Function getLeftPointAt

Engine/CoonsRegularization.cpp:126–189

}

static Point
getLeftPointAt(const BezierCPs& cps,
               double time,
               double t)
{
    int ncps = (int)cps.size();

    assert(ncps);
    if (!ncps) {
        throw std::logic_error("getLeftPointAt()");
    }
    if (t < 0) {
        t += ncps;
    }
    int t_i = (int)std::floor(t) % ncps;
    int t_i_plus_1 = t_i % ncps;
    assert(t_i >= 0 && t_i < ncps && t_i_plus_1 >= 0 && t_i_plus_1 < ncps);
    if (t == t_i) {
        BezierCPs::const_iterator it = cps.begin();
        std::advance(it, t_i);
        Point ret;
        (*it)->getLeftBezierPointAtTime(false, time, ViewIdx(0), &ret.x, &ret.y);

        return ret;
    } else if (t == t_i_plus_1) {
        BezierCPs::const_iterator it = cps.begin();
        std::advance(it, t_i_plus_1);
        Point ret;
        (*it)->getLeftBezierPointAtTime(false, time, ViewIdx(0), &ret.x, &ret.y);

        return ret;
    }

    BezierCPs::const_iterator it = cps.begin();
    std::advance(it, t_i);
    BezierCPs::const_iterator next = it;
    ++next;
    if ( next == cps.end() ) {
        next = cps.begin();
    }

    t = t - t_i;

    Point a, b, c, ab, bc, abc;
    Point ret;
    (*it)->getPositionAtTime(false, time, ViewIdx(0), &a.x, &a.y);
    (*it)->getRightBezierPointAtTime(false, time, ViewIdx(0), &b.x, &b.y);
    (*next)->getLeftBezierPointAtTime(false, time, ViewIdx(0), &c.x, &c.y);
    ab.x = (1. - t) * a.x + t * b.x;
    ab.y = (1. - t) * a.y + t * b.y;

    bc.x = (1. - t) * b.x + t * c.x;
    bc.y = (1. - t) * b.y + t * c.y;

    abc.x = (1. - t) * ab.x + t * bc.x;
    abc.y = (1. - t) * ab.y + t * bc.y;
    if ( (abc.x == a.x) && (abc.y == a.y) ) {
        (*it)->getLeftBezierPointAtTime(false, time, ViewIdx(0), &ret.x, &ret.y);