org.eclipse.gef.layout.algorithms

Class GridLayoutAlgorithm

java.lang.Object

org.eclipse.gef.layout.algorithms.GridLayoutAlgorithm

All Implemented Interfaces:

ILayoutAlgorithm

Direct Known Subclasses:

BoxLayoutAlgorithm

public class GridLayoutAlgorithm
extends java.lang.Object
implements ILayoutAlgorithm

The GridLayoutAlgorithm lays out nodes in a grid.

Constructor Summary

Constructors

Constructor and Description
GridLayoutAlgorithm() Default constructor.

Method Summary

Modifier and Type	Method and Description
void	applyLayout(LayoutContext context, boolean clean) Makes this algorithm perform layout computation and apply it to its context.
protected void	calculateGrid(Rectangle bounds) Calculates all the dimensions of grid that layout entities will be fit in.
protected double[]	calculateNodeSize(double colWidth, double rowHeight) Calculates and returns the width and height of a single node depending on the padding (20%), colWidth, rowHeight, and aspect ratio.
protected int[]	calculateNumberOfRowsAndCols_rectangular(int numChildren) Calculates and returns an array containing the number of columns and the number of rows, so that there is an equal number of rows and columns.
protected int[]	calculateNumberOfRowsAndCols_square(int numChildren, double boundX, double boundY, double boundWidth, double boundHeight) Calculates and returns an array containing the number of columns and the number of rows, so that the nodes are layed out in squares.
protected int[]	calculateNumberOfRowsAndCols(int numChildren, double boundX, double boundY, double boundWidth, double boundHeight) Calculates and returns an array containing the number of columns and the number of rows.
boolean	isResizing()
void	setAspectRatio(double aspectRatio) Sets the preferred aspect ratio for layout entities.
void	setResizing(boolean resizing)
void	setRowPadding(int rowPadding) Sets the padding between rows in the grid

Methods inherited from class java.lang.Object

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

Constructor Detail

GridLayoutAlgorithm

public GridLayoutAlgorithm()

Default constructor.

Method Detail

applyLayout

public void applyLayout(LayoutContext context,
                        boolean clean)

Description copied from interface: ILayoutAlgorithm

Makes this algorithm perform layout computation and apply it to its context.

Specified by:

applyLayout in interface ILayoutAlgorithm

Parameters:

context - The LayoutContext that provides all relevant information about what to layout.

clean - if true the receiver should assume that the layout context has changed significantly and recompute the whole layout even if it keeps track of changes with listeners. False can be used after dynamic layout in a context is turned back on so that layout algorithm working in background can apply accumulated changes. Static layout algorithm can ignore this call entirely if clean is false.

calculateGrid

protected void calculateGrid(Rectangle bounds)

Calculates all the dimensions of grid that layout entities will be fit in.

Parameters:

bounds - A Rectangle representing the layout bounds.

calculateNumberOfRowsAndCols

protected int[] calculateNumberOfRowsAndCols(int numChildren,
                                             double boundX,
                                             double boundY,
                                             double boundWidth,
                                             double boundHeight)

Calculates and returns an array containing the number of columns and the number of rows. If the aspect ratio is set to 1, then the calculateNumberOfRowsAndCols_square(int, double, double, double, double) method is used for the computation. Otherwise, the calculateNumberOfRowsAndCols_rectangular(int) is used for the computation.

Parameters:

numChildren - The number of nodes.

boundX - The horizontal offset.

boundY - The vertical offset.

boundWidth - The bounds' width.

boundHeight - The bounds' height.

Returns:

An array containing the number of columns, and the number of rows.

calculateNumberOfRowsAndCols_square

protected int[] calculateNumberOfRowsAndCols_square(int numChildren,
                                                    double boundX,
                                                    double boundY,
                                                    double boundWidth,
                                                    double boundHeight)

Calculates and returns an array containing the number of columns and the number of rows, so that the nodes are layed out in squares.

Parameters:

numChildren - The number of nodes.

boundX - The horizontal offset.

boundY - The vertical offset.

boundWidth - The bounds' width.

boundHeight - The bounds' height.

Returns:

An array containing the number of columns and the number of rows.

calculateNumberOfRowsAndCols_rectangular

protected int[] calculateNumberOfRowsAndCols_rectangular(int numChildren)

Calculates and returns an array containing the number of columns and the number of rows, so that there is an equal number of rows and columns.

Parameters:

numChildren - The number of nodes.

Returns:

An array containing the number of columns and the number of rows.

calculateNodeSize

protected double[] calculateNodeSize(double colWidth,
                                     double rowHeight)

Calculates and returns the width and height of a single node depending on the padding (20%), colWidth, rowHeight, and aspect ratio.

Parameters:

colWidth - The width of a column.

rowHeight - The height of a row.

Returns:

An array containing the width and height of a node.

setRowPadding

public void setRowPadding(int rowPadding)

Sets the padding between rows in the grid

Parameters:

rowPadding - padding - should be greater than or equal to 0

setAspectRatio

public void setAspectRatio(double aspectRatio)

Sets the preferred aspect ratio for layout entities. The default aspect ratio is 1.

Parameters:

aspectRatio - aspect ratio - should be greater than 0

isResizing

public boolean isResizing()

Returns:

true if this algorithm is set to resize elements

setResizing

public void setResizing(boolean resizing)

Parameters:

resizing - true if this algorithm should resize elements (default is false)