2.1: Intro to Code, Shapes and Styling

How can I draw shapes on a digital canvas?

Teacher Notes and Overview

This lesson kicks off the students' journey into coding! They will sign up for the website that will house their code and will begin by learning basics and getting simple shapes to appear on the screen. While this lesson will likely take a single period, it could be extended if you wanted to give a more open-ended practice project.

If you are looking for further resources, activities, or would generally like a deeper dive into these topics, we recommend taking a look at the following lessons from our Introduction to Computational Media curriculum:

Objectives

Students will be able to:

Create new sketches in the p5 editor
Adjust canvas size and background color
Draw basic shapes - circles, rectangles, lines, and points.
Utilize the reference sheet

Suggested Duration

1-2 Days

NYS Standards

9-12.DL.1 Type proficiently on a keyboard.
9-12.DL.2 Communicate and work collaboratively with others using digital tools to support individual learning and contribute to the learning of others.

Vocabulary

p5.js - a JavaScript library built on Processing, a library for Java. It is intended to be used for web-based, visual creative coding projects.
code - instructions written for a computer to follow
IDE - integrated development environment, a place online where you can write code
function - a sequence of program instructions that performs a specific task, packaged as a unit. (We see these units as ellipse(), rect(), createCanvas(), etc in this lesson - functions will always have () after the name of the unit!)

Planning Notes and Materials

Please note that there is a grid worksheet of the p5.js coordinates - you may want copies or laminated versions to use in class.

Resources

JavaScript in 100 Seconds (Youtube Video)
What is p5.js? (Codecademy Additional Resource)
p5 Reference Sheet (p5 Website)
p5 Grid Worksheet (PDF Worksheet)
Desmos p5 Coordinate Grid Tool (Optional Resource)
Lesson 1, Part 1 Starter Code (p5 Editor)

Assessments

Formative:

Code Challenge Projects

Summative:

Upcoming Mini Project

Do Now/Warm Up (~3 min - 5 min)

Ask students to navigate to the p5 editor website and create an account.

p5.js Web Editor

Note that due to DOE settings, if they are signing up with a DOE (@schools.nyc.gov) email, they will not be able to use the 'Sign Up with Google', 'Sign in with Google', or any other SSO option. They must manually type their email address and password.

Intro: Your First p5 Sketch (~10 - 15 minutes)

Explain to students that for this unit, they will be learning to use p5.js, which is a library that builds onto the JavaScript programming language. You may or may not want to show them the brief video on JavaScript or other resources linked in the above Resource section, depending on how much prior coding experience they may or may not have.

p5.js and it's Java equivalent, Processing, are both libraries used for creative coding and by artists such as Casey Reas.

We will be coding in the p5 editor, which students made an account for in the Do Now. This is an example of an online IDE - integrated development environment - which is a place where people write code.

To get us started, we will work off the same sketch together in a code along - this is when a teacher demonstrates code on the screen and students - spoiler alert - code along. This code along will be a mix of teacher led information and student information.

Ask students to duplicate the starter code. Please note that they will need to manually hit save - this is a huge sticking point for students who did not grow up having to do this! Remind them to save when they first duplicate and often thereafter.

Begin by introducing students to the code - they can hit play if they want to see the results. At the top, there is a code comment that begins with //. All code comments in JavaScript will begin that way - comments will not be read by the computer and are just for us to see.

Next, note that there are two big functions here - setup and draw. These are foundational to making p5 sketches run and we always need them. Note for students the { } curly braces - these are important in our code as it shows the computer where certain things begin and end. In this case, we can see setup begins on line 3 and ends on line 5 (putting your cursor by one brace will highlight the other). The draw function begins on line 7 and ends on line 12. Adding things to one of these functions means putting it between the curly braces.

Outside of the setup and draw, we have other functions inside of these functions that make things happen on our screen. We know we are dealing with a function because it will always be a word with () after it - these () may or may not hold arguments which are values that change how the function runs.

Let's examine these functions from the top down and determine what they do. Begin with createCanvas(400, 400). Ask students to change each number to a different value, one at a time, hitting the play button after each change. They should keep changing the values until they think they can explain what each does, and then they should leave that as a comment. Allow ~30 seconds - 1 minute of play time and then review together - ensure students have something like:

createCanvas(400, 400) //first num width, second num height of canvas

Reset the values back to 400, 400 or something else that is a decent size before continuing into draw and repeating htis process for the 3 functions there. First, direct students to adjust the values in background and fill. Same as before, they should adjust one number at a time, hit play, and then adjust the other. Note that each of these has a maximum value of 255. Once students think they know what each controls, have them leave a comment. After ~30 seconds - 1 minute of play, reconvene to make sure they have something like:

function draw() {
  background(220) //max value 255, background color of canvas, low numbers dark, high numbers light
  
  fill(255) //max value 255, color of ellipse, low numbers dark, high numbers light
  ellipse(150, 200, 50, 75)
}

