import processing.serial.*;
 PImage a;
 PImage b;
 PImage c;
 Serial myPort;        // The serial port
 int xPos = 1;         // horizontal position of the graph
 int drawPicture=0;
 int threshold= 870;
 int threshold2= 760;
 void setup () {
 // set the window size:
 size(screen.width, screen.height);
        
  
  a=loadImage("DV-inverse.jpg");
  b=loadImage("DV.jpg");
  c=loadImage("surveillance.jpg");
 // List all the available serial ports
 println(Serial.list());
 // I know that the first port in the serial list on my mac
 // is always my  Arduino, so I open Serial.list()[0].
 // Open whatever port is the one you're using.
 myPort = new Serial(this, Serial.list()[3], 9600);
 // don't generate a serialEvent() unless you get a newline character:
 myPort.bufferUntil('\n');
 // set inital background:
 background(0);
 }
 
 void draw () {
   background(0);
 // everything happens in the serialEvent()
 if (drawPicture==0){
 image(a, 0, 0, screen.width, screen.height);
 } else if (drawPicture==1){
  image(c, 0, 0, screen.width, screen.height);
 }else{
 image(b, 0, 0, screen.width, screen.height);
 }
 }
 
 void serialEvent (Serial myPort) {
 // get the ASCII string:
 String inString = myPort.readStringUntil('\n');
 
 if (inString != null) {
 // trim off any whitespace:
 inString = trim(inString);
 // convert to an int and map to the screen height:
 float inByte = float(inString); 
 //inByte = map(inByte, 0, 1023, 0, height);
 //float value=inByte;
 
 println(inByte);
 if (inByte>threshold) {
  
  println("GOT HERE");
  drawPicture=2;
 } 
 
 else if (inByte>threshold2) {
   println("ALMOST HERE");
   drawPicture=1;}
 else {
   drawPicture=0;
   println("NOT HERE");
 }
 }
 }