html5 – 用线条连接画布

我需要用一条线连接两个画布来创建动态工作流.

我将生成画布矩形动态(我在DB的步骤数量),但我需要用线连接步骤.

有人有想法吗？

解决方法

以下是如何使用线自动连接2个可拖动的画布矩形

首先,定义一些盒子和连接器：

// define any Boxes that will be drawn
    var Boxes=[];
    Boxes.push({x:50,y:25,w:75,h:50});    // x,y,width,height
    Boxes.push({x:200,y:100,w:50,h:50});

    // define any connectors between any Boxes
    var connectors=[];
    connectors.push({Box1:0,Box2:1});

绘制框并自动绘制连接器：

function draw(){

        // clear the canvas
        ctx.clearRect(0,canvas.width,canvas.height);

        for(var i=0;i<Boxes.length;i++){
            var Box=Boxes[i];
            ctx.fillRect(Box.x,Box.y,Box.w,Box.h);
        }
        for(var i=0;i<connectors.length;i++){
            var connector=connectors[i];
            var Box1=Boxes[connector.Box1];
            var Box2=Boxes[connector.Box2];
            ctx.beginPath();
            ctx.moveto(Box1.x+Box1.w/2,Box1.y+Box1.h/2);
            ctx.lineto(Box2.x+Box2.w/2,Box2.y+Box2.h/2);
            ctx.stroke();
        }

    }

下面的代码允许拖动任何框并保持连接.

这是代码和小提琴：http://jsfiddle.net/m1erickson/GX6HS/

<!doctype html>
<html>
<head>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>

<style>
    body{ background-color: ivory; padding:20px;}
    #canvas{border:1px solid red;}
</style>

<script>
$(function(){

    var canvas=document.getElementById("canvas");
    var ctx=canvas.getContext("2d");

    var canvasOffset=$("#canvas").offset();
    var offsetX=canvasOffset.left;
    var offsetY=canvasOffset.top;

    var startX;
    var startY;
    var isDown=false;
    var dragTarget;

    var Boxes=[];
    Boxes.push({x:50,h:50});


    var connectors=[];
    connectors.push({Box1:0,Box2:1});

    draw();

    function draw(){

        // clear the canvas
        ctx.clearRect(0,Box2.y+Box2.h/2);
            ctx.stroke();
        }

    }

    function hit(x,y){
        for(var i=0;i<Boxes.length;i++){
            var Box=Boxes[i];
            if(x>=Box.x && x<=Box.x+Box.w && y>=Box.y && y<=Box.y+Box.h){
                dragTarget=Box;
                return(true);
            }
        }
        return(false);
    }

    function handleMouseDown(e){
      startX=parseInt(e.clientX-offsetX);
      startY=parseInt(e.clientY-offsetY);

      // Put your mousedown stuff here
      isDown=hit(startX,startY);
    }

    function handleMouseUp(e){
      // Put your mouseup stuff here
      dragTarget=null;
      isDown=false;
    }

    function handleMouSEOut(e){
        handleMouseUp(e);
    }

    function handleMouseMove(e){
      if(!isDown){return;}

      mouseX=parseInt(e.clientX-offsetX);
      mouseY=parseInt(e.clientY-offsetY);

      // Put your mousemove stuff here
      var dx=mouseX-startX;
      var dy=mouseY-startY;
      startX=mouseX;
      startY=mouseY;
      dragTarget.x+=dx;
      dragTarget.y+=dy;
      draw();
    }

    $("#canvas").mousedown(function(e){handleMouseDown(e);});
    $("#canvas").mousemove(function(e){handleMouseMove(e);});
    $("#canvas").mouseup(function(e){handleMouseUp(e);});
    $("#canvas").mouSEOut(function(e){handleMouSEOut(e);});

}); // end $(function(){});
</script>

</head>

<body>
    <p>Drag Boxes--they remain connected</p>
    <canvas id="canvas" width=300 height=300></canvas>
</body>
</html>

html5 – 用线条连接画布

解决方法

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