PSlider slid1 , slid2;
PButton btn1, btn2;
PFont myFont;
color bkColor = color(220,255,255);

void setup() {  
  size( 400, 500 );
  slid1 = new PSlider (30, 445, 150, 15, "re (C) = ", -2.0, 2.0);
  slid2 = new PSlider (30, 480, 150, 15, "im (C) = ", -2.0, 2.0);
  slid1.x = 63.72; 
  slid2.x =97.5;
  btn1 = new PButton( 220, 445, 60, 18, "Plot");
  btn2 = new PButton( 300, 445, 60, 18, "Reset");
  framerate(30);
  background(bkColor);
  myFont = loadFont("sansserif-14.vlw");
  textFont(myFont);
}

void draw(){
   btn1.display();
   btn2.display();
   slid1.display();
   slid2.display();
   }
 
 //event handler
  void mouseDragged()
  {if(slid1.overThumb())
     slid1.changeValue();
   if(slid2.overThumb())
    slid2.changeValue();
// add dragging action in other area if any
   }

void mouseReleased () 
{ if(btn1.over()) btn1Action();
  if(btn2.over()) btn2Action();
  if(slid1.over()) slid1.changeValue();
  if(slid2.over()) slid2.changeValue();
//add clicking action in any other area 
}
 
void btn1Action()
  {noStroke(); fill(bkColor);  rect(0, 0,  400, 428);stroke(0);
   runthis();   } 
void btn2Action()
  {loop();
  noStroke(); 
  fill(bkColor); rect(0, 0,  400, 428);
  fill(bkColor); rect(195, 480,  200, 19);
  stroke(0);
  }

void runthis(){
float t1, t2;
  t1 = millis();
float x, y, cre, cim;
int j = 0;
int k =0;
int period = 40;
float modsqr;
float x1, y1;
color[] colA = {#0000FF, #2323DC, #4646B9, #696996, #8C8C73, #AFAF50,
                 #D2D22D, #F5F50A, #FFFF00};

      cre = slid1.slv;
      cim = slid2.slv;

while( j <401){
for(int i=0; i<400; i++)  
  {   
      x = -1.5 + 3.0* i/400.0;
      y = 1.5 - 3.0* j/400.0;
      modsqr = x*x + y*y;
      stroke(#000000);
 		while ((k<period) && (modsqr<4)) {
			x1 = cre+(x*x-y*y);
                        y1 = 2*x*y + cim ;
			x = x1;
			y = y1;
			modsqr = x*x+y*y;
			k++;
		}
		if (k<18) {
                        stroke(colA[floor(k/2)]);
		}
		k = 0;
       point(i,j); 
        }
  j++;}
 t2 = millis();
 t2 -= t1;
 t2 /= 1000;
 fill(#000000);
// text("Elapsed time =   " + str(t2) + " secs", 10, 420);
text(" Julia Set    Z\' = Z*Z + C                    Elapsed time = "+ str(t2) + " secs", 10, 420);

text("Reset first before changing C values.", 195, 490);
 noLoop();
}

class PButton {
  float x, y;
  float w, h;
  String label = ""; 
  PFont myFont;
  PButton( float x, float y , float w, float h, String lab1) {
    this.x = x;
    this.y = y;
    this.w = w;
    this.h = h;
    label = lab1;
  }
  void display(){
    fill (220);
    rect(x, y, w, h);
    myFont = loadFont("serif-14.vlw");
    textFont(myFont);
fill(#888888);
    rect(x,y, w,h);
fill(#000000);
    text (label, x+12, y+14);
  } 
  boolean over(){ 
    boolean result = false; 
    if (mouseX>x && mouseX<x+w && mouseY>y && mouseY<y+h) 
      result = true;
    return result;
  }
}// End of PButton class

class PSlider {
  float xpos, ypos;
  float x, y;
  float w, l;
  float delL ;
  float delS ;
  float  maxv, minv, ratio,  slv; 
  String label;
  boolean dragging = false;

