function linePolygonIntersect(a1x, a1y, a2x, a2y, points) {
    for (var i = 0, p2 = points[points.length - 1]; i < points.length; i++) {
        var p = points[i];
        if (lineLineIntersect(a1x, a1y, a2x, a2y, p[0], p[1], p2[0], p2[1])) {
            return true;
        }
        p2 = p;
    }
}
Get color property or get color from option.textStyle.color
@param {boolean} [isEmphasis]
@return {string}