Method isPointInPoly

src/openlayers/overlay/Label.js:953–960

* @function Label.prototype.isPointInPoly * @description 判断一个点是否在多边形里面（射线法）。 * @param {Object} pt - 需要判定的点对象，该对象含有属性 x（横坐标），属性 y（纵坐标）。 * @param {Array. } poly - 多边形节点数组。例如一个四边形：[{"x":1,"y":1},{"x":3,"y":1},{"x":6,"y":4},{"x":2,"y":10},{"x":1,"y":1}]。 * @returns {boolean} 点

(pt, poly)

     * @returns {boolean} 点是否在多边形内。
     */
    isPointInPoly(pt, poly) {
        for (var isIn = false, i = -1, l = poly.length, j = l - 1; ++i < l; j = i) {
            ((poly[i].y <= pt.y && pt.y < poly[j].y) || (poly[j].y <= pt.y && pt.y < poly[i].y)) &&
            (pt.x < (poly[j].x - poly[i].x) * (pt.y - poly[i].y) / (poly[j].y - poly[i].y) + poly[i].x) &&
            (isIn = !isIn);
        }
        return isIn;
    }


    canvasFunctionInternal_(extent, resolution, pixelRatio, size, projection) { // eslint-disable-line no-unused-vars