com.sun.javafx.geom

Class Rectangle

java.lang.Object

com.sun.javafx.geom.Rectangle

public class Rectangle
extends Object

A Rectangle specifies an area in a coordinate space that is enclosed by the Rectangle object's upper-left point (x,y) in the coordinate space, its width, and its height.

A Rectangle object's width and height are public fields. The constructors that create a Rectangle, and the methods that can modify one, do not prevent setting a negative value for width or height.

A Rectangle whose width or height is exactly zero has location along those axes with zero dimension, but is otherwise considered empty. The isEmpty() method will return true for such a Rectangle. Methods which test if an empty Rectangle contains or intersects a point or rectangle will always return false if either dimension is zero. Methods which combine such a Rectangle with a point or rectangle will include the location of the Rectangle on that axis in the result as if the #add(Point) method were being called.

A Rectangle whose width or height is negative has neither location nor dimension along those axes with negative dimensions. Such a Rectangle is treated as non-existant along those axes. Such a Rectangle is also empty with respect to containment calculations and methods which test if it contains or intersects a point or rectangle will always return false. Methods which combine such a Rectangle with a point or rectangle will ignore the Rectangle entirely in generating the result. If two Rectangle objects are combined and each has a negative dimension, the result will have at least one negative dimension.

Methods which affect only the location of a Rectangle will operate on its location regardless of whether or not it has a negative or zero dimension along either axis.

Note that a Rectangle constructed with the default no-argument constructor will have dimensions of 0x0 and therefore be empty. That Rectangle will still have a location of (0,0) and will contribute that location to the union and add operations. Code attempting to accumulate the bounds of a set of points should therefore initially construct the Rectangle with a specifically negative width and height or it should use the first point in the set to construct the Rectangle. For example:

     Rectangle bounds = new Rectangle(0, 0, -1, -1);
     for (int i = 0; i < points.length; i++) {
         bounds.add(points[i]);
     }
 

or if we know that the points array contains at least one point:

     Rectangle bounds = new Rectangle(points[0]);
     for (int i = 1; i < points.length; i++) {
         bounds.add(points[i]);
     }
 

This class uses 32-bit integers to store its location and dimensions. Frequently operations may produce a result that exceeds the range of a 32-bit integer. The methods will calculate their results in a way that avoids any 32-bit overflow for intermediate results and then choose the best representation to store the final results back into the 32-bit fields which hold the location and dimensions. The location of the result will be stored into the x and y fields by clipping the true result to the nearest 32-bit value. The values stored into the width and height dimension fields will be chosen as the 32-bit values that encompass the largest part of the true result as possible. Generally this means that the dimension will be clipped independently to the range of 32-bit integers except that if the location had to be moved to store it into its pair of 32-bit fields then the dimensions will be adjusted relative to the "best representation" of the location. If the true result had a negative dimension and was therefore non-existant along one or both axes, the stored dimensions will be negative numbers in those axes. If the true result had a location that could be represented within the range of 32-bit integers, but zero dimension along one or both axes, then the stored dimensions will be zero in those axes.

Field Summary

Fields

Modifier and Type	Field and Description
int	height The height of the Rectangle.
int	width The width of the Rectangle.
int	x The X coordinate of the upper-left corner of the Rectangle.
int	y The Y coordinate of the upper-left corner of the Rectangle.

Constructor Summary

Constructors

Constructor and Description
Rectangle() Constructs a new Rectangle whose upper-left corner is at (0, 0) in the coordinate space, and whose width and height are both zero.
Rectangle(BaseBounds b) Constructs a new Rectangle, initialized to match the values of the specified Rectangle.
Rectangle(int width, int height) Constructs a new Rectangle whose upper-left corner is at (0, 0) in the coordinate space, and whose width and height are specified by the arguments of the same name.
Rectangle(int x, int y, int width, int height) Constructs a new Rectangle whose upper-left corner is specified as (x,y) and whose width and height are specified by the arguments of the same name.
Rectangle(Rectangle r) Constructs a new Rectangle, initialized to match the values of the specified BaseBounds.

