import processing.serial.*;
int dg;
int angle;
Serial port;
float mx =0.0;

void setup(){
  size(640,480);
  noStroke();
  frameRate(50);
  
  port = new Serial(this,"/dev/cu.usbserial-A700eEjj",9600);
}

void draw(){
  background(0); //background is black
  
  fill(204); //set Panel's fill color to 204
  rect(40,height/2+135,560,50); // panel rect(x,y,width,height)

  float dif = mouseX -mx;
  if (abs(dif) > 1.0){ 
    mx +=dif/4.0; 
  }
  
  mx = constrain(mx,0,540); 
  noStroke();
  
  fill(255); // white bar 255
  rect (50,(height/2)+145, 540,30);
  
  fill(204,102,0); //fill(R,G,B) Red cursor
  rect(50, height/2+145,4+mx,30); 
  
  //int angle = int(map(mx,0,540,0,255));
    angle = int(map(mx,0,540,0,255));
  int vol = int(map(mx,0,540,0,100));
textSize(32);
 text(vol,290,350);
  text("%",355,350);
 
  fill(225);
ellipse(320,200,180,180);
 
 
 fill(50);
 for (int d = 0; d <=4; d++){
   arc(320, 200, 150,150,0-PI/2*d+PI/900*dg*angle,PI/4-PI/2*d+PI/900*dg*angle);
 }
 fill(225);
ellipse(320,200,30,30);
 
 if (angle > 0){
 dg++;
 }
 
 if (dg == 900)
   dg =0;
    port.write(angle);
  }