chart.js图表库案例赏析，饼图添加文字
Chart.js 是一个令人印象深刻的 JavaScript 图表库，建立在 HTML5 Canvas 基础上。目前，它支持6种图表类型（折线图，条形图，雷达图，饼图，柱状图和极地区域区）。而且，这是一个独立的包，不依赖第三方 JavaScript 库，小于 5KB。
前天用了一下，由于以前也稍微用过，今天总结了一下（水平有限，如果问题，请不吝赐教）：
开发中文文档：http://www.bootcss.com/p/chart.js/docs/
chart.js下载：
把所有的图标全都写了一遍，并把所有的可控属性（颜色等）均已随机数出现，大小自己控制；
这是所有的代码，只有一个Chart.js外部文件，引来即用：
<!doctype html>
<html>
<head>
<title>Chart</title>
<mate charset="utf-8"></mate>
<script src="Chart.js"></script>
</head>
<body>
<div style="50%;margin: 0px auto;">
<!--柱状图开始-->
<div>
<h1>柱状图（Bar chart）</h1>
<canvas id="canvas-bar" height="450" width="600"></canvas>
</div>
<script>
var randomScalingFactor = function(){ return Math.round(Math.random()*100)};
var randomScalingFactor_255 = function(){ return Math.round(Math.random()*255)};
var radom_color = function(){
return '#'+('00000'+(Math.random()*0x1000000<<0).toString(16)).slice(-6);
}
var barChartData = {
labels : ["January","February","March","April","May","June","July"],
datasets : [
{
fillColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",0.5)",
strokeColor : "rgba(" + randomScalingFactor_255()+","+ randomScalingFactor_255()+"," + randomScalingFactor_255() + ",0.8)",
highlightFill: "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",0.75)",
highlightStroke: "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
data : [randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor()]
},
{
fillColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",0.5)",
strokeColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",0.8)",
highlightFill : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",0.75)",
highlightStroke : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
data : [randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor()]
}
]
}
var ctx = document.getElementById("canvas-bar").getContext("2d");
window.myBar = new Chart(ctx).Bar(barChartData, {
responsive : true
});
</script>
<!--柱状图结束-->
<!--曲线图（Line chart）开始-->
<div>
<h1>曲线图（Line chart）</h1>
<canvas id="canvas-line" height="450" width="600"></canvas>
</div>
<script>
var randomScalingFactor = function(){ return Math.round(Math.random()*100)};
var lineChartData = {
labels : ["January","February","March","April","May","June","July"],
datasets : [
{
label: "My First dataset",
fillColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",0.2)",
strokeColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
pointColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
pointStrokeColor : radom_color(),
pointHighlightFill : radom_color(),
pointHighlightStroke : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
data : [randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor()]
},
{
label: "My Second dataset",
fillColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",0.2)",
strokeColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
pointColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
pointStrokeColor : radom_color(),
pointHighlightFill : radom_color(),
pointHighlightStroke : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
data : [randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor()]
},
{
label: "My First dataset",
fillColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",0.3)",
strokeColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
pointColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
pointStrokeColor : '#'+('00000'+(Math.random()*0x1000000<<0).toString(16)).slice(-6),
pointHighlightFill : '#'+('00000'+(Math.random()*0x1000000<<0).toString(16)).slice(-6),
pointHighlightStroke : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
data : [randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor()]
}
]
}
var ctx = document.getElementById("canvas-line").getContext("2d");
window.myLine = new Chart(ctx).Line(lineChartData, {
responsive: true
})
</script>
<!--曲线图（Line chart）结束-->
<!--雷达图或蛛网图（Radar chart）开始-->
<div>
<h1>雷达图或蛛网图（Radar chart）</h1>
<canvas id="canvas-radar" height="450" width="600"></canvas>
</div>
<script>
