// imagelines
//    -- does a liney thing to the image loaded in
//    ** window size should be twice the image size 
//    ** window: 200x200   image: 100x100
//
//   Scott "Jerry" Lawrence
//   http://www.cis.rit.edu/~jerry/Software/p5
//

BImage ji;
int esize = 2;

// setup - initialize stuff 
void setup()
{
  size(200, 200);
  noBackground();  // persistant background
  noStroke();  // our ellipses will be solid colored
  
  fill(0);
  rect( 0, 0, width, height );  // clear the screen
  
  ellipseMode(CENTER_DIAMETER);  // we need to draw ellipses from the center
  
  ji = loadImage( "0.jpg" );  // load in our input image (my livejournal icon)
  
}

int sx = 0;
int sy = 0;
boolean upOrOver = false;

void loop()
{
  // random coordinate in the image
  int dx = int( random(width - 1) );
  int dy = int( random(height - 1) );
  
  int x = sx;
  int y = sy;
  
  if( upOrOver )
  {
    for( x=min(sx,dx) ; x<=max(sx, dx) ; x++ )
    {
      // snag the source pixel
      color c = ji.pixels[ (x/2) + ( (y/2) * ji.width ) ];
  
      // set the location in the destination (with an ellipse)
      fill( c ); ellipse( x, y, esize, esize );
    }
  }
    
  for( y=min(sy,dy) ; y<=max(sy, dy) ; y++ )
  {
    // snag the source pixel
    color c = ji.pixels[ (x/2) + ( (y/2) * ji.width ) ];
  
    // set the location in the destination (with an ellipse)
    fill( c ); ellipse( x, y, esize, esize );
  }
  
  if( !upOrOver )
  {
    for( x=min(sx,dx) ; x<=max(sx, dx) ; x++ )
    {
      // snag the source pixel
      color c = ji.pixels[ (x/2) + ( (y/2) * ji.width ) ];
  
      // set the location in the destination (with an ellipse)
      fill( c ); ellipse( x, y, esize, esize );
    }
  }
  
  if( upOrOver )
    upOrOver = false;
  else
    upOrOver = true;
  
  sx = dx;  sy = dy;
}