GMap.net 地图标绘实现（一）
孟杰
- GeometryUtil帮助类：主要用于空间参考（坐标）转换，距离计算等等。
public class GeometryUtil
{
private const double EARTH_RADIUS = 6378.137;//地球半径
/// <summary>
/// 获取多边形几何中心点
/// </summary>
/// <param name="mapPolygon"></param>
/// <returns></returns>
public static PointLatLng GetCenterPoint(GMapPolygon mapPolygon)
{
if (mapPolygon == null)
{
return new PointLatLng();
}
List<GeoAPI.Geometries.Coordinate> coordinates = new List<GeoAPI.Geometries.Coordinate>();
foreach (var value in mapPolygon.Points)
{
GeoAPI.Geometries.Coordinate coordinate = new GeoAPI.Geometries.Coordinate(value.Lng, value.Lat);
coordinates.Add(coordinate);
}
if (mapPolygon.Points.Count == 2)
{
NetTopologySuite.Geometries.LineString lineString = new NetTopologySuite.Geometries.LineString(coordinates.ToArray());
IPoint point = lineString.Centroid;
return new PointLatLng(point.Y, point.X);
}
else
{
if (mapPolygon.Points[0].Lng != mapPolygon.Points[mapPolygon.Points.Count - 1].Lng ||
mapPolygon.Points[0].Lat != mapPolygon.Points[mapPolygon.Points.Count - 1].Lat)
{
coordinates.Add(new GeoAPI.Geometries.Coordinate(mapPolygon.Points[0].Lng, mapPolygon.Points[0].Lat));
}
NetTopologySuite.Geometries.LinearRing linearRing = new NetTopologySuite.Geometries.LinearRing(coordinates.ToArray());
NetTopologySuite.Geometries.Polygon polygon = new NetTopologySuite.Geometries.Polygon(linearRing);
IPoint point = polygon.Centroid;
return new PointLatLng(point.Y, point.X);
}
}
public static List<Coordinate> WGS84ToWebMercator(List<PointLatLng> pointLatLngs)
{
if (pointLatLngs == null)
return null;
IList<Coordinate> coors = PointsToCoords(pointLatLngs);
NetTopologySuite.Geometries.PrecisionModel precisionModel = new NetTopologySuite.Geometries.PrecisionModel(GeoAPI.Geometries.PrecisionModels.Floating);
GeoAPI.CoordinateSystems.ICoordinateSystem wgs84 = ProjNet.CoordinateSystems.GeographicCoordinateSystem.WGS84;
GeoAPI.CoordinateSystems.ICoordinateSystem webMercator = ProjNet.CoordinateSystems.ProjectedCoordinateSystem.WebMercator;
int SRID_wgs84 = Convert.ToInt32(wgs84.AuthorityCode); //WGS84 SRID
int SRID_webMercator = Convert.ToInt32(webMercator.AuthorityCode); //WebMercator SRID
ProjNet.CoordinateSystems.Transformations.CoordinateTransformationFactory ctFact = new ProjNet.CoordinateSystems.Transformations.CoordinateTransformationFactory();
GeoAPI.CoordinateSystems.Transformations.ICoordinateTransformation transformation = ctFact.CreateFromCoordinateSystems(wgs84, webMercator);
NetTopologySuite.Geometries.GeometryFactory factory_wgs84 = new NetTopologySuite.Geometries.GeometryFactory(precisionModel, SRID_wgs84);
IList<Coordinate> coords = transformation.MathTransform.TransformList(coors);
//var gcgs2000 = CreateCoordinateSystemFromWkt("GEOGCS[\"China Geodetic Coordinate System 2000\",DATUM[\"China_2000\",SPHEROID[\"CGCS2000\",6378137,298.257222101,AUTHORITY[\"EPSG\",\"1024\"]],AUTHORITY[\"EPSG\",\"1043\"]],PRIMEM[\"Greenwich\",0,AUTHORITY[\"EPSG\",\"8901\"]],UNIT[\"degree\",0.0174532925199433,AUTHORITY[\"EPSG\",\"9122\"]],AUTHORITY[\"EPSG\",\"4490\"]]");
//var gcgs4508 = CreateCoordinateSystemFromWkt("PROJCS[\"CGCS2000 / Gauss-Kruger CM 111E\",GEOGCS[\"China Geodetic Coordinate System 2000\",DATUM[\"China_2000\",SPHEROID[\"CGCS2000\",6378137,298.257222101,AUTHORITY[\"EPSG\",\"1024\"]],AUTHORITY[\"EPSG\",\"1043\"]],PRIMEM[\"Greenwich\",0,AUTHORITY[\"EPSG\",\"8901\"]],UNIT[\"degree\",0.0174532925199433,AUTHORITY[\"EPSG\",\"9122\"]],AUTHORITY[\"EPSG\",\"4490\"]],PROJECTION[\"Transverse_Mercator\"],PARAMETER[\"latitude_of_origin\",0],PARAMETER[\"central_meridian\",111],PARAMETER[\"scale_factor\",1],PARAMETER[\"false_easting\",500000],PARAMETER[\"false_northing\",0],UNIT[\"metre\",1,AUTHORITY[\"EPSG\",\"9001\"]],AUTHORITY[\"EPSG\",\"4508\"]]");
