Blurry PDF at some zoom levels in version 7.0.11

warwickmm · December 6, 2024

I updated to version 7.0.11 (64-bit) on Linux and noticed that a certain PDF is blurry when the zoom level is set to "Zoom to Page Height".

Version 7.0.10 at "Zoom to Page Height":

https://s3.amazonaws.com/zotero.org/images/forums/u7554954/xhza1b9uttqmt72o3sil.png

Version 7.0.11 at "Zoom to Page Height":

https://s3.amazonaws.com/zotero.org/images/forums/u7554954/mk4u16dy6mr80nzcenzj.png

Version 7.0.11 zoomed out one step from "Zoom to Page Height":

https://s3.amazonaws.com/zotero.org/images/forums/u7554954/6feus9anygoikd4z4hoq.png

Version 7.0.11 zoomed in one step from "Zoom to Page Height":

https://s3.amazonaws.com/zotero.org/images/forums/u7554954/tf21qqeg60e8fsxtlpae.png

warwickmm · December 6, 2024

The problematic PDF can be found here:

https://wiki.epfl.ch/edicpublic/documents/Candidacy exam/millerdavenport2010.pdf

martynas_b · December 9, 2024

Can you notice this in other zoom modes?

warwickmm · December 9, 2024

I have not noticed this in other zoom modes. When zooming in and out using Ctrl +/-, the text is momentarily blurry before regaining focus (this was the behavior in 7.0.10 as well). At the "Zoom to Page Height" level, it just remains blurry.

I also found that the problem occurs with a number of PDFs (but not all of them). Here's another one:

https://comptes-rendus.academie-sciences.fr/mathematique/item/10.1016/j.crma.2008.03.014.pdf

The problem also seems to occur with a lot of IEEE Transactions articles as well.

warwickmm · December 10, 2024

This occurs with both my laptop screen (1920x1200) as well as an external screen (2560x1440).

warwickmm · December 11, 2024

Another interesting observation. If I:

1. Zoom to page height (this is blurry).
2. Check Split Horizontally.
3. Uncheck Split Hoizontally.

The page is no longer blurry. However, if I then Zoom to page width and then Zoom to page height, the page is blurry again.

warwickmm · December 17, 2024

This sounds similar to

https://forums.zotero.org/discussion/comment/480964#Comment_480964

However, I'm still experiencing this in 7.0.11 and 7.0.12-beta.1+31bbf2acf (64-bit) on Linux.

abccccc · February 20, 2025

It seems I have got the same issue after updating to 7.0.12:
https://forums.zotero.org/discussion/122029/font-blurred-in-reader-after-upgrade-to-7-0-12

abccccc · February 21, 2025

Upgrade to 7.0.13 solves the issue.

dstillman · February 21, 2025

It might not. @abccccc, you were seeing a specific regression in 7.0.12 — due to some backported fixes from the Zotero 7.1 beta — that wasn't present in 7.0.11. There may be one or two other, rarer issues with zoom and text sharpness that are still present. @warwickmm, let us know if you still see this in 7.0.13 and/or the current 7.1 beta.

warwickmm · February 21, 2025

I still see this with version 7.1-beta.14+2e9b9d407 (64-bit) on Linux.

warwickmm · February 21, 2025

I also see this with version 7.0.13 (64-bit) on Linux, albeit at a different zoom level than with 7.1-beta.14.

The below examples show blurry versions when initially using Zoom to Page Height. If I then check and then uncheck Split Horizontally, the text becomes clear:

Zoom to Page Height:

https://s3.amazonaws.com/zotero.org/images/forums/u7554954/3bvxhusv1lom1qwbjj9n.png

After checking and then unchecking Split Horizontally:

https://s3.amazonaws.com/zotero.org/images/forums/u7554954/oqxfi76pf7zwep0o1c8c.png

Zoom to Page Height:

https://s3.amazonaws.com/zotero.org/images/forums/u7554954/2a8ysgobrq1v5kotx9ku.png

After checking and then unchecking Split Horizontally:

https://s3.amazonaws.com/zotero.org/images/forums/u7554954/rieg9ababxorvfdclg91.png

warwickmm · February 22, 2025

In fact, I'm finding many more cases of blurriness with 7.0.13 (64-bit) than with 7.1-beta.14

warwickmm · March 11, 2025

Just wanted to note that this is still an issue with 7.1-beta.20+b78bf8e24 (64-bit) on Linux.

