Preview Update Issue - Page 3

DiapDealer · 12-03-2025, 04:57 PM

Quote:

Originally Posted by KevinH

I think to due to how complicated this issue may turn out, we should move the entire sequence to its own thread.

Good call (both moving the thread AND turning off acceleration)!

A newer version of Qt means more video cards (or their drivers) start acting a little flaky.

@Turtle91: make sure your video drivers are the latest. You might be able to reenable acceleration. But honestly, I've not met the epub that doesn't open and refresh just as fast regardless of acceleration. Mine's been off for a long time.

Let me know if anyone would like a different title for this new thread.

KevinH · 12-03-2025, 05:14 PM

We moved to Qt 6.9.3 and I bet there is a Windows bug that prevents the update from happening somehow. So either a Qt bug or a driver bug. The Qt 6.9.3 now direct writes to a Qt screen buffer each time that QtWebEngine is "updated". There may be a new bug in them doing that that turning off acceleration prevents.

So happy you have found a workaround.

BeckyEbook · 12-03-2025, 05:59 PM

FYI: I always have GPU acceleration turned off.

The problem is difficult to pinpoint because it has a certain element of randomness, so repeatability is hard to achieve. But if I manage to find a repeatable example, I will definitely share it.

It's not that I'm complaining a lot, because if there is a workaround (choosing a different xhtml file), then it's something I can live with.

KevinH · 12-03-2025, 06:26 PM

Quote:

Originally Posted by BeckyEbook

FYI: I always have GPU acceleration turned off.

The problem is difficult to pinpoint because it has a certain element of randomness, so repeatability is hard to achieve. But if I manage to find a repeatable example, I will definitely share it.

It's not that I'm complaining a lot, because if there is a workaround (choosing a different xhtml file), then it's something I can live with.

Good to know. Thank you. Once this release settles down we can chat about if handling Replace Class, and Custom CSS cycling, when editing CSS and (not xhtml) should be handled some other way besides ignoring it (what we do now) or invalidating the cache (which would blank out Preview completely) forcing a user to reload the xhtml manually.

theducks · 12-03-2025, 08:32 PM

Quote:

Originally Posted by KevinH

I tried your instructions (see my test case) and I could not see any issue. BeckyEbook also tried my simple testcase and it worked on Windows. She then pointed out other "inconsistencies" but they are all expected behaviour and have existed in Sigil for many many releases.

She says she can recreate your issue but no one yet has provided a epub test case that shows it since my simple test case does not show it on any platform.

I would add a vote for been inconsistent for a while. Usually a Save corrected it.

KevinH · 12-04-2025, 10:24 AM

Those inconsistencies were all related to Rename Class, and using different injected custom stylesheets which are actually operating as designed since they use a cached xhtml page.

If you are seeing inconsistencies in Preview not updating when edit editing of css, then please try disabling gpu acceleration if you are on Windows. If it still happens, please post a test case epub along with a clear set of instructions so that we can recreate it.

Thanks!

12-03-2025, 05:14 PM	#32
KevinH Sigil Developer Posts: 9,124 Karma: 6404930 Join Date: Nov 2009 Device: many	We moved to Qt 6.9.3 and I bet there is a Windows bug that prevents the update from happening somehow. So either a Qt bug or a driver bug. The Qt 6.9.3 now direct writes to a Qt screen buffer each time that QtWebEngine is "updated". There may be a new bug in them doing that that turning off acceleration prevents. So happy you have found a workaround. Last edited by KevinH; 12-03-2025 at 05:30 PM.

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12-03-2025, 05:59 PM	#33
BeckyEbook Guru Posts: 906 Karma: 3501166 Join Date: Jan 2017 Location: Poland Device: Various	FYI: I always have GPU acceleration turned off. The problem is difficult to pinpoint because it has a certain element of randomness, so repeatability is hard to achieve. But if I manage to find a repeatable example, I will definitely share it. It's not that I'm complaining a lot, because if there is a workaround (choosing a different xhtml file), then it's something I can live with.

12-04-2025, 10:24 AM	#36
KevinH Sigil Developer Posts: 9,124 Karma: 6404930 Join Date: Nov 2009 Device: many	Those inconsistencies were all related to Rename Class, and using different injected custom stylesheets which are actually operating as designed since they use a cached xhtml page. If you are seeing inconsistencies in Preview not updating when edit editing of css, then please try disabling gpu acceleration if you are on Windows. If it still happens, please post a test case epub along with a clear set of instructions so that we can recreate it. Thanks!