diva.canvas
Class CanvasUtilities

java.lang.Object
  diva.canvas.CanvasUtilities

public final class CanvasUtilities
extends java.lang.Object

A collection of canvas utilities. These utilities perform useful functions related to the structural aspects of diva.canvas that do not properly belong in any one class. Some of them perform utility geometric functions that are not available in the Java 2D API, while others accept iterators over Figures or Shapes and compute a useful composite result.

Version:

$Id: CanvasUtilities.java 40701 2006-02-07 00:50:57Z cxh $

Author:

John Reekie

Accepted Rating:

Red

Field Summary

private static boolean	_transformRectangularShapeIsBroken
static double	EAST double representation of EAST: 0 degrees
private static int	m00
private static int	m02
private static int	m11
private static int	m12
static double	NORTH double representation of NORTH: -90 degrees (-PI/2)
static double	NORTHEAST double representation of NORTHEAST: -45 degrees (PI/4)
static double	NORTHWEST double representation of NORTHWEST: -135 degrees (-PI*3/4)
static double	SOUTH double representation of SOUTH: 90 degrees (PI/2)
static double	SOUTHEAST double representation of SOUTHEAST: 45 degrees (PI/4)
static double	SOUTHWEST double representation of SOUTHWEST: 135 degrees (PI*3/4)
static double	WEST double representation of WEST: 180 degrees (PI)

Constructor Summary

private

CanvasUtilities() Cannot instantiate

Method Summary

static java.awt.Shape	clone(java.awt.Shape s) Deprecated. Use ShapeUtilities.cloneShape() instead
static java.awt.geom.Rectangle2D	computeCompositeBounds(java.util.Iterator i) Compute a composite bounding box.
static java.awt.Shape	computeCompositeShape(java.util.Iterator i) Compute a composite shape.
static java.awt.geom.AffineTransform	computeFitTransform(java.awt.geom.RectangularShape r, java.awt.geom.RectangularShape s) Get the transform that will make the first rectangle change fit within the second, while preserving the shape.
static java.awt.geom.Rectangle2D	computeSiteBounds(java.util.Iterator i) Compute the bounding box of a set of connectors.
static java.awt.geom.AffineTransform	computeTransform(java.awt.geom.RectangularShape r, java.awt.geom.RectangularShape s) Get the transform that will make the first rectangle change into the second.
static java.awt.geom.Point2D	getCenterPoint(Figure f) Return the point at the center of a figure.
static java.awt.geom.Point2D	getCenterPoint(Figure f, TransformContext root) Return the point at the center of a figure, in the given transform context.
static java.awt.geom.Point2D	getCenterPoint(java.awt.geom.Rectangle2D r) Return the point at the center of a Rectangle.
static int	getDirection(double angle) Return the closest direction from SwingConstants, based on the given angle.
static java.awt.geom.Point2D	getLocation(java.awt.geom.Rectangle2D r, int location) Get the point on the given rectangular shape indicated by the location flag.
static double	getNormal(int direction) Return an angle in radians, given a direction from SwingConstants.
static boolean	isOrthogonal(java.awt.geom.AffineTransform at) Return true if the given transform maps a rectangle to a rectangle.
static double	moduloAngle(double angle) Return the angle between -PI and PI that corresponds to the given angle.
static Figure	pick(java.util.Iterator i, java.awt.geom.Rectangle2D region) Return the first figure that is hit by the given region.
static Figure	pick(java.util.Iterator i, java.awt.geom.Rectangle2D region, Filter filter) Return the first figure that is hit by the given region.
static java.util.Iterator	pickIter(java.util.Iterator i, java.awt.geom.Rectangle2D region) Return an iterator over the figures hit by the given region.
static int	reverseDirection(int direction) Reverse a direction flag.
static java.awt.Shape	transform(java.awt.geom.RectangularShape r, java.awt.geom.AffineTransform at) Deprecated. Use diva.util.java2d.ShapeUtilities.transformRectangle() or diva.util.java2d.ShapeUtilities.transformRectangularShape()
static java.awt.Shape	transform(java.awt.Shape s, java.awt.geom.AffineTransform at) Deprecated. Use ShapeUtilities.transformModify()
static java.awt.geom.Point2D	transformInto(java.awt.geom.Point2D p, TransformContext local, TransformContext root) Deprecated. Use local.getTransform(root) instead.
static void	translate(Figure f, double distance, int direction) Translate a figure the given distance in the direction given by the flag.
static java.awt.geom.Point2D	translate(java.awt.geom.Point2D.Double p, double distance, int direction) Translate a point the given distance in the direction given by the flag.
static java.awt.geom.Point2D	translate(java.awt.geom.Point2D.Float p, double distance, int direction) Translate a point the given distance in the direction given by the flag.
static java.awt.geom.Point2D	translate(java.awt.geom.Point2D p, double distance, int direction) Translate a point the given distance in the direction given by the flag.
static java.awt.Shape	translate(java.awt.Shape s, double x, double y) Deprecated. Use ShapeUtilities.translateModify()
static void	translateTo(Figure f, double x, double y) Move a figure so that its origin is located at the given coordinates.