//IList<Coordinate> temps = ConvertCoordinates(coors.ToList(), gcgs2000,gcgs4508);
//IList<Coordinate> temps1= ConvertCoordinates(temps.ToList(), gcgs4508,gcgs2000);
return coords.ToList();
}
public static List<PointLatLng> WGS84ToWebMercator2(List<PointLatLng> pointLatLngs)
{
List<Coordinate> temps = WGS84ToWebMercator(pointLatLngs);
List<PointLatLng> points = CoordsToPoints(temps);
return points;
}
public static List<PointLatLng> WebMercatorToWGS84(List<PointLatLng> pointLatLngs)
{
return ConvertCoordinates(pointLatLngs, ProjNet.CoordinateSystems.ProjectedCoordinateSystem.WebMercator, ProjNet.CoordinateSystems.GeographicCoordinateSystem.WGS84);
}
public static List<PointLatLng> CoordsToPoints(List<Coordinate> coords)
{
List<PointLatLng> points = new List<PointLatLng>();
foreach (var entity in coords)
{
points.Add(new PointLatLng(entity.Y, entity.X));
}
return points;
}
public static List<Coordinate> PointsToCoords(List<PointLatLng> points)
{
List<Coordinate> coords = new List<Coordinate>();
foreach(var entity in points)
{
coords.Add(new Coordinate(entity.Lng, entity.Lat));
}
return coords;
}
/// <summary>
/// 默认创建EPSG:4490 国家2000大地坐标系
/// </summary>
/// <param name="wkt"></param>
/// <returns></returns>
public static GeoAPI.CoordinateSystems.ICoordinateSystem CreateCoordinateSystemFromWkt(string wkt)
{
if (string.IsNullOrEmpty(wkt))
wkt = "GEOGCS[\"China Geodetic Coordinate System 2000\",DATUM[\"China_2000\",SPHEROID[\"CGCS2000\",6378137,298.257222101,AUTHORITY[\"EPSG\",\"1024\"]],AUTHORITY[\"EPSG\",\"1043\"]],PRIMEM[\"Greenwich\",0,AUTHORITY[\"EPSG\",\"8901\"]],UNIT[\"degree\",0.0174532925199433,AUTHORITY[\"EPSG\",\"9122\"]],AUTHORITY[\"EPSG\",\"4490\"]]";
try
{
ICoordinateSystemFactory coordinateSystemFactory = new ProjNet.CoordinateSystems.CoordinateSystemFactory();
GeoAPI.CoordinateSystems.ICoordinateSystem coordinateSystem = coordinateSystemFactory.CreateFromWkt(wkt);
return coordinateSystem;
}
catch
{
return null;
}
}
public static List<Coordinate> ConvertCoordinates(List<Coordinate> coordinates, ICoordinateSystem sourceCoordinateSystem, ICoordinateSystem targetCoordinateSystem)
{
if (coordinates == null || sourceCoordinateSystem == null || targetCoordinateSystem==null)
throw new Exception("请输入正确的参数");
NetTopologySuite.Geometries.PrecisionModel precisionModel = new NetTopologySuite.Geometries.PrecisionModel(GeoAPI.Geometries.PrecisionModels.Floating);
int SRID_source = Convert.ToInt32(sourceCoordinateSystem.AuthorityCode); //source SRID
int SRID_target = Convert.ToInt32(targetCoordinateSystem.AuthorityCode); //target SRID
ProjNet.CoordinateSystems.Transformations.CoordinateTransformationFactory transformationFactory = new ProjNet.CoordinateSystems.Transformations.CoordinateTransformationFactory();
GeoAPI.CoordinateSystems.Transformations.ICoordinateTransformation transformation = transformationFactory.CreateFromCoordinateSystems(sourceCoordinateSystem, targetCoordinateSystem);
//NetTopologySuite.Geometries.GeometryFactory factory_source = new NetTopologySuite.Geometries.GeometryFactory(precisionModel, SRID_source);
