android-Rect

Rect

public final class Rect 

extends Object 

implements Parcelable

java.lang.Object
↳	android.graphics.Rect

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).

Note that the right and bottom coordinates are exclusive. This means a Rect being drawn untransformed onto a 

Canvas

 will
draw into the column and row described by its left and top coordinates, but not those of its bottom and right.

Summary

Inherited constants
From interface  android.os.Parcelable

Fields
public static finalCreator<Rect>	CREATOR
public int	bottom
public int	left
public int	right
public int	top

Public constructors
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).

Public methods
final int	centerX()
final int	centerY()
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.
boolean	contains(int x, int y) Returns true if (x,y) is inside the rectangle.
int	describeContents() Parcelable interface methods
boolean	equals(Object o) Indicates whether some other object is "equal to" this one.
final float	exactCenterX()
final float	exactCenterY()
String	flattenToString() Return a string representation of the rectangle in a well-defined format.
int	hashCode() Returns a hash code value for the object.
final 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.
final 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	toShortString() Return a string representation of the rectangle in a compact form.
String	toString() Returns a string representation of the object.
staticRect	unflattenFromString(String str) Returns a Rect from a string of the form returned by  flattenToString() , or null if the string is not of that form.
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.
void	union(int x, int y) Update this Rect to enclose itself and the [x,y] coordinate.
final int	width()
void	writeToParcel(Parcel out, int flags) Write this rectangle to the specified parcel.

Inherited methods
From class  java.lang.Object
From interface  android.os.Parcelable

Fields

CREATOR

Added in API level 1

Creator<Rect> CREATOR

bottom

Added in API level 1

int bottom

left

Added in API level 1

int left

right

Added in API level 1

int right

top

Added in API level 1

int top

Public constructors

Rect

Added in API level 1

Rect ()

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

Rect

Added in API level 1

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	int : The X coordinate of the left side of the rectangle
top	int : The Y coordinate of the top of the rectangle
right	int : The X coordinate of the right side of the rectangle
bottom	int : The Y coordinate of the bottom of the rectangle

Rect

Added in API level 1

Rect (Rect r)

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

Parameters
r	Rect : The rectangle whose coordinates are copied into the new rectangle.

Public methods

centerX

Added in API level 1

int centerX ()

Returns
int	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

Added in API level 1

int centerY ()

Returns
int	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.

contains

Added in API level 1

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	int : The left side of the rectangle being tested for containment
top	int : The top of the rectangle being tested for containment
right	int : The right side of the rectangle being tested for containment
bottom	int : The bottom of the rectangle being tested for containment

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

contains

Added in API level 1

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	Rect : The rectangle being tested for containment.

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

contains

Added in API level 1

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	int : The X coordinate of the point being tested for containment
y	int : The Y coordinate of the point being tested for containment

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

describeContents

Added in API level 1

int describeContents ()

Parcelable interface methods

Returns
int	a bitmask indicating the set of special object types marshaled by this Parcelable object instance.

equals

Added in API level 1

boolean equals (Object o)

Indicates whether some other object is "equal to" this one.
The 

equals

 method implements an equivalence relation on non-null object references:
It is reflexive: for any non-null reference value 

x

, 

x.equals(x)

 should return 

true

.
It is symmetric: for any non-null reference values 

x

 and 

y

, 

x.equals(y)

 should return 

true

 if and only if 

y.equals(x)

 returns 

true

.
It is transitive: for any non-null reference values 

x

, 

y

, and 

z

, if 

x.equals(y)

 returns 

true

 and 

y.equals(z)

 returns 

true

,
then 

x.equals(z)

 should return

true

.
It is consistent: for any non-null reference values 

x

 and 

y

, multiple invocations of 

x.equals(y)

 consistently return 

true

 or consistently
return 

false

, provided no information used in 

equals

 comparisons on the objects is modified.
For any non-null reference value 

x

, 

x.equals(null)

 should return 

false

.
The 

equals

 method for class 

Object

 implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values 

x

 and 

y

,
this method returns 

true

 if and only if 

x

 and 

y

 refer to the same object (

x == y

 has the value 

true

).
Note that it is generally necessary to override the 

hashCode

 method whenever this method is overridden, so as to maintain the general contract for the

hashCode

 method,
which states that equal objects must have equal hash codes.

Parameters
o	Object : the reference object with which to compare.

Returns
boolean	true  if this object is the same as the obj argument;  false  otherwise.

exactCenterX

Added in API level 1

float exactCenterX ()

Returns
float	the exact horizontal center of the rectangle as a float.

exactCenterY

Added in API level 1

float exactCenterY ()

Returns
float	the exact vertical center of the rectangle as a float.

flattenToString

Added in API level 7

String flattenToString ()

Return a string representation of the rectangle in a well-defined format.
You can later recover the Rect from this string through 

unflattenFromString(String)

.

