flex+BlazeDS关于军标的实现思路和算法

转：http://bbs.esrichina-bj.cn/esri/viewthread.php?tid=57166

本帖最后由 _daniel 于 2009-11-12 22:26 编辑

前几天说要传军标的算法思想呢，结果有事耽误了，现在我把我军标思想给说一下。
首先利用的技术：前端as语言绘制军标（其实就是个多边形），把多边形的点组成 XML字符串《这里也可以传对象，但是在后台java段也要有相同的对应对象》通过BlazeDS的 RemoteObject方式传到后台。
后台可以通过java保存到数据库中，这个最好是保存为Clob字段。
下面我把关键代码给大家分享一下。。

//处理鼠标单击事件
? public function map_mouseClickHandler(event:MouseEvent):void
? {
?? map.mapNavigationEnabled=false;
?? //确定点击的地图点的坐标，然后放到数组中
?? var m_point:MapPoint=map.toMapFromStage(event.stageX,event.stageY);
?? if (m_firstpoints == null)
?? {
??? m_firstpoints=new Array();
?? }
?? m_firstpoints.push(m_point);
? }
? //处理鼠标双击事件
? public function map_mouseDoubleClickHandler(event:MouseEvent):void
? {
?? m_gbjGeometry=new Polyline();
?? //定义军标的多边形
?? if (m_firstpoints.length <= 2)
?? {
??? m_firstpoints.splice(0);
??? Alert.show("请最少点击三个点才能完成对军标的画法","Error INFO");
??? return;
?? }
?? //根据贝塞尔曲线算法来画线和面
?? drawBezierCurve();
?? //形成graphic
?? full_polygon_graphic=new Graphic(full_gbjpolygon,gbjSymbol);
?? full_polygon_graphic.toolTip="gbj";
?? full_gbjpolygon.spatialReference=map.spatialReference;
?? graphicsLayer.add(full_polygon_graphic);
?? map.removeEventListener(MouseEvent.CLICK,map_mouseClickHandler);
?? map.removeEventListener(MouseEvent.DOUBLE_CLICK,map_mouseDoubleClickHandler);
?? m_firstpoints.splice(0);
?? this.dispatchEvent(new DrawEvent("drawEnd",full_polygon_graphic));
? }

/**
?? *这个是贝塞尔曲线算法函数用于画军标
?? *
?? */
? private function drawBezierCurve():void
? {
?? //主要算法思想是：由中轴线的两点确定一条直线，做直线的垂线，并取垂线上一定距离的点，作成上边曲线和下边曲线
?? if ((m_gbjGeometry.paths != null) && (m_gbjGeometry.paths.length > 0))
?? {
??? m_gbjGeometry.removePath(0);
?? }
?? //判断点击点的季偶性,得到军标的多边形
?? var jishu:Boolean=true;
?? if (m_firstpoints.length % 2 == 0)
?? {
??? jishu=false;
?? }
?? clogger.logger.info("你点击的个数是不是奇数:"+jishu);
?? var curvepoints:Array=getzz_geometry(m_firstpoints,jishu);

?? var dgbj_geometry:Array=getdbx_geometry(curvepoints);
?? full_gbjpolygon=new Polygon(dgbj_geometry);
? }
? /**
?? * 这个函数就是用来求中轴线的，中轴线上的所有点
?? * @param clickarray
?? * @param jishu
?? * @return
?? *
?? */
? private function getzz_geometry(clickarray:Array,jishu:Boolean):Array
? {
?? //首先定义中轴曲线的点坐标
?? var curvepoints:Array=new Array();
?? //数组长度
?? var array_length:Number=clickarray.length;
?? if (jishu)
?? {
??? clogger.logger.info("你点击的次数是奇数个：并且他大于等于三，是：" + clickarray.length + "个");
??? for (var i:int=0; i < clickarray.length - 2; i=i + 2)
??? {
???? for (var j:Number=0; j <= 1; j=j + 0.1)
???? {
????? if (i != 0 && j == 0)
?????? continue;
