android.graphics
Class Rect

java.lang.Object
  android.graphics.Rect

All Implemented Interfaces:

Parcelable

public final class Rect
extends Object
implements Parcelable

Rect holds four integer coordinates for a rectangle. The rectangle is represented by the coordinates of its 4 edges (left, top, right bottom). These fields can be accessed directly. Use width() and height() to retrieve the rectangle's width and height. Note: most methods do not check to see that the coordinates are sorted correctly (i.e. left <= right and top <= bottom).

Nested Class Summary

Nested classes/interfaces inherited from interface android.os.Parcelable

Parcelable.Creator<T>

Field Summary

int	bottom
static Parcelable.Creator<Rect>	CREATOR
int	left
int	right
int	top

Fields inherited from interface android.os.Parcelable

CONTENTS_FILE_DESCRIPTOR, PARCELABLE_WRITE_RETURN_VALUE

Constructor Summary

Rect()
Create a new empty Rect.

Rect(int left, int top, int right, int bottom)
Create a new rectangle with the specified coordinates.

Rect(Rect r)
Create a new rectangle, initialized with the values in the specified rectangle (which is left unmodified).

Method Summary

int	centerX()
int	centerY()
boolean	contains(int x, int y) Returns true if (x,y) is inside the rectangle.
boolean	contains(int left, int top, int right, int bottom) Returns true iff the 4 specified sides of a rectangle are inside or equal to this rectangle.
boolean	contains(Rect r) Returns true iff the specified rectangle r is inside or equal to this rectangle.
int	describeContents() Parcelable interface methods
boolean	equals(Object obj) Compares the argument to the receiver, and returns true if they represent the same object using a class specific comparison.
float	exactCenterX()
float	exactCenterY()
int	height()
void	inset(int dx, int dy) Inset the rectangle by (dx,dy).
boolean	intersect(int left, int top, int right, int bottom) If the rectangle specified by left,top,right,bottom intersects this rectangle, return true and set this rectangle to that intersection, otherwise return false and do not change this rectangle.
boolean	intersect(Rect r) If the specified rectangle intersects this rectangle, return true and set this rectangle to that intersection, otherwise return false and do not change this rectangle.
boolean	intersects(int left, int top, int right, int bottom) Returns true if this rectangle intersects the specified rectangle.
static boolean	intersects(Rect a, Rect b) Returns true iff the two specified rectangles intersect.
boolean	isEmpty() Returns true if the rectangle is empty (left >= right or top >= bottom)
void	offset(int dx, int dy) Offset the rectangle by adding dx to its left and right coordinates, and adding dy to its top and bottom coordinates.
void	offsetTo(int newLeft, int newTop) Offset the rectangle to a specific (left, top) position, keeping its width and height the same.
void	readFromParcel(Parcel in) Set the rectangle's coordinates from the data stored in the specified parcel.
void	set(int left, int top, int right, int bottom) Set the rectangle's coordinates to the specified values.
void	set(Rect src) Copy the coordinates from src into this rectangle.
void	setEmpty() Set the rectangle to (0,0,0,0)
boolean	setIntersect(Rect a, Rect b) If rectangles a and b intersect, return true and set this rectangle to that intersection, otherwise return false and do not change this rectangle.
void	sort() Swap top/bottom or left/right if there are flipped (i.e.
String	toString() Returns a string containing a concise, human-readable description of the receiver.
void	union(int x, int y) Update this Rect to enclose itself and the [x,y] coordinate.
void	union(int left, int top, int right, int bottom) Update this Rect to enclose itself and the specified rectangle.
void	union(Rect r) Update this Rect to enclose itself and the specified rectangle.
int	width()
void	writeToParcel(Parcel out, int flags) Write this rectangle to the specified parcel.

Methods inherited from class java.lang.Object

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

Field Detail

left

public int left

top

public int top

right

public int right

bottom

public int bottom

CREATOR

public static final Parcelable.Creator<Rect> CREATOR

Constructor Detail

Rect

public Rect()

Create a new empty Rect. All coordinates are initialized to 0.

Rect

public Rect(int left,
            int top,
            int right,
            int bottom)

Create a new rectangle with the specified coordinates. Note: no range checking is performed, so the caller must ensure that left <= right and top <= bottom.

Parameters:

left - The X coordinate of the left side of the rectagle

top - The Y coordinate of the top of the rectangle

right - The X coordinate of the right side of the rectagle

bottom - The Y coordinate of the bottom of the rectangle

Rect

public Rect(Rect r)

Create a new rectangle, initialized with the values in the specified rectangle (which is left unmodified).

