import processing.serial.*; 

float c;
int colour_rgb, colour_r, colour_g, colour_b, spos=90;

Serial port; 

PImage img;

void setup(){
//  img = loadImage("colour-wood.jpg");
  img = loadImage("RGB-wheel.jpg");
  size(((img.width)/2), ((img.height)/2));
  rectMode(RADIUS);
    
//  println(Serial.list());
  port = new Serial(this, Serial.list()[4], 19200);
}

// calculate servo postion from mouseX and send to serial port
void update(int x) 
{
  //Calculate servo postion from mouseX
  spos= 360*x/(180-(img.width));
  //println(spos);

//write servo position ( from 0 to 180) to serial port with byte id at beginning (S) and dud value (L)  
  port.write("SL"); 
  port.write(spos); 
}

void draw(){
  //draw image
  image(img, 0, 0, ((img.width)/2), ((img.height)/2));
  //get rgb colour values where mouse pointer is
  color c = get(mouseX, mouseY);
  fill(c);
  stroke(255);

//  assign rgb values into individual variables
  colour_r = int(red(c));
  colour_g = int(green(c));
  colour_b = int(blue(c));

//call update function to find servo position based on x position of mouse pointer
  update(mouseX);
  
//write rgb variables to serial port with byte id at beginning (C) and dud value (L)  
  port.write("CL");
  port.write(colour_r);
  port.write(colour_g);
  port.write(colour_b);
  
//  println(colour_r);
//  println(colour_g);
//  println(colour_b);

  rect(mouseX, mouseY, 10, 10); 
}