关于QWT的学习问题--下面代码注释处的问题,请问大家来帮忙解决一下?
void Plotter::paintEvent(QPaintEvent * /* event */)
{
QStylePainter painter(this);
painter.drawPixmap(0, 0, pixmap);
if (rubberBandIsShown) {
painter.setPen(palette().light().color());
painter.drawRect(rubberBandRect.normalized()
.adjusted(0, 0, -1, -1));
}
if (hasFocus()) {
QStyleOptionFocusRect option;
option.initFrom(this);
option.backgroundColor = palette().dark().color();/*这里的表达式是什么意思?*/
painter.drawPrimitive(QStyle::PE_FrameFocusRect, option);
}
}