docs: public void add(double x, double y)
      {
          if (count >= xarr.length)
          {
              grow();
          }
          xarr[count] = x;
          yarr[count++] = y;
          minX = Math.min(minX, x);
          minY = Math.min(minY, y);
          maxX = Math.max(maxX, x);
          maxY = Math.max(maxY, y);
      }