Android
android.graphics
public class

android.graphics.RectF

java.lang.Object
android.graphics.RectF

RectF holds four float 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).

Summary

Fields

public      float  bottom   
public      float  left   
public      float  right   
public      float  top   

Public Constructors

            RectF()
Create a new empty RectF.
            RectF(float left, float top, float right, float bottom)
Create a new rectangle with the specified coordinates.
            RectF(RectF r)
Create a new rectangle, initialized with the values in the specified rectangle (which is left unmodified).
            RectF(Rect r)

Public Methods

    final      float  centerX()
    final      float  centerY()
          boolean  contains(RectF r)
Returns true iff the specified rectangle r is inside or equal to this rectangle.
          boolean  contains(float x, float y)
Returns true if (x,y) is inside the rectangle.
          boolean  contains(float left, float top, float right, float bottom)
Returns true iff the 4 specified sides of a rectangle are inside or equal to this rectangle.
    final      float  height()
          void  inset(float dx, float dy)
Inset the rectangle by (dx,dy).
          boolean  intersect(RectF 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  intersect(float left, float top, float right, float 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.
      static    boolean  intersects(RectF a, RectF b)
Returns true iff the two specified rectangles intersect.
          boolean  intersects(float left, float top, float right, float bottom)
Returns true if this rectangle intersects the specified rectangle.
    final      boolean  isEmpty()
Returns true if the rectangle is empty (left >= right or top >= bottom)
          void  offset(float dx, float dy)
Offset the rectangle by adding dx to its left and right coordinates, and adding dy to its top and bottom coordinates.
          void  offsetTo(float newLeft, float newTop)
Offset the rectangle to a specific (left, top) position, keeping its width and height the same.
          void  round(Rect dst)
Set the dst integer Rect by rounding this rectangle's coordinates to their nearest integer values.
          void  roundOut(Rect dst)
Set the dst integer Rect by rounding "out" this rectangle, choosing the floor of top and left, and the ceiling of right and bottom.
          void  set(Rect src)
Copy the coordinates from src into this rectangle.
          void  set(float left, float top, float right, float bottom)
Set the rectangle's coordinates to the specified values.
          void  set(RectF src)
Copy the coordinates from src into this rectangle.
          void  setEmpty()
Set the rectangle to (0,0,0,0)
          boolean  setIntersect(RectF a, RectF 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(float x, float y)
Update this Rect to enclose itself and the [x,y] coordinate.
          void  union(float left, float top, float right, float bottom)
Update this Rect to enclose itself and the specified rectangle.
          void  union(RectF r)
Update this Rect to enclose itself and the specified rectangle.
    final      float  width()
Methods inherited from class java.lang.Object

Details

Fields

public float bottom

public float left

public float right

public float top

Public Constructors

public RectF()

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

public RectF(float left, float top, float right, float 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

public RectF(RectF 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.

public RectF(Rect r)

Public Methods

public final float centerX()

Returns

  • the horizontal center of the rectangle. This does not check for a valid rectangle (i.e. left <= right)

public final float centerY()

Returns

  • the vertical center of the rectangle. This does not check for a valid rectangle (i.e. top <= bottom)

public boolean contains(RectF 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

public boolean contains(float x, float 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

public boolean contains(float left, float top, float right, float 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

public final float height()

Returns

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

public void inset(float dx, float 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)

public boolean intersect(RectF 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.

public boolean intersect(float left, float top, float right, float 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.

public static boolean intersects(RectF a, RectF 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.

public boolean intersects(float left, float top, float right, float 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.

public final boolean isEmpty()

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

public void offset(float dx, float 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

public void offsetTo(float newLeft, float 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

public void round(Rect dst)

Set the dst integer Rect by rounding this rectangle's coordinates to their nearest integer values.

public void roundOut(Rect dst)

Set the dst integer Rect by rounding "out" this rectangle, choosing the floor of top and left, and the ceiling of right and bottom.

public void set(Rect src)

Copy the coordinates from src into this rectangle.

Parameters

src The rectangle whose coordinates are copied into this rectangle.

public void set(float left, float top, float right, float 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

public void set(RectF src)

Copy the coordinates from src into this rectangle.

Parameters

src The rectangle whose coordinates are copied into this rectangle.

public void setEmpty()

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

public boolean setIntersect(RectF a, RectF 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.

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.

public String toString()

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

Returns

  • String a printable representation for the receiver.

public void union(float x, float 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

public void union(float left, float top, float right, float 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

public void union(RectF 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

public final float width()

Returns

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