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java.lang.Objectcom.trolltech.qt.QSignalEmitter
com.trolltech.qt.QtJambiObject
com.trolltech.qt.core.QRect
public class QRect
The QRect
class defines a rectangle in the plane using integer precision. A rectangle is normally expressed as an upper-left corner and a size. The size (width and height) of a QRect
is always equivalent to the mathematical rectangle that forms the basis for its rendering.
A QRect
can be constructed with a set of left, top, width and height integers, or from a QPoint
and a QSize
. The following code creates two identical rectangles.
QRect r1(100, 200, 11, 16); QRect r2(QPoint(100, 200), QSize(11, 16));There is a third constructor that creates a
QRect
using the top-left and bottom-right coordinates, but we recommend that you avoid using it. The rationale is that for historical reasons the values returned by the bottom()
and right()
functions deviate from the true bottom-right corner of the rectangle. The QRect
class provides a collection of functions that return the various rectangle coordinates, and enable manipulation of these. QRect
also provide functions to move the rectangle relative to the various coordinates. In addition there is a moveTo()
function that moves the rectangle, leaving its top left corner at the given coordinates. Alternatively, the translate()
function moves the rectangle the given offset relative to the current position, and the translated()
function returns a translated copy of this rectangle.
The size()
function returns the rectange's dimensions as a QSize
. The dimensions can also be retrieved separately using the width()
and height()
functions. To manipulate the dimensions use the setSize()
, setWidth()
or setHeight()
functions. Alternatively, the size can be changed by applying either of the functions setting the rectangle coordinates, for example, setBottom()
or setRight()
.
The contains()
function tells whether a given point is inside the rectangle or not, and the intersects()
function returns true if this rectangle intersects with a given rectangle. The QRect
class also provides the intersected()
function which returns the intersection rectangle, and the united()
function which returns the rectangle that encloses the given rectangle and this:
isEmpty()
function returns true if left()
> right()
or top()
> bottom()
. Note that an empty rectangle is not valid: The isValid()
function returns true if left()
<= right()
andtop()
<= bottom()
. A null rectangle (isNull()
== true) on the other hand, has both width and height set to 0. Note that due to the way QRect
and QRectF
are defined, an empty QRect
is defined in essentially the same way as QRectF
.
Finally, QRect
objects can be streamed as well as compared.
anti-aliased
painter, the boundary line of a QRect
will be rendered symmetrically on both sides of the mathematical rectangle's boundary line. But when using an aliased painter (the default) other rules apply. Then, when rendering with a one pixel wide pen the QRect
's boundary line will be rendered to the right and below the mathematical rectangle's boundary line.
When rendering with a two pixels wide pen the boundary line will be split in the middle by the mathematical rectangle. This will be the case whenever the pen is set to an even number of pixels, while rendering with a pen with an odd number of pixels, the spare pixel will be rendered to the right and below the mathematical rectangle as in the one pixel case.
![]() | ![]() |
Logical representation | One pixel wide pen |
![]() | ![]() |
Two pixel wide pen | Three pixel wide pen |
QRect
class provides a collection of functions that return the various rectangle coordinates, and enable manipulation of these. QRect
also provide functions to move the rectangle relative to the various coordinates. For example the left()
, setLeft()
and moveLeft()
functions as an example: left()
returns the x-coordinate of the rectangle's left edge, setLeft()
sets the left edge of the rectangle to the given x coordinate (it may change the width, but will never change the rectangle's right edge) and moveLeft()
moves the entire rectangle horizontally, leaving the rectangle's left edge at the given x coordinate and its size unchanged.
bottom()
and right()
functions deviate from the true bottom-right corner of the rectangle: The right()
function returns left() + width() - 1 and the bottom()
function returns top() + height() - 1. The same is the case for the point returned by the bottomRight()
convenience function. In addition, the x and y coordinate of the topRight()
and bottomLeft()
functions, respectively, contain the same deviation from the true right and bottom edges. We recommend that you use x()
+ width()
and y()
+ height()
to find the true bottom-right corner, and avoid right()
and bottom()
. Another solution is to use QRectF
: The QRectF
class defines a rectangle in the plane using floating point accuracy for coordinates, and the QRectF::right()
and QRectF::bottom()
functions do return the right and bottom coordinates.
It is also possible to add offsets to this rectangle's coordinates using the adjust()
function, as well as retrieve a new rectangle based on adjustments of the original one using the adjusted()
function. If either of the width and height is negative, use the normalized()
function to retrieve a rectangle where the corners are swapped.
In addition, QRect
provides the getCoords() function which extracts the position of the rectangle's top-left and bottom-right corner, and the getRect() function which extracts the rectangle's top-left corner, width and height. Use the setCoords()
and setRect()
function to manipulate the rectangle's coordinates and dimensions in one go.
