HTML plátno

Obsah

HTML Canvas je ideální pro Scatter Plots

HTML Canvas je ideální pro Čárové grafy

HTML Canvas je ideální pro kombinaci Scatter a Line

Rozptylové pozemky

Zdrojový kód

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];

// Plot Scatter
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();
}

Zkuste to sami →

<!DOCTYPE html>
<html>
<body>

<canvas id="myCanvas" width="400" height="400" style="border:1px solid grey"></canvas>

<script>
const canvas = document.getElementById("myCanvas");
const ctx = canvas.getContext("2d");
canvas.height = canvas.width;
ctx.transform(1, 0, 0, -1, 0, canvas.height)

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];

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, 3, 3, 0, 0, Math.PI * 2);
  ctx.fill();
}
</script>

</body>
</html>

Spojnicové grafy

Zdrojový kód

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

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

// Line Function
function f(x) {
  return x * slope + intercept;
}

Zkuste to sami →

<!DOCTYPE html>
<html>
<body>
<canvas id="myCanvas" width="400" height="400" style="border:1px solid grey"></canvas>

<script>
const canvas = document.getElementById("myCanvas");
const ctx = canvas.getContext("2d");
ctx.fillStyle = "#FF0000";
canvas.height = canvas.width;
ctx.transform(1, 0, 0, -1, 0, canvas.height)

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

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

function f(x) {
  return x * slope + intercept;
}
</script>

</body>
</html>

Kombinovaný

Zdrojový kód

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];

// Plot Scatter
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();

// Line Function
function f(x) {
  return x * slope + intercept;
}

Zkuste to sami →

<!DOCTYPE html>
<html>
<body>
<canvas id="myCanvas" width="400" height="400" style="border:1px solid grey"></canvas>

<script>
const canvas = document.getElementById("myCanvas");
const ctx = canvas.getContext("2d");
ctx.fillStyle = "#FF0000";
canvas.height = canvas.width;
ctx.transform(1, 0, 0, -1, 0, canvas.height)

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];

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

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

// Line Function<br>
function f(x) {
  return x * slope + intercept;
}
</script>

</body>
</html>