Slide 15 : Dependency Graph System in action
The following window illustrates the Dependency Graph System (DGS) in action. The window involves a run time assembly of the following types of components
- A SolidBackDrop component, used to paint the back drop a uniform white colour.
- A Board component, allowing components on the board to be positioned by dragging them around with the mouse.
- Text components, used to display the title and description.
- Image components used to display the formulae (eg v = u + at)
- Slider components to define u,t and a.
- Formula components that allow for an expression to be evaluated and displayed.
As the slider thumb positions are moved with the mouse the calculated values update automatically. The DGS achieves this through its efficient incremental update algorithm. The dependency graph is dynamic because it depends on the expression entered by the user in the formula components.
