Finding indices and number pixels for rectangle shapes

This module will find the indices of rectangle or square shape and count the
  number of pixels in that shape.

```python
left, right = np.max([]), np.min([])
top, bottom = np.max([]), np.min([])

area = (right - left) * (bottom - top)
slc1 = slice(left, right)
slc2 = slice(top, bottom)