Method Summary

Modifier and Type	Method and Description
void	add(int newx, int newy) Adds a point, specified by the integer arguments newx,newy to the bounds of this Rectangle.
void	add(Rectangle r) Adds a Rectangle to this Rectangle.
boolean	contains(int cx, int cy) Checks whether or not this Rectangle contains the point at the specified location (cx,cy).
boolean	contains(int cx, int cy, int cw, int ch) Checks whether this Rectangle entirely contains the Rectangle at the specified location (cx,cy) with the specified dimensions (cw,ch).
boolean	contains(Rectangle r) Checks whether or not this Rectangle entirely contains the specified Rectangle.
boolean	equals(Object obj) Checks whether two rectangles are equal.
void	grow(int h, int v) Resizes the Rectangle both horizontally and vertically.
int	hashCode()
Rectangle	intersection(Rectangle r)
void	intersectWith(Rectangle r)
boolean	isEmpty()
void	setBounds(BaseBounds b)
void	setBounds(int x, int y, int width, int height) Sets the bounding Rectangle of this Rectangle to the specified x, y, width, and height.
void	setBounds(Rectangle r) Sets the bounding Rectangle of this Rectangle to match the specified Rectangle.
RectBounds	toRectBounds()
String	toString() Returns a String representing this Rectangle and its values.
void	translate(int dx, int dy) Translates this Rectangle the indicated distance, to the right along the X coordinate axis, and downward along the Y coordinate axis.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

x

public int x

The X coordinate of the upper-left corner of the Rectangle.

y

public int y

The Y coordinate of the upper-left corner of the Rectangle.

width

public int width

The width of the Rectangle.

height

public int height

The height of the Rectangle.

Constructor Detail

Rectangle

public Rectangle()

Constructs a new Rectangle whose upper-left corner is at (0, 0) in the coordinate space, and whose width and height are both zero.

Rectangle

public Rectangle(BaseBounds b)

Constructs a new Rectangle, initialized to match the values of the specified Rectangle.

Parameters:

r - the Rectangle from which to copy initial values to a newly constructed Rectangle

Rectangle

public Rectangle(Rectangle r)

Constructs a new Rectangle, initialized to match the values of the specified BaseBounds. Since BaseBounds has float values, the Rectangle will be created such that the bounding rectangle of the specified BaseBounds would always lie within the bounding box specified by this Rectangle.

Parameters:

r - the BaseBounds from which to copy initial values to a newly constructed Rectangle

Rectangle

public Rectangle(int x,
                 int y,
                 int width,
                 int height)

Constructs a new Rectangle whose upper-left corner is specified as (x,y) and whose width and height are specified by the arguments of the same name.

Parameters:

x - the specified X coordinate

y - the specified Y coordinate

width - the width of the Rectangle

height - the height of the Rectangle

Rectangle

public Rectangle(int width,
                 int height)

Constructs a new Rectangle whose upper-left corner is at (0, 0) in the coordinate space, and whose width and height are specified by the arguments of the same name.

Parameters:

width - the width of the Rectangle

height - the height of the Rectangle

Method Detail

setBounds

public void setBounds(Rectangle r)

Sets the bounding Rectangle of this Rectangle to match the specified Rectangle.

This method is included for completeness, to parallel the setBounds method of Component.

Parameters:

r - the specified Rectangle

See Also:

#getBounds, Component.setBounds(java.awt.Rectangle)

setBounds

public void setBounds(int x,
                      int y,
                      int width,
                      int height)

Sets the bounding Rectangle of this Rectangle to the specified x, y, width, and height.

This method is included for completeness, to parallel the setBounds method of Component.

Parameters:

x - the new X coordinate for the upper-left corner of this Rectangle

y - the new Y coordinate for the upper-left corner of this Rectangle

width - the new width for this Rectangle

height - the new height for this Rectangle

See Also:

#getBounds, Component.setBounds(int, int, int, int)

setBounds

public void setBounds(BaseBounds b)

contains

public boolean contains(int cx,
                        int cy)

Checks whether or not this Rectangle contains the point at the specified location (cx,cy).

