Qt Assistant help file (qgis.qch) style issues

[jakimowb]

Description

The QGIS C++ API documentation can be downloaded as Qt Help file (qgis.qch) from https://qgis.org/api
Added to the Qt Assistant, this allows to browse and search the API docs very fast.

Since QGIS 3.18, the qgis.qch seems to have some broken styles affecting hyperlinks and table (?) elements, which makes it pretty unreadable:

Affected versions

The following files are affected by these changes:

https://qgis.org/api/qgis.qch
https://qgis.org/api/3.18/qgis.qch

The latest version where it looks fine to me is:
https://qgis.org/api/3.16/qgis.qch

Environment:

So far I found this error on Windows 10 only, were I tested it with the Qt Assistant for QGIS 3.19 (via OSGeo4W for testing) and QGIS 3.18 (via conda forge).

[roya0045]

what is the qt version of the assistant and your qgis installs? The files should be generated by qt and a mismatch may be the cause of those issues.

[jakimowb]

Tested Environments:

Testd Helpfile Versions
qgis-3.21.qch https://qgis.org/api/qgis.qch (current development branch)
qgis-3.20.qch https://qgis.org/api/3.20/qgis.qch
qgis-3.18.qch https://qgis.org/api/3.18/qgis.qch
qgis-3.16.qch https://qgis.org/api/3.16/qgis.qch

OS	QGIS	Env	Qt / Qt Assistant	Style problems?
Win10	3.19	OSGeo4W	5.15.2 QTextBrowser	qgis-3.21.qch qgis-3.20.qch qgis-3.18.qch
Win10	3.18.1	conda	5.12.9 QTextBrowser	qgis-3.19.qch qgis-3.18.qch
Ubuntu 18.04.5	3.18.1	conda	5.12.9 QTextBrowser	qgis-3.19.qch qgis-3.18.qch

[jakimowb]

@roya0045

Looks like these styling issues appear only when Qt Assistant uses the QTextBrowser instead of the Qt WebKit

[roya0045]

@jakimowb That would explain why the webtags were faulty. Thanks!

[jakimowb]

I created a ticked in the OSGeo4W issue tracker (@jef-n , https://trac.osgeo.org/osgeo4w/ticket/708), as this seems to be a problem that affects mostly windows users