PrintWriter output;
void setup() {
  output = createWriter("positions.txt");
  size(300,300);
}
void draw() {
}
void mouseDragged(){
  point(mouseX, mouseY);
  output.println(mouseX + "," + mouseY + "\r");
}
void keyPressed() {
  output.flush();
  output.close(); // Closes the file
}