The overall design of this basic application utilises OO design and SOLID principles to meet the brief. However, time constraints didn't allow for an extensive implementation + testing.

The first major decision made was to allow Widgets to exist without coordinates. This is in-line with common real world use cases where a Widget can be designed/saved in isolation without existing on a drawing surface.

The idea of an ActiveWidget is to represent a Widget on some coordinate-based system IDrawingSurface. The IDrawingSurface allows the creation of ActiveWidgets and holds references to these in memory. The output of Widget information is managed by the IDrawingSurface but uses property information collated and exposed by the Widget.

Derived classes of the base Widget class must specify a Type and must override GetProperties() to retrieve property information.

No further work was done to break up Widget properties into base classes, causing minor duplication of properties (eg. width/height in multiple Widgets). This also presents potential extension issues in future - with more effort allocated these would be seperated into base classes.