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因为要实现拖拽连线研究了一下基于extjs 和html5的不同实现方法
extjs底层的画图引擎是svg 不知道在html5大潮即将袭来的前夕一贯走在技术前沿的extjs开发团队没有自己封装基于html5的画图引擎，而是选择了svg 。
下边是花了不到一天的时间实现的任意点连线和拖动功能，代码没有优化，稍微乱了点
如果单纯应用canvas进行画图，拖拽是非常麻烦的，我们往往要基于第三方的画图类库，这里实现是基于kineticjs
为了测试方便我使用了双击事件控制拖动还是划线 。
代码
<!DOCTYPE HTML><html> <head> <style> body { margin: 0px; padding: 0px; } canvas { border: 1px solid #9C9898; } </style> <script type="text/javascript" src="ext/bootstrap.js"></script> <!-- ENDLIBS --><script type="text/javascript" src="ext/ext-all-debug.js"></script> <script src="js/kinetic-v3.10.2.min.js"></script> <script> Ext.onReady(function(){ /**自动判断顶点连线算法*/ var stage=new Kinetic.Stage({ container:'container', width:1000, height:1000 }); var layer=new Kinetic.Layer(); var flag=false; var imgArray=[]; var lineArray=[]; var tmpMoveImg=null; var loop=0; function Pos(x,y){ this.x=x; this.y=y; }; function LineImage(img,line){ this.img=img; this.line=line; }; function NewImage(img,opsArray){ this.img=img; this.opsArray=opsArray; }; var imgA= new Image(); imgA.onload=function(){ var imgObjA= createImage(imgA,100,100,100,100) var array=new Array(); var na=new NewImage(imgObjA,array); imgArray.push(na); layer.add(imgObjA); stage.add(layer); } var imgB= new Image(); imgB.onload=function(){ var imgObjB= createImage(imgB,400,400,100,100) var array=new Array(); var nb=new NewImage(imgObjB,array); imgArray.push(nb); layer.add(imgObjB); stage.add(layer); } var imgC= new Image(); imgC.onload=function(){ var imgObjC= createImage(imgC,700,100,100,100) var array=new Array(); var nc=new NewImage(imgObjC,array); imgArray.push(nc); layer.add(imgObjC); stage.add(layer); } var rect=new Kinetic.Rect({ x:0, y:0, width:1000, height:1000, fill:'white', storke:'red', storkeWidth:5 }); layer.add(rect); imgA.src='img/db.png'; imgB.src='img/mj.png'; imgC.src="img/kt1.png"; rect.on('dblclick',function(){ if(loop%2==0){ flag=true; for(var i=0;i<imgArray.length;i++){ imgArray.img.setDraggable(false); } }else{ flag=false; for(var i=0;i<imgArray.length;i++){ imgArray.img.setDraggable(true); imgArray.img.on('mouseover',function(){ var p=new Pos(this.getX(),this.getY()); tmpMoveImg=getImgByPos(p); }) imgArray.img.on('dragmove',function(){ for(var j=0;j<tmpMoveImg.opsArray.length;j++){ var realPoints=[]; calculateStartEndPos(tmpMoveImg.opsArray[j].img,this,realPoints); var line= createLine(realPoints); var oldLine=tmpMoveImg.opsArray[j].line; var p=new Pos(tmpMoveImg.opsArray[j].img.getX(),tmpMoveImg.opsArray[j].img.getY()); var oppoImg= getImgByPos(p); replaceOppoLine(oppoImg,oldLine,line); layer.remove(tmpMoveImg.opsArray[j].line); tmpMoveImg.opsArray[j].line=line; layer.add(line); layer.draw(); realPoints=[]; } layer.draw(); }) } } loop++; for(var i=0;i<imgArray.length;i++){ var innerFlag=false; var points=[];//标记性的点，为了获取img 使用 var realPoints=[];//真正计算后合理的划线点 imgArray.img.on('mousedown',function(){ if(flag){ var pos= stage.getMousePosition(); points.push(this.getX()); points.push(this.getY()); innerFlag=true; } }); imgArray.img.on('mouseup',function(){ if(flag&&innerFlag){ var pos= stage.getMousePosition(); points.push(this.getX()); points.push(this.getY()); var p=new Pos(points[0],points[1]); var op=new Pos(points[2],points[3]); var opImg=getImgByPos(p); var owImg=getImgByPos(op);if(opImg!=owImg){calculateStartEndPos(opImg.img,owImg.img,realPoints); var line= createLine(realPoints); var opLine=new LineImage(opImg.img,line);var owLine=new LineImage(owImg.img,line); owImg.opsArray.push(opLine); opImg.opsArray.push(owLine); flag=false; innerFlag=false; points=[]; realPoints=[]; layer.add(line); layer.draw();} } }); } }) /** * 通过坐标获取Img对象 */ function getImgByPos(pos){ for(var i=0;i<imgArray.length;i++){ if(imgArray.img.getX()==pos.x&&imgArray.img.getY()==pos.y){ return imgArray; } } } /** * 替换对方中line */ function replaceOppoLine(imgObj,oldLine,newLine){ for(var i=0;i<imgObj.opsArray.length;i++){ if(imgObj.opsArray.line==oldLine){ imgObj.opsArray.line=newLine; } } } /** 划线 */ function createLine(points){ var line=new Kinetic.Line({ points:points, stroke:'bule', strokeWidth:5, lineCap:'round', lineJoin:'round' }); return line; } /** * 计算划线的开始坐标 */ function calculateStartEndPos(imgStart,imgEnd,realPoints){ var realSx=0; var realSy=0; var realEx=0; var realEy=0; var sx=imgStart.getX(); var sy=imgStart.getY(); var swidth=imgStart.getWidth(); var sheight=imgStart.getHeight(); var ex=imgEnd.getX(); var ey=imgEnd.getY(); var ewidth=imgEnd.getWidth(); var eheight=imgEnd.getHeight(); var arrayx=calculateX(sx,swidth,ex,ewidth ); var arrayy=calculateY(sy,sheight,ey,eheight ); realPoints.push(arrayx[0]); realPoints.push(arrayy[0]); realPoints.push(arrayx[1]); realPoints.push(arrayy[1]); } /** 计算开始和结束节点x坐标 */ function calculateX(sx,swidth,ex,ewidth ){ var arrayX=[]; if(sx>ex){ arrayX.push(sx); arrayX.push(ex+ewidth); }else if(sx==ex){ arrayX.push(sx+(swidth/2)); arrayX.push(sx+(ewidth/2)); }else{ arrayX.push(sx+swidth); arrayX.push(ex); } return arrayX; } /** 计算开始和结束节点y坐标 */ function calculateY(sy,sheight,ey,eheight ){ var arrayY=[]; if(sy>ey){ arrayY.push(sy+(sheight/2)); arrayY.push(ey+(eheight/2)); }else if(sy==ey){ arrayY.push(sy+(sheight/2)); arrayY.push(sy+(eheight/2)); }else{ arrayY.push(sy+(sheight/2)); arrayY.push(ey+(eheight/2)); } return arrayY; } /** 画图 */ function createImage(img,x,y,width,height){ var imgObj=new Kinetic.Image({ x:x, y:y, width:width, height:height, draggable:true, image:img }); imgObj.on("mouseover", function(){ document.body.style.cursor = "pointer"; }); imgObj.on("mouseout", function(){ document.body.style.cursor = "default"; }); return imgObj } }); </script> </head> <body> <div id="container"></div> </body></html>  效果如下
代码里还有一项基于extjs4 的实现和纯html5 canvas 的实现 |
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