Parameters:

r - The rectangle whose coordinates are copied into the new rectangle.

Method Detail

equals

public boolean equals(Object obj)

Description copied from class: Object

Compares the argument to the receiver, and returns true if they represent the same object using a class specific comparison. The implementation in Object returns true only if the argument is the exact same object as the receiver (==).

Overrides:

equals in class Object

Parameters:

obj - Object the object to compare with this object.

Returns:

boolean true if the object is the same as this object false if it is different from this object.

See Also:

Object.hashCode()

toString

public String toString()

Description copied from class: Object

Returns a string containing a concise, human-readable description of the receiver.

Overrides:

toString in class Object

Returns:

String a printable representation for the receiver.

isEmpty

public final boolean isEmpty()

Returns true if the rectangle is empty (left >= right or top >= bottom)

width

public final int width()

Returns:

the rectangle's width. This does not check for a valid rectangle (i.e. left <= right) so the result may be negative.

height

public final int height()

Returns:

the rectangle's height. This does not check for a valid rectangle (i.e. top <= bottom) so the result may be negative.

centerX

public final int centerX()

Returns:

the horizontal center of the rectangle. If the computed value is fractional, this method returns the largest integer that is less than the computed value.

centerY

public final int centerY()

Returns:

the vertical center of the rectangle. If the computed value is fractional, this method returns the largest integer that is less than the computed value.

exactCenterX

public final float exactCenterX()

Returns:

the exact horizontal center of the rectangle as a float.

exactCenterY

public final float exactCenterY()

Returns:

the exact vertical center of the rectangle as a float.

setEmpty

public void setEmpty()

Set the rectangle to (0,0,0,0)

set

public void set(int left,
                int top,
                int right,
                int bottom)

Set the rectangle's coordinates to the specified values. Note: no range checking is performed, so it is up to the caller to ensure that left <= right and top <= bottom.

Parameters:

left - The X coordinate of the left side of the rectagle

top - The Y coordinate of the top of the rectangle

right - The X coordinate of the right side of the rectagle

bottom - The Y coordinate of the bottom of the rectangle

set

public void set(Rect src)

Copy the coordinates from src into this rectangle.

Parameters:

src - The rectangle whose coordinates are copied into this rectangle.

offset

public void offset(int dx,
                   int dy)

Offset the rectangle by adding dx to its left and right coordinates, and adding dy to its top and bottom coordinates.

Parameters:

dx - The amount to add to the rectangle's left and right coordinates

dy - The amount to add to the rectangle's top and bottom coordinates

offsetTo

public void offsetTo(int newLeft,
                     int newTop)

Offset the rectangle to a specific (left, top) position, keeping its width and height the same.

Parameters:

newLeft - The new "left" coordinate for the rectangle

newTop - The new "top" coordinate for the rectangle

inset

public void inset(int dx,
                  int dy)

Inset the rectangle by (dx,dy). If dx is positive, then the sides are moved inwards, making the rectangle narrower. If dx is negative, then the sides are moved outwards, making the rectangle wider. The same holds true for dy and the top and bottom.

Parameters:

dx - The amount to add(subtract) from the rectangle's left(right)

dy - The amount to add(subtract) from the rectangle's top(bottom)

contains

public boolean contains(int x,
                        int y)

Returns true if (x,y) is inside the rectangle. The left and top are considered to be inside, while the right and bottom are not. This means that for a x,y to be contained: left <= x < right and top <= y < bottom. An empty rectangle never contains any point.

Parameters:

x - The X coordinate of the point being tested for containment

y - The Y coordinate of the point being tested for containment

Returns:

true iff (x,y) are contained by the rectangle, where containment means left <= x < right and top <= y < bottom

contains

public boolean contains(int left,
                        int top,
                        int right,
                        int bottom)

Returns true iff the 4 specified sides of a rectangle are inside or equal to this rectangle. i.e. is this rectangle a superset of the specified rectangle. An empty rectangle never contains another rectangle.

Parameters:

left - The left side of the rectangle being tested for containment

top - The top of the rectangle being tested for containment

right - The right side of the rectangle being tested for containment

bottom - The bottom of the rectangle being tested for containment

Returns:

true iff the the 4 specified sides of a rectangle are inside or equal to this rectangle

contains

public boolean contains(Rect r)

Returns true iff the specified rectangle r is inside or equal to this rectangle. An empty rectangle never contains another rectangle.

Parameters:

r - The rectangle being tested for containment.

