示例#1
0
int mglnrel::ptInArea(
    const Point2d& pt, int count, const Point2d* pts, 
    int& order, const Tol& tol, bool closed)
{
    int i;
    int odd = 1;    // 1: 交点数为偶数, 0: 交点数为奇数
    float minDist = tol.equalPoint();
    Point2d nearpt;
    
    order = -1;
    for (i = 0; i < count && tol.equalPoint() < 1.e5f; i++)
    {
        // P与某顶点重合. 返回 kPtAtVertex, order = 顶点号 [0, count-1]
        float d = pt.distanceTo(pts[i]);
        if (minDist > d) {
            minDist = d;
            order = i;
        }
    }
    if (order >= 0) {
        return kPtAtVertex;
    }
    
    order = -1;
    minDist = tol.equalPoint();
    
    for (i = 0; i < (closed ? count : count - 1); i++)
    {
        const Point2d& p1 = pts[i];
        const Point2d& p2 = (i+1 < count) ? pts[i+1] : pts[0];
        
        // P在某条边上. 返回 kPtOnEdge, order = 边号 [0, count-1]
        float d = mglnrel::ptToBeeline2(p1, p2, pt, nearpt);
        if (minDist > d) {
            minDist = d;
            order = i;
        }
        else if (!PtInArea_Edge(odd, pt, p1, p2, 
                                i > 0 ? pts[i-1] : pts[count-1])) {
            continue;
        }
    }
    if (order >= 0) {
        return kPtOnEdge;
    }

    // 如果射线和多边形的交点数为偶数, 则 p==1, P在区外, 返回 kPtOutArea
    // 为奇数则p==0, P在区内, 返回 kPtInArea
    return 0 == odd ? kPtInArea : kPtOutArea;
}
示例#2
0
bool mglnrel::isBetweenLine2(
    const Point2d& a, const Point2d& b, const Point2d& pt, const Tol& tol)
{
    if (!mglnrel::isColinear2(a, b, pt, tol))
        return false;
    
    // If ab not vertical, check betweenness on x; else on y.
    if (a.x != b.x) 
    {
        return ((a.x <= pt.x + tol.equalPoint()) 
            && (pt.x <= b.x + tol.equalPoint())) 
            || ((a.x >= pt.x - tol.equalPoint()) 
            && (pt.x >= b.x - tol.equalPoint()));
    }
    else
    {
        return ((a.y <= pt.y + tol.equalPoint()) 
            && (pt.y <= b.y + tol.equalPoint())) 
            || ((a.y >= pt.y - tol.equalPoint()) 
            && (pt.y >= b.y - tol.equalPoint()));
    }
}
示例#3
0
bool mglnrel::isLeftOn2(
    const Point2d& a, const Point2d& b, const Point2d& pt, const Tol& tol)
{
    float dist = (b-a).distanceToVector(pt-a);
    return dist > -tol.equalPoint();
}
示例#4
0
bool mglnrel::isColinear2(
    const Point2d& a, const Point2d& b, const Point2d& pt, const Tol& tol)
{
    float dist = (b-a).crossProduct(pt-a);
    return fabsf(dist) < tol.equalPoint();
}
示例#5
0
// 判断点pt是否在有向直线a->b的左边
GEOMAPI bool mgIsLeft2(
    const Point2d& a, const Point2d& b, const Point2d& pt, const Tol& tol)
{
    float dist = (b-a).distanceToVector(pt-a);
    return dist > tol.equalPoint();
}