text: /*
   *  BMKCircle.h
   *  BMapKit
   *
   *  Copyright 2011 Baidu Inc. All rights reserved.
   *
   */
  
  #import "BMKShape.h"
  #import "BMKMultiPoint.h"
  #import "BMKOverlay.h"
  #import "BMKGeometry.h"
  
  /// 该类用于定义一个圆
  @interface BMKCircle : BMKMultiPoint <BMKOverlay> {
  @package
      BOOL _invalidate;
      CLLocationCoordinate2D _coordinate;
      CLLocationDistance _radius;
      
      BMKMapRect _boundingMapRect;
  }
  
  /**
   *根据中心点和半径生成圆
   *@param coord 中心点的经纬度坐标
   *@param radius 半径，单位：米
   *@return 新生成的圆
   */
  + (BMKCircle *)circleWithCenterCoordinate:(CLLocationCoordinate2D)coord
                                    radius:(CLLocationDistance)radius;
  
  /**
   *根据指定的直角坐标矩形生成圆，半径由较长的那条边决定，radius = MAX(width, height)/2
   *@param mapRect 指定的直角坐标矩形
   *@return 新生成的圆
   */
  + (BMKCircle *)circleWithMapRect:(BMKMapRect)mapRect;
  
  /// 中心点坐标
  @property (nonatomic, readonly) CLLocationCoordinate2D coordinate;
  
  /// 半径，单位：米
  @property (nonatomic, readonly) CLLocationDistance radius;
  
  /// 该圆的外接矩形
  @property (nonatomic, readonly) BMKMapRect boundingMapRect; 
  
  @end
  