There was no way to merge removal of properties which is required in
case you want to unset some property on the current selected text in a
text document. For example in case your text has font size set in pixels
and you want to change it to point size, that would be impossible before
this change. With this change you can set the font point size to what
you want and then set font pixel size to QVariant().
This is maybe not the most obvious way to do it but any other way I
could think of would require new api and quite some code duplication.
[ChangeLog][QtGui][Text] QTextFormat now allows setting properties to an
invalid QVariant to allow clearing properties via a merge. This changes
behavior slightly where code iterating over a QTextFormats properties
would never encounter invalid variants, which is now possible if
setProperty with an invalid variant was used instead of using the
clearProperty function to remove properties.
Change-Id: Ie8290088d457bf19d9c4785cfe91ae6a1de572c4
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>
b2aeac9891