IList<Coordinate> coords = transformation.MathTransform.TransformList(coordinates);
return coords.ToList();
}
public static List<PointLatLng> ConvertCoordinates(List<PointLatLng> coordinates, ICoordinateSystem sourceCoordinateSystem, ICoordinateSystem targetCoordinateSystem)
{
List<Coordinate> tempCoordinates = new List<Coordinate>();
foreach(var entity in coordinates)
{
tempCoordinates.Add(new Coordinate(x: entity.Lng, y: entity.Lat));
}
if (coordinates == null || sourceCoordinateSystem == null || targetCoordinateSystem == null)
throw new Exception("请输入正确的参数");
NetTopologySuite.Geometries.PrecisionModel precisionModel = new NetTopologySuite.Geometries.PrecisionModel(GeoAPI.Geometries.PrecisionModels.Floating);
int SRID_source = Convert.ToInt32(sourceCoordinateSystem.AuthorityCode); //source SRID
int SRID_target = Convert.ToInt32(targetCoordinateSystem.AuthorityCode); //target SRID
ProjNet.CoordinateSystems.Transformations.CoordinateTransformationFactory transformationFactory = new ProjNet.CoordinateSystems.Transformations.CoordinateTransformationFactory();
GeoAPI.CoordinateSystems.Transformations.ICoordinateTransformation transformation = transformationFactory.CreateFromCoordinateSystems(sourceCoordinateSystem, targetCoordinateSystem);
//NetTopologySuite.Geometries.GeometryFactory factory_source = new NetTopologySuite.Geometries.GeometryFactory(precisionModel, SRID_source);
IList<Coordinate> coords = transformation.MathTransform.TransformList(tempCoordinates);
List<PointLatLng> points = new List<PointLatLng>();
foreach(var entity in coords)
{
if (double.IsNaN(entity.X) || double.IsNaN(entity.Y))
continue;
points.Add(new PointLatLng(entity.Y, entity.X));
}
return points;
}
public static double GetArea(List<PointLatLng> pointLatLngs)
{
if (pointLatLngs == null)
{
return 0;
}
if (pointLatLngs.Count <= 2)
{
return 0;
}
List<GeoAPI.Geometries.Coordinate> coordinates = WGS84ToWebMercator(pointLatLngs);
if (coordinates[0].X != coordinates[coordinates.Count - 1].X ||
coordinates[0].Y != coordinates[coordinates.Count - 1].Y)
{
coordinates.Add(new GeoAPI.Geometries.Coordinate(coordinates[0].X, coordinates[0].Y));
}
NetTopologySuite.Geometries.LinearRing linearRing = new NetTopologySuite.Geometries.LinearRing(coordinates.ToArray());
NetTopologySuite.Geometries.Polygon polygon = new NetTopologySuite.Geometries.Polygon(linearRing);
IPoint point = polygon.Centroid;
return polygon.Area;
}
public static double GetArea(GMapPolygon mapPolygon)
{
if (mapPolygon == null)
{
return 0;
}
return GetArea(mapPolygon.Points);
}
public static RectLatLng GetRegionMaxRect(GMapPolygon polygon)
{
double latMin = 90;
double latMax = -90;
double lngMin = 180;
double lngMax = -180;
foreach (var point in polygon.Points)
{
if (point.Lat < latMin)
{
latMin = point.Lat;
}
if (point.Lat > latMax)
{
latMax = point.Lat;
}
if (point.Lng < lngMin)
{
lngMin = point.Lng;
}
if (point.Lng > lngMax)
{
lngMax = point.Lng;
}
}
return new RectLatLng(latMax, lngMin, lngMax - lngMin, latMax - latMin);
}
public static double GetDistance(double lat1, double lng1, double lat2, double lng2)
{
PointLatLng first = new PointLatLng(lat2,lng1);
PointLatLng second = new PointLatLng(lat2,lng2);
List<PointLatLng> pointLatLngs = new List<PointLatLng>();
pointLatLngs.Add(first);
pointLatLngs.Add(second);
var coordinates= WGS84ToWebMercator(pointLatLngs);
NetTopologySuite.Geometries.LineString lineString = new NetTopologySuite.Geometries.LineString(coordinates.ToArray());
