欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识！
您现在的位置是： 首页  >  web前端

js封装成插件_Canvas统计图插件编写实例_javascript技巧

程序员文章站 2022-04-26 09:46:28
...
下面小编就为大家带来一篇js封装成插件_Canvas统计图插件编写实例。小编觉得挺不错的，现在就分享js源码给大家，也给大家做个参考。对js感兴趣的一起跟随小编过来看看吧

之前就说过，我想写一个canvas画统计图的插件，现在写好了

先说下实现的功能吧：

　　1.可以通过自定义X轴坐标属性和Y轴坐标属性按比例画出统计图

　　2.可以选择画折现图还是柱形统计图，或者两者都实现

　　3.可以*定义折现颜色，坐标颜色，柱形图颜色 和canvas边框颜色，当然边框你也可以选择要或者不要

　　4.可以选择是否实现柱形图和折现图的动画实现

实现过程

画坐标——画箭头——做X轴和Y轴的标注——画柱形图——画折现图

话不多说，上代码

(function(window,document){
 var ChartDraws = function(options){
  if(!(this instanceof ChartDraws))return new ChartDraws(options);
  this.options = $.extend({
   //报表所需的参数
   "containerId" : "",  //canvas所在容器id
   "canvasWidth" : 400,
   "canvasHeight" : 300,
   "paddingLeft" : 20,
   "paddingTop" : 20,
   "columnChartData" :[], //柱形图的数量和对应得名称以及百分比
   "yChartData" :[],   //y轴的数量及名称
   "axisColor" : "white",  //坐标轴颜色
   "columnChartColor" : "#EEE685", //柱形图颜色
   "isNeedAnimation" : true, //是否需要动画
   "isNeedLineChart" : true, //是否需要折线图
   "isNeedColumnChart" : true, //是否需要柱形图
   "lineChartColor" : "#90EE90", //折线图颜色，当isNeedLineChart=true时有效
   "isNeedBorder" : false,  //canvas是否需要外边框
   "borderColor" : "white"  //外边框颜色
  },options);
  if(this.options.canvasWidth<=500)
  {
   this.axisBorderWidth = 3;
   this.fontSize = 8;
  }
  else if(this.options.canvasWidth<=800){
   this.axisBorderWidth = 4;
   this.fontSize = 12;
  }
  else{
   this.axisBorderWidth = 5;
   this.fontSize = 16;
  }
  var self = this;
  _init();
  function _init(){
   var canvasDom = document.createElement("canvas");
   canvasDom.id = self.options.containerId+"_"+"canvas";
   canvasDom.width = self.options.canvasWidth;
   canvasDom.height = self.options.canvasHeight;
   if(self.options.isNeedBorder){
    canvasDom.style.borderWidth = 1;
    canvasDom.style.borderStyle = "solid";
    canvasDom.style.borderColor = self.options.borderColor;
   }
   document.getElementById(self.options.containerId).appendChild(canvasDom);
   self.context = document.getElementById(self.options.containerId+"_"+"canvas");
   self.ctx = self.context.getContext("2d");
   _drawAxis();
  }

  function _drawAxis(){
   var XYData =transformAxis( [{x:self.options.paddingLeft,y:self.options.canvasHeight-self.options.paddingTop},{x:self.options.paddingLeft,y:self.options.paddingTop},{x:self.options.canvasWidth-self.options.paddingLeft,y:self.options.paddingTop}]);
   self.ctx.strokeStyle=self.options.axisColor;
   drawLine(self.ctx,XYData,self.axisBorderWidth);
   //画三角箭头
   //画y轴三角箭头
   drawLine(self.ctx,transformAxis([{x:self.options.paddingLeft-self.axisBorderWidth,y:self.options.canvasHeight-self.options.paddingTop-self.axisBorderWidth*2},{x:self.options.paddingLeft,y:self.options.canvasHeight-self.options.paddingTop},{x:self.options.paddingLeft+self.axisBorderWidth,y:self.options.canvasHeight-self.options.paddingTop-self.axisBorderWidth*2}]),self.axisBorderWidth);
   //画x轴三角箭头
   drawLine(self.ctx,transformAxis([{x:self.options.canvasWidth-self.options.paddingLeft-self.axisBorderWidth*2,y:self.options.paddingTop+self.axisBorderWidth},{x:self.options.canvasWidth-self.options.paddingLeft,y:self.options.paddingTop},{x:self.options.canvasWidth-self.options.paddingLeft-self.axisBorderWidth*2,y:self.options.paddingTop-self.axisBorderWidth}]),self.axisBorderWidth);
   _drawCoordinatePoints();
  }

