final int WIDTH = 400;
final int HEIGHT = 200;
final int PAD_X = 20;
final int PAD_Y = 10;

boolean debounce = true;

String s;

String avg_int_str(String s) {
    final int mid = floor(s.length() / 3);
    final String[] parts = {s.substring(0, mid), s.substring(mid, mid * 2), s.substring(mid * 2)};
    String result = "";
    char newChar;
    int charCodeSum;
    for (int i = 0; i < mid; i++) {
        charCodeSum = 0;
        for (int j = 0; j < parts.length; j++) {
            charCodeSum += parts[j].charAt(i);
        }
        newChar = (char) floor(charCodeSum / parts.length);
        result += newChar;
    }
    return result;
}

void gen_barcode() {
    float r, p;
    for (int i = PAD_X; i < WIDTH - PAD_X; i += r + p) {
        r = random(0, 5);
        p = random(2, 4);
        s += floor(r + p);
        for (int j = 0; j < r; j++) {
            line(i + j, PAD_Y, i + j, HEIGHT - PAD_Y - 20);
        }
    }
    textAlign(CENTER);
    print(avg_int_str(s));
    text(avg_int_str(s), WIDTH / 2, HEIGHT - PAD_Y - 5);
}

void setup() {
    size(400, 200); //Processing doesn't allow variables (or consts) as parameters for the size parameter
    stroke(2);
    fill(0,0,0);
}

void draw() {
    s = "";
    if (keyPressed == true && debounce) {
      if(key == 's') {
        save("barcode.tga");
      } else {
        background(255,255,255);
        debounce = false;
        gen_barcode();
      }
    } else if(!debounce) {
      debounce = true;
    }
}