关于QT的QPainterPath::arcTo 详解

void TestArcTo::paintEvent(QPaintEvent *)
{
QPoint startPt(30, 30);
QRect rect(startPt.x(), startPt.y(), 200, 200);
QPainter p(this); 
p.setRenderHint(QPainter::Antialiasing); //抗锯齿
p.fillRect(rect, QColor(255, 255, 255));

int arcR = rect.width()/2;
int rectSize = rect.width();
QPainterPath path;

path.moveTo(startPt.x() + arcR, startPt.y() + arcR); //先移动到圆心
path.arcTo(rect, 00.0f, 180.0f);      //以0度起点，逆时针画180度

p.fillPath(path, QBrush(QColor(122, 122, 122)));
}