Chart.js
Chart.js 是一个免费的 JavaScript 库，用于制作基于 HTML 的图表。它是最简单的 JavaScript 可视化库之一，并带有以下内置图表类型
- 散点图
- 折线图
- 柱状图
- 饼图
- 甜甜圈图
- 气泡图
- 面积图
- 雷达图
- 组合图
如何使用 Chart.js？
Chart.js 易于使用。
首先，添加一个 CDN（内容分发网络）的链接
<script
src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js">
</script>
然后，添加一个 <canvas> 元素到你想要绘制图表的位置
<canvas id="myChart" style="width:100%;max-width:700px"></canvas>
canvas 元素必须有一个唯一的 ID。
就是这样！
典型的散点图语法
const myChart = new Chart("myChart", {
type: "scatter",
data: {},
options: {}
});
典型的折线图语法
const myChart = new Chart("myChart", {
type: "line",
data: {},
options: {}
});
典型的柱状图语法
const myChart = new Chart("myChart", {
type: "bar",
data: {},
options: {}
});
散点图
房价 vs. 面积
源代码
const xyValues = [
{x:50, y:7},
{x:60, y:8},
{x:70, y:8},
{x:80, y:9},
{x:90, y:9},
{x:100, y:9},
{x:110, y:10},
{x:120, y:11},
{x:130, y:14},
{x:140, y:14},
{x:150, y:15}
];
new Chart("myChart", {
type: "scatter",
data: {
datasets: [{
pointRadius: 4,
pointBackgroundColor: "rgba(0,0,255,1)",
data: xyValues
}]
},
options:{...}
});
折线图
房价 vs. 面积
源代码
const xValues = [50,60,70,80,90,100,110,120,130,140,150];
const yValues = [7,8,8,9,9,9,10,11,14,14,15];
new Chart("myChart", {
type: "line",
data: {
labels: xValues,
datasets: [{
backgroundColor:"rgba(0,0,255,1.0)",
borderColor: "rgba(0,0,255,0.1)",
data: yValues
}]
},
options:{...}
});
如果将 borderColor 设置为零，则可以将折线图显示为散点图。
borderColor: "rgba(0,0,0,0)",
多行
源代码
const xValues = [100,200,300,400,500,600,700,800,900,1000];
new Chart("myChart", {
type: "line",
data: {
labels: xValues,
datasets: [{
data: [860,1140,1060,1060,1070,1110,1330,2210,7830,2478],
borderColor: "red",
fill: false
},{
data: [1600,1700,1700,1900,2000,2700,4000,5000,6000,7000],
borderColor: "green",
fill: false
},{
data: [300,700,2000,5000,6000,4000,2000,1000,200,100],
borderColor: "blue",
fill: false
}]
},
options: {
legend: {display: false}
}
});
线性图
源代码
const xValues = [];
const yValues = [];
generateData("x * 2 + 7", 0, 10, 0.5);
new Chart("myChart", {
type: "line",
data: {
labels: xValues,
datasets: [{
fill: false,
pointRadius: 1,
borderColor: "rgba(255,0,0,0.5)",
data: yValues
}]
},
options: {...}
});
function generateData(value, i1, i2, step = 1) {
for (let x = i1; x <= i2; x += step) {
yValues.push(eval(value));
xValues.push(x);
}
}
函数图
柱状图
源代码
var xValues = ["意大利", "法国", "西班牙", "美国", "阿根廷"];
var yValues = [55, 49, 44, 24, 15];
var barColors = ["red", "green","blue","orange","brown"];
new Chart("myChart", {
type: "bar",
data: {
labels: xValues,
datasets: [{
backgroundColor: barColors,
data: yValues
}]
},
options: {...}
});
颜色渐变
var barColors = [
"rgba(0,0,255,1.0)",
"rgba(0,0,255,0.8)",
"rgba(0,0,255,0.6)",
"rgba(0,0,255,0.4)",
"rgba(0,0,255,0.2)",
];
饼图
示例
new Chart("myChart", {
type: "pie",
data: {
labels: xValues,
datasets: [{
backgroundColor: barColors,
data: yValues
}]
},
options: {
title: {
display: true,
text: "世界葡萄酒产量"
}
}
});
