Programmatically applying the Qt mouse-hover button highlighting on any button - c++

Question

In a Qt application On Windows, when the mouse cursor hovers over a QPushButton, it will be highlighted with a shimmering outline.
I would like to tell any QPushButton to be highlighted like that, programmatically, without it having the mouse cursor actually hovering it.
Is this possible? I've tried setting focus to the button and played with different stylesheets, but I can't seem to access the mouse-hover outline effect.

Answer 1

Solution
If you want to simulate, that a button is constantly under the mouse, my solution would be to inherit from QPushButton and reimplement the paintEvent method, explicitly setting the state of the button to QStyle::State_MouseOver:
option.state |= QStyle::State_MouseOver;
Note: Please, be aware, that this solution will have different effects on different operating systems, as they use different ways to indicate a hovered button. Under Windows 7 for example the whole button will be highlighted, instead of adding a glowing border.
Background
QPushButton is drawn by QStylePainter, as seen in the source code:
void QPushButton::paintEvent(QPaintEvent *)
{
QStylePainter p(this);
QStyleOptionButton option;
initStyleOption(&option);
p.drawControl(QStyle::CE_PushButton, option);
}
The way the button is drawn is determined by the settings held in QStyleOptionButton, which is a subclass of QStyleOption. QStyleOption in turn has a public state attribute, which holds the state flags that are used when drawing the button. The flag QStyle::State_MouseOver is used to indicate that the button is under the mouse.
Example
Finally, here is an example you could try:
In GlowyButton.cpp:
#include "GlowyButton.h"
#include <QStylePainter>
#include <QStyleOptionButton>
...
void GlowyButton::paintEvent(QPaintEvent * /*event*/)
{
QStylePainter p(this);
QStyleOptionButton option;
initStyleOption(&option);
option.state |= QStyle::State_MouseOver;
p.drawControl(QStyle::CE_PushButton, option);
}
...
The full code of the example could be downloaded from GitHub.