opencv3求两点间距离以及点到直线距离函数

求两点间距离

/***** 求两点间距离*****/
float getDistance(CvPoint pointO, CvPoint pointA)
{
    float distance;
    distance = powf((pointO.x - pointA.x), 2) + powf((pointO.y - pointA.y), 2);
    distance = sqrtf(distance);
    return distance;
}

点到直线的距离:P到AB的距离

/***** 点到直线的距离:P到AB的距离*****/
//P为线外一点，AB为线段两个端点
float getDist_P2L(CvPoint pointP, CvPoint pointA, CvPoint pointB)
{
    //求直线方程
    int A = 0, B = 0, C = 0;
    A = pointA.y - pointB.y;
    B = pointB.x - pointA.x;
    C = pointA.x*pointB.y - pointA.y*pointB.x;
    //代入点到直线距离公式
    float distance = 0;
    distance = ((float)abs(A*pointP.x + B*pointP.y + C)) / ((float)sqrtf(A*A + B*B));
    return distance;
}