At any given moment, Graphics has a mode. The Graphics mode determines how gestures will be interpreted. The graphics mode is determined by values for Smooth, Open, Filled and, Track settings for Graphics
Lines
Needs two touches, the end points.
With Track 'ON'
Rectangles
Needs two touches, the end points of one of the two diagonals(anyone will do)
With Track 'ON'.
Circles and Ellipses
Needs two touches, the end points needed for the rectangle in which it will be inscribed.
With Track 'ON'.
Filled areas
With 'Smooth' OFF
Arbitrary Closed Curves
One touch, continuous movement
Cropping a Pano to a closed curve
A graphic unfilled curve can be used to crop a pano.
Choose the image(here from Roll) Create a closed curve(1) on top. Adjust the curve by zooming/moving the layer,
press 'i'(info button), pick the details
Turn use as crop on, press 'Done' Save the pano(current image is Load the saved image.
not cropped)