QRectF
, and QRegion
.
Nested Class Summary |
---|
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter |
---|
QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9 |
Constructor Summary | |
---|---|
QRect()
Constructs a null rectangle. |
|
QRect(int left,
int top,
int width,
int height)
Constructs a rectangle with (x, y) as its top-left corner and the given width and height. |
|
QRect(QPoint topleft,
QPoint bottomright)
Constructs a rectangle with the given topLeft and bottomRight corners. |
|
QRect(QPoint topleft,
QSize size)
Constructs a rectangle with the given topLeft corner and the given size. |
Method Summary | |
---|---|
void |
adjust(int x1,
int y1,
int x2,
int y2)
Adds dx1, dy1, dx2 and dy2 respectively to the existing coordinates of the rectangle. |
QRect |
adjusted(int x1,
int y1,
int x2,
int y2)
Returns a new rectangle with dx1, dy1, dx2 and dy2 added respectively to the existing coordinates of this rectangle. |
int |
bottom()
Returns the y-coordinate of the rectangle's bottom edge. |
QPoint |
bottomLeft()
Returns the position of the rectangle's bottom-left corner. |
QPoint |
bottomRight()
Returns the position of the rectangle's bottom-right corner. |
QPoint |
center()
Returns the center point of the rectangle. |
QRect |
clone()
This method is reimplemented for internal reasons |
boolean |
contains(int x,
int y)
Returns true if the point (x, y) is inside this rectangle, otherwise returns false. |
boolean |
contains(int x,
int y,
boolean proper)
Returns true if the point (x, y) is inside or on the edge of the rectangle, otherwise returns false. |
boolean |
contains(QPoint p)
Returns true if the the given point is inside or on the edge of the rectangle, otherwise returns false. |
boolean |
contains(QPoint p,
boolean proper)
Returns true if the the given point is inside or on the edge of the rectangle, otherwise returns false. |
boolean |
contains(QRect r)
Returns true if the given rectangle is inside this rectangle. |
boolean |
contains(QRect r,
boolean proper)
Returns true if the given rectangle is inside this rectangle. |
static QRect |
fromNativePointer(QNativePointer nativePointer)
|
int |
height()
Returns the height of the rectangle. |
QRect |
intersected(QRect other)
Returns the intersection of this rectangle and the given rectangle. |
boolean |
intersects(QRect r)
Returns true if this rectangle intersects with the given rectangle (i.e., there is at least one pixel that is within both rectangles), otherwise returns false. |
boolean |
isEmpty()
Returns true if the rectangle is empty, otherwise returns false. |
boolean |
isNull()
Returns true if the rectangle is a null rectangle, otherwise returns false. |
boolean |
isValid()
Returns true if the rectangle is valid, otherwise returns false. |
int |
left()
Returns the x-coordinate of the rectangle's left edge. |
void |
moveBottom(int pos)
Moves the rectangle vertically, leaving the rectangle's bottom edge at the given y coordinate. |
void |
moveBottomLeft(QPoint p)
Moves the rectangle, leaving the bottom-left corner at the given position. |
void |
moveBottomRight(QPoint p)
Moves the rectangle, leaving the bottom-right corner at the given position. |
void |
moveCenter(QPoint p)
Moves the rectangle, leaving the center point at the given position. |
void |
moveLeft(int pos)
Moves the rectangle horizontally, leaving the rectangle's left edge at the given x coordinate. |
void |
moveRight(int pos)
Moves the rectangle horizontally, leaving the rectangle's right edge at the given x coordinate. |
void |
moveTo(int x,
int t)
Moves the rectangle, leaving the top-left corner at the given position (x, y). |
void |
moveTo(QPoint p)
Moves the rectangle, leaving the top-left corner at the given position. |
void |
moveTop(int pos)
Moves the rectangle vertically, leaving the rectangle's top edge at the given y coordinate. |
void |
moveTopLeft(QPoint p)
Moves the rectangle, leaving the top-left corner at the given position. |
void |
moveTopRight(QPoint p)
Moves the rectangle, leaving the top-right corner at the given position. |
static QNativePointer |
nativePointerArray(QRect[] array)
|
QRect |
normalized()
Returns a normalized rectangle; i.e., a rectangle that has a non-negative width and height. |
void |
readFrom(QDataStream arg__1)
|
int |
right()
Returns the x-coordinate of the rectangle's right edge. |
void |
setBottom(int pos)
Sets the bottom edge of the rectangle to the given y coordinate. |
void |
setBottomLeft(QPoint p)
Set the bottom-left corner of the rectangle to the given position. |
void |
setBottomRight(QPoint p)
Set the bottom-right corner of the rectangle to the given position. |
void |
setCoords(int x1,
int y1,
int x2,
int y2)