Parameters:

cx - the specified X coordinate

cy - the specified Y coordinate

Returns:

true if the point (cx,cy) is inside this Rectangle; false otherwise.

contains

public boolean contains(Rectangle r)

Checks whether or not this Rectangle entirely contains the specified Rectangle.

Parameters:

r - the specified Rectangle

Returns:

true if the Rectangle is contained entirely inside this Rectangle; false otherwise

contains

public boolean contains(int cx,
                        int cy,
                        int cw,
                        int ch)

Checks whether this Rectangle entirely contains the Rectangle at the specified location (cx,cy) with the specified dimensions (cw,ch).

Parameters:

cx - the specified X coordinate

cy - the specified Y coordinate

cw - the width of the Rectangle

ch - the height of the Rectangle

Returns:

true if the Rectangle specified by (cx, cy, cw, ch) is entirely enclosed inside this Rectangle; false otherwise.

intersection

public Rectangle intersection(Rectangle r)

intersectWith

public void intersectWith(Rectangle r)

translate

public void translate(int dx,
                      int dy)

Translates this Rectangle the indicated distance, to the right along the X coordinate axis, and downward along the Y coordinate axis.

Parameters:

dx - the distance to move this Rectangle along the X axis

dy - the distance to move this Rectangle along the Y axis

See Also:

Rectangle.setLocation(int, int), Rectangle.setLocation(java.awt.Point)

toRectBounds

public RectBounds toRectBounds()

add

public void add(int newx,
                int newy)

Adds a point, specified by the integer arguments newx,newy to the bounds of this Rectangle.

If this Rectangle has any dimension less than zero, the rules for non-existant rectangles apply. In that case, the new bounds of this Rectangle will have a location equal to the specified coordinates and width and height equal to zero.

After adding a point, a call to contains with the added point as an argument does not necessarily return true. The contains method does not return true for points on the right or bottom edges of a Rectangle. Therefore, if the added point falls on the right or bottom edge of the enlarged Rectangle, contains returns false for that point. If the specified point must be contained within the new Rectangle, a 1x1 rectangle should be added instead:

     r.add(newx, newy, 1, 1);
 

Parameters:

newx - the X coordinate of the new point

newy - the Y coordinate of the new point

add

public void add(Rectangle r)

Adds a Rectangle to this Rectangle. The resulting Rectangle is the union of the two rectangles.

If either Rectangle has any dimension less than 0, the result will have the dimensions of the other Rectangle. If both Rectangles have at least one dimension less than 0, the result will have at least one dimension less than 0.

If either Rectangle has one or both dimensions equal to 0, the result along those axes with 0 dimensions will be equivalent to the results obtained by adding the corresponding origin coordinate to the result rectangle along that axis, similar to the operation of the #add(Point) method, but contribute no further dimension beyond that.

If the resulting Rectangle would have a dimension too large to be expressed as an int, the result will have a dimension of Integer.MAX_VALUE along that dimension.

Parameters:

r - the specified Rectangle

grow

public void grow(int h,
                 int v)

Resizes the Rectangle both horizontally and vertically.

This method modifies the Rectangle so that it is h units larger on both the left and right side, and v units larger at both the top and bottom.

The new Rectangle has (x - h, y - v) as its upper-left corner, width of (width + 2h), and a height of (height + 2v).

If negative values are supplied for h and v, the size of the Rectangle decreases accordingly. The grow method will check for integer overflow and underflow, but does not check whether the resulting values of width and height grow from negative to non-negative or shrink from non-negative to negative.

Parameters:

h - the horizontal expansion

v - the vertical expansion

isEmpty

public boolean isEmpty()

equals

public boolean equals(Object obj)

Checks whether two rectangles are equal.

The result is true if and only if the argument is not null and is a Rectangle object that has the same upper-left corner, width, and height as this Rectangle.

Overrides:

equals in class Object

Parameters:

obj - the Object to compare with this Rectangle

Returns:

true if the objects are equal; false otherwise.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Returns a String representing this Rectangle and its values.

Overrides:

toString in class Object

Returns:

a String representing this Rectangle object's coordinate and size values.