HTML Canvas

HTML Canvas 非常适合散点图（Scatter Plots）。

HTML Canvas 非常适合折线图（Line Graphs）。

HTML Canvas 非常适合组合散点图和折线图。

散点图

源代码

const xArray = [50,60,70,80,90,100,110,120,130,140,150];
const yArray = [7,8,8,9,9,9,10,11,14,14,15];

// 散点图
ctx.fillStyle = "red";
for (let i = 0; i < xArray.length-1; i++) {
  let x = xArray[i]*400/150;
  let y = yArray[i]*400/15;
  ctx.beginPath();
  ctx.ellipse(x, y, 2, 3, 0, 0, Math.PI * 2);
  ctx.fill();
}

亲自试一试

折线图

源代码

let xMax = canvas.height;
let slope = 1.2;
let intercept = 70;

// 散点图
ctx.moveTo(0, intercept);
ctx.lineTo(xMax, f(xMax));
ctx.strokeStyle = "black";
ctx.stroke();

// 折线函数
function f(x) {
  return x * slope + intercept;
}

亲自试一试

组合

源代码

let xMax = canvas.height;
let yMax = canvas.width;
let slope = 1.2;
let intercept = 70;

const xArray = [50,60,70,80,90,100,110,120,130,140,150];
const yArray = [7,8,8,9,9,9,10,11,14,14,15];

// 散点图
ctx.fillStyle = "red";
for (let i = 0; i < xArray.length-1; i++) {
  let x = xArray[i]*400/150;
  let y = yArray[i]*400/15;
  ctx.beginPath();
  ctx.ellipse(x, y, 2, 3, 0, 0, Math.PI * 2);
  ctx.fill();
}

// Plot Line
ctx.moveTo(0, intercept);
ctx.lineTo(xMax, f(xMax));
ctx.strokeStyle = "black";
ctx.stroke();

// 折线函数
function f(x) {
  return x * slope + intercept;
}

亲自试一试