????? var pos_x:Number=Math.pow((1 - j),2) * clickarray.x + 2 * j * (1 - j) * clickarray[i + 1].x + Math.pow(j,2) * clickarray[i + 2].x;
????? var pos_y:Number=Math.pow((1 - j),2) * clickarray.y + 2 * j * (1 - j) * clickarray[i + 1].y + Math.pow(j,2) * clickarray[i + 2].y;
????? var m_point:MapPoint=new MapPoint(pos_x,pos_y);
????? curvepoints.push(m_point);
???? }
??? }
?? }
?? //下面的是偶数时后,前面那些点还是用三个点来确定，后面四个点用三次贝塞尔曲线来搞定。
?? if (!jishu)
?? {
??? //判断点击的点是不是大于6个，如果是六个的话，首先是先用二次贝塞尔曲线算出前三个来。
??? if (clickarray.length >= 6)
??? {
???? clogger.logger.info("你点击的次数是偶数个：并且他大于等于6，是：" + clickarray.length + "个");
???? for (var i:int=0; i < clickarray.length - 5; i=i + 2)
???? {
????? for (var j:Number=0; j <= 1; j=j + 0.1)
????? {
?????? if (i != 0 && j == 0)
??????? continue;
?????? var pos_x:Number=Math.pow((1 - j),2) * clickarray[i + 2].x;
?????? var pos_y:Number=Math.pow((1 - j),2) * clickarray[i + 2].y;
?????? var m_point:MapPoint=new MapPoint(pos_x,pos_y);
?????? //中轴线的点数
?????? curvepoints.push(m_point);
????? }
???? }
???? //这最后四个点用三次贝塞尔曲线来确定
???? var p_1:MapPoint=clickarray[array_length - 4];
???? var p_2:MapPoint=clickarray[array_length - 3];
???? var p_3:MapPoint=clickarray[array_length - 2];
???? var p_4:MapPoint=clickarray[array_length - 1];
???? for (var k:Number=0; k < 1; k=k + 0.1)
???? {
????? if (k == 0)
?????? continue;
????? var pos_x:Number=p_1.x * Math.pow((1 - k),3) + 3 * p_2.x * k * Math.pow((1 - k),2) + 3 * p_3.x * Math.pow(k,2) * (1 - k) + p_4.x * Math.pow(k,3);
????? var pos_y:Number=p_1.y * Math.pow((1 - k),3) + 3 * p_2.y * k * Math.pow((1 - k),2) + 3 * p_3.y * Math.pow(k,2) * (1 - k) + p_4.y * Math.pow(k,3);
????? var m_point:MapPoint=new MapPoint(pos_x,pos_y);
????? //中心轴的添加
????? curvepoints.push(m_point);
???? }
??? }
??? //如果仅仅就四个点的话，下面是求只有四个点的公式
??? else
??? {
???? clogger.logger.info("你点击的次数是4个，他是：" + clickarray.length + "个");
???? var p_1:MapPoint=clickarray[0];
???? var p_2:MapPoint=clickarray[1];
???? var p_3:MapPoint=clickarray[2];
???? var p_4:MapPoint=clickarray[3];
???? for (var k:Number=0; k < 1; k=k + 0.1)
???? {
????? var pos_x:Number=p_1.x * Math.pow((1 - k),pos_y);
????? //中心轴的添加
????? curvepoints.push(m_point);
???? }
??? }
?? }
?? clogger.logger.info("这个中轴线上的所有的点的个数是：" + curvepoints.length);
?? return curvepoints;
? }

