这个函数是永远return 0 吗?
uint ShadeWidget::colorAt(int x){ generateShade(); QPolygonF pts = m_hoverPoints->points(); for (int i=1; i < pts.size(); ++i) { if (pts.at(i-1).x() <= x && pts.at(i).x() >= x) { QLineF l(pts.at(i-1), pts.at(i)); l.setLength(l.length() * ((x - l.x1()) / l.dx())); return m_shade.pixel(qRound(qMin(l.x2(), (qreal(m_shade.width() - 1)))), qRound(qMin(l.y2(), qreal(m_shade.height() - 1)))); } } return 0;}