使用 EaselJS 在 html5 画布中绘制一条线

I am very new to Easel and HTML5 itself. I am trying to draw a line using on a canvas using EaselJS. The X- Co ordinate is fixedd to 100 and the Y-Co ordinate is got from a array list. The code that i have written is given below. Could please someone let me know where i am going wrong?

function myFunction(attachPoint)
{
//Code for canvas creation is written here.[Not shown];
//created a stage.
stage = new createjs.Stage(canvas.domElement());
//3. create some shapes.MagnitudeLessThanTwo is the array where we get the YAxis Coordinates from
alert("The lenght before function is"+MagnitudeLessThanTwo.length);
myShape = new drawLineGraph(MagnitudeLessThanTwo);
//4. finally add that shape to the stage
stage.addChild(myShape);
//5. set up the ticker
if (!createjs.Ticker.hasEventListener("tick")) { 
createjs.Ticker.addEventListener("tick", ourTickFunction);
  };
};

function drawLineGraph(dataList)
{
this.index=0;//To keep the track of the index of the array from which we get the Y Axis.
var graphics = new createjs.Graphics();
graphics.setStrokeStyle(1);
graphics.beginStroke("white");
graphics.moveTo(50,(dataList[this.index].magnitude)*100); 
graphics.lineTo(50,(dataList[(this.index)++].magnitude)*100);
createjs.Shape.call(this,graphics);
this.tick = function() {
graphics.moveTo(100,(dataList[this.index].magnitude)*100); 
graphics.lineTo(100,(dataList[(this.index)++].magnitude)*100);
stage.addChild(graphics);
  };
};
drawLineGraph.prototype = new createjs.Shape(); //set prototype
drawLineGraph.prototype.constructor = drawLineGraph; //fix constructor pointer


I am getting the following Error.
"Object [object Object] has no method 'isVisible'"- This is inside the EaselJS Library.

推荐答案

这里有几个问题.您看到的错误是因为您将图形添加到舞台，而不是形状.

this.tick = function() {
    graphics.moveTo(100,(dataList[this.index].magnitude)*100); 
    graphics.lineTo(100,(dataList[(this.index)++].magnitude)*100);
    stage.addChild(graphics);
};