? /** ?? * 这个函数是用来求多边行的各个点的 ?? * 他利用的原理就是求垂线的距离 ?? * @return ?? * ?? */ ? private function getdbx_geometry(curvepoints:Array):Array ? { ?? //定义上边曲线的点坐标数组(当确定军标多边形的时候我是从这个数组开始的) ?? var topcurepoints:Array=new Array(); ?? //定义下边曲线的点坐标数组 ?? var bottomcurepoints:Array=new Array(); ?? //定义左上测的直线 ?? var left_top_points:Array=new Array(); ?? //定义左下侧的直线 ?? var left_bottom_points:Array=new Array(); ?? //定义右上角边的数组 ?? var right_top_points:Array=new Array(); ?? //定义中轴线离上下两边的距离 ?? var dis:Number=(8 - map.level) * (8 - map.level) * 40; ?? //大的框架肯定是从0--1 ?? var c_length:Number=curvepoints.length; ?? for (var u:Number=0; u < curvepoints.length; u++) ?? { ??? if (u == 0) ??? { ???? continue; ??? } ??? else ??? { ???? var m_point:MapPoint=curvepoints; ???? var pos_x:Number=m_point.x; ???? var pos_y:Number=m_point.y; ???? //先求上一点的坐标 ???? var pre_point:MapPoint=curvepoints[u - 1]; ???? //进行计算取的上下边的点 ???? var pre_pos_x:Number=pre_point.x; ???? var pre_pos_y:Number=pre_point.y; ???? var slope:Number=(pos_y - pre_pos_y) / (pos_x - pre_pos_x); ???? //上边点确定 ???? var bb:Number=dis * (1 - u / c_length * 0.9); ???? var cos_number:Number=Math.cos(Math.atan(slope) - Math.PI / 2); ???? var sin_number:Number=Math.sin(Math.atan(slope) - Math.PI / 2); ???? var top_pos_x:Number=0.0; ???? var top_pos_y:Number=0.0; ???? //下面分四种情况画线。 ???? if (pre_pos_x <= pos_x && pre_pos_y <= pos_y) ???? { ????? top_pos_x=pre_pos_x - ((bb * cos_number) < 0 ? (-bb * cos_number) : (bb * cos_number)); ????? top_pos_y=pre_pos_y + ((bb * sin_number) < 0 ? (-bb * sin_number) : (bb * sin_number)); ???? } ???? else if (pre_pos_x <= pos_x && pre_pos_y > pos_y) ???? { ????? top_pos_x=pre_pos_x + ((bb * cos_number) < 0 ? (-bb * cos_number) : (bb * cos_number)); ????? top_pos_y=pre_pos_y + ((bb * sin_number) < 0 ? (-bb * sin_number) : (bb * sin_number)); ???? } ???? else if (pre_pos_x >= pos_x && pre_pos_y >= pos_y) ???? { ????? top_pos_x=pre_pos_x + ((bb * cos_number) < 0 ? (-bb * cos_number) : (bb * cos_number)); ????? top_pos_y=pre_pos_y - ((bb * sin_number) < 0 ? (-bb * sin_number) : (bb * sin_number)); ???? } ???? else if (pre_pos_x >= pos_x && pre_pos_y <= pos_y) ???? { ????? top_pos_x=pre_pos_x - ((bb * cos_number) < 0 ? (-bb * cos_number) : (bb * cos_number)); ????? top_pos_y=pre_pos_y - ((bb * sin_number) < 0 ? (-bb * sin_number) : (bb * sin_number)); ???? } ???? var top_point:MapPoint=new MapPoint(top_pos_x,top_pos_y); ???? clogger.logger.info("上半部分是：" + top_pos_x + "yy:" + top_pos_y); ???? topcurepoints.push(top_point); ???? //下面来确定下边的曲线 ???? var bottom_pos_x:Number; ???? var bottom_pos_y:Number; ???? if (pre_pos_x <= pos_x && pre_pos_y <= pos_y) ???? { ????? bottom_pos_x=pre_pos_x + ((bb * cos_number) < 0 ? (-bb * cos_number) : (bb * cos_number)); ????? bottom_pos_y=pre_pos_y - ((bb * sin_number) < 0 ? (-bb * sin_number) : (bb * sin_number)); ???? } ???? else if (pre_pos_x <= pos_x && pre_pos_y > pos_y) ???? { ????? bottom_pos_x=pre_pos_x - ((bb * cos_number) < 0 ? (-bb * cos_number) : (bb * cos_number)); ????? bottom_pos_y=pre_pos_y - ((bb * sin_number) < 0 ? (-bb * sin_number) : (bb * sin_number)); ???? } ???? else if (pre_pos_x >= pos_x && pre_pos_y >= pos_y) ???? { ????? bottom_pos_x=pre_pos_x - ((bb * cos_number) < 0 ? (-bb * cos_number) : (bb * cos_number)); ????? bottom_pos_y=pre_pos_y + ((bb * sin_number) < 0 ? (-bb * sin_number) : (bb * sin_number)); ???? } ???? else if (pre_pos_x >= pos_x && pre_pos_y <= pos_y) ???? { ????? bottom_pos_x=pre_pos_x + ((bb * cos_number) < 0 ? (-bb * cos_number) : (bb * cos_number)); ????? bottom_pos_y=pre_pos_y + ((bb * sin_number) < 0 ? (-bb * sin_number) : (bb * sin_number)); ???? } ???? var bottom_point:MapPoint=new MapPoint(bottom_pos_x,bottom_pos_y); ???? bottomcurepoints.push(bottom_point); ??? } ?? } ?? /* ??? **下面是添加军标箭头的程序,因为现在已经得到上下边界的曲线了。 ??? ** ??? */ ?? var end_curvepoint:MapPoint=curvepoints[curvepoints.length - 1]; ?? var end_top_point:MapPoint=topcurepoints[topcurepoints.length - 1]; ?? var end_top_point2:MapPoint=topcurepoints[topcurepoints.length - 2]; ?? //求箭头上方的点 ?? var x2:Number=end_curvepoint.x; ?? var y2:Number=end_curvepoint.y; ?? var pos_x:Number=end_top_point.x; ?? var pos_y:Number=end_top_point.y; ?? var pre_pos_x:Number=end_top_point2.x; ?? var pre_pos_y:Number=end_top_point2.y; ?? var end_slope:Number=(pre_pos_y - pos_y) / (pre_pos_x - pos_x); ?? var b:Number=dis; ?? var end_point_x:Number; ?? var end_point_y:Number; ?? var cos_number:Number=Math.cos(Math.atan(end_slope) - Math.PI / 2); ?? var sin_number:Number=Math.sin(Math.atan(end_slope) - Math.PI / 2); ?? //下面分四种情况画线。 ?? if (pre_pos_x <= pos_x && pre_pos_y <= pos_y) ?? { ??? end_point_x=pre_pos_x - ((b * cos_number) < 0 ? (-b * cos_number) : (b * cos_number)); ??? end_point_y=pre_pos_y + ((b * sin_number) < 0 ? (-b * sin_number) : (b * sin_number)); ?? } ?? else if (pre_pos_x <= pos_x && pre_pos_y > pos_y) ?? { ??? end_point_x=pre_pos_x + ((b * cos_number) < 0 ? (-b * cos_number) : (b * cos_number)); ??? end_point_y=pre_pos_y + ((b * sin_number) < 0 ? (-b * sin_number) : (b * sin_number)); ?? } ?? else if (pre_pos_x >= pos_x && pre_pos_y >= pos_y) ?? { ??? end_point_x=pre_pos_x + ((b * cos_number) < 0 ? (-b * cos_number) : (b * cos_number)); ??? end_point_y=pre_pos_y - ((b * sin_number) < 0 ? (-b * sin_number) : (b * sin_number)); ?? } ?? else if (pre_pos_x >= pos_x && pre_pos_y <= pos_y) ?? { ??? end_point_x=pre_pos_x - ((b * cos_number) < 0 ? (-b * cos_number) : (b * cos_number)); ??? end_point_y=pre_pos_y - ((b * sin_number) < 0 ? (-b * sin_number) : (b * sin_number)); ?? } ?? //创建第三个点，然后创建三角形 ?? clogger.logger.info("右上面的点的横坐标点x:" + end_point_x + "----------右上方点的纵坐标的y:" + end_point_y); ?? //得到右上方的点 ?? var end_right_point:MapPoint=new MapPoint(end_point_x,end_point_y); ?? topcurepoints.push(end_right_point); ?? //最右边，箭头顶点的坐标是 ?? clogger.logger.info("顶点的横坐标是x:" + end_curvepoint.x + "---------顶点的纵坐标y:" + end_curvepoint.y); ?? topcurepoints.push(end_curvepoint); ?? //下边线 ?? var end_bottom_point:MapPoint=bottomcurepoints[bottomcurepoints.length - 1]; ?? var end_bottom_point2:MapPoint=bottomcurepoints[bottomcurepoints.length - 2]; ?? //求箭头下方向的点 ?? var bx1:Number=end_bottom_point.x; ?? var by1:Number=end_bottom_point.y; ?? var bx0:Number=end_bottom_point2.x; ?? var by0:Number=end_bottom_point2.y; ?? var bend_slope:Number=(by1 - by0) / (bx1 - bx0); ?? var bend_point_x:Number; ?? var bend_point_y:Number; ?? var bend_cos_number:Number=Math.cos(Math.atan(bend_slope) - Math.PI / 2); ?? var bend_sin_number:Number=Math.sin(Math.atan(bend_slope) - Math.PI / 2); ?? if (bx0 <= bx1 && by0 <= by1) ?? { ??? bend_point_x=bx0 + ((b * bend_cos_number) < 0 ? (-b * bend_cos_number) : (b * bend_cos_number)); ??? bend_point_y=by0 - ((b * bend_sin_number) < 0 ? (-b * bend_sin_number) : (b * bend_sin_number)); ?? } ?? else if (bx0 <= bx1 && by0 > by1) ?? { ??? bend_point_x=bx0 - ((b * bend_cos_number) < 0 ? (-b * bend_cos_number) : (b * bend_cos_number)); ??? bend_point_y=by0 - ((b * bend_sin_number) < 0 ? (-b * bend_sin_number) : (b * bend_sin_number)); ?? } ?? else if (bx0 >= bx1 && by0 >= by1) ?? { ??? bend_point_x=bx0 - ((b * bend_cos_number) < 0 ? (-b * bend_cos_number) : (b * bend_cos_number)); ??? bend_point_y=by0 + ((b * bend_sin_number) < 0 ? (-b * bend_sin_number) : (b * bend_sin_number)); ?? } ?? else if (bx0 >= bx1 && by0 <= by1) ?? { ??? bend_point_x=bx0 + ((b * bend_cos_number) < 0 ? (-b * bend_cos_number) : (b * bend_cos_number)); ??? bend_point_y=by0 + ((b * bend_sin_number) < 0 ? (-b * bend_sin_number) : (b * bend_sin_number)); ?? } ?? clogger.logger.info("下方的点的横坐标x为:" + bend_point_x + "-------下方的点的纵坐标y为:" + bend_point_y); ?? //得到右下方的点 ?? var bend_right_point:MapPoint=new MapPoint(bend_point_x,bend_point_y); ?? topcurepoints.push(bend_right_point); ?? for (var k:Number=bottomcurepoints.length - 1; k >= 0; k--) ?? { ??? //? 这个是下半部分 ??? clogger.logger.info("由此开始下半部分:" + bottomcurepoints[k].x + "yyyyy:" + bottomcurepoints[k].y); ??? topcurepoints.push(bottomcurepoints[k]); ?? } ?? //添加尾部的部分,至此完成对军标多边行的算法， ?? topcurepoints.push(curvepoints[1]); ?? topcurepoints.push(topcurepoints[0]); ?? clogger.logger.info("军标上的点的个数是" + topcurepoints.length); ?? var rings:Array=new Array(); ?? rings.push(topcurepoints); ?? return rings; ? }