Returns
String	Returns a new String of the form "left top right bottom"

hashCode

Added in API level 1

int hashCode ()

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by 

HashMap

.
The general contract of 

hashCode

 is:
Whenever it is invoked on the same object more than once during an execution of a Java application, the 

hashCode

 method must consistently return the same integer, provided no information used in 

equals

 comparisons
on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
If two objects are equal according to the 

equals(Object)

 method, then calling the 

hashCode

 method on each of the two objects must produce the same integer result.
It is not required that if two objects are unequal according to the 

equals(java.lang.Object)

 method,
then calling the 

hashCode

 method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash
tables.
As much as is reasonably practical, the hashCode method defined by class 

Object

 does return distinct integers for distinct objects. (This is typically implemented by converting the internal
address of the object into an integer, but this implementation technique is not required by the JavaTMprogramming language.)

Returns
int	a hash code value for this object.

height

Added in API level 1

int height ()

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

inset

Added in API level 1

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	int : The amount to add(subtract) from the rectangle's left(right)
dy	int : The amount to add(subtract) from the rectangle's top(bottom)

intersect

Added in API level 1

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(Rect,
Rect)

.

Parameters
left	int : The left side of the rectangle being intersected with this rectangle
top	int : The top of the rectangle being intersected with this rectangle
right	int : The right side of the rectangle being intersected with this rectangle.
bottom	int : The bottom of the rectangle being intersected with this rectangle.

Returns
boolean	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

Added in API level 1

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	Rect : The rectangle being intersected with this rectangle.

Returns
boolean	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.

intersects

Added in API level 1

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	int : The left side of the rectangle being tested for intersection
top	int : The top of the rectangle being tested for intersection
right	int : The right side of the rectangle being tested for intersection
bottom	int : The bottom of the rectangle being tested for intersection

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

intersects

Added in API level 1

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(Rect)

or 

setIntersect(Rect,
Rect)

.

Parameters
a	Rect : The first rectangle being tested for intersection
b	Rect : The second rectangle being tested for intersection

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

isEmpty

Added in API level 1

boolean isEmpty ()

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

Returns
boolean

offset

Added in API level 1

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	int : The amount to add to the rectangle's left and right coordinates
dy	int : The amount to add to the rectangle's top and bottom coordinates

offsetTo

Added in API level 1

void offsetTo (int newLeft,
int newTop)

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

Parameters
newLeft	int : The new "left" coordinate for the rectangle
newTop	int : The new "top" coordinate for the rectangle

readFromParcel

Added in API level 1

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	Parcel : The parcel to read the rectangle's coordinates from

set

Added in API level 1

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	int : The X coordinate of the left side of the rectangle
top	int : The Y coordinate of the top of the rectangle
right	int : The X coordinate of the right side of the rectangle
bottom	int : The Y coordinate of the bottom of the rectangle

set

Added in API level 1

void set (Rect src)

Copy the coordinates from src into this rectangle.

Parameters
src	Rect : The rectangle whose coordinates are copied into this rectangle.

setEmpty

Added in API level 1

void setEmpty ()

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

setIntersect

Added in API level 1

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	Rect : The first rectangle being intersected with
b	Rect : The second rectangle being intersected with

Returns
boolean	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.

sort

Added in API level 1

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.

toShortString

Added in API level 3

String toShortString ()

Return a string representation of the rectangle in a compact form.

Returns
String

toString

Added in API level 1

String toString ()

Returns a string representation of the object. In general, the 

toString

 method returns a string that "textually represents" this object. The result should be a concise but informative representation
that is easy for a person to read. It is recommended that all subclasses override this method.
The 

toString

 method for class 

Object

 returns a string consisting of the name of the class of which the object is an instance, the at-sign character `

@

',
and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 

Returns
String	a string representation of the object.

unflattenFromString

Added in API level 7

Rect unflattenFromString (String str)

Returns a Rect from a string of the form returned by 

flattenToString()

,
or null if the string is not of that form.

Parameters
str	String

Returns
Rect

union

Added in API level 1

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	int : The left edge being unioned with this rectangle
top	int : The top edge being unioned with this rectangle
right	int : The right edge being unioned with this rectangle
bottom	int : The bottom edge being unioned with this rectangle

union

Added in API level 1

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	Rect : The rectangle being unioned with this rectangle

union

Added in API level 1

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	int : The x coordinate of the point to add to the rectangle
y	int : The y coordinate of the point to add to the rectangle

width

Added in API level 1

int width ()

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

writeToParcel

Added in API level 1

void writeToParcel (Parcel out,
int flags)

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

Parameters
out	Parcel : The parcel to write the rectangle's coordinates into
flags	int : Additional flags about how the object should be written. May be 0 or  PARCELABLE_WRITE_RETURN_VALUE .