import processing.video.*; 
 
// Variable for capture device 
Capture video; 
color trackColor; 
 
 
void setup() 
{ 
  size(200, 200); 
  framerate(30); 
  colorMode(RGB,255,255,255,100); 
  // Using the default capture device 
  video = new Capture(this, 200, 200, 12); 
  trackColor = color(255); // Start off tracking for white 
  noFill(); 
  smooth(); 
  strokeWeight(4.0); 
  stroke(0); 
 
} 
 
void captureEvent(Capture camera) 
{ 
  camera.read(); 
} 
 
void draw() 
{ 
 
  loadPixels(); 
  
  // Draw the video image on the background 
  image(video,0,0); 
  // Local variables to track the color 
  float closestDiff = 500.0f; 
  int closestX = 0; 
  int closestY = 0; 
  // Begin loop to walk through every pixel 
  for ( int x = 0; x < video.width; x++) { 
    for ( int y = 0; y < video.height; y++) { 
      int loc = x + y*video.width; 
      // What is current color 
      color currentColor = video.pixels[loc]; 
      float r1 = red(currentColor); float g1 = green(currentColor); float b1 = blue(currentColor); 
      float r2 = red(trackColor);   float g2 = green(trackColor);   float b2 = blue(trackColor); 
      // Using euclidean distance to compare colors 
      float d = dist(r1,g1,b1,r2,g2,b2); 
      // If current color is more similar to tracked color than 
      // closest color, save current location and current difference 
      if (d < closestDiff) { 
        closestDiff = d; 
        closestX = x; 
        closestY = y; 
      } 
    } 
  } 
  // Draw a circle at the tracked pixel 
  ellipse(closestX,closestY,16,16); 
} 
 
void mousePressed() { 
  // Save color where the mouse is clicked in trackColor variable 
  int loc = mouseX + mouseY*video.width; 
  trackColor = video.pixels[loc]; 
}