Sets the coordinates of the rectangle's top-left corner to (x1, y1), and the coordinates of its bottom-right corner to (x2, y2). |
void |
setHeight(int h)
Sets the height of the rectangle to the given height. |
void |
setLeft(int pos)
Sets the left edge of the rectangle to the given x coordinate. |
void |
setRect(int x,
int y,
int w,
int h)
Sets the coordinates of the rectangle's top-left corner to (x, y), and its size to the given width and height. |
void |
setRight(int pos)
Sets the right edge of the rectangle to the given x coordinate. |
void |
setSize(QSize s)
Sets the size of the rectangle to the given size. |
void |
setTop(int pos)
Sets the top edge of the rectangle to the given y coordinate. |
void |
setTopLeft(QPoint p)
Set the top-left corner of the rectangle to the given position. |
void |
setTopRight(QPoint p)
Set the top-right corner of the rectangle to the given position. |
void |
setWidth(int w)
Sets the width of the rectangle to the given width. |
void |
setX(int x)
Sets the left edge of the rectangle to the given x coordinate. |
void |
setY(int y)
Sets the top edge of the rectangle to the given y coordinate. |
QSize |
size()
Returns the size of the rectangle. |
int |
top()
Returns the y-coordinate of the rectangle's top edge. |
QPoint |
topLeft()
Returns the position of the rectangle's top-left corner. |
QPoint |
topRight()
Returns the position of the rectangle's top-right corner. |
java.lang.String |
toString()
|
void |
translate(int dx,
int dy)
Moves the rectangle dx along the x axis and dy along the y axis, relative to the current position. |
void |
translate(QPoint p)
Moves the rectangle offset. x() along the x axis and offset.y() along the y axis, relative to the current position. |
QRect |
translated(int dx,
int dy)
Returns a copy of the rectangle that is translated dx along the x axis and dy along the y axis, relative to the current position. |
QRect |
translated(QPoint p)
Returns a copy of the rectangle that is translated offset. x() along the x axis and offset.y() along the y axis, relative to the current position. |
QRect |
united(QRect other)
Returns the bounding rectangle of this rectangle and the given rectangle. |
int |
width()
Returns the width of the rectangle. |
void |
writeTo(QDataStream arg__1)
|
int |
x()
Returns the x-coordinate of the rectangle's left edge. |
int |
y()
Returns the y-coordinate of the rectangle's top edge. |
Methods inherited from class com.trolltech.qt.QtJambiObject |
---|
dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr |
Methods inherited from class com.trolltech.qt.QSignalEmitter |
---|
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread |
Methods inherited from class java.lang.Object |
---|
getClass, hashCode, notify, notifyAll, wait, wait, wait |
Methods inherited from interface com.trolltech.qt.QtJambiInterface |
---|
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership |
Constructor Detail |
---|
public QRect()
isNull()
.
public QRect(QPoint topleft, QPoint bottomright)
setTopLeft()
, and setBottomRight()
.
public QRect(QPoint topleft, QSize size)
setTopLeft()
, and setSize()
.
public QRect(int left, int top, int width, int height)
setRect()
.
Method Detail |
---|
public final void adjust(int x1, int y1, int x2, int y2)
adjusted()
, and setRect()
.
public final QRect adjusted(int x1, int y1, int x2, int y2)
adjust()
.
public final int bottom()
Note that for historical reasons this function returns top()
+ height()
- 1; use y()
+ height()
to retrieve the true y-coordinate.
setBottom()
, bottomLeft()
, and bottomRight()
.
public final QPoint bottomLeft()
QPoint
(left()
, top()
+ height()
- 1). setBottomLeft()
, bottom()
, and left()
.
public final QPoint bottomRight()
Note that for historical reasons this function returns QPoint
(left()
+ width()
-1, top()
+ height()
- 1).
setBottomRight()
, bottom()
, and right()
.
public final QPoint center()
moveCenter()
.
public final boolean contains(QPoint p)
intersects()
.
public final boolean contains(QPoint p, boolean proper)
intersects()
.
public final boolean contains(QRect r)
public final boolean contains(QRect r, boolean proper)
public final boolean contains(int x, int y)
public final boolean contains(int x, int y, boolean proper)
public final int height()
setHeight()
, width()
, and size()
.
public final QRect intersected(QRect other)
intersects()
, united()
, and operator&=().
public final boolean intersects(QRect r)
The intersection rectangle can be retrieved using the intersected()
function.
contains()
.
public final boolean isEmpty()
An empty rectangle has a left()
> right()
or top()
> bottom()
. An empty rectangle is not valid (i.e., isEmpty()
== !isValid()
).
