pointilism processing

int _w;int _h;PImage img;String path_to_img  = "d:\\face.jpg";// display flagboolean display = false;// tile sizeint tile_s = 10;// circle sizeint radius = tile_s / 2 ; int loclr = 0x0;int hiclr = 0xDE2626;float max_bright = 255.0f;void setup(){  background(loclr);  // fill(0xde2626);  img = loadImage(path_to_img);  _w = img.width;  _h = img.height; size(_w,_h);    img.loadPixels();  process();  //subsample(8,8,8,_w,_h,img.pixels);  img.updatePixels();    // debug  if(display)image(img);}void draw(){}void process(){  for(int y = 0; y < _h; y += tile_s)  {    for(int x = 0; x < _w; x += tile_s)    {      int[] sub = subsample(x,y,tile_s,_w,_h,img.pixels);      float c     = avg_bright(sub);      float f = c / max_bright;            float rf = (float)Math.ceil(tile_s * f);            int t_half = tile_s / 2;      ellipse(x, y ,rf, rf);         }  }}void image(PImage i){  image(i,0,0);}int[] subsample(int x, int y, int s, int w, int h, int[] img){  if(s > w || s > h) return null;    // counters  int n = 0;  int m = 0;    int[] buffer = new int[s*s];   int bpos = 0;    // position markers  int v_off = (y * w);  int pos = x + (v_off);  int end = ((s-1) + ((s-1) * w))+pos;    //println("pos: "+pos+" end: "+end);    // old ((v_off)+(w-s+1))    for(int i = pos; i <= end; i += ((++n) % s) == 0 ?  ((w-s)+1) : 1 )  {    try {     buffer[bpos++] = img[i];     } catch(Exception e)     {       // out of bounds     }  }  return buffer; }float avg_bright(int[] subsample){  int len = subsample.length;  int c = 0;  for(int i = 0; i < len; i++)  {      c += (subsample[i] / len);  }   return (brightness(c));}int[] subsample(int x, int y, int s, int[] img){  return subsample(x,y,s,_w,_h,img);}