JS TutorialLesson #271
HTML Canvas
> HTML Canvas is perfect for Scatter Plots
HTML Canvas is perfect for Scatter Plots
> HTML Canvas is perfect for Line Graphs
> HTML Canvas is perfect for combining Scatter and Lines
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Scatter Plots
Source Code
```javascript 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
Interactive Code Examples
Source Code
javascriptJavaScript syntax and algorithm demonstration.
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();
}Source Code
javascriptJavaScript syntax and algorithm demonstration.
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;
}Source Code
javascriptJavaScript syntax and algorithm demonstration.
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;
}