Methods inherited from class java.lang.Object

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

Field Detail

m00

private static final int m00

See Also:

Constant Field Values

m11

private static final int m11

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Constant Field Values

m02

private static final int m02

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Constant Field Values

m12

private static final int m12

See Also:

Constant Field Values

WEST

public static final double WEST

double representation of WEST: 180 degrees (PI)

See Also:

Constant Field Values

NORTH

public static final double NORTH

double representation of NORTH: -90 degrees (-PI/2)

See Also:

Constant Field Values

EAST

public static final double EAST

double representation of EAST: 0 degrees

See Also:

Constant Field Values

SOUTH

public static final double SOUTH

double representation of SOUTH: 90 degrees (PI/2)

See Also:

Constant Field Values

NORTHWEST

public static final double NORTHWEST

double representation of NORTHWEST: -135 degrees (-PI*3/4)

See Also:

Constant Field Values

NORTHEAST

public static final double NORTHEAST

double representation of NORTHEAST: -45 degrees (PI/4)

See Also:

Constant Field Values

SOUTHWEST

public static final double SOUTHWEST

double representation of SOUTHWEST: 135 degrees (PI*3/4)

See Also:

Constant Field Values

SOUTHEAST

public static final double SOUTHEAST

double representation of SOUTHEAST: 45 degrees (PI/4)

See Also:

Constant Field Values

_transformRectangularShapeIsBroken

private static boolean _transformRectangularShapeIsBroken

Constructor Detail

CanvasUtilities

private CanvasUtilities()

Cannot instantiate

Method Detail

clone

public static java.awt.Shape clone(java.awt.Shape s)

Deprecated. Use ShapeUtilities.cloneShape() instead

Clone a shape. This method is needed because Shape by itself does not define clone(), although many (all?) shape instances do.

computeCompositeShape

public static java.awt.Shape computeCompositeShape(java.util.Iterator i)

Compute a composite shape. The iterator must contain figures, from which the shapes are obtained and joined into a more complex shape. If the iterator is empty, return a very small rectangle.

computeSiteBounds

public static java.awt.geom.Rectangle2D computeSiteBounds(java.util.Iterator i)

Compute the bounding box of a set of connectors. The iterator must contain connectors.

computeCompositeBounds

public static java.awt.geom.Rectangle2D computeCompositeBounds(java.util.Iterator i)

Compute a composite bounding box. The iterator must contain figures, from which the bounding boxes are obtained and joined into a more complex shape. If the iterator is empty, return a very small rectangle.

computeTransform

public static java.awt.geom.AffineTransform computeTransform(java.awt.geom.RectangularShape r,
                                                             java.awt.geom.RectangularShape s)

Get the transform that will make the first rectangle change into the second.

computeFitTransform

public static java.awt.geom.AffineTransform computeFitTransform(java.awt.geom.RectangularShape r,
                                                                java.awt.geom.RectangularShape s)

Get the transform that will make the first rectangle change fit within the second, while preserving the shape.

getCenterPoint

public static java.awt.geom.Point2D getCenterPoint(java.awt.geom.Rectangle2D r)

Return the point at the center of a Rectangle.

getCenterPoint

public static java.awt.geom.Point2D getCenterPoint(Figure f)

Return the point at the center of a figure. This is simple but so common it's worth having a method for it.

getCenterPoint

public static java.awt.geom.Point2D getCenterPoint(Figure f,
                                                   TransformContext root)

Return the point at the center of a figure, in the given transform context. This is simple but so common it's worth having a method for it.

getDirection

public static int getDirection(double angle)

Return the closest direction from SwingConstants, based on the given angle. West corresponds to 0 degrees and south is PI/2.

getNormal

public static double getNormal(int direction)

Return an angle in radians, given a direction from SwingConstants. West corresponds to 0 degrees and south is PI/2. The angle returned is between -PI and PI as per the normalizeAngle method.

getLocation

public static java.awt.geom.Point2D getLocation(java.awt.geom.Rectangle2D r,
                                                int location)

Get the point on the given rectangular shape indicated by the location flag. This flag must be one of those defined in javax.swing.Constants.

isOrthogonal

public static boolean isOrthogonal(java.awt.geom.AffineTransform at)

Return true if the given transform maps a rectangle to a rectangle. If this method returns true, then passing a rectangle to transform() is guaranteed to return a rectangle.

moduloAngle

public static double moduloAngle(double angle)

Return the angle between -PI and PI that corresponds to the given angle.

pick

public static Figure pick(java.util.Iterator i,
                          java.awt.geom.Rectangle2D region)

Return the first figure that is hit by the given region. The figures tested are contained in the given iterator, which must contain only figures. And figure that is also a FigureContainer is descended into recursively; other figures are simply tested using their hit() method.