return lineString.Length;
}
public static double GetDistance2(double lat1, double lng1, double lat2, double lng2)
{
double radLat1 = DegreesToRadians(lat1);
double radLat2 = DegreesToRadians(lat2);
double a = radLat1 - radLat2;
double b = DegreesToRadians(lng1) - DegreesToRadians(lng2);
double s = 2 * Math.Asin(Math.Sqrt(Math.Pow(Math.Sin(a / 2), 2) +
Math.Cos(radLat1) * Math.Cos(radLat2) * Math.Pow(Math.Sin(b / 2), 2)));
s = s * EARTH_RADIUS;
s = Math.Round(s * 10000) / 10000;
return s;
}
/// <summary>
/// 求B点经纬度
/// </summary>
/// <param name="A">已知点的经纬度</param>
/// <param name="distance">AB两地的距离 单位km</param>
/// <param name="angle">AB连线与正北方向的夹角（0~360）</param>
/// <returns>B点的经纬度</returns>
public static CustomLatLng GetCustomLatLng(CustomLatLng A, double distance, double angle)
{
double dx = distance * 1000 * Math.Sin(DegreesToRadians(angle));
double dy = distance * 1000 * Math.Cos(DegreesToRadians(angle));
double bjd = (dx / A.Ed + A.m_RadLo) * 180 / Math.PI;
double bwd = (dy / A.Ec + A.m_RadLa) * 180 / Math.PI;
return new CustomLatLng(bjd, bwd);
}
//度 转换成 弧度
public static double DegreesToRadians(double degrees)
{
const double degToRadFactor = Math.PI / 180;
return degrees * degToRadFactor;
}
/// <summary>
/// 弧度 转换成 度
/// </summary>
/// <param name="radians"></param>
/// <returns></returns>
public static double RadiansToDegrees(double radians)
{
const double radToDegFactor = 180 / Math.PI;
return radians * radToDegFactor;
}
/// <summary>
/// 描述：以centerP为圆心，绘制半径为radius的圆
/// </summary>
/// <param name="gMapControl">overlay：图层</param>
/// <param name="overlay">图层</param>
/// <param name="centerP">圆心点</param>
/// <param name="radius">圆半径(单位: km)</param>
/// <param name="name">多边形id</param>
public static GMapPolygon DrawEllipse(GMapControl gMapControl, GMapOverlay overlay, PointLatLng centerP, int radius, string name)
{
try
{
if (radius <= 0)
return null;
List<PointLatLng> latLngs = new List<PointLatLng>();
CustomLatLng centerLatLng = new CustomLatLng(centerP.Lng, centerP.Lat);
// 0 - 360度 寻找半径为radius，圆心为centerP的圆上点的经纬度
for (int i = 0; i < 360; i++)
{
//获取目标经纬度
CustomLatLng tempLatLng = GetCustomLatLng(centerLatLng, radius, i);
//将自定义的经纬度类 转换成 标准经纬度类
PointLatLng p = new PointLatLng(tempLatLng.m_Latitude, tempLatLng.m_Longitude);
latLngs.Add(p);
}
//安全性检查
if (latLngs.Count < 20)
{
return null;
}
//通过绘制多边形的方式绘制圆
GMapPolygon gpol = new GMapPolygon(latLngs, name);
gpol.Stroke = new Pen(Color.Red, 1.0f);
gpol.Fill = new SolidBrush(Color.FromArgb(20, Color.Red));
gpol.IsHitTestVisible = true;
overlay.Polygons.Add(gpol);
return gpol;
}
catch (Exception ex)
{
return null;
}
}
}
//自定义经纬度类
public class CustomLatLng
{
public double Rc = 6378137; //赤道半径
public double Rj = 6356725; //极半径
public double m_LoDeg, m_LoMin, m_LoSec;
public double m_LaDeg, m_LaMin, m_LaSec;
public double m_Longitude, m_Latitude;
public double m_RadLo, m_RadLa;
public double Ec;
public double Ed;
public CustomLatLng(double longitude, double latitude)
{
m_LoDeg = (int)longitude;
m_LoMin = (int)((longitude - m_LoDeg) * 60);
m_LoSec = (longitude - m_LoDeg - m_LoMin / 60) * 3600;
m_LaDeg = (int)latitude;
m_LaMin = (int)((latitude - m_LaDeg) * 60);
m_LaSec = (latitude - m_LaDeg - m_LaMin / 60) * 3600;
m_Longitude = longitude;
m_Latitude = latitude;
m_RadLo = longitude * Math.PI / 180;
m_RadLa = latitude * Math.PI / 180;
Ec = Rj + (Rc - Rj) * (90 - m_Latitude) / 90;
Ed = Ec * Math.Cos(m_RadLa);
}
}
- 用于绘制的接口定义IPlot
