Specifies the types of non-rectangular Region of Interest (ROI).
Values:
| IG_ROI_IS_RECTANGLE | The ROI is a rectangle. |
| IG_ROI_IS_ELLIPSE | The ROI is an ellipse. |
| IG_ROI_IS_POLYGON | The ROI is a polygon. |
Remarks:
These modes are used with IG_IP_NR_ROI_to_HIGEAR_mask and describe what kind of non-rectangular ROI is passed in.