  function _drawCoordinatePoints(){
   self.reactAngleWidth = (1-2*0.04)*(self.options.canvasWidth-(2*self.options.paddingLeft))/(self.options.columnChartData.length*2-1);
   self.lineDataList = [];
   for(var i = 0;i<self.options.columnChartData.length;i++)
   {
    drawXText(self.ctx,2*self.options.columnChartData[i].NO*self.reactAngleWidth+self.options.paddingLeft+0.04*(self.options.canvasWidth-(2*self.options.paddingLeft))+self.reactAngleWidth/2,self.options.paddingTop/2,self.options.columnChartData[i].Name);
    self.lineDataList.push({
     x:2*self.options.columnChartData[i].NO*self.reactAngleWidth+self.options.paddingLeft+0.04*(self.options.canvasWidth-(2*self.options.paddingLeft))+self.reactAngleWidth/2,
     y:self.options.canvasHeight-(self.options.paddingTop+(self.options.canvasHeight-2*self.options.paddingTop)*self.options.columnChartData[i].PT)
    })
   }

   //画Y轴title 画y轴虚线
   self.reactAngleHeight = (self.options.canvasHeight-2*self.options.paddingTop)/(self.options.yChartData.length+1);
   for(var j = 0;j<self.options.yChartData.length;j++)
   {
    drawYText(self.ctx,3*self.options.paddingLeft/4,self.options.paddingTop+self.reactAngleHeight*(j+1),self.options.yChartData[j].Name);
    //画虚线
    drawDottedLine(self.ctx,self.options.paddingLeft,self.options.paddingTop+self.reactAngleHeight*(j+1),self.options.canvasWidth-self.options.paddingLeft,self.options.paddingTop+self.reactAngleHeight*(j+1),self.options.canvasWidth-2*self.options.paddingLeft,10,self.axisBorderWidth/2);
   }
   _drawColumnChart();
  }

  function _drawColumnChart(){
   //柱形图循环
   var reactAngleTimer = 1;
   function loopColumnChart()
   {
    var columnChartLooped = window.requestAnimationFrame(loopColumnChart);
    if(reactAngleTimer<=100)
    {
     for(var k=0;k<self.options.columnChartData.length;k++)
     {
      self.ctx.fillStyle =self.options.columnChartColor;
      drawRectangle(self.ctx,self.lineDataList[k].x-self.reactAngleWidth/2,self.options.canvasHeight-((self.options.canvasHeight-2*self.options.paddingTop)*self.options.columnChartData[k].PT*reactAngleTimer/100+self.options.paddingTop),self.reactAngleWidth,(self.options.canvasHeight-2*self.options.paddingTop)*self.options.columnChartData[k].PT*reactAngleTimer/100);
     }
     reactAngleTimer++;
    }
    else
    {
     window.cancelAnimationFrame(columnChartLooped);
     columnChartLooped = null;
     reactAngleTimer = 1;
     if(self.options.isNeedLineChart)
     {
      loopLineChart();
     }
    }
   }
   //折线图循环
   var lineTimer = 0;
   function loopLineChart()
   {
    var lineChartLooped = window.requestAnimationFrame(loopLineChart);
    if(lineTimer<self.lineDataList.length-1)
    {
     self.ctx.lineWidth = 2*self.axisBorderWidth/3;
     if(lineTimer == 0)
     {
      drawCircle(self.ctx,self.lineDataList[lineTimer].x,self.lineDataList[lineTimer].y);
     }
     drawCircle(self.ctx,self.lineDataList[lineTimer+1].x,self.lineDataList[lineTimer+1].y);
     self.ctx.beginPath();
     self.ctx.moveTo(self.lineDataList[lineTimer].x,self.lineDataList[lineTimer].y);
     self.ctx.lineTo(self.lineDataList[lineTimer+1].x,self.lineDataList[lineTimer+1].y);
     self.ctx.strokeStyle = self.options.lineChartColor;
     self.ctx.lineWidth = 2*self.axisBorderWidth/3;
     self.ctx.stroke();
     lineTimer++;
    }
    else
    {
     window.cancelAnimationFrame(lineChartLooped);
     lineChartLooped = null;
     lineTimer = 0;
    }
   }
   //画柱形图
   function drawRectangle(context,x,y,width,height){
    context.beginPath();
    context.fillRect(x,y,width,height);
   }
   //画圆
   function drawCircle(context,x,y){
    context.beginPath();
    context.arc(x,y,self.axisBorderWidth/2,0,2*Math.PI,true);
    context.strokeStyle=self.options.lineChartColor;
    context.stroke();
    context.closePath();
   }
   if(self.options.isNeedAnimation)
   {
    if(self.options.isNeedColumnChart)
    {
     loopColumnChart();
    }
    else
    {
     if(self.options.isNeedLineChart) {
      loopLineChart();
     }
    }
   }
   else
   {
    if(self.options.isNeedColumnChart)
    {
     for(var k=0;k<self.options.columnChartData.length;k++)
     {
      self.ctx.fillStyle =self.options.columnChartColor;
      drawRectangle(self.ctx,self.lineDataList[k].x-self.reactAngleWidth/2,self.options.canvasHeight-((self.options.canvasHeight-2*self.options.paddingTop)*self.options.columnChartData[k].PT+self.options.paddingTop),self.reactAngleWidth,(self.options.canvasHeight-2*self.options.paddingTop)*self.options.columnChartData[k].PT);
     }
    }
    if(self.options.isNeedLineChart) {
     for (var l = 0; l < self.lineDataList.length - 1; l++) {
      self.ctx.lineWidth = 4;
      if (l == 0) {
       drawCircle(self.ctx, self.lineDataList[l].x, self.lineDataList[l].y);
      }
      drawCircle(self.ctx, self.lineDataList[l + 1].x, self.lineDataList[l + 1].y);
      self.ctx.beginPath();
      self.ctx.moveTo(self.lineDataList[l].x, self.lineDataList[l].y);
      self.ctx.lineTo(self.lineDataList[l + 1].x, self.lineDataList[l + 1].y);
      self.ctx.strokeStyle = self.options.lineChartColor;
      self.ctx.lineWidth = 2*self.axisBorderWidth/3;
      self.ctx.stroke();
     }
    }
   }
  }


