code…

Technically, nothing is complicated.
We currently have a way to do it and we wouldn’t want to just “copy” whatever another OS does, although it has some merits.
Designing is usually a hard part…

The code is in kio-extras thumbnails.

LSLSLS · May 23, 2026, 8:37am

So instead, you want to reinvent the wheel?

Nubnubbud · May 24, 2026, 4:00am

for more context, I haven’t had the time or skill to pursue this strongly yet, which is why I’m asking to be pointed in the right direction for what I would need to look at first. Thank you for the response, I appreciate your time.

well, yes, but even on 1440p monitors, I tend to have quite small folders, and many of them. I do VFX, game design, and so on, so being able to see at a glance what colors and shapes are in the images in certain folders is important to me, even when-
actually- especially when I have over twenty on the screen at once and reading the name of each or doing a search seems cumbersome just to go to a folder, or even randomly or procedurally generated folder.

My issue was that the specific kind of “multiple smaller images” preview breaks down at smaller resolutions VERY quickly. There’s enough space to fit six preview files on each, or to double their size if they were sideways, and they’d still only be a quarter of the icon.

my entire point is that if you “tilt” the image, you can effectively have three or four full size previews, instead of four quarter-size previews.

This is actual size on my windows machine (blame software and nvidia- my production software requires my workstation to be windows even though I mostly use blender and nuke)

even at the smallest scale, I can still readily see that all my backgrounds are dark, the top level image in my engineering folder is of my old clear red PETG prints, and even if I can’t make out what’s in my reaction gifs and video dump, all four icons are identifiably different and give previews at a glance.

also I emphatically disagree with this. If someone else makes wheels that are round, keeping yours octagonal because they did it first, is a very good way to become irrelevant via a thousand cuts. There’s no good reason not to identify the best features everyone else has, even if you don’t like or want to imitate the people who made them. I would even accept “I don’t like the look, go away” more readily. I was ready to hear “well, we would have to rewrite the entire x part of the kernel” or something.

one of my best contributions to blender… was translating and implementing some code from a 2017 siggraph paper in 2024. it completely fixed normal mapping in rendering. At that point I understood that I don’t have to be the one to figure out a better design.

for example, windows DOES NOT have text or code file previews. That’s cool! that would add just one more level to how nice it would be to see the previews at full icon size, y’know? I wanna be able to see that better too.

I have no interest in copying. I wanna build upon it.

skyfishgoo · May 24, 2026, 1:58pm

since the thumbnail previews can clearly be transformed and even layered over one another with drop shadows and everything… it should only be a matter of the transformation coding to change these previews into another look.

lets call this default look: Folder Closed - Oriented Bottom

which gives a view of the contents spread out on top of the folder

we could also have: Folder Open - Oriented Bottom

which gives an open view of the folder with the contents fanned out inside like a rolladex

then we could offer: Folder Open - Oriented Side

which would show the same view as above but with the folder on it’s side like OP has been showing.

or even offer: Folder Spilt - Oriented Random

for total chaos

amilias · May 24, 2026, 4:27pm

I’ll just add I also never liked dolphin’s folder previews that much, for the exact reason that the way multiple files are displayed makes them very small and hard to see (even more so on smaller icon sizes). I’m not sure if copying the windows style is the definitive way to go, but you have to admit it’s a pretty good UX for once

meven · May 25, 2026, 9:38am

Out of context.

We currently have a way to do it and we wouldn’t want to just “copy” whatever another OS does, although it has some merits.

Nubnubbud · May 29, 2026, 12:41am

Yeah, as long as there’s a simple transform library or code that can handle skew or affine transformation, (though perspective and projective also work) this is doable as a tech… and on a glance through the calls for Qt- yes, it has a dedicated shear, which should work fine.

However, the more important part (in my mind) is that it’s easily definable within an icon pack, so that it may be a legitimized part of dolphin that can be customized without compiling. That involves adding at the very least a new variable for icon packs to access, having what we currently have as the default otherwise (for backwards compatibility), and so on…

but I think offering a “transform stack” would be better than presets, now that I see how this works. basically it would simply be a set of 4 values you set for up to 8 images. The angle is already semi-implemented but hardcoded ±8 degrees. basically in pseudocode:

apply folder icon first layer (if folder previews are off or not included, skip all remaining steps)
translate thumbnail 1
rotate thumbnail 1
skew thumbnail 1
scale thumbnail 1
repeat steps 2-5 for thumbnails 2-8
apply folder icon top layer

so in practice if you were making an icon pack and wanted custom previews, you would be able to break from the default by simply adding a section like this:

in this case, the furthest back preview has slightly random location, the second has slightly random rotation, and the third has slightly random “perspective”.
if it’s not there or false, it’s not invoked and you get base dolphin. If CustomPreviews is true, then it will look for the second folder icon to put on top. the preview count should be a user-facing option in Dolphin if it isn’t already, and like this, you can have a UI option for randomness scale and preview count.

My biggest concern at this point would be backward compatibility and performance, but I believe this is why windows only populates folder previews when you enter the folder- and also uses that to decide when to update thumbnails. Could also do it whenever something is placed into it, but for recognition’s sake, by default it shouldn’t change till the user has seen the new files inside to remember them. Could you make an absolute mess of a window manager with an icon pack or theme like this?
Oh, absolutely~

but yeah, it’s not quite enough for me to know I COULD code and compile it myself. That’s lonely and wasted effort. I want this sort of customization to be accessible to people who aren’t as comfortable compiling their own stuff, or even just through an icon pack designer. After all, linux is becoming more mainstream, and there’s no reason not to make features as accessible as possible.