public interface IPlot
{
/// <summary>
/// 是否为图元
/// </summary>
/// <returns></returns>
bool IsPlot();
/// <summary>
/// 获取当前图元的点集数量
/// </summary>
/// <param name="value"></param>
void SetPoints(PointLatLng[] value);
/// <summary>
/// 获取当前图元的点集
/// </summary>
/// <returns>图元的点集</returns>
PointLatLng[] GetPoints();
/// <summary>
/// 获取当前图元的点集数量
/// </summary>
/// <returns>图元的点集的数量</returns>
int GetPointCount();
/// <summary>
/// 更新某个索引的点
/// </summary>
/// <param name="point">点</param>
/// <param name="index">位置</param>
void UpdatePoint(PointLatLng point, int index);
/// <summary>
/// 更新最后一个点
/// </summary>
/// <param name="point">{ol.Coordinate}</param>
void UpdateLastPoint(PointLatLng point);
/// <summary>
/// 图元绘制逻辑.各个图元用来覆盖
/// </summary>
void Generate();
/// <summary>
/// 图元结束绘制回调
/// </summary>
void FinishDrawing();
}
- Constants：常量定义
public class Constants
{
public static readonly double TWO_PI = Math.PI*2;
public static readonly double HALF_PI = Math.PI / 2;
public static readonly int FITTING_COUNT = 100;
public static readonly double ZERO_TOLERANCE = 0.0001;
}
- PlotTypes：标绘图元枚举类型
public enum PlotTypes
{
[Description("点")]
MARKER =1,
[Description("折线")]
POLYLINE =2,
[Description("多边形")]
POLYGON =3,
[Description("圆")]
CIRCLE =4,
[Description("椭圆")]
ELLIPSE=5,
[Description("矩形")]
RECTANGLE =6,
[Description("弧线")]
ARC =7,
[Description("进攻箭头")]
ATTACK_ARROW =8,
[Description("曲线面")]
CLOSED_CURVE =9,
[Description("曲线")]
CURVE =10,
[Description("双箭头")]
DOUBLE_ARROW =11,
[Description("细直箭头")]
FINE_ARROW =12,
[Description("突击方向")]
ASSAULT_DIRECTION =13,
[Description("自由线")]
FREEHAND_LINE =14,
[Description("自由面")]
FREEHAND_POLYGON =15,
[Description("聚集地")]
GATHERING_PLACE =16,
[Description("弓形")]
LUNE =17,
[Description("扇形")]
SECTOR =18,
[Description("分队战斗行动")]
SQUAD_COMBAT=19,
[Description("直箭头")]
STRAIGHT_ARROW =20,
[Description("进攻箭头（尾）")]
TAILED_ATTACK_ARROW =21,
[Description("分队战斗行动（尾）")]
TAILED_SQUAD_COMBAT =22,
}
- PlotUtil：这个是核心类库，包括箭头算法、贝塞尔曲线和B样条曲线等。这儿的箭头计算坐标是EPSG:4326下的坐标
public class PlotUtil
{
public static double ConvertDegreesToRadians(double degrees)
{
double radians = (Math.PI / 180) * degrees;
return (radians);
}
public static double Distance(PointLatLng pnt1,PointLatLng pnt2)
{
return Math.Sqrt(Math.Pow((pnt1.Lng - pnt2.Lng), 2) + Math.Pow((pnt1.Lat - pnt2.Lat), 2));
}
public static double WholeDistance(List<PointLatLng> points)
{
double _distance = 0.0;
for(int i = 0; i < points.Count-1; i++)
{
_distance += Distance(points[i], points[i + 1]);
}
return _distance;
}
public static double GetBaseLength(List<PointLatLng> points)
{
return Math.Pow(WholeDistance(points), 0.99);
}
public static PointLatLng Mid(PointLatLng pnt1,PointLatLng pnt2)
{
return new PointLatLng((pnt1.Lat + pnt2.Lat) / 2, (pnt1.Lng + pnt2.Lng) / 2);
}
public static PointLatLng GetCircleCenterOfThreePoints(PointLatLng pnt1, PointLatLng pnt2, PointLatLng pnt3)
{
var pntA = new PointLatLng((pnt1.Lat + pnt2.Lat) / 2, (pnt1.Lng + pnt2.Lng) / 2);
var pntB = new PointLatLng(pntA.Lat + pnt1.Lng - pnt2.Lng, pntA.Lng - pnt1.Lat + pnt2.Lat);
var pntC = new PointLatLng((pnt1.Lat + pnt3.Lat) / 2, (pnt1.Lng + pnt3.Lng) / 2);
var pntD = new PointLatLng(pntC.Lat + pnt1.Lng - pnt3.Lng, pntC.Lng - pnt1.Lat + pnt3.Lat);
return GetIntersectPoint(pntA, pntB, pntC, pntD);
}
public static PointLatLng GetIntersectPoint(PointLatLng pntA, PointLatLng pntB, PointLatLng pntC, PointLatLng pntD)
{
if (pntA.Lat == pntB.Lat)
{
