// Draw an HSB circle
// I used this to render & save a color picker wheel for a Flash 6 app.
// - Jim Bumgardner

int sz = 300;
int margin = 10;
int rad = (sz-margin*2)/2;
int cx = sz/2;
int cy = cx;

void setup()
{
  size(sz,sz);
  noLoop();
  colorMode(HSB, 1.0);
}

void draw()
{
  noStroke();
  for (int y = 0; y < sz; ++y) 
  {
    for (int x = 0; x < sz; ++x)
    {
      float  dy = y - cy;
      float  dx = x - cx;
      float  dst = sqrt(dy*dy+dx*dx);
      float  ang = atan2(dy,dx);
      float  h = (float) (ang+PI)/(2*PI);
      float  s = (float) 1.0;
      float  b = (float) (dst <= rad? 1 : 0);
      fill(h,s,b);
      rect(x,y,1,1);
    }
  }
}