使用 QIcon alignleft 和文本居中对齐构造 QPushButton

Question

I would like to create QPushButton with QIcon left align (not to the center as default) and text center align. I don't want to use a style sheet. I know that might be possibly using QPainter but I wasn't able to do it. I had little clue and tried this code:

void MyPushButton::paintEvent(QPaintEvent *)
{
    QStylePainter painter(this);
    QStyleOptionButton opt;
    initStyleOption(&opt);
    painter.drawItemPixmap(opt.rect, Qt::AlignLeft, opt.icon);
    painter.drawItemText(opt.rect, Qt::AlignCenter, palette(), 1, opt.text);
    painter.drawPrimitive(QStyle::PE_PanelButtonCommand, opt);
}

which produces this error message

no matching function for call to 'QStylePainter::drawItemPixmap(QRect&, Qt::AlignmentFlag, QIcon&)' painter.drawItemPixmap(opt.rect, Qt::AlignCenter, opt.icon);

What's wrong with code above?

Answer 1

you're getting

this error code error: no matching function for call to 'QStylePainter::drawItemPixmap(QRect&, Qt::AlignmentFlag, QIcon&)' painter.drawItemPixmap(opt.rect, Qt::AlignCenter, opt.icon);

because drawItemPixmap draws... a pixmap. Not an icon. So all you need to do is get the icons pixmap using the pixmap() accessor.

change

painter.drawItemPixmap(opt.rect, Qt::AlignLeft, opt.icon);

to

// or whaever size you want
painter.drawItemPixmap(opt.rect, Qt::AlignLeft, opt.icon.pixmap(QSize(16,16)));