  PSlider( float x1, float y1, float len1, float h1, String lab1, float minv1, float maxv1 ) {
    rectMode(CORNER); 
    xpos = x1;
    ypos = y1;
    w = h1; 
    l = len1;
    x = x1 + l/2.0 -w/2;
    y = y1;
    maxv = maxv1;
    minv = minv1;
    delS = (l-3*w)/(maxv- minv)/1000;
    delL = delS*10;
    ratio =  (maxv - minv)/(l-3*w);
    slv = round(10000*(x-xpos - w)*ratio)/10000 + minv;
    label = lab1;
  }

  void initPos (float slv_init) {
    x =(slv_init -minv ) * (l-3.0*w)/(maxv - minv) +xpos +w ; 
  }

  boolean over(){ 
    boolean result = false; 
    if (mouseX>xpos && mouseX<xpos+l && mouseY>ypos && mouseY<ypos+w) 
      result = true;
    return result;
  }
  boolean overM(){ 
    boolean result = false; 
    if ( mouseX>xpos && mouseX<xpos+w && mouseY>y && mouseY<y+w) 
      result = true;
    return result;
  }
  boolean overP(){ 
    boolean result = false; 
    if ( mouseX>xpos+l-w && mouseX<xpos+l && mouseY>y && mouseY<y+w) 
      result = true;
    return result;
  }
  boolean overPTrack(){  
    boolean result = false; 
    if ( mouseX>x + w && mouseX<xpos+l-w && mouseY>y && mouseY<y+w) 
      result = true;
    return result;
  }
  boolean overMTrack(){  
    boolean result = false; 
    if ( mouseX>xpos+w && mouseX<x && mouseY>y && mouseY<y+w) 
      result = true;
    return result;
  }  

  boolean overThumb(){ 
    boolean result = false; 
    if (mouseX>x && mouseX<x+w && mouseY>y && mouseY<y+w) 
      result = true;
    return result;
  }
  void dragThumb(){
    dragging =  (overThumb() && mouseX>x &&  mouseX<x+w  && mousePressed) ;
  }
  void decByOneL(){
    if (x>xpos+w) x -= delL;  
    fill(200, 200,255);
    rect( xpos+w, y, x-xpos -w, w );
  }
  void incByOneL(){
    if (x<xpos+l-w) x += delL;  
    fill(200, 200,255); 
    rect( x+w, y, l + xpos- 2.0*w -x, w );
  }
  void decByOneS(){
    if (x>xpos+w+delS/10) x -= delS;  
    fill(200, 255, 200); 
    rect( xpos, y, w, w );
  }
  void incByOneS(){
    if (x<xpos+l-w-w-delS/10) x += delS;  
    fill(200, 255, 200); 
    rect( xpos + l-w, y, w, w );
  }      
  void changeValue(){
    if(overThumb())
      dragThumb();
    if(overP())
      incByOneS();
    if(overM())
      decByOneS();
    if(overMTrack())
      decByOneL();
    if(overPTrack())
      incByOneL();
  }    

  void display() {
    fill(255);
    rect(xpos+w, ypos, l-2*w, w);
    fill(150);
    rect(xpos, ypos, w,w);
    triangle(xpos+w, ypos, xpos, ypos+w/2, xpos+w, ypos+w);
    rect(xpos+l-w, ypos, w,w);
    triangle(xpos+l-w, ypos, xpos+l, ypos+w/2, xpos+l-w, ypos+w);
    if (dragging) { 
      x = constrain (mouseX-w/2,  xpos+w,  xpos+l-2*w); 
      fill(255, 200,200);
    } 
    else {
      fill(255);
    }
    rect( x, y, w, w );
    slv = (x-xpos - w)*ratio + minv;
    noStroke(); 
    fill(bkColor); 
    rect(xpos - 10, ypos -17,  100, 16);
    stroke(0);
    fill(255, 0, 0 );
    text(label+nfp(slv, 1,3), xpos, ypos-3);
    //     rectMode(CENTER); 
  }
}