DOC: Find the indices and number of pixels for rectangle shapes

open this branch due to conflicts in the previous branch( merge conflicts markers)
You can do this as `col_coor, row_coor, col_val, row_val = roi_data[i]`.

In fact, this whole loop can be simplified as

```python
for i, (col_coor, row_coor, col_val, row_val) in enumerate(roi_data, 1):
    pass
```