Demonstrates how to use ExplicitLayout to:
- Implement less 'rectangular' layouts
- Position components relative to an ellipse
- Position components relative to a line
- Position and size the line or ellipse
relative to other components and the container
- Paint container based to the layout.
The dashed black lines are painted by the container to show
the line and ellipse on which the layout is based. A point
on the line is specified by a parameter between 0.0 and 1.0.
A point on an ellipse is specified by an angle between 0 and 360
degrees.