Using Variables - Week 06

Welcome to week 6 of Intro to Web Dev!

Now you know how to use p5.js to write code and call functions to draw on the screen.

This week, you’ll learn how to use variables to get information from the computer.

Work through the activities in this page to complete the week!

Using Variables

First, read through this tutorial:


Now you know how to use variables to get information from the computer.

To practice that, create a p5.js sketch that uses the width and height variables.

Your sketch must run without any errors. Your sketch must contain at least five function calls that use the width and/or height variables. You can draw the same shape multiple times, and you can have more than 5 function calls. But I’ll be looking for a minimum of 5.

Note: You can also use other variables like mouseX and mouseY if you want! I’ll be looking for any five function calls that use any variables as their arguments.

For example:

function setup() {
  createCanvas(400, 400);

function draw() {
  ellipse(width / 2, height / 2, width * .75, height * .75);
  rect(width * .25, height * .25, width * .5, height * .5);

This code contains two function calls that use the width and height variables: ellipse() and rect(). Note that the createCanvas() and background() functions don’t use width or height, so I’m not counting those.

As you write your code, try changing the size of your canvas to make sure your sketch works with different widths and heights. Try these sizes:

  • createCanvas(400, 400);
  • createCanvas(200, 400);
  • createCanvas(400, 200);
  • createCanvas(200, 200);

It’s okay if your drawing looks smooshed or distorted at different sizes. The important thing is that you’re practicing using the width and height variables!