<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title>canvas绘制图表</title>
<style type="text/css">
*{
margin:0;
padding:0;
}
body{
text-align:center;
background-color:black;
}
#c1{
background-color:white;
}
</style>
<script type="text/javascript">
function rnd(n,m){
return parseInt(Math.random()*(m-n)+n);
}
window.onload = function(){
var canvas = document.getElementById(‘c1‘);
var gd = canvas.getContext(‘2d‘);
var aData = [100,200,300];
var space = 20;
var topSpace = 100;
var iMax=Math.max.apply(null,aData)
var w=40;
var lastR=0; //前一个柱子的right
for(var i=0;i<3;i++){
//原点
var l=lastR+space;
var t;
//根据canvas 和 比例 来确定高, 而不是根据给出的高度
var h=(aData[i]/iMax)*(canvas.height-topSpace);
//原点
t=canvas.height-h;
gd.fillStyle=‘rgb(‘+rnd(0, 256)+‘, ‘+rnd(0, 256)+‘, ‘+rnd(0, 256)+‘)‘;
gd.fillRect(l,t,w,h);
lastR=l+w;
}
}
</script>
</head>
<body>
<canvas width=‘500‘ height="500" id="c1"></canvas>
</body>
</html>
时间： 2024-10-10 13:31:56