KIML Layout Options
KIML defines a whole set of standard layout options that many layout algorithms support. Whether an algorithm supports a layout option depends on the option and on the algorithm. When an option is supported by an algorithm, it may change the option's default value. Algorithms may also provide more specialized documentation for a given layout option.
Contents
Overview
Beside a human-readable name, layout options are defined by the following properties:
- An ID to identify them.
- A type. One of Boolean, String, Int, Float, Enum, EnumSet (a Set over a given enumeration), or Object. The types Enum and EnumSet have to be further defined by an enumeration class. The Object type can be constricted to a certain class.
- The kinds of graph objects the option applies to. At least one of Parents (nodes that have children, including the diagram root node), Nodes, Edges, Ports, and Labels.
- An optional default value. If an option is not set on an object and if the option does not have a default value, null is returned when it is accessed.
KIML defines the following set of layout options:
Option | ID | Type | Applies to | Default |
|---|---|---|---|---|
Alignment | de.cau.cs.kieler.alignment | Enum | Nodes | AUTOMATIC |
Aspect Ratio | de.cau.cs.kieler.aspectRatio | Float | Parents | 0.0 |
Bend Points | de.cau.cs.kieler.bendPoints | Object | Edges |
|
Border Spacing | de.cau.cs.kieler.borderSpacing | Float | Parents | -1.0 |
Comment Box | de.cau.cs.kieler.commentBox | Boolean | Nodes | false |
Debug Mode | de.cau.cs.kieler.debugMode | Boolean | Parents | false |
Diagram Type | de.cau.cs.kieler.diagramType | String |
|
|
Direction | de.cau.cs.kieler.direction | Enum | Parents | UNDEFINED |
Edge Label Placement | de.cau.cs.kieler.edgeLabelPlacement | Enum | Labels | UNDEFINED |
de.cau.cs.kieler.edgeRouting | Enum | Parents | UNDEFINED | |
Edge Type | de.cau.cs.kieler.edgeType | Enum | Edges | NONE |
Expand Nodes | de.cau.cs.kieler.expandNodes | Boolean | Parents | false |
Font Name | de.cau.cs.kieler.fontName | String | Labels |
|
Font Size | de.cau.cs.kieler.fontSize | Int | Labels |
|
Hypernode | de.cau.cs.kieler.hypernode | Boolean | Nodes | false |
Interactive | de.cau.cs.kieler.interactive | Boolean | Parents | false |
Label Spacing | de.cau.cs.kieler.labelSpacing | Float | Edges | -1.0 |
Layout Hierarchy | de.cau.cs.kieler.layoutHierarchy | Boolean | Parents | false |
Layout Algorithm | de.cau.cs.kieler.algorithm | String | Parents |
|
Minimal Height | de.cau.cs.kieler.minHeight | Float | Nodes | 0.0 |
Minimal Width | de.cau.cs.kieler.minWidth | Float | Nodes | 0.0 |
No Layout | de.cau.cs.kieler.noLayout | Boolean |
| false |
Node Label Placement | de.cau.cs.kieler.nodeLabelPlacement | EnumSet | Nodes |
|
Port Constraints | de.cau.cs.kieler.portConstraints | Enum | Nodes | UNDEFINED |
Port Label Placement | de.cau.cs.kieler.portLabelPlacement | Enum | Nodes | OUTSIDE |
de.cau.cs.kieler.offset | Float | Ports |
| |
Port Side | de.cau.cs.kieler.portSide | Enum | Ports | UNDEFINED |
Position | de.cau.cs.kieler.position | Object | Labels |
|
Priority | de.cau.cs.kieler.priority | Int | Edges |
|
Randomization Seed | de.cau.cs.kieler.randomSeed | Int | Parents |
|
Separate Connected Components | de.cau.cs.kieler.separateConnComp | Boolean | Parents |
|
Size Constraint | de.cau.cs.kieler.sizeConstraint | EnumSet | Nodes |
|
Size Options | de.cau.cs.kieler.sizeOptions | EnumSet | Nodes | DEFAULT_MINIMUM_SIZE |
Spacing | de.cau.cs.kieler.spacing | Float | Parents | -1.0 |
The Most Important Options
TODO: Write a bit of documentation about the most important layout options and how to use them, possibly with a simple example or something.
Detailed Documentation
This section explains every layout option in more detail.
Edge Routing
This option influences the way in which edges are routed between the nodes they connect. The following settings are available:
- POLYLINE
Edges consist of one or more segments defined by a list of bend points. - ORTHOGONAL
Edges are routed orthogonally, meaning that each segment of an edge runs either horizontally or vertically, but never at an angle. - SPLINE
Edges are routed as splines (smooth curves). TODO: Add more documentation on how the returned bend points are to be interpreted. - UNDEFINED
No particular edge routing style is selected. The result produced by the layout algorithm may be undefined.
TODO: Add an image illustrating the different routing styles.
Port Offset
The port offset is used to specify how much space a layout algorithm should leave between a port and the border of its node. This is usually zero, but doesn't have to be. If the offset is not defined for a given port, a layout algorithm can try to infer the offset from the port's coordinates and its node's size in the input graph. This of course requires both properties to be set to sensible values.
Set this property if one of the following cases applies:
- The port constraints on a node are set to FREE, FIXED_SIDES or FIXED_ORDER.
- The port constraints on a node are set to FIXED_RATIO or FIXED_POS, and the size of the node is not fixed. (Note that this is especially true for ports of compound nodes.)