Scaling in 4k (150%)?

I have a lot of problems with how Calibre scales up in Win10 on 4k monitor (two monitors setup - main 4k with scale function on and one 1440p without scaling).

Especially some cover images are really tinny and some are fine despite being the same resolution...

Does anyone have similar problems?

[Sirtel]

Originally Posted by Merithyn

I have a lot of problems with how Calibre scales up in Win10 on 4k monitor (two monitors setup - main 4k with scale function on and one 1440p without scaling).

Especially some cover images are really tinny and some are fine despite being the same resolution...

Does anyone have similar problems?

Do you have the option for adjusting for high-resolution screens switched on?
No problems here with a 4k screen and Win10.

Originally Posted by Sirtel

Do you have the option for adjusting for high-resolution screens switched on?
No problems here with a 4k screen and Win10.

Yes, I have it turned on but it doesn't help.

The thing is some covers are displaying smaller than others but when I set the same image for cover again the thumbnail refreshes and become proper size... but I don't really want to reset the covers for hundreds of my books one by one...

[Cyphigma]

Umm... I remember something about fit image height/width? Or fit proportional? Aspect ratio? Something about cover art and the display size. No idea where I saw it though.

[theducks]

Originally Posted by Cyphigma

Umm... I remember something about fit image height/width? Or fit proportional? Aspect ratio? Something about cover art and the display size. No idea where I saw it though.

I think yo are remembering the Conversion Output options (as well as the device chosen)

Preferences: Look and Feel: COVER GRID
But what I think might have happened (and probably shoulden't), is the (small) covers for the grid were cached when you had an older monitor. (I use 3:4 with a standard monitor)

[crane3]

If you click/select a cover in the cover display mode, you should see the outline for what is allocated for each cover/picture. I think the size/scaling depends on the 'resolution' of the cover & how it fits into the allocated space when scaled up. Having said that, I have a couple of covers that did not scale well as the resolutions were less than ??/180; then the one with a real cover is the front page of an AVR manual that is in pdf.

I don't see a "problem" as it is like a line of text is either word wrapped or not. Visually, I would like to see a graphic cover fill the space as much as possible without distortion. On a TV, there is a difference in presentation of 'full screen' & 'adjusted/anamophic' (?) where the picture is either distorted to fill a screen or having parts of the picture cut off.

The only 'cure' is to select or adjust each cover's resolution to be the same size; I think adjusting the cover picture is too much work for me as I rather that downloaded cover is what it is supposed to be & accommodated for the book.

I have win10 & a LG 4k monitor; I do not use the LG's monitor driver as had found that win10 had/has a conflict under some situations in the scaling of what I was viewing.

edit mode: In the cover mode, you can also see the resolution display when moving the arrow to the detail at the right side & hover with the arrow. Looks to be nice for comparing the 'full size' & smaller size cover resolutions which will help to change the cover sizes if so desired.

[kovidgoyal]

Preferences->look & feel->cover grid->performance->empty disk cache

then restart calibre. That should take care of any stale cache issues.

[theducks]

Originally Posted by kovidgoyal

Preferences->look & feel->cover grid->performance->empty disk cache

then restart calibre. That should take care of any stale cache issues.

I did not even realize there were side tabs

Originally Posted by kovidgoyal

Preferences->look & feel->cover grid->performance->empty disk cache

then restart calibre. That should take care of any stale cache issues.

Thanks. I didn't notice that feature either.

That did it for like 60% of the small images. There are still some remaining for some reason.

There was 500MB+ of old cache data there, now calibre shows only half of that but there are still some old files in the cache folders with dates other than current?

[kovidgoyal]

You can always empty the cache folder manually using windows explorer -- shutdown calibre first.

[theducks]

Is it possible that some of those images are NOT really small? They are the ones that have huge transparent borders. Look at the dimensions of those full size, cover images (they seem to always be square). Those will need to be replaced (Trimming wlil get rid the border, but resolution now suffers)

No, images are all ok.

It seems automatic function doesn't delete all of the old thumbnail cache.
Manually deleting everything in ~Calibre Portable\Calibre Settings\caches\gui-thumbnail-cache as suggested by kovidgoyal did the trick. So thanks again for the solution.