map组件 怎样判断用户位置是否在多边形范围内，用来判断签到逻辑

1. 绘制打卡范围

                var points = new Array(  
                    this.bd2gcjString(116.1820943298403, 39.750488978269416),  
                    this.bd2gcjString(116.19165426654206, 39.750488978269416),  
                    this.bd2gcjString(116.19165426654206, 39.74736124994377),  
                    this.bd2gcjString(116.1820943298403, 39.74736124994377)  
                );  
                var polygonObj = new plus.maps.Polygon(points);  
                polygonObj.setStrokeColor( #0199FE );  
                polygonObj.setFillColor( #66faff );  
                polygonObj.setFillOpacity(0.5);  
                polygonObj.setLineWidth(3);  
                mapContent.$getAppMap().addOverlay(polygonObj);

2. 获取个人位置后，判断范围

            mapContent.$getAppMap().getUserLocation(function(state, point) {  
                    if (0 == state) {  
                        that.latitude = point.latitude;  
                        that.longitude = point.longitude;  
                        console.log( 个人位置：  + JSON.stringify(point));  
                        var markObj = new plus.maps.Marker(point);  
                        markObj.setIcon( static/ic_baidu_local.png );  
                        markObj.setLabel( 当前所在位置 );  
                        var bubble = new plus.maps.Bubble( 当前所在位置 );  
                        markObj.setBubble(bubble);  
                        mapContent.$getAppMap().addOverlay(markObj);  
                        //判断是否在打卡范围内  
                        if (that.IsPtInPoly(point, polygonObj)) {  
                            that.locText =  在范围内 ;  
                        } else {  
                            that.locText =  在范围外 ;  
                        }  
                    }  
                });

3. 方法

IsPtInPoly(o, l) {  
            var t = l.getPath();  
            var h = t.length;  
            var n = true;  
            var j = 0;  
            var g = 2e-10;  
            var s, q;  
            var e = o;  
            s = t[0];  
            for (var f = 1; f <= h; ++f) {  
                if (e.equals(s)) {  
                    return n;  
                }  
                q = t[f % h];  
                if (e.latitude < Math.min(s.latitude, q.latitude) || e.latitude > Math.max(s.latitude, q.latitude)) {  
                    s = q;  
                    continue;  
                }  
                if (e.latitude > Math.min(s.latitude, q.latitude) && e.latitude < Math.max(s.latitude, q.latitude)) {  
                    if (e.longitude <= Math.max(s.longitude, q.longitude)) {  
                        if (s.latitude == q.latitude && e.longitude >= Math.min(s.longitude, q.longitude)) {  
                            return n;  
                        }  
                        if (s.longitude == q.longitude) {  
                            if (s.longitude == e.longitude) {  
                                return n;  
                            } else {  
                                ++j;  
                            }  
                        } else {  
                            var r = ((e.latitude - s.latitude) * (q.longitude - s.longitude)) / (q.latitude - s.latitude) + s.longitude;  
                            if (Math.abs(e.longitude - r) < g) {  
                                return n;  
                            }  
                            if (e.longitude < r) {  
                                ++j;  
                            }  
                        }  
                    }  
                } else {  
                    if (e.latitude == q.latitude && e.longitude <= q.longitude) {  
                        var m = t[(f + 1) % h];  
                        if (e.latitude >= Math.min(s.latitude, m.latitude) && e.latitude <= Math.max(s.latitude, m.latitude)) {  
                            ++j;  
                        } else {  
                            j += 2;  
                        }  
                    }  
                }  
                s = q;  
            }  
            if (j % 2 == 0) {  
                return false;  
            } else {  
                return true;  
            }  
        }


bd2gcjString(latitude, longitude) {  
            var x_pi = (3.14159265358979324 * 3000.0) / 180.0;  
            var x = latitude - 0.0065,  
                y = longitude - 0.006;  
            var z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * x_pi);  
            var theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * x_pi);  
            return new plus.maps.Point(z * Math.cos(theta), z * Math.sin(theta));  
        }