var f = (pntD.Lng - pntC.Lng) / (pntD.Lat - pntC.Lat);
var x = f * (pntA.Lat - pntC.Lat) + pntC.Lng;
var y = pntA.Lat;
return new PointLatLng(y, x);
}
if (pntC.Lat == pntD.Lat)
{
var e = (pntB.Lng - pntA.Lng) / (pntB.Lat - pntA.Lat);
var x = e * (pntC.Lat - pntA.Lat) + pntA.Lng;
var y = pntC.Lat;
return new PointLatLng(y, x);
}
else
{
var e = (pntB.Lng - pntA.Lng) / (pntB.Lat - pntA.Lat);
var f = (pntD.Lng - pntC.Lng) / (pntD.Lat - pntC.Lat);
var y = (e * pntA.Lat - pntA.Lng - f * pntC.Lat + pntC.Lng) / (e - f);
var x = e * y - e * pntA.Lat + pntA.Lng;
return new PointLatLng(y, x);
}
}
/// <summary>
/// 获取方位角
/// </summary>
/// <param name="startPnt">起点</param>
/// <param name="endPnt">终点</param>
public static double GetAzimuth(PointLatLng startPnt,PointLatLng endPnt)
{
double azimuth = 0.0;
var angle = Math.Asin(Math.Abs(endPnt.Lat - startPnt.Lat) / Distance(startPnt, endPnt));
if (endPnt.Lat >= startPnt.Lat && endPnt.Lng >= startPnt.Lng)
azimuth = angle + Math.PI;
else if (endPnt.Lat >= startPnt.Lat && endPnt.Lng < startPnt.Lng)
azimuth = Constants.TWO_PI - angle;
else if (endPnt.Lat < startPnt.Lat && endPnt.Lng < startPnt.Lng)
azimuth = angle;
else if (endPnt.Lat < startPnt.Lat && endPnt.Lng >= startPnt.Lng)
azimuth = Math.PI - angle;
return azimuth;
}
public static double GetAngleOfThreePoints(PointLatLng pntA, PointLatLng pntB, PointLatLng pntC)
{
var angle = GetAzimuth(pntB, pntA) - GetAzimuth(pntB, pntC);
return (angle < 0 ? angle + Constants.TWO_PI : angle);
}
public static bool IsClockWise(PointLatLng pnt1, PointLatLng pnt2, PointLatLng pnt3)
{
return ((pnt3.Lat - pnt1.Lat) * (pnt2.Lng - pnt1.Lng) > (pnt2.Lat - pnt1.Lat) * (pnt3.Lng - pnt1.Lng));
}
public static PointLatLng GetPointOnLine(double t,PointLatLng startPnt,PointLatLng endPnt)
{
var x = startPnt.Lng + (t * (endPnt.Lng - startPnt.Lng));
var y = startPnt.Lat + (t * (endPnt.Lat - startPnt.Lat));
return new PointLatLng(y,x);
}
public static PointLatLng GetCubicValue(double t, PointLatLng startPnt, PointLatLng cPnt1, PointLatLng cPnt2, PointLatLng endPnt)
{
t = Math.Max(Math.Min(t, 1), 0);
var tp = 1 - t;
var t2 = t * t;
var t3 = t2 * t;
var tp2 = tp * tp;
var tp3 = tp2 * tp;
var x = (tp3 * startPnt.Lng) + (3 * tp2 * t * cPnt1.Lng) + (3 * tp * t2 * cPnt2.Lng) + (t3 * endPnt.Lng);
var y = (tp3 * startPnt.Lat) + (3 * tp2 * t * cPnt1.Lat) + (3 * tp * t2 * cPnt2.Lat) + (t3 * endPnt.Lat);
return new PointLatLng(y,x);
}
public static PointLatLng GetThirdPoint(PointLatLng startPnt, PointLatLng endPnt, double angle,double distance,bool clockWise)
{
var azimuth = GetAzimuth(startPnt, endPnt);
var alpha = clockWise ? azimuth + angle : azimuth - angle;
var dx = distance * Math.Cos(alpha);
var dy = distance * Math.Sin(alpha);
return new PointLatLng(endPnt.Lat + dy,endPnt.Lng + dx);
}
public static List<PointLatLng> GetArcPoints(PointLatLng center, double radius, double startAngle, double endAngle)
{
List<PointLatLng> pnts = new List<PointLatLng>();
var angleDiff = endAngle - startAngle;
angleDiff = angleDiff < 0 ? angleDiff + Constants.TWO_PI : angleDiff;
for (var i = 0; i <= Constants.FITTING_COUNT; i++)
{
var angle = startAngle + angleDiff * i / Constants.FITTING_COUNT;
double x = center.Lng + radius * Math.Cos(angle);
double y = center.Lat + radius * Math.Sin(angle);
pnts.Add(new PointLatLng(y,x));
}
return pnts;
}
public static PointLatLng[] GetBisectorNormals(double t, PointLatLng pnt1, PointLatLng pnt2, PointLatLng pnt3)