Use the normalized()
function to retrieve a rectangle where the corners are swapped.
isNull()
, isValid()
, and normalized()
.
public final boolean isNull()
A null rectangle has both the width and the height set to 0 (i.e., right()
== left()
- 1 and bottom()
== top()
- 1). A null rectangle is also empty, and hence is not valid.
isEmpty()
, and isValid()
.
public final boolean isValid()
A valid rectangle has a left()
< right()
and top()
< bottom()
. Note that non-trivial operations like intersections are not defined for invalid rectangles. A valid rectangle is not empty (i.e., isValid()
== !isEmpty()
).
isNull()
, isEmpty()
, and normalized()
.
public final int left()
x()
. setLeft()
, topLeft()
, and bottomLeft()
.
public final void moveBottom(int pos)
bottom()
, setBottom()
, and moveTop()
.
public final void moveBottomLeft(QPoint p)
setBottomLeft()
, moveBottom()
, and moveLeft()
.
public final void moveBottomRight(QPoint p)
setBottomRight()
, moveRight()
, and moveBottom()
.
public final void moveCenter(QPoint p)
center()
.
public final void moveLeft(int pos)
left()
, setLeft()
, and moveRight()
.
public final void moveRight(int pos)
right()
, setRight()
, and moveLeft()
.
public final void moveTo(QPoint p)
public final void moveTo(int x, int t)
translate()
, and moveTopLeft()
.
public final void moveTop(int pos)
top()
, setTop()
, and moveBottom()
.
public final void moveTopLeft(QPoint p)
setTopLeft()
, moveTop()
, and moveLeft()
.
public final void moveTopRight(QPoint p)
setTopRight()
, moveTop()
, and moveRight()
.
public final QRect normalized()
If width()
< 0 the function swaps the left and right corners, and it swaps the top and bottom corners if height()
< 0.
isValid()
, and isEmpty()
.
public final void writeTo(QDataStream arg__1)
public final void readFrom(QDataStream arg__1)
public final int right()
Note that for historical reasons this function returns left()
+ width()
- 1; use x()
+ width()
to retrieve the true x-coordinate.
setRight()
, topRight()
, and bottomRight()
.
public final void setBottom(int pos)
bottom()
, and moveBottom()
.
public final void setBottomLeft(QPoint p)
bottomLeft()
, and moveBottomLeft()
.
public final void setBottomRight(QPoint p)
bottomRight()
, and moveBottomRight()
.
public final void setCoords(int x1, int y1, int x2, int y2)
setRect()
.
public final void setHeight(int h)
height()
, and setSize()
.
public final void setLeft(int pos)
Equivalent to setX()
.
left()
, and moveLeft()
.
public final void setRect(int x, int y, int w, int h)
setCoords()
.
public final void setRight(int pos)
right()
, and moveRight()
.
public final void setSize(QSize s)
size()
, setWidth()
, and setHeight()
.
public final void setTop(int pos)
Equivalent to setY()
.
top()
, and moveTop()
.
public final void setTopLeft(QPoint p)
topLeft()
, and moveTopLeft()
.
public final void setTopRight(QPoint p)
topRight()
, and moveTopRight()
.
public final void setWidth(int w)
width()
, and setSize()
.
public final void setX(int x)
Equivalent to setLeft()
.
x()
, setY()
, and setTopLeft()
.
public final void setY(int y)
Equivalent to setTop()
.
y()
, setX()
, and setTopLeft()
.
public final QSize size()
setSize()
, width()
, and height()
.
public final int top()
y()
. setTop()
, topLeft()
, and topRight()
.
public final QPoint topLeft()
setTopLeft()
, top()
, and left()
.
public final QPoint topRight()
Note that for historical reasons this function returns QPoint
(left()
+ width()
-1, top()
).
setTopRight()
, top()
, and right()
.
public final void translate(QPoint p)
x()
along the x axis and offset.y()
along the y axis, relative to the current position.
public final void translate(int dx, int dy)
moveTopLeft()
, moveTo()
, and translated()
.
public final QRect translated(QPoint p)
x()
along the x axis and offset.y()
along the y axis, relative to the current position.
public final QRect translated(int dx, int dy)
translate()
.
public final QRect united(QRect other)
intersected()
.
public final int width()
setWidth()
, height()
, and size()
.
public final int x()
left()
. setX()
, y()
, and topLeft()
.
public final int y()
top()
. setY()
, x()
, and topLeft()
.
public static QRect fromNativePointer(QNativePointer nativePointer)
public static QNativePointer nativePointerArray(QRect[] array)
public java.lang.String toString()
toString
in class java.lang.Object
public QRect clone()
clone
in class java.lang.Object
|
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