Chart.js

Chart.js 是免费的 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（Scatter Plot）
  • 折线图（Line Chart）
  • 条形图（Bar Chart）
  • 饼图（Pie Chart）
  • 甜甜圈图（Donut Chart）
  • 气泡图（Bubble Chart）
  • 面积图（Area Chart）
  • 雷达图（Radar Chart）
  • 混合图（Mixed Chart）

如何使用 Chart.js？

Chart.js 很容易使用。

首先，添加指向提供 CDN（内容分发网络）的链接：

然后，将 添加到要绘制图表的位置：

canvas 元素必须有一个唯一的 id。

这是这样！

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: {}
);

典型的条形图语法：

const myChart = new Chart("myChart", {
  type: "bar",
  data: {},
  options: {}
);

Scatter Plot

House Price vs. Area

Source Code

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:{...}
);

Try It Yourself

Line Graph

House Price vs. Area

Source Code

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:{...}
);

Try It Yourself

If the borderColor is set to 0Then, a line graph can be drawn as a scatter plot:

borderColor: "rgba(0,0,0,0)",

Try It Yourself

Multi-line

Source Code

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}
  }
);

Try It Yourself

Linear Graph

Source Code

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);
  }
}

Try It Yourself

Function Chart

Same as the linear chart. Just change the generateData parameters:

generateData("Math.sin(x)", 0, 10, 0.5);

Try It Yourself

Bar Chart

Source Code

var xValues = ["Italy", "France", "Spain", "USA", "Argentina"];
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: {...}
);

Try It Yourself

Color only one bar:

var barColors = ["blue"];

Try It Yourself

All bars have only one color:

var barColors ="red";

Try It Yourself

colors of different shades:

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)",
];

Try It Yourself

Horizontal Bar Chart

Just change the type from "bar" Change to "horizontalBar":

type: "horizontalBar",

Try It Yourself

Pie Chart

Instance

new Chart("myChart", {
  type: "pie",
  data: {
    labels: xValues,
    datasets: [{
      backgroundColor: barColors,
      data: yValues
    }]
  },
  options: {
    title: {
      display: true,
      text: "Global Wine Production"
    }
  }
);

Try It Yourself

Doughnut Chart

Just change the type from "pie" Change to "doughnut":

type: "doughnut";

Try It Yourself