/**
 * Cycloid 1
 *
 * For messing around with cycloids of various sorts
 *
 * Matthew Conroy ( conroy (at) math dot washington dot edu )
 **/

HScrollbar hs1, hs2, hs3, hs4;

PImage top, bottom;         // Two image to load
int topWidth, bottomWidth;  // The width of the top and bottom images
float lasta, lastb; // to keep track of whether things have changed
int lastm;

float[] coeffs = new float[30]; //array for the coefficients of the taylor polynomials

void setup()
{
  size(700, 560);
  noStroke();
  //hs1 = new HScrollbar(0, height-80, width, 10, 3*5+1);
  hs2 = new HScrollbar(0, height-60, width, 10, 3*5+1,50);
  hs3 = new HScrollbar(0, height-40, width, 10, 3*5+1,50);
  hs4 = new HScrollbar(0, height-20, width, 10, 3*5+1,50);


   PFont fontA = loadFont("CourierNew36.vlw");
   textFont(fontA, 18);
}

void draw()
{
  background(255);

  // Get the position of the top scrollbar
  // and convert to a value to display the top image
  //float Pos1 = hs1.getPos();
  float Pos2 = hs2.getPos();
  float Pos3 = hs3.getPos();
  float Pos4 = hs4.getPos();

  float xx=0;
  float yy=0;
  float xxLast=0,yyLast=0,xx0=0,yy0=0;
  
  float scale=7.5;

 //  float a=0.+1.0*Pos1/width;
 //  float b=(Pos2/width-1./2.)*2*3.1415926535;

  float x1 = Pos2;
  float r1 = 5+Pos3/5.;
  float r2 = 5+Pos4/5.;

  smooth();
  strokeWeight(1);
    
    //draw axes
    stroke(33);
    line(0,height/2,width,height/2);
    //line(width/2,0,width/2,height);
    
    //draw cycloid
    int numPoints=1000;
    for(int i = 0; i<numPoints; ++i) {
        float t = (i-numPoints/2)/scale;
        xx = width/2.+r1*t-r2*sin(t);
        yy = height/2.-(r1-r2*cos(t));
        stroke(77);
        if (i>0) {
          line(xx,yy,xxLast,yyLast);
        }
        else {
          xx0=xx;
          yy0=yy;
        }
        xxLast=xx;
        yyLast=yy;
    }

   //draw rolling circle
   numPoints=100;
   for(int i=0; i<numPoints; ++i) {
     float t = i*2*3.1415926/numPoints;
     xx=x1+r1*cos(t);
     yy=height/2.-(r1+r1*sin(t));
     if (i>0) {
       line(xx,yy,xxLast,yyLast);
     }
     else {
       xx0=xx;
       yy0=yy;
     }
     xxLast=xx;
     yyLast=yy;
   }
    line(xxLast,yyLast,xx0,yy0);
    
    
    //draw the dot
    stroke(77);
    xx = x1+r2*cos(-(x1-width/2.)/r1-3.1415926/2.);
    yy = height/2.-(r1+r2*sin(-(x1-width/2.)/r1-3.1415926/2.));
    ellipse(xx,yy,5,5);
    line(x1,height/2.-r1,xx,yy);
   
    stroke(128);
    //hs1.update();
    hs2.update();
    hs3.update();
    hs4.update();
    //hs1.draw();
    hs2.draw();
    hs3.draw();
    hs4.draw();
  

  //words

   //text("a="+int(a*100)/100.+" b="+int(b*10)/10.+" m="+z1Fact+" n="+z2Fact,10,height-100);

     fill(0);
     //text("a="+int(100*a)/100.,10,height-100);
     //text("b="+int(100*b)/100.,10+width*0.25,height-100);
     //text("b="+int(100*mm)/100.,10+width*0.5,height-60);
     //text("n="+n,10+width*0.75,height-60);
     
    // lasta=a;
    // lastb=b;
    // lastm=m;
  //} // end of if things have changed
   
  
  //println(hs1.getPos());
}


class HScrollbar
{
  int swidth, sheight;    // width and height of bar
  int xpos, ypos;         // x and y position of bar
  float spos, newspos;    // x position of slider
  int sposMin, sposMax;   // max and min values of slider
  int loose;              // how loose/heavy
  boolean over;           // is the mouse over the slider?
  boolean locked;
  float ratio;

  HScrollbar (int xp, int yp, int sw, int sh, int l, int sposition) {
    swidth = sw;
    sheight = sh;
    int widthtoheight = sw - sh;
    ratio = (float)sw / (float)widthtoheight;
    xpos = xp;
    ypos = yp-sheight/2;
    // note the width and height of the slider are both sheight
    spos = xpos+sheight/2.+sposition/100.*(swidth-sheight)-sheight/2.;
    newspos = spos;
    sposMin = xpos;
    sposMax = xpos + swidth - sheight;
    loose = l;
  }

  void update() {
    if(over()) {
      over = true;
    } else {
      over = false;
    }
    if(mousePressed && over) {
      locked = true;
    }
    if(!mousePressed) {
      locked = false;
    }
    if(locked) {
      newspos = constrain(mouseX-sheight/2, sposMin, sposMax);
    }
    if(abs(newspos - spos) > 1) {
      spos = spos + (newspos-spos)/loose;
    }
  }

  int constrain(int val, int minv, int maxv) {
    return min(max(val, minv), maxv);
  }

  boolean over() {
    if(mouseX > xpos && mouseX < xpos+swidth &&
    mouseY > ypos && mouseY < ypos+sheight) {
      return true;
    } else {
      return false;
    }
  }

  void draw() {
    fill(255);
    rect(xpos, ypos, swidth, sheight);
    if(over || locked) {
      fill(128);
    } else {
      fill(0);
    }
    rect(spos, ypos, sheight, sheight);
  }

  float getPos() {
    // convert spos to be values between
    // 0 and the total width of the scrollbar
    return spos * ratio;
  }
}