Returns:

true iff the specified rectangle r is inside or equal to this rectangle

intersect

public boolean intersect(int left,
                         int top,
                         int right,
                         int bottom)

If the rectangle specified by left,top,right,bottom intersects this rectangle, return true and set this rectangle to that intersection, otherwise return false and do not change this rectangle. No check is performed to see if either rectangle is empty. Note: To just test for intersection, use intersects()

Parameters:

left - The left side of the rectangle being intersected with this rectangle

top - The top of the rectangle being intersected with this rectangle

right - The right side of the rectangle being intersected with this rectangle.

bottom - The bottom of the rectangle being intersected with this rectangle.

Returns:

true if the specified rectangle and this rectangle intersect (and this rectangle is then set to that intersection) else return false and do not change this rectangle.

intersect

public boolean intersect(Rect r)

If the specified rectangle intersects this rectangle, return true and set this rectangle to that intersection, otherwise return false and do not change this rectangle. No check is performed to see if either rectangle is empty. To just test for intersection, use intersects()

Parameters:

r - The rectangle being intersected with this rectangle.

Returns:

true if the specified rectangle and this rectangle intersect (and this rectangle is then set to that intersection) else return false and do not change this rectangle.

setIntersect

public boolean setIntersect(Rect a,
                            Rect b)

If rectangles a and b intersect, return true and set this rectangle to that intersection, otherwise return false and do not change this rectangle. No check is performed to see if either rectangle is empty. To just test for intersection, use intersects()

Parameters:

a - The first rectangle being intersected with

b - The second rectangle being intersected with

Returns:

true iff the two specified rectangles intersect. If they do, set this rectangle to that intersection. If they do not, return false and do not change this rectangle.

intersects

public boolean intersects(int left,
                          int top,
                          int right,
                          int bottom)

Returns true if this rectangle intersects the specified rectangle. In no event is this rectangle modified. No check is performed to see if either rectangle is empty. To record the intersection, use intersect() or setIntersect().

Parameters:

left - The left side of the rectangle being tested for intersection

top - The top of the rectangle being tested for intersection

right - The right side of the rectangle being tested for intersection

bottom - The bottom of the rectangle being tested for intersection

Returns:

true iff the specified rectangle intersects this rectangle. In no event is this rectangle modified.

intersects

public static boolean intersects(Rect a,
                                 Rect b)

Returns true iff the two specified rectangles intersect. In no event are either of the rectangles modified. To record the intersection, use intersect() or setIntersect().

Parameters:

a - The first rectangle being tested for intersection

b - The second rectangle being tested for intersection

Returns:

true iff the two specified rectangles intersect. In no event are either of the rectangles modified.

union

public void union(int left,
                  int top,
                  int right,
                  int bottom)

Update this Rect to enclose itself and the specified rectangle. If the specified rectangle is empty, nothing is done. If this rectangle is empty it is set to the specified rectangle.

Parameters:

left - The left edge being unioned with this rectangle

top - The top edge being unioned with this rectangle

right - The right edge being unioned with this rectangle

bottom - The bottom edge being unioned with this rectangle

union

public void union(Rect r)

Update this Rect to enclose itself and the specified rectangle. If the specified rectangle is empty, nothing is done. If this rectangle is empty it is set to the specified rectangle.

Parameters:

r - The rectangle being unioned with this rectangle

union

public void union(int x,
                  int y)

Update this Rect to enclose itself and the [x,y] coordinate. There is no check to see that this rectangle is non-empty.

Parameters:

x - The x coordinate of the point to add to the rectangle

y - The y coordinate of the point to add to the rectangle

sort

public void sort()

Swap top/bottom or left/right if there are flipped (i.e. left > right and/or top > bottom). This can be called if the edges are computed separately, and may have crossed over each other. If the edges are already correct (i.e. left <= right and top <= bottom) then nothing is done.

describeContents

public int describeContents()

Parcelable interface methods

Specified by:

describeContents in interface Parcelable

Returns:

a bitmask indicating the set of special object types marshalled by the Parcelable.

writeToParcel

public void writeToParcel(Parcel out,
                          int flags)

Write this rectangle to the specified parcel. To restore a rectangle from a parcel, use readFromParcel()

Specified by:

writeToParcel in interface Parcelable

Parameters:

out - The parcel to write the rectangle's coordinates into

flags - Additional flags about how the object should be written. May be 0 or Parcelable.PARCELABLE_WRITE_RETURN_VALUE.

readFromParcel

public void readFromParcel(Parcel in)

Set the rectangle's coordinates from the data stored in the specified parcel. To write a rectangle to a parcel, call writeToParcel().

Parameters:

in - The parcel to read the rectangle's coordinates from