// Learning Processing
  // Daniel Shiffman
  // http://www.learningprocessing.com
  
  // Example 20-2: Doorbell with Sonia
  
  // A Class to describe a "doorbell" (really a button)
  class Doorbell {
    // Location and size
    float x;
    float y;
    float r;
    
    // Create the doorbell
    Doorbell (float x_, float y_, float r_) {
      x = x_;
      y = y_;
      r = r_;
    }
    
    // Is a point inside the doorbell? (used for mouse rollover, etc.)
    boolean contains(float mx, float my) {
      if (dist(mx,my,x,y) < r) {
        return true;
      } else {
        return false;
      }
    }
    
    // Show the doorbell (hardcoded colors, could be improved)
    void display(float mx, float my) {
      if (contains(mx,my)) {
        fill(100);
      } else {
        fill(175);
      }
      stroke(0);
      ellipse(x,y,r,r);
    }
  }