void setup() {
  size(240,300);
  noSmooth();
}

int gridcount=100;
int grid=int(pow(gridcount,2));
int size1= 2;
float temp1;
float temp2;
float hew;
float lum;
float sat;
float linePosition=150;
int select=1;
int rectsize=20;
int rect1x=50;
int rect2x=120;
int rect3x=190;
int recty=262;
int liney=230;

int[] xpos = new int[grid];
int[] ypos = new int[grid];




void draw () {


  background(220);

  stroke(60);
  line(19,liney,219,liney);
  noStroke();

  rectMode(RADIUS);
  
  if (  abs(mouseY-recty) < rectsize && mousePressed == true ) {
    if (  abs(mouseX-rect1x) < rectsize ) {
      select = 1;
    } else if (  abs(mouseX-rect2x) < rectsize ) {
      select = 2;
    } else if (  abs(mouseX-rect3x) < rectsize ) {
      select = 3;
    }  
  }   
  
  
  if ( select == 1 ) {fill(30);} else {fill(150);}
  rect(rect1x,recty,rectsize,rectsize);

  if ( select == 2 ) {fill(30);} else {fill(150);}
  rect(rect2x,recty,rectsize,rectsize);

  if ( select == 3 ) {fill(30);} else {fill(150);}
  rect(rect3x,recty,rectsize,rectsize);  
  
  
  if (  abs(mouseX-120) < 100 && abs(mouseY-230) < 10
        && mousePressed == true ) {
    linePosition = mouseX;    
  } 

  fill(60);
  rectMode(RADIUS);
  rect(linePosition,230,5,5);
  float mousemove1 = (linePosition-20)/(gridcount * size1);


  translate(20,20);
  for(int i=0; i < grid ; i++) {

    xpos[i] = i/gridcount;
    ypos[i] = i%gridcount;  


    float xaxis= float(i/gridcount) / gridcount;
    float yaxis= float(i%gridcount) / gridcount;         
    
    
    if ( select == 1 ) {
      hew=mousemove1;
      sat=xaxis;
      lum=1-yaxis;    
    } else if ( select == 2 ) {
      hew=xaxis;
      sat=mousemove1;
      lum=1-yaxis;
    } else if ( select == 3 ) {  
      hew=yaxis;
      sat=xaxis;
      lum=mousemove1;
    }
    
    if (lum < .5 ) {
      temp2=lum*(1+sat);
    } else {
      temp2=(lum+sat)-(lum*sat);
    }

    temp1=2*lum-temp2;
    
    float Rtemp3 = hueToRGB(hew+1.0/3.0, temp1, temp2);
    float Gtemp3 = hueToRGB(hew+0.0/3.0, temp1, temp2);
    float Btemp3 = hueToRGB(hew-1.0/3.0, temp1, temp2);

    fill( Rtemp3*256, Gtemp3*256, Btemp3*256);

    rectMode(RADIUS);

    rect(xpos[i]*(size1+0),ypos[i]*(size1+0),size1/2,size1/2);
  }  

}

float hueToRGB (float temp3, float temp1, float temp2) {
  float thiscolor;
  if (temp3 < 0) {
    temp3 = temp3 + 1.0;
  } else if (temp3 > 1) {
    temp3 = temp3 - 1.0;
  }

  if ( 6.0 * temp3 < 1 ) {
    thiscolor = temp1 + ( temp2 - temp1 ) * 6.0 * temp3;
  } else if (2.0*temp3 < 1)  {
    thiscolor=temp2;
  } else if (3.0*temp3 < 2) {
    thiscolor = temp1 + ( temp2-temp1 ) * ( (2.0/3.0) - temp3 ) * 6.0;
  } else {
    thiscolor = temp1;
  }

  return thiscolor;

}