  function transformAxis(data)
  {
   var newData=[];
   for(var i=0;i<data.length;i++){
    newData.push({
     x:data[i].x,
     y:self.options.canvasHeight-data[i].y
    })
   }
   return newData;
  }

  function drawLine(context,point,width){
   context.beginPath();
   context.moveTo(point[0].x,point[0].y);
   if(point.length>2)
   {
    for(var i=1;i<point.length;i++)
    {
     context.lineTo(point[i].x,point[i].y);
    }
   }
   context.lineWidth = width;
   context.lineJoin='round';
   context.stroke();
   context.closePath();
  }

  //画y轴title
  function drawYText(context,x,y,str) {
   context.beginPath();
   context.font = '{fontSize} Microsoft Yahei'.replace("{fontSize}",self.fontSize+"px");
   context.fillStyle = 'white';
   context.textAlign = 'right';
   context.fillText(str,x,self.options.canvasHeight-y);
   context.closePath();
  }
  //画x轴title
  function drawXText(context,x,y,str) {
   context.beginPath();
   context.font = '{fontSize} Microsoft Yahei'.replace("{fontSize}",self.fontSize+"px");
   context.fillStyle = 'white';
   context.textAlign = 'center';
   context.fillText(str,x,self.options.canvasHeight-y);
   context.closePath();
  }
  function drawDottedLine(context,x1,y1,x2,y2,totalLength,length,lineWidth){
   y1 = self.options.canvasHeight-y1;
   y2 = self.options.canvasHeight-y2;
   var dashLen = length === undefined ? 5 : length;
   //计算有多少个线段
   context.beginPath();
   var num = Math.floor(totalLength/dashLen);
   context.lineWidth = lineWidth;
   for(var i = 0 ; i < num; i++)
   {
    context[i%2==0 ? 'moveTo' : 'lineTo'](x1+(x2-x1)/num*i,y1+(y2-y1)/num*i);
   }
   context.stroke();
  }
 };
 window.ChartDraws = ChartDraws;
}(window,document));

下面还有一个是实现requestAnimationFrame浏览器兼容的

(function(){
 var lastTime = 0;
 var prefixes = ['ms','webkit','o','moz']; //各浏览器前缀

 var requestAnimationFrame = window.requestAnimationFrame;
 var cancelAnimationFrame = window.cancelAnimationFrame;

 var prefix;
 //通过遍历各浏览器前缀，来得到requestAnimationFrame和cancelAnimationFrame在当前浏览器的实现形式
 for( var i = 0; i < prefixes.length; i++ ) {
  if ( requestAnimationFrame && cancelAnimationFrame ) {
   break;
  }
  prefix = prefixes[i];
  requestAnimationFrame = requestAnimationFrame || window[ prefix + 'RequestAnimationFrame' ];
  cancelAnimationFrame = cancelAnimationFrame || window[ prefix + 'CancelAnimationFrame' ] || window[ prefix + 'CancelRequestAnimationFrame' ];
 }

 //如果当前浏览器不支持requestAnimationFrame和cancelAnimationFrame，则会退到setTimeout
 if ( !requestAnimationFrame || !cancelAnimationFrame ) {
  requestAnimationFrame = function( callback, element ) {
   var currTime = new Date().getTime();
   //为了使setTimteout的尽可能的接近每秒60帧的效果
   var timeToCall = Math.max( 0, 16 - ( currTime - lastTime ) );
   var id = window.setTimeout( function() {
    callback( currTime + timeToCall );
   }, timeToCall );
   lastTime = currTime + timeToCall;
   return id;
  };
  cancelAnimationFrame = function( id ) {
   window.clearTimeout( id );
  };
 }

 window.requestAnimationFrame = requestAnimationFrame;
 window.cancelAnimationFrame = cancelAnimationFrame;
}());