Finally, we've reached the ellipse. This function has four arguments. Once again, they should change each number one at a time and hit play after each change until they understand what each number does and can leave it as a comment. This may require slightly longer to do - allow ~2 minutes before reconvening to discuss:

function draw() {
  background(220) //max value 255, background color of canvas, low numbers dark, high numbers light
  
  fill(255) //max value 255, color of ellipse, low numbers dark, high numbers light
  ellipse(150, 200, 50, 75) //left/right position, up/down position, width, height
}

Introducing: the Reference Sheet && p5 Grid (~5 - 10 minutes)

Students were able to figure out what the numbers meant; but it would be hard to guess all the possible things available in the p5 library, or even to remember what all the arguments do (and taking 5 minutes to experiment each time can be annoying). Luckily, the developers have made a reference sheet for us to use - this is called documentation and it is something all good programmers should practice.

With students, find the ellipse() function (either via search or by scrolling down to Shape --> 2D Primitives). Review the documentation together and make sure it matches what they agreed upon from their exploration; then, return to the canvas and add another ellipse in the draw function (recall it must be before the ending curly brace):

function draw() {
  background(220) //max value 255, background color of canvas, low numbers dark, high numbers light
  
  fill(255) //max value 255, color of ellipse, low numbers dark, high numbers light
  ellipse(150, 200, 50, 75) //left/right position, up/down position, width, height
  
  //second ellipse
  ellipse(50, 50, 100, 100) //adjust nums based on student input
}

Now, one thing students may notice is that the coordinates might not make sense with cartesian planes they usually see in math. This is because on a JavaScript canvas (and in many other programming languages), the origin is seen as the top left of the screen - that's because this is where screens turn on from! Display or distribute the p5 Grid Worksheet to give students an idea of how this works.

NB: These can be great to have laminated and available throughout the unit, or to have taped down to the corners of desks or tables for quick reference.

Using what you know about the grid and the reference sheet, ask students to add a rectangle that will appear somewhere near the top right side of the screen. Give them ~2 minutes to navigate the reference sheet and draw their shape, then reconvene - ask students to provide you with the values for their rectangle OR ask a student to display their code and explain their choices. Values may vary, but you will likely end up with something like this:


function draw() {
  background(220) //max value 255, background color of canvas, low numbers dark, high numbers light
  
  fill(255) //max value 255, color of ellipse, low numbers dark, high numbers light
  ellipse(150, 200, 50, 75) //left/right position, up/down position, width, height
  
  //second ellipse
  ellipse(50, 50, 100, 100) //adjust nums based on student input
  
  //rectangle top right area
  rect(300, 50, 75, 75)
}

Noticing fill() (~5 - 10 minutes)

Now, with at least three shapes on our canvas, we may notice that whatever fill() was set above the first ellipse applies to all shapes. Explaint o students that this is because the draw function runs in an endless loop forever (the setup function runs just once, at the start of the program) which allows us to get some interesting interactions.

If we wanted to make each shape it's own color, they would each need to have their own fill. Changes to the shape should happen before the shape is drawn, like so:

function draw() {
  background(220) //max value 255, background color of canvas, low numbers dark, high numbers light
  
  fill(255) //max value 255, color of ellipse, low numbers dark, high numbers light
  ellipse(150, 200, 50, 75) //left/right position, up/down position, width, height
  
  //second ellipse
  fill(120)
  ellipse(50, 50, 100, 100) //adjust nums based on student input
  
  //rectangle top right area
  fill(0)
  rect(300, 50, 75, 75)
}

Your Challenge (10 - 15 min)

Ask students to create a new project in the p5 editor - this is their chance to practice naming and saving their new files.

Once created, students will attempt to recreate the following (the sketch can build - no need to make multiple files:

This task will require them to layer shapes; shapes drawn first in the code are drawn first, which means they may appear behind shapes drawn later. Once students have gotten the design down, encourage them to practice adding a fill to each shape.

Wrap Up (~3 - 5 minutes)

Ask students to share what they have made and/or answer any combination of the following questions:

What is something you learned today?
What was challenging today?
What is something you still have questions about, or would like to learn about?

Extensions and Additions

If you are looking to challenge your students, consider having them spend time making a more complex design out of the given shapes. 'Drawing a robot' tends to lend itself well to only having circles and rectangles available, but they could make this prompt anything!

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Last updated 11 months ago