示例#1
0
Length Toolbox::arcRadius(const Point& p1, const Point& p2,
                          const Angle& a) noexcept {
  if (a == 0) {
    return Length(0);
  } else {
    qreal x1    = p1.getX().toMm();
    qreal y1    = p1.getY().toMm();
    qreal x2    = p2.getX().toMm();
    qreal y2    = p2.getY().toMm();
    qreal angle = a.mappedTo180deg().toRad();
    qreal d     = qSqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1));
    qreal r     = d / (2 * qSin(angle / 2));
    return Length::fromMm(r);
  }
}
示例#2
0
Point Toolbox::arcCenter(const Point& p1, const Point& p2,
                         const Angle& a) noexcept {
  if (a == 0) {
    // there is no arc center...just return the middle of start- and endpoint
    return (p1 + p2) / 2;
  } else {
    // http://math.stackexchange.com/questions/27535/how-to-find-center-of-an-arc-given-start-point-end-point-radius-and-arc-direc
    qreal x0       = p1.getX().toMm();
    qreal y0       = p1.getY().toMm();
    qreal x1       = p2.getX().toMm();
    qreal y1       = p2.getY().toMm();
    qreal angle    = a.mappedTo180deg().toRad();
    qreal angleSgn = (angle >= 0) ? 1 : -1;
    qreal d        = qSqrt((x1 - x0) * (x1 - x0) + (y1 - y0) * (y1 - y0));
    qreal r        = d / (2 * qSin(angle / 2));
    qreal h        = qSqrt(r * r - d * d / 4);
    qreal u        = (x1 - x0) / d;
    qreal v        = (y1 - y0) / d;
    qreal a        = ((x0 + x1) / 2) - h * v * angleSgn;
    qreal b        = ((y0 + y1) / 2) + h * u * angleSgn;
    return Point::fromMm(a, b);
  }
}