# The Joy of Code: Playing with Processing, Example 1

This semester, I’m teaching an online course using the Processing programming language. Processing is a language that is based on Java and is somewhat designed by artists, for artists. (You might ask why an artist would design a language based on Java. Maybe they hate their peers.) Anyway, this week the students are exploring pixels and filters. I spent about three hours tonight coming up with instructions and examples for them.

One of the first examples was an animation to illustrate a simple point. Here’s the gist. For frame i, the program turns every ith pixel white. (Everything else gets set to black.) That’s it. I had intended the example to get them thinking about how the two-dimensional grid of pixels gets mapped to a one-dimensional array. However, it turns out to have some interesting effects, at least from my perspective.

Here’s the code.

color black = color(0);
color white = color(255);
int frame = 0;

void setup() {
size(100, 100);
frameRate(5);
} // setup()

void draw() {
println(frame);
frame = (frame % pixels.length) + 1;
for (int i = 0; i < pixels.length; i++) {
if (i % frame == 0) {
pixels[i] = white;
} else {
pixels[i] = black;
}
} // for
updatePixels();
} // draw

I had thought that you could readily see the space between pixels increasing. And, at times, you can. But you also get some very interesting patterns and transitions between patterns. Download Processing, run this program, and maybe you’ll understand what I mean about it being somewhat surprising. You can also try to view the video, but I haven’t had much luck with it.

Here’s what I like most about the program. It took me less than ten minutes to write. It creates an interesting animation (or at least interesting to me). It’s easily adaptable for new things (e.g., I’m already thinking about other ways to update the array of pixels, such as using changing colors, or alternating setting black and white, wthout setting the other color, or ….) I could probably spend hours playing with new versions of the program, relying both on systematic experimentation and unpredictability (or at least unpredictability to my limited way of thinking).

While I don’t like the Processing is a Java variant (and there are some excellent critiques of using the Java model), I like that I can throw together programs quickly, discover new things, and play to my heart’s content.

When code and art come together, it brings me joy. I spent more than three hours coming up with examples and instructions for my students, so I had the opportunity for a lot of joy. Maybe I’ll share some of the interesting filters I’ve written in another post (particularly when I decide on an easy way to include images in posts).

Yesterday, I wrote about how I choose what kind of essay to write. Can you tell how the use led me to this one?

Version 1.0 released on 2016-10-17.

Version 1.0.1 of 2018-01-02.