Tannenfreund 87 · March 27, 2025

It depends on your display scaling. It's an underlying bug in firefox, the base of zotero:
> https://bugzilla.mozilla.org/show_bug.cgi?id=1771184
> https://github.com/zotero/zotero/issues/1972
> https://github.com/mozilla/pdf.js/issues/10807

I have perfectly fine fonts at 100%, 125%, 150% and 200%. Everything else becomes various levels of blurriness. Same for firefox and zotero. Now the PDFs render worse on my high PPI screen than on a regular 96 PPI one.

warwickmm · March 27, 2025

Thanks. I'm experiencing the issue on a non-4k monitor without scaling.

I just noticed that the problem appears to be fixed in version 7.0.15, but still exists in 7.1-beta.24+929147b33.

I believe 7.0.15 has this patch.

warwickmm · June 25, 2025

This seems to be fixed in version 7.1-beta.41+355c61e6d (64-bit).

warwickmm · 2025-08-04T15:27:55+00:00

The blurry text has come back in version 8.0-beta.2+2bff6541f (64-bit) on Linux.

martynas_b · 2025-08-05T09:58:02+00:00

Can anyone reproduce this on Windows or macOS using 8.0-beta?

poettli · 2025-08-08T09:29:37+00:00

I have tried on Linux and macOS with 8.0-beta.4+96dd7b16a, I don't see any blurry font

Zoom to Page Height:
https://s3.amazonaws.com/zotero.org/images/forums/u2119014/4d1he9dxp4llj5r2vzh7.png
After checking and then unchecking Split Horizontally:
https://s3.amazonaws.com/zotero.org/images/forums/u2119014/tcyhb4aj5j35pdgnp0kr.png
Ubuntu 22.04.5 LTS
Resolution: 2560 x 1440
Refresh rate: 74.93 Hz
Scale: 100%

warwickmm · 2025-08-08T15:25:59+00:00

It doesn't happens with all PDFs (the one that poettli shows is now fine). However, it still happens with this one:

https://wiki.epfl.ch/edicpublic/documents/Candidacy exam/millerdavenport2010.pdf

When using Odd Spreads and Zoom to Page Width:

7.1-beta.48:

https://s3.amazonaws.com/zotero.org/images/forums/u7554954/hwhyybr1p2h8q7nmfc7t.png

8.0-beta.4:

https://s3.amazonaws.com/zotero.org/images/forums/u7554954/tvltrk3ltp82g2ev2hhx.png

The checking/unchecking Split Horizontally no longer does anything for me. Simply using Odd Spreads with Zoom to Page Width results in blurry text for several PDFs.

If I use No Spreads, then the text is clear.

Arch Linux with 6.15.8 kernel
Resolution: 2560x1440
Refresh rate: 59.95 Hz
Scale: 100%

iagogv · 2025-08-08T23:44:25+00:00

I can reproduce

https://s3.amazonaws.com/zotero.org/images/forums/u6735168/x87lvtajuvwbgk89v32x.png

openSUSE Tumbleweed 20250807 with kernel 6.15.8-1-default
Resolution: 1920 x 1080
Refresh rate: 60.04
Zotero 8.0-beta.4+96dd7b16a (64-bit)
vs
Firefox 141.0 (64-bit)
Scale: On Firefox, 630%. On Zotero, I do not know, as it does not appear specified anywhere (wouldn't be great to have a place to look at the exact zoom used?)