org.eclipse.gef4.layout.algorithms

Class AlgorithmHelper

java.lang.Object

org.eclipse.gef4.layout.algorithms.AlgorithmHelper

public class AlgorithmHelper
extends java.lang.Object

The AlgorithmHelper class contains utility methods for the laying out of entities within bounds.

Field Summary

Fields

Modifier and Type	Field and Description
static int	MIN_NODE_SIZE The minimum size of a node.
static double	PADDING_PERCENT This percent of a node's maximum size is reserved for the node, the rest is used as padding, i.e.

Constructor Summary

Constructors

Constructor and Description
AlgorithmHelper()

Method Summary

Modifier and Type	Method and Description
static void	fitWithinBounds(IEntityLayout[] entities, Rectangle destinationBounds, boolean resize) Fits given entities within given bounds, preserving their relative locations.
static Rectangle	getLayoutBounds(IEntityLayout[] entities, boolean includeNodeSize) Find the bounds in which the nodes are located.
static Dimension	getMinimumDistance(IEntityLayout[] entities) minDistance is the closest that any two points are together.
static void	maximizeSizes(IEntityLayout[] entities) Resizes the nodes so that they have a maximal area without overlapping each other, with additional empty space of 20% of node's width (or height, if bigger).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MIN_NODE_SIZE

public static int MIN_NODE_SIZE

The minimum size of a node.

PADDING_PERCENT

public static double PADDING_PERCENT

This percent of a node's maximum size is reserved for the node, the rest is used as padding, i.e. node_size = max_size * PADDING_PERCENT.

Constructor Detail

AlgorithmHelper

public AlgorithmHelper()

Method Detail

fitWithinBounds

public static void fitWithinBounds(IEntityLayout[] entities,
                                   Rectangle destinationBounds,
                                   boolean resize)

Fits given entities within given bounds, preserving their relative locations. If an entity is resizable and the resize flag is set to true, then the entity will be scaled according to the bounds change, i.e. scale_factor = dst_bounds / start_bounds.

Parameters:

entities - The IEntityLayouts to fit.

destinationBounds - The Rectangle representing the layout bounds.

resize - true to indicate that the entities can be resized, otherwise false.

maximizeSizes

public static void maximizeSizes(IEntityLayout[] entities)

Resizes the nodes so that they have a maximal area without overlapping each other, with additional empty space of 20% of node's width (or height, if bigger). It does nothing if there's less than two nodes.

Parameters:

entities - The IEntityLayouts of which the sizes are maximized.

getLayoutBounds

public static Rectangle getLayoutBounds(IEntityLayout[] entities,
                                        boolean includeNodeSize)

Find the bounds in which the nodes are located. Using the bounds against the real bounds of the screen, the nodes can proportionally be placed within the real bounds. The bounds can be determined either including the size of the nodes or not. If the size is not included, the bounds will only be guaranteed to include the center of each node.

Parameters:

entities - The IEntityLayouts for which the layout bounds are computed.

includeNodeSize - true to indicate that the entities' sizes should be taken into consideration, otherwise false.

Returns:

A Rectangle representing the layout bounds of the given IEntityLayouts.

getMinimumDistance

public static Dimension getMinimumDistance(IEntityLayout[] entities)

minDistance is the closest that any two points are together. These two points become the center points for the two closest nodes, which we wish to make them as big as possible without overlapping. This will be the maximum of minDistanceX and minDistanceY minus a bit, lets say 20% We make the recommended node size a square for convenience.

    _______
   |       | 
   |       |
   |   +   |
   |   |\  |
   |___|_\_|_____
       | | \     |
       | |  \    |
       +-|---+   |
         |       |
         |_______|
 

Parameters:

entities - The IEntityLayouts for which the minimum distance is computed.

Returns:

A Dimension representing the minimum distance (in x- and y-direction).