ClearAreaLayout

To define custom components instead of using the predefined strategies, use componentIds. In this case, the value of componentAssignmentStrategy will be ignored.

While the algorithm may move a whole component, it tries to not move only a subset of its elements, thus, all elements of a component are not moved at all or moved by the same offset.

• CONNECTED components are defined by the connected components of the graph.
• CLUSTERING: components are defined by edge betweenness clustering.
• SINGLE: each node is a separate component which basically means that there are no components that should explicitly be kept together.

If enabled, edges that must be rerouted are not allowed to intersect the area that is cleared. Furthermore, edges whose source and target node are not moved but where segments intersect the area in the input graph are rerouted in order to remove that intersection.

If disabled, edges are allowed to intersect the area that is cleared. This has the effect that the area is cleared of nodes only.

Several types of edges can be routed by this algorithm:

1. Edges where one or both endpoints were displaced in order to clear the area. It depends on the strategy if such edges are actually handled by the routing algorithm or if they are implicitly moved. For example, strategy PRESERVE_SHAPES tries to keep the shapes and can avoid rerouting in many cases.
2. So-called inter-edges resulting from the areaNodes component. If such a component exists, the inter-edges are the edges connecting area nodes with non-area nodes. They are always handled by this routing algorithm, independent of the strategy.
3. Edges connecting to a specifically marked expandedNode and to the descendants of the expanded node in case it is a group node.

Changing the value of property edgeRoutingStyle automatically sets a new edge router instance according to the specified routing style, thus, overwriting any previously set instances. The following routing algorithms are set:

• EdgeRouter for strategies ORTHOGONAL and OCTILINEAR.
• OrganicEdgeRouter for style ORGANIC.
• StraightLineEdgeRouter for style STRAIGHT_LINE.

The algorithm assumes that the existing edges have paths according to the specified style and takes this into account when moving nodes and edges in order to clear the area. If the AUTOMATIC style is set, then no assumptions are made but the given paths are analyzed to derive the best fitting routing style. Note that in this case, the algorithm may use different routing styles for the edges.

This routing style is also relevant when edges need to be rerouted, as it determines the routing algorithm used for rerouting, see edgeRouter for more details.

This property is relevant for edges that are rerouted in order to clear the area, i.e., edges where one or both endpoints are displaced or edges that intersect the area in the input graph (depending on property considerEdges) and that are consequently handled by the specified edgeRouter. Inter-edges resulting from the areaNodes component are not affected by this property (edges connecting area nodes with non-area nodes). For such edges, the behavior is the same as if this property would be disabled, see the following description. The same applies for edges incident to the expandedNode or the descendants of the expanded node (if one endpoint is not the expanded node or a descendant).

If the ports are fixed, then the port side and location are not changed, except for group nodes that grow due to the area inside them. Edges at these groups keep the port side, but the absolute location is not fixed.

If disabled, the algorithm considers specified LayoutPortCandidates when rerouting edges. If there are no such constraints for an edge, then the ports of that edge can be freely placed. This can often produce better edge routes in the resulting drawing, however, the overall shape of the edge may then not be preserved.

Elements are moved by multiples of this value, thus, keeping their offset to the grid. That way, components or parts of them that were placed on a grid before, will stay on their original grid.

The grid spacing needs to be a non-negative value. If it is set to 0, no grid is considered.

The orientation affects the direction that the algorithm prefers when moving elements. For the vertical orientations TOP_TO_BOTTOM and BOTTOM_TO_TOP, moving elements horizontally (i.e. to the left and to the right) is preferred. For the horizontal orientations LEFT_TO_RIGHT and RIGHT_TO_LEFT, the vertical moving direction is preferred. This is mainly useful for layouts that have a clear direction and nodes are divided into layers with respect to this direction, like e.g., hierarchical layouts.

If this behavior is undesired, the orientation can be ignored by specifying NONE. No specific moving direction will be preferred in that case. The orientation can also be automatically detected based on the flow direction of the edges when choosing AUTO_DETECT.

This spacing only affects the moving of elements out of the area. Elements keep the specified distance to other elements. Carefully observe that if the distance between two elements is already smaller, then they may not be moved apart.

Strategies PRESERVE_SHAPES, PRESERVE_SHAPES_UNIFORM and GLOBAL consider the spacing for all graph elements, including nodes, edges, node labels and edge labels when they are encountered during the movement process. On the other hand, strategies LOCAL and LOCAL_UNIFORM consider the spacing only with respect to nodes.