public static void fillFourthQuadrantWithSectorPoints(int radius,Map<String,Point> sector,List<String> indexesKeys,Map<String,Integer> keysIndexes){
  if (SHOW_LOGS)   Log.v(TAG,">> fillFourthQuadrantWithSectorPoints, size " + sector.size());
  for (int y=1; y <= radius; y++) {
    int x=(int)Math.sqrt(Math.pow(radius,2) - Math.pow(y,2));
    String key=getSectorKey(x,y);
    if (SHOW_LOGS)     Log.v(TAG,"fillFourthQuadrantWithSectorPoints, key[" + key + "]");
    indexesKeys.add(key);
    keysIndexes.put(key,indexesKeys.size() - 1);
    sector.put(key,new Point(x,y));
  }
  if (SHOW_LOGS)   Log.v(TAG,"<< fillFourthQuadrantWithSectorPoints");
}

public static void fillFourthQuadrantWithSectorPoints ( int radius , Map < String , Point > sector , List < String > indexesKeys , Map < String , Integer > keysIndexes ) { if ( SHOW_LOGS ) Log . v ( TAG , ">> fillFourthQuadrantWithSectorPoints, size " + sector . size ( ) ) ; for ( int y = 1 ; y <= radius ; y ++ ) { int x = ( int ) Math . sqrt ( Math . pow ( radius , 2 ) - Math . pow ( y , 2 ) ) ; String key = getSectorKey ( x , y ) ; if ( SHOW_LOGS ) Log . v ( TAG , "fillFourthQuadrantWithSectorPoints, key[" + key + "]" ) ; indexesKeys . add ( key ) ; keysIndexes . put ( key , indexesKeys . size ( ) - 1 ) ; sector . put ( key , new Point ( x , y ) ) ; } if ( SHOW_LOGS ) Log . v ( TAG , "<< fillFourthQuadrantWithSectorPoints" ) ; }
| | x - - - - - - | - - - - - - - - - - > | the formula is r ^ 2 = x ^ 2 + y ^ 2 | we are calculating a circle points . | start and y = 1 and increment y up to " radius " y v