var randomScalingFactor = function(){ return Math.round(Math.random()*100)};
var radarData = {
labels : ["January","February","March","April","May","June","July"],
datasets : [
{
label: "My First dataset",
fillColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",0.2)",
strokeColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
pointColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
pointStrokeColor : '#'+('00000'+(Math.random()*0x1000000<<0).toString(16)).slice(-6),
pointHighlightFill : '#'+('00000'+(Math.random()*0x1000000<<0).toString(16)).slice(-6),
pointHighlightStroke : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
data : [randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor()]
},
{
label: "My Second dataset",
fillColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",0.2)",
strokeColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
pointColor : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
pointStrokeColor : '#'+('00000'+(Math.random()*0x1000000<<0).toString(16)).slice(-6),
pointHighlightFill : '#'+('00000'+(Math.random()*0x1000000<<0).toString(16)).slice(-6),
pointHighlightStroke : "rgba(" + randomScalingFactor_255() + "," + randomScalingFactor_255() + "," + randomScalingFactor_255() + ",1)",
data : [randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor()]
},
]
}
var ctx = document.getElementById("canvas-radar").getContext("2d");
window.myLine = new Chart(ctx).Radar(radarData, {
responsive: true
})
</script>
<!--雷达图或蛛网图（Radar chart）结束-->
<!--极地区域图（Polar area chart）开始-->
<div>
<h1>极地区域图（Polar area chart）</h1>
<canvas id="canvas-polar" height="450" width="600"></canvas>
</div>
<script>
var randomScalingFactor = function(){ return Math.round(Math.random()*100)};
var polarData = [
{
value: 300,
color:"#F7464A",
highlight: "#FF5A5E",
label: "Red"
},
{
value: 50,
color: "#46BFBD",
highlight: "#5AD3D1",
label: "Green"
},
{
value: 100,
color: "#FDB45C",
highlight: "#FFC870",
label: "Yellow"
},
{
value: 40,
color: "#949FB1",
highlight: "#A8B3C5",
label: "Grey"
},
{
value: 120,
color: "#4D5360",
highlight: "#616774",
label: "Dark Grey"
}
];
var ctx = document.getElementById("canvas-polar").getContext("2d");
window.myLine = new Chart(ctx).PolarArea(polarData, {
responsive: true
})
</script>
<!--极地区域图（Polar area chart）结束-->
<!--饼图（Pie chart）开始-->
<div>
<h1>饼图（Pie chart）</h1>
<canvas id="chart-pie" width="450" height="450"/>
</div>
<script>
var pieData = [
{
value: 300,
color: radom_color(),
highlight: radom_color(),
label: "Red"
},
{
value: 200,
color: radom_color(),
highlight: radom_color(),
label: "Green"
},
{
value: 100,
color: radom_color(),
highlight: radom_color(),
label: "Yellow"
},
{
value: 400,
color: radom_color(),
highlight: radom_color(),
label: "Grey"
},
{
value: 120,
color: radom_color(),
highlight: radom_color(),
label: "Dark Grey"
}
];
var ctx = document.getElementById("chart-pie").getContext("2d");
window.myPie = new Chart(ctx).Pie(pieData);
</script>
<!--饼图（Pie chart）结束-->
<!--环形图（Doughnut chart）开始-->
<div style=" 600px;height:600px;">
<h1>环形图（Doughnut chart）</h1>
<canvas id="chart-Doughnut" width="300" height="300"/>
</div>
<script>
var doughnutData = [
{
value: 1,
label: "One",
color:radom_color()
},
{
value: 2,
label: "Two",
color:radom_color()
},
{
value: 3,
label: "Three",
color:radom_color()
},
{
value: 4,
label: "Four",
color:radom_color()
},
{
value: 5,
label: "Five",
color:radom_color()
}
];
var ctx = document.getElementById("chart-Doughnut").getContext("2d");
window.myDoughnut = new Chart(ctx).Doughnut(doughnutData, {responsive : true});
</script>
<!--环形图（Doughnut chart）结束-->
</div>
</body>
</html>
项目需要在饼图上写字（最后没用），找到了一个高手改过源码之后的文件：http://download.csdn.net/detail/renfufei/7102809
具体做法：
饼状图,添加文字
1. 修改的是 Chart.js,大致在 772行 编码,也可以搜索 renfufei@qq.com
2. 示例是 samples/pie.html,使用的是 UTF-8编码
--
var pieData = [
{
value: 30,
color:"#F38630"
,text: "男生"
},
{
value : 50,
color : "#E0E4CC"
,text: "女生"
},
{
value : 100,
color : "#69D2E7"
,text: "男人"
}
];
--
chart.js可以完成功能，但是对于项目中的特殊需求并不能很好的实现~