Porting Code from Version 2.x

Renamed Classes

The majority of classes work without significant changes, you might need to rename some base clasess you are inheriting from.

Classes in v2	Classes in v3	Comment
Node	–	The node is represented now just by its internal id which is stored in a central graph class.
Connection	–	Ditto
NodeDataModel	NodeDelegateModel	In new terms a single model defines the whole graph structure. Hence smaller per-node models became delegates.
DataModelRegistry	NodeDelegateModelRegistry	See comment above
FlowView	GraphicsView
FlowScene	DataFlowGraphicsScene	The new class inherits from `BasicGraphicsScene`
–	DataFlowGraphModel	This is a new central class that defines the whole graph structure. The class takes `NodeDelegatNodeDelegateModelRegistry` in the constructur and populates delegate models internally. The graph model itself is then passed to the `DataFlowGraphicsScene`.
NodePainter	DefaultNodePainter	Previously a `NodePainter` was created dynamically on the stack right in the painting routine. Now painter is a class instance constanly living in the scene. It could be replaced by a user-defined clas inherited from `AbstractNodePainter`

Some minor capabilities were removed in version 3:

Warning messages at the bottom of the nodes. They were shown when the data was incosistent or upon any other error signalized by a node. The feature was useful in some cases but wasn’t visually appealing and caused a node resize/repainting events.
Data Type Converters. Such classes were registered among Node Data Models and made ports of different types compatible. I prefer to leave it up to the AbstractGraphModel derivative to decide what could be attached and what not. See the function AbstractGraphModel::connectionPossible.