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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 final Creator<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.

static 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.

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 JavaTM programming 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.
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