In the documentation https://pyqtgraph.readthedocs.io/en/latest/graphicsItems/roi.html, it is mentioned that the pos argument "(length-2 sequence) Indicates the position of the ROI’s origin. For most ROIs, this is the lower-left corner of its bounding rectangle . "
In practice (for example Indicator Array of ROI in PyQtgraph), it turns out often that when I move my ROI or change the location of the points involved in ROI, the pos argument also changes despite that I never use a command to change the origin of the ROI (I wish it to stay at (0,0)). Is there any intuitive explanation about why such change happens and how does it happen ?