AttributeStructure

Graph Element Attributes are organised in a tree structure. For example, some attributes that can be found on a node are...

• graphics of type *NodeGraphicAttribute*

  • coordinate
  • dimension
  • fill
  • opacity
  • ...

• labelgraphics of type *NodeLabelAttribute*

  (only present if the graph element indeed has a label)

  • alignment
  • fontSize
  • text
  • ...

Note that attributes themselves do not describe any drawing routine. This is done via NodeComponent / EdgeComponent and attribute components that access these attributes.

Accessing Attributes

See this wiki page.

Attributes and Attribute Components

To an attribute, we can assign an attribute component. This attribute component (amongst other things) describes a draw routine. This can be used, for example, to draw the label of a node.

An attribute component is not limited to the information its corresponding attribute holds.

Indeed, it is common in Vanted to implement additional visualisations to a graph element by creating

• an attribute that holds little to no information
• and a corresponding attribute component that accesses (and visualises) information from other sources. To this end, StringAttribute can be used.

Attributes are always of a specific subclass of AbstractAttribute.

The steps needed to display a custom attribute are as follows:

// register a color map attribute
this.attributes = new Class[1];
this.attributes[0] = ColorMapAttribute.class;

// register the color map attribute as a string attribute
// A String attribute is simply an attribute that contains a string.
StringAttribute.putAttributeType(ColorMapAttribute.name, ColorMapAttribute.class);

// link the attribute and the attribute component
attributeComponents.put(ColorMapAttribute.class, ColorMapAttributeComponent.class);

See:

• LabelAttribute and LabelComponent
• StarAttribute and StarAttributeComponent (in the example Add-On)
• Example-Addon, as described in the wiki