html5中怎么生成柱状图效果

2024-04-02 19:04:59 944人浏览泡泡鱼

摘要

HTML5中怎么生成柱状图效果，很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。<html> &

HTML5中怎么生成柱状图效果，很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。

<html>    
<canvas id="a_canvas" width="1000" height="700"></canvas>    
<script>    
    (function (){    
     
        window.addEventListener("load", function(){    
     
          var data = [1000,1300,2000,3000,2000,2000,1000,1500,2000,5000,1000,1000];    
          var xinfORMa = ['1月','2月','3月','4月','5月','6月','7月','8月','9月','10月','11月','12月'];    
     
          // 获取上下文    
          var a_canvas = document.getElementById('a_canvas');    
          var context = a_canvas.getContext("2d");    
     
     
          // 绘制背景    
          var gradient = context.createLinearGradient(0,0,0,300);    
     
     
         // gradient.addColorStop(0,"#e0e0e0");    
          //gradient.addColorStop(1,"#ffffff");    
     
     
          context.fillStyle = gradient;    
     
          context.fillRect(0,0,a_canvas.width,a_canvas.height);    
     
          var realheight = a_canvas.height-15;    
          var realwidth = a_canvas.width-40;    
          // 描绘边框    
          var grid_cols = data.length + 1;    
          var grid_rows = 4;    
          var cell_height = realheight / grid_rows;    
          var cell_width = realwidth / grid_cols;    
          context.lineWidth = 1;    
          context.strokeStyle = "#a0a0a0";    
     
          // 结束边框描绘    
          context.beginPath();    
          // 准备画横线    
              
              
            //划横线    
            context.moveTo(0,realheight);    
            context.lineTo(realwidth,realheight);    
                    
                 
            //画竖线    
          context.moveTo(0,20);    
           context.lineTo(0,realheight);    
          context.lineWidth = 1;    
          context.strokeStyle = "black";    
          context.stroke();    
                  
     
          var max_v =0;    
              
          for(var i = 0; i<data.length; i++){    
            if (data[i] > max_v) { max_v =data[i]};    
          }    
          max_vmax_v = max_v * 1.1;    
          // 将数据换算为坐标    
          var points = [];    
          for( var i=0; i < data.length; i++){    
            var v= data[i];    
            var px = cell_width *　(i +1);    
            var py = realheight - realheight*(v / max_v);    
            //alert(py);    
            points.push({"x":px,"y":py});    
          }    
     
          //绘制坐标图形    
          for(var i in points){    
            var p = points[i];    
            context.beginPath();    
            context.fillStyle="green";    
            context.fillRect(p.x,p.y,15,realheight-p.y);    
                 
            context.fill();    
          }    
          //添加文字    
          for(var i in points)    
          {  var p = points[i];    
            context.beginPath();    
            context.fillStyle="black";    
            context.fillText(data[i], p.x + 1, p.y - 15);    
             context.fillText(xinforma[i],p.x + 1,realheight+12);    
             context.fillText('月份',realwidth,realheight+12);    
             context.fillText('资金量',0,10);    
              }    
        },false);    
      })();    
           
</script>    
</html>

运行结果：

html5中怎么生成柱状图效果