Path / mask creation related tools

Draw poly-line
Tap everywhere where nodes should appear sequentially.

Draw curve
Tap and drag in the direction of the node handle each time you need to add a new node.

Draw shape with sharp and smooth corners
Combine approach from Draw poly-line and Draw curve: use the appropriate finger movement or just tap depending on whether this corner of the shape should be sharp or smooth.

Draw mask
Use the same approach as for drawing arbitrary line in Draw shape with sharp and smooth corner, but at first enable Mask object sub-tool.

Finish drawing
Use Start new path sub-tool when you need to finish your line.

Each object can contain several masks applied in the stack order from top to bottom.