Calibre update causes the Viewer to look low-res

[rumplestiltskin]

Originally Posted by rumplestiltskin

Can confirm the issue is with 6.12 and is resolved when reverting to 6.11. My PC is running Win10 Home 22H2 fully updated. Display scaling is 100%. I'll leave it here until I upgrade to Win11 (but I'll check my other PC running Win11 with 6.12 later this evening and report back).
Thanks to all for the dialog.

Just checked and, indeed, my LG Gram running Win11 (updated per M$) and Calibre v6.12 does NOT have any of the font issues in the Viewer (which, in Win10, displayed in an ePub in the Viewer and in the Viewer Preferences screen overlay).

Just to clarify things, Kovid; Calibre 6.12 is using a new version of Qt which Win11 is now also using (and Win10 does not)?

Thank you

[DNSB]

Originally Posted by rumplestiltskin

Just to clarify things, Kovid; Calibre 6.12 is using a new version of Qt which Win11 is now also using (and Win10 does not)?

Totally incorrect. The Windows 11 install uses the same QT version as the Windows 10 install. The issues with QT tend to revolve around the video drivers. IMNSHO, QT's quality assurance has been tossed by the wayside. Sometimes, updating video drivers has helped, other times, success has been found in downgrading video drivers.

[kovidgoyal]

calibre uses the same version of Qt on all platforms/installs. In calibre 6.12 that version of Qt was increased from 6.3 to 6.4.2. This issue seems to affect only some Win10 users. I suggest such users stick with calibre 6.11 until they are in a position to update windows.

[miss_p1nky]

Hi, is this fixed in 6.16?

[miss_p1nky]

Hello, is there a fix for this bug now? Thanks.

[kovidgoyal]

no there isnt

[JSWolf]

Originally Posted by miss_p1nky

Hello, I've just updated to Calibre 6.12 and now all books' fonts and images looks low-res or 'broken' (don't know the proper term). Attached are some screenshots.

https://puu.sh/Jyp3O/5757d0b90c.png

https://puu.sh/Jyp3U/3ee6cb81c9.png

https://puu.sh/Jyp3Z/fd5c7da07e.png

https://puu.sh/Jyp45/f182154e86.png

In the future, would you please not use this push and attach your images so they don't expire?

[JSWolf]

I don't see the viewer looking low-res on Windows 11.

[miss_p1nky]

Originally Posted by JSWolf

In the future, would you please not use this push and attach your images so they don't expire?

Apologies

Originally Posted by JSWolf

I don't see the viewer looking low-res on Windows 11.

Your computer needs to be in a certain setting, it seems but I'm not alone as you can see in the thread, several other people experiences this.

[JSWolf]

Originally Posted by miss_p1nky

Your computer needs to be in a certain setting, it seems but I'm not alone as you can see in the thread, several other people experiences this.

I do have the following system variable set.

QT_ENABLE_HIGHDPI_SCALING=0

[Sirtel]

Originally Posted by miss_p1nky

Hello, is there a fix for this bug now? Thanks.

Adjusting the viewer's width slightly fixed it for me.

[Comfy.n]

https://www.mobileread.com/forums/sh...d.php?t=348475

[miss_p1nky]

Originally Posted by Sirtel

Adjusting the viewer's width slightly fixed it for me.

Every single time? Yes it works. You don't even have to adjust the width. Just move the window a bit, it'd clear up to normal but I would like to have a more permanent solution rather than have to tinker with the Viewer window every single time I need to open a book.

[JSWolf]

Originally Posted by miss_p1nky

Every single time? Yes it works. You don't even have to adjust the width. Just move the window a bit, it'd clear up to normal but I would like to have a more permanent solution rather than have to tinker with the Viewer window every single time I need to open a book.

have you tried adding the environment variable I posted a few messages ago?

[Comfy.n]

Originally Posted by miss_p1nky

Every single time? Yes it works. You don't even have to adjust the width. Just move the window a bit, it'd clear up to normal but I would like to have a more permanent solution rather than have to tinker with the Viewer window every single time I need to open a book.

It's a Qt glitch, I think Kovid can't provide a workaround for that.

Now and then I get that too, and just recently i had to fiddle with Windows scaling settings again in order to get rid of this issue.

In the thread I referenced above there are some pointers on what to look into:

- disable Qt DPI scaling: you can use the file alternative - QT_disable_DPI_scaling.cmd in the zip

- also see this, from @DNSB - https://www.mobileread.com/forums/sh...97&postcount=5

alternatively, if you don't want to to set your Windows scaling to an integer kind (100%), I find this tool useful, as it enables a different kind of scaling from Windows 8.1, and provides more precise control over custom scaling:

https://windows10-dpi-fix.xpexplorer.com/

What works for me currently on a 1920 x 1080 display is

- 103% scaling
- High dpi settings set as in screenshot below
- QT_ENABLE_HIGHDPI_SCALING=0 in env vars