MButton cr = new MButton(740,100,50,50,255,0,0,"");
MButton cg = new MButton(740,200,50,50,0,255,0,"");
MButton cb = new MButton(740,300,50,50,0,0,255,"");
MButton[] colorbuttons = {cr,cg,cb};
MButton resetb = new MButton(650,50,75,30,200,0,100,"Re-start");
MButton clearb = new MButton(740,50,50,30,200,0,100,"Clear");
PFont myfont;
float[] a1 = new float[2];
float[] a2 = new float[2];
float[] c1 = new float[2];
float[] c2 = new float[2];
String[] msgs = new String[4];
int turn =0;
int strcol = 0;
int stgcol = 255;
int stbcol = 0;



void setup() {
  size(800,600);
  background(255);
  myfont = createFont("Ariel",18);
  msgs[0] ="Set anchor 1";
  msgs[3] = "Set anchor 2";
  msgs[1] = "Set control 1";
  msgs[2] = "Set control 2";
  frameRate(6);
 }
 
void draw() {
  textFont(myfont);
  fill(0);
  text(msgs[turn],10,50);
  drawbuttons();
}

void drawbuttons() {
  fill(0);
  textFont(myfont);
  text("Click mouse to set anchor and control points for continuous Bezier curve.",50,20);
  for (int i=0;i<colorbuttons.length;i++) {
    colorbuttons[i].drawit();
  }
  resetb.drawit();
  clearb.drawit();
}


void mousePressed() {
  if (checkbuttons()) 
   {
  stroke(strcol,stgcol,stbcol);
  triangle(mouseX,mouseY, mouseX, mouseY+3,mouseX+3,mouseY);
  switch(turn) {
    case 0:
      a1[0] = mouseX;
      a1[1] = mouseY;
      break;
    case 3:
      a2[0] = mouseX;
      a2[1] = mouseY;
      break;
     case 1:
      c1[0] = mouseX;
      c1[1] = mouseY;
      break;
    case 2:
      c2[0] = mouseX;
      c2[1] = mouseY;
      break;
  }
  turn++;
  if (turn<4) {
    //erasing old message
    fill(255);
  noStroke();
    rect(10,30,300,60);
    fill(0);
     text(msgs[turn],10,50);    
  }
  else {
    turn=1;
     //erasing old message
    fill(255);
   noStroke();
    rect(10,30,300,60);
    noFill();
   // fill(255,0,0);
   stroke(strcol,stgcol,stbcol);
    bezier(a1[0],a1[1],c1[0],c1[1],c2[0],c2[1],a2[0],a2[1]);
     a1[0]= a2[0];
    a1[1] = a2[1];
    fill(0);
    text(msgs[turn],10,50);
  }
   }
}
boolean checkbuttons() {
  //returns false if button clicked, true if not
  //does action
 
  if (clearb.onbutton(mouseX,mouseY)) {
    background(255);
    drawbuttons();
    turn=0;
    text(msgs[0],10,50);
    return false;
  }
  else if (resetb.onbutton(mouseX,mouseY)) {
    turn=0;
    fill(255);
    noStroke();
    rect(10,30,300,60);
    fill(0);
    text(msgs[0],10,50);
    return false;
  }
  for (int i=0;i<colorbuttons.length;i++) {
    if (colorbuttons[i].onbutton(mouseX,mouseY)) {
        strcol = colorbuttons[i].rcol;
        stgcol = colorbuttons[i].gcol;
        stbcol = colorbuttons[i].bcol;
        return false;
    }  
  }
  return true;
}


class MButton {
  int xpos, ypos, xlen, ylen;
  int rcol, gcol, bcol;
  String btext;
  MButton (int x, int y, int w, int h, int r, int g, int b, String t) {
    xpos = x;
    ypos = y;
    xlen = w;
    ylen = h;
    rcol = r;
    gcol = g;
    bcol = b;
    btext = t;
    
  }
  void drawit() {
    fill(rcol,gcol,bcol);
    rect(xpos,ypos,xlen,ylen);
    fill(0,0,0);
    textFont(myfont);
    text(btext,xpos+2,ypos+18);
  }
  boolean onbutton(int x, int y) {
    if ((x>=xpos)&&(x<=(xpos+xlen))&&(y>=ypos)&&(y<=(ypos+ylen))) return true;
    else return false;
    
  }
}