Parameters:

i - An iterator over figures

region - A rectangle which represents the pick or hit region

Returns:

The topmost descendent under the pick region, or null there isn't one.

pick

public static Figure pick(java.util.Iterator i,
                          java.awt.geom.Rectangle2D region,
                          Filter filter)

Return the first figure that is hit by the given region. The figures tested are contained in the given iterator, which must contain only figures. And figure that is also a FigureContainer is descended into recursively; other figures are simply tested using their hit() method.

Parameters:

i - An iterator over figures

region - A rectangle which represents the pick or hit region

Returns:

The topmost descendent under the pick region, or null there isn't one.

pickIter

public static java.util.Iterator pickIter(java.util.Iterator i,
                                          java.awt.geom.Rectangle2D region)

Return an iterator over the figures hit by the given region. The figures tested are contained in the given iterator, which must contain only figures. And figure that is also a FigureContainer is descended into recursively; other figures are simply tested using their hit() method. XXX how to do this?

Parameters:

i - An iterator over figures

region - A rectangle which represents the pick or hit region

Returns:

An iterator over the hit figures.

reverseDirection

public static int reverseDirection(int direction)

Reverse a direction flag. The flag must one of the eight compass directions defined in SwingConstants. Return the flag that represents the opposite direction.

transform

public static java.awt.Shape transform(java.awt.geom.RectangularShape r,
                                       java.awt.geom.AffineTransform at)

Deprecated. Use diva.util.java2d.ShapeUtilities.transformRectangle() or diva.util.java2d.ShapeUtilities.transformRectangularShape()

Transform a shape with the supplied transform. If the shape is an instance of RectangularShape, then the transformation will modify that shape and return it if it is possible to do so. Otherwise, AffineTransform.createTransformedShape() is used to create a new shape, which is then returned.

transform

public static java.awt.Shape transform(java.awt.Shape s,
                                       java.awt.geom.AffineTransform at)

Deprecated. Use ShapeUtilities.transformModify()

Transform a shape with the supplied transform. As much as possible, this method attempts to preserve the type of the shape and to modify it directly if possible: if the shape of this figure is an instance of RectangularShape or Polyline, then the shape may be modified directly. Otherwise, a general transformation is used that creates and returns a new instance of GeneralPath.

transformInto

public static java.awt.geom.Point2D transformInto(java.awt.geom.Point2D p,
                                                  TransformContext local,
                                                  TransformContext root)

Deprecated. Use local.getTransform(root) instead.

Transform a point from a local transform context into a root transform context. The root context must enclose the local one, otherwise this method goes into an infinite loop. You asked for it.

translate

public static void translate(Figure f,
                             double distance,
                             int direction)

Translate a figure the given distance in the direction given by the flag. The flag must one of the eight compass directions defined in SwingConstants.

translate

public static java.awt.geom.Point2D translate(java.awt.geom.Point2D p,
                                              double distance,
                                              int direction)

Translate a point the given distance in the direction given by the flag. The flag must one of the eight compass directions defined in SwingConstants. Return the same point, but modified.

translate

public static java.awt.geom.Point2D translate(java.awt.geom.Point2D.Double p,
                                              double distance,
                                              int direction)

Translate a point the given distance in the direction given by the flag. The flag must one of the eight compass directions defined in SwingConstants. Return the same point, but modified.

translate

public static java.awt.geom.Point2D translate(java.awt.geom.Point2D.Float p,
                                              double distance,
                                              int direction)

Translate a point the given distance in the direction given by the flag. The flag must one of the eight compass directions defined in SwingConstants. Return the same point, but modified.

translate

public static java.awt.Shape translate(java.awt.Shape s,
                                       double x,
                                       double y)

Deprecated. Use ShapeUtilities.translateModify()

Translate a shape the given distance. If it is possible to do so, perform this translation efficiently, modifying and returning the passed shape. Otherwise use AffineTransform.createTransformedShape() to create a new translated shape, and return that.

translateTo

public static void translateTo(Figure f,
                               double x,
                               double y)

Move a figure so that its origin is located at the given coordinates.