{
var normal = GetNormal(pnt1, pnt2, pnt3);
var dist = Math.Sqrt(normal.Lng * normal.Lng + normal.Lat * normal.Lat);
var uX = normal.Lng / dist;
var uY = normal.Lat / dist;
var d1 = Distance(pnt1, pnt2);
var d2 = Distance(pnt2, pnt3);
PointLatLng bisectorNormalRight;
PointLatLng bisectorNormalLeft;
if (dist > Constants.ZERO_TOLERANCE)
{
if (IsClockWise(pnt1, pnt2, pnt3))
{
var dt = t * d1;
var x = pnt2.Lng - dt * uY;
var y = pnt2.Lat + dt * uX;
bisectorNormalRight = new PointLatLng(y, x);
dt = t * d2;
x = pnt2.Lng + dt * uY;
y = pnt2.Lat - dt * uX;
bisectorNormalLeft = new PointLatLng(y, x);
}
else
{
var dt = t * d1;
var x = pnt2.Lng + dt * uY;
var y = pnt2.Lat - dt * uX;
bisectorNormalRight = new PointLatLng(y, x);
dt = t * d2;
x = pnt2.Lng - dt * uY;
y = pnt2.Lat + dt * uX;
bisectorNormalLeft = new PointLatLng(y, x);
}
}
else
{
var x = pnt2.Lng + t * (pnt1.Lng - pnt2.Lng);
var y = pnt2.Lat + t * (pnt1.Lat - pnt2.Lat);
bisectorNormalRight = new PointLatLng(y, x);
x = pnt2.Lng + t * (pnt3.Lng - pnt2.Lng);
y = pnt2.Lat + t * (pnt3.Lat - pnt2.Lat);
bisectorNormalLeft = new PointLatLng(y, x);
}
return new PointLatLng[] { bisectorNormalRight, bisectorNormalLeft };
}
public static PointLatLng GetNormal(PointLatLng pnt1, PointLatLng pnt2, PointLatLng pnt3)
{
var dX1 = pnt1.Lng - pnt2.Lng;
var dY1 = pnt1.Lat - pnt2.Lat;
var d1 = Math.Sqrt(dX1 * dX1 + dY1 * dY1);
dX1 /= d1;
dY1 /= d1;
var dX2 = pnt3.Lng - pnt2.Lng;
var dY2 = pnt3.Lat- pnt2.Lat;
var d2 = Math.Sqrt(dX2 * dX2 + dY2 * dY2);
dX2 /= d2;
dY2 /= d2;
var uX = dX1 + dX2;
var uY = dY1 + dY2;
return new PointLatLng(uY,uX);
}
public static List<PointLatLng> GetCurvePoints(double t, PointLatLng[] controlPoints)
{
var leftControl = GetLeftMostControlPoint(t, controlPoints);
List<PointLatLng> normals = new List<PointLatLng> { leftControl };
for (int i = 0; i < controlPoints.Length - 2; i++)
{
var pnt1 = controlPoints[i];
var pnt2 = controlPoints[i + 1];
var pnt3 = controlPoints[i + 2];
var normalPoints = GetBisectorNormals(t, pnt1, pnt2, pnt3);
normals = normals.Concat(normalPoints).ToList();
}
var rightControl = GetRightMostControlPoint(t,controlPoints);
normals.Add(rightControl);
List<PointLatLng> points = new List<PointLatLng>();
for (int i = 0; i < controlPoints.Length - 1; i++)
{
var pnt1 = controlPoints[i];
var pnt2 = controlPoints[i + 1];
points.Add(pnt1);
for(var k = 0.0; k < Constants.FITTING_COUNT; k++)
{
PointLatLng pnt = GetCubicValue(k / Constants.FITTING_COUNT, pnt1, normals[i * 2], normals[i * 2 + 1], pnt2);
points.Add(pnt);
}
points.Add(pnt2);
}
return points;
}
public static PointLatLng GetLeftMostControlPoint(double t, PointLatLng[] controlPoints)
{
var pnt1 = controlPoints[0];
var pnt2 = controlPoints[1];
var pnt3 = controlPoints[2];
var pnts = GetBisectorNormals(0, pnt1, pnt2, pnt3);
var normalRight = pnts[0];
var normal = GetNormal(pnt1, pnt2, pnt3);
var dist = Math.Sqrt(normal.Lng * normal.Lng + normal.Lat * normal.Lat);
double controlX = 0;
double controlY = 0;
if (dist > Constants.ZERO_TOLERANCE)
{
var arr_mid = Mid(pnt1, pnt2);
var pX = pnt1.Lng - arr_mid.Lng;
var pY = pnt1.Lat - arr_mid.Lat;
var d1 = Distance(pnt1, pnt2);
// normal at midpoint
var n = 2.0 / d1;
var nX = -n * pY;
var nY = n * pX;
// upper triangle of symmetric transform matrix
var a11 = nX * nX - nY * nY;
var a12 = 2 * nX * nY;
var a22 = nY * nY - nX * nX;
var dX = normalRight.Lng - arr_mid.Lng;
var dY = normalRight.Lat - arr_mid.Lat;
