Processing.js

Pulses

Software drawing instruments can follow a rhythm or abide by rules independent of drawn gestures. This is a form of collaborative drawing in which the draftsperson controls some aspects of the image and the software controls others.

Original Processing.org Example: Pulses

// All Examples Written by Casey Reas and Ben Fry
// unless otherwise stated.
int angle = 0;

void setup() 
{
  size(200, 200);
  background(102);
  smooth();
  noStroke();
  fill(0, 102);
}

void draw() 
{
  // Draw only when mouse is pressed
  if (mousePressed == true) {
    angle += 10;
    float val = cos(radians(angle)) * 6.0;
    for (int a = 0; a < 360; a += 75) {
      float xoff = cos(radians(a)) * val;
      float yoff = sin(radians(a)) * val;
      fill(0);
      ellipse(mouseX + xoff, mouseY + yoff, val/2, val/2);
    }
    fill(255);
    ellipse(mouseX, mouseY, 2, 2);
  }
}