附上<script>调用

ChartDraws({
  "containerId" : "chart1",  //canvas所在容器id
  "canvasWidth" : 1000,
  "canvasHeight" : 250,
  "paddingLeft" : 50,
  "paddingTop" : 50,
  "columnChartData": [
   {NO:0,PT:0.2,Name:"Html/Css"},
   {NO:1,PT:0.4,Name:"Html5/Css3"},
   {NO:2,PT:0.4,Name:"JavaScript"},
   {NO:3,PT:0.5,Name:"JQuery"},
   {NO:4,PT:0.2,Name:"Angular.js"},
   {NO:5,PT:0.8,Name:"BootStrap"},
   {NO:6,PT:0.6,Name:"React.js"},
   {NO:7,PT:0.5,Name:"Java"}
  ],
  "yChartData" : [
   {NO:0,Name:"熟悉"},
   {NO:1,Name:"掌握"},
   {NO:2,Name:"精通"}
  ],
  "isNeedAnimation" : false,
  "isNeedBorder" : false,
  "isNeedLineChart":true,
  "axisColor" : "#8DEEEE"
 });
 ChartDraws({
  "containerId" : "chart2",  //canvas所在容器id
  "canvasWidth" : 1000,
  "canvasHeight" : 250,
  "paddingLeft" : 50,
  "paddingTop" : 50,
  "columnChartData": [
   {NO:0,PT:0.4,Name:"Html/Css"},
   {NO:1,PT:0.5,Name:"Html5/Css3"},
   {NO:2,PT:0.2,Name:"JavaScript"},
   {NO:3,PT:0.7,Name:"JQuery"},
   {NO:4,PT:0.2,Name:"Angular.js"},
   {NO:5,PT:0.3,Name:"BootStrap"},
   {NO:6,PT:0.8,Name:"React.js"},
   {NO:7,PT:0.2,Name:"Java"}
  ],
  "yChartData" : [
   {NO:0,Name:"熟悉"},
   {NO:1,Name:"掌握"},
   {NO:2,Name:"精通"}
  ],
  "isNeedAnimation" : false,
  "isNeedBorder" : false,
  "isNeedLineChart":false,
  "isNeedColumnChart" : true,
  "columnChartColor":"#9370DB"
 });

 ChartDraws({
  "containerId" : "chart3",  //canvas所在容器id
  "canvasWidth" : 1000,
  "canvasHeight" : 250,
  "paddingLeft" : 50,
  "paddingTop" : 50,
  "columnChartData": [
   {NO:0,PT:0.4,Name:"Html/Css"},
   {NO:1,PT:0.5,Name:"Html5/Css3"},
   {NO:2,PT:0.2,Name:"JavaScript"},
   {NO:3,PT:0.7,Name:"JQuery"},
   {NO:4,PT:0.2,Name:"Angular.js"},
   {NO:5,PT:0.3,Name:"BootStrap"},
   {NO:6,PT:0.8,Name:"React.js"},
   {NO:7,PT:0.2,Name:"Java"}
  ],
  "yChartData" : [
   {NO:0,Name:"熟悉"},
   {NO:1,Name:"掌握"},
   {NO:2,Name:"精通"}
  ],
  "isNeedAnimation" : false,
  "isNeedBorder" : true,
  "isNeedLineChart":true,
  "isNeedColumnChart" : false,
  "lineChartColor" : "#8DB6CD",
  "borderColor" : "#87CEFA"
 })

html代码

<p class="section">
 <p id="chart1"></p>
 <p id="chart2"></p>
 <p id="chart3"></p>
 </p>

下面是一个实现后的效果图

js封装成插件_Canvas统计图插件编写实例_javascript技巧

在整个编码的过程中我把代码改过一次，为什么改呢，因为在第一次的时候我在js里面使用了大量的 ChartDraws.prototype.XXXX = function(){};

后来我一想不对啊，我为什么要把这么多的方法暴露给外部呢......这不是没事找事么.......

所以现在就改成这样了，如果有不对的地方和可以改进的地方，希望路过的指点下，谢谢！还有那个白条代码背景怎么删不掉...........

相关推荐：

JavaScript构造器模式实例分析

javascript如何计算对象长度

javascript中的typeof和类型判断详解

以上就是js封装成插件_Canvas统计图插件编写实例_javascript技巧的详细内容，更多请关注其它相关文章！

相关标签： javascript Canvas 插件

上一篇： 懒加载过程中添加loading

下一篇： 关于js 索引下标之li集合绑定点击事件实例分享

推荐阅读