The Diagram Interchange (DI) package enables interchange of graphical information that language users have control over, such as position of nodes and line routing points. Language specifications specialize elements of DI to define diagram interchange elements for a language. DiagramElement is the abstract super type of all elements in diagrams, including diagrams themselves. When contained in a diagram, diagram elements are laid out relative to the diagram’s origin. a reference to a depicted model element, which can be any MOF-based element a reference to the diagram element that directly owns this diagram element. a collection of diagram elements that are directly owned by this diagram element. a reference to an optional locally-owned style for this diagram element. a reference to an optional shared style element for this diagram element. Edge is a diagram element that renders as a polyline, connecting a source diagram element to a target diagram element, and is positioned relative to the origin of the diagram. the edge's source diagram element, i.e. where the edge starts from. the edge's target diagram element, i.e. where the edge ends at. an optional list of points relative to the origin of the nesting diagram that specifies the connected line segments of the edge Diagram is an abstract container of a graph of diagram elements. Diagrams are diagram elements with an origin point in the x-y coordinate system. Their elements are laid out relative to their origin point. the name of the diagram. the documentation of the diagram. the resolution of the diagram expressed in user units per inch. Shape is a diagram element with given bounds that is laid out relative to the origin of the diagram the optional bounds of the shape relative to the origin of its nesting plane. Style contains formatting properties that affect the appearance or style of diagram elements, including diagram themselves. a collection of edges that reference this diagram element as a target. a collection of edges that reference this diagram element as a source.