// Learning Processing
  // Daniel Shiffman
  // http://www.learningprocessing.com
  
  // Example 17-8: Characters along a curve 
  
  // The message to be displayed
  String message = "text along a curve";
  PFont f;
  
  // The radius of a circle
  float r = 100;
  
  void setup() {
    size(320,320);
    f = createFont("Georgia",40,true);
    textFont(f);
     // The text must be centered!
    textAlign(CENTER);
    smooth();
  }
  
  void draw() {
    background(255);
    
    // Start in the center and draw the circle
    translate(width/2, height/2);
    noFill();
    stroke(0);
    ellipse(0, 0, r*2, r*2);
    
    // We must keep track of our position along the curve
    float arclength = 0;
    
    // For every box
    for (int i = 0; i < message.length(); i ++ ) {
      
      // The character and its width
      char currentChar = message.charAt(i);
      // Instead of a constant width, we check the width of each character.
      float w = textWidth(currentChar); 
      // Each box is centered so we move half the width
      arclength += w/2;
      
      // Angle in radians is the arclength divided by the radius
      // Starting on the left side of the circle by adding PI
      float theta = PI + arclength / r;
      
      pushMatrix();
      
      // Polar to Cartesian conversion allows us to find the point along the curve. See Chapter 13 for a review of this concept.
      translate(r*cos(theta), r*sin(theta)); 
      // Rotate the box (rotation is offset by 90 degrees)
      rotate(theta + PI/2); 
      
      // Display the character
      fill(0);
      text(currentChar,0,0);
      
      popMatrix();
      
      // Move halfway again
      arclength += w/2;
    }
  }