I wrote a utility to copy the .tags
files from selected module(s) in a Qt docs install folder and place them somewhere local to the Doxygen config. It will optionally concatenate the input files into one big .tags
file so the Doxygen config becomes much simpler if linking to online help (vs. generating a .qhp).
If I have:
project/
doc/
Doxyfile
html/
tagfiles/
qt.tags
src/
The single file can be used like so:
TAGFILES = tagfiles/qt.tags=https://doc.qt.io/qt-5/
Or for QHP:
TAGFILES = \
tagfiles/qtcore.tags=qthelp://org.qt-project.qtcore/qtcore/ \
tagfiles/qtgui.tags=qthelp://org.qt-project.qtgui/qtgui/ \
tagfiles/qtwidgets.tags=qthelp://org.qt-project.qtwidgets/qtwidgets/
Here's an example of docs generated from that repo. All the linking to Qt docs is automatic, including all the inherited stuff in the expandable trees.
Adding the large Qt tags noticeably slows down Doxygen runs, so I would definitely limit the imported tags to only the Qt modules one needs to link to.
UPDATE: There is a bug (QTBUG-61790) (fixed in Qt 5.15.0) in Qt's generation of tags for enumeration values which prevents Doxygen from generating proper links to them. I added a separate utility which fixes the tag files, and also updated the copy utility I linked to at the top to implement the enum fixes.