// coordinates of reflected vector
controlX = arr_mid.Lng + a11 * dX + a12 * dY;
controlY = arr_mid.Lat + a12 * dX + a22 * dY;
}
else
{
controlX = pnt1.Lng + t * (pnt2.Lng - pnt1.Lng);
controlY = pnt1.Lat + t * (pnt2.Lat - pnt1.Lat);
}
return new PointLatLng(controlY, controlX);
}
public static PointLatLng GetRightMostControlPoint(double t, PointLatLng[] controlPoints)
{
var count = controlPoints.Length;
var pnt1 = controlPoints[count - 3];
var pnt2 = controlPoints[count - 2];
var pnt3 = controlPoints[count - 1];
var pnts = GetBisectorNormals(0, pnt1, pnt2, pnt3);
var normalLeft = pnts[1];
var normal = GetNormal(pnt1, pnt2, pnt3);
var dist = Math.Sqrt(normal.Lng * normal.Lng + normal.Lat * normal.Lat);
double controlX = 0;
double controlY = 0;
if (dist > Constants.ZERO_TOLERANCE)
{
var arr_mid = Mid(pnt2, pnt3);
var pX = pnt3.Lng - arr_mid.Lng;
var pY = pnt3.Lat - arr_mid.Lat;
var d1 = Distance(pnt2, pnt3);
// normal at midpoint
var n = 2.0 / d1;
var nX = -n * pY;
var nY = n * pX;
// upper triangle of symmetric transform matrix
var a11 = nX * nX - nY * nY;
var a12 = 2 * nX * nY;
var a22 = nY * nY - nX * nX;
var dX = normalLeft.Lng - arr_mid.Lng;
var dY = normalLeft.Lat - arr_mid.Lat;
// coordinates of reflected vector
controlX = arr_mid.Lng + a11 * dX + a12 * dY;
controlY = arr_mid.Lat + a12 * dX + a22 * dY;
}
else
{
controlX = pnt3.Lng + t * (pnt2.Lng - pnt3.Lng);
controlY = pnt3.Lat + t * (pnt2.Lat - pnt3.Lat);
}
return new PointLatLng(controlY, controlX);
}
public static List<PointLatLng> GetBezierPoints(PointLatLng[] points)
{
if (points.Length <= 2)
return points.ToList();
List<PointLatLng> bezierPoints = new List<PointLatLng>();
var n = points.Length - 1;
for (var t = 0.0; t <= 1; t += 0.01)
{
double x = 0.0;
double y = 0.0;
for (var index = 0; index <= n; index++)
{
var factor = GetBinomialFactor(n, index);
var a = Math.Pow(t, index);
var b = Math.Pow((1 - t), (n - index));
x += factor * a * b * points[index].Lng;
y += factor * a * b * points[index].Lat;
}
bezierPoints.Add(new PointLatLng(y, x));
}
bezierPoints.Add(points[n]);
return bezierPoints;
}
public static double GetBinomialFactor(double n, double index)
{
return GetFactorial(n) / (GetFactorial(index) * GetFactorial(n - index));
}
public static double GetFactorial(double n)
{
if (n <= 1)
return 1;
if (n == 2)
return 2;
if (n == 3)
return 6;
if (n == 4)
return 24;
if (n == 5)
return 120;
var result = 1;
for (var i = 1; i <= n; i++)
result *= i;
return result;
}
public static List<PointLatLng> GetQBSplinePoints(PointLatLng[] points)
{
if (points.Length <= 2)
return points.ToList();
int n = 2;
List<PointLatLng> bSplinePoints = new List<PointLatLng>();
int m = points.Length - n - 1;
bSplinePoints.Add(points[0]);
for (int i = 0; i <= m; i++)
{
for (var t = 0.0; t <= 1; t += 0.05)
{
var x = 0.0;
var y = 0.0;
for (var k = 0; k <= n; k++)
{
var factor = GetQuadricBSplineFactor(k, t);
x += factor * points[i + k].Lng;
y += factor * points[i + k].Lat;
}
bSplinePoints.Add(new PointLatLng(y, x));
}
}
bSplinePoints.Add(points[points.Length - 1]);
return bSplinePoints;
}
public static double GetQuadricBSplineFactor(int k, double t)
{
if (k == 0)
return Math.Pow(t - 1, 2) / 2;
if (k == 1)
return (-2 * Math.Pow(t, 2) + 2 * t + 1) / 2;
if (k == 2)
return Math.Pow(t, 2) / 2;
return 0;
}
}
- 全部接口和帮助类全部从js到C#重写完毕，重写设计以后不合理的地方应该蛮多。有能力的可以自己设计重写。下一篇将开始写对应图元构建类。
- 刚开始写博客，存在太多问题，希望多多包涵。
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