c++ - 找到绘制的线的交点

Question

在qt中是否可以找到两个QLineF的交点。我画了一条线交叉到另一条线，我想找到两条线的交点。我在 qgraphicsitem 绘画事件中绘图。

Answer 1

是的，it is possible .

IntersectType QLineF::intersect(const QLineF & line, QPointF * intersectionPoint) const

Returns a value indicating whether or not this line intersects with the given line.

The actual intersection point is extracted to intersectionPoint (if the pointer is valid). If the lines are parallel, the intersection point is undefined.

因此，您将在 intersectionPoint 输出参数中获得交点。因此，你会写这样的东西:

// Get the two lines
myLineF1.interect(myLineF2, myIntersectionPoint);
// Do something with myIntersectionPoint