Introduce KContextualHelpButton - QtWidgets Edition
Summary
KContextualHelpButton allows to hide text of any length behind a small icon-only button. Hovering over the button with a mouse cursor or pressing the button will show the text. It can contain images and links. It is accessible by keyboard and to screen readers. See the documentation within the header file if you want more details.
Motivation
I introduced the Contextual Help Button to QML a while ago (https://commits.kde.org/plasma-desktop/ca49df931ba82688668e4e0bc24ab59eb76fe571). After some early doubts about its usefulness, it has been adopted more and more and is now used on many settings pages. It is also being added as one of the recommendations in our Human Interface Guidelines.
People stop me in the streets and ask: "Aren't you the guy who revolutionised inline help discoverability on Linux?"
And I say: "Why yes. Thank you. And you are welcome!"
Then we both make finger guns at each other. Afterwards I wake up and remember that normal people don't really think about this kind of stuff.
Where was I? In any case I thought we definitely should also have such a component in the QtWidgets world, so here it is.
Video
Testing
There is the Dolphin MR system/dolphin!746 (closed) for testing.