QRect class defines a rectangle in the plane using integer precision. 更多...
Header: | #include <QRect> |
qmake: | QT += core |
注意: 此类的所有函数 可重入 .
QRect () | |
QRect (const QPoint & topLeft , const QPoint & bottomRight ) | |
QRect (const QPoint & topLeft , const QSize & size ) | |
QRect (int x , int y , int width , int height ) | |
void | adjust (int dx1 , int dy1 , int dx2 , int dy2 ) |
QRect | adjusted (int dx1 , int dy1 , int dx2 , int dy2 ) const |
int | bottom () const |
QPoint | bottomLeft () const |
QPoint | bottomRight () const |
QPoint | center () const |
bool | contains (const QPoint & point , bool proper = false) const |
bool | contains (const QRect & rectangle , bool proper = false) const |
bool | contains (int x , int y ) const |
bool | contains (int x , int y , bool proper ) const |
void | getCoords (int * x1 , int * y1 , int * x2 , int * y2 ) const |
void | getRect (int * x , int * y , int * width , int * height ) const |
int | height () const |
QRect | intersected (const QRect & rectangle ) const |
bool | intersects (const QRect & rectangle ) const |
bool | isEmpty () const |
bool | isNull () const |
bool | isValid () const |
int | left () const |
QRect | marginsAdded (const QMargins & margins ) const |
QRect | marginsRemoved (const QMargins & margins ) const |
void | moveBottom (int y ) |
void | moveBottomLeft (const QPoint & position ) |
void | moveBottomRight (const QPoint & position ) |
void | moveCenter (const QPoint & position ) |
void | moveLeft (int x ) |
void | moveRight (int x ) |
void | moveTo (int x , int y ) |
void | moveTo (const QPoint & position ) |
void | moveTop (int y ) |
void | moveTopLeft (const QPoint & position ) |
void | moveTopRight (const QPoint & position ) |
QRect | normalized () const |
int | right () const |
void | setBottom (int y ) |
void | setBottomLeft (const QPoint & position ) |
void | setBottomRight (const QPoint & position ) |
void | setCoords (int x1 , int y1 , int x2 , int y2 ) |
void | setHeight (int height ) |
void | setLeft (int x ) |
void | setRect (int x , int y , int width , int height ) |
void | setRight (int x ) |
void | setSize (const QSize & size ) |
void | setTop (int y ) |
void | setTopLeft (const QPoint & position ) |
void | setTopRight (const QPoint & position ) |
void | setWidth (int width ) |
void | setX (int x ) |
void | setY (int y ) |
QSize | size () const |
CGRect | toCGRect () const |
int | top () const |
QPoint | topLeft () const |
QPoint | topRight () const |
void | translate (int dx , int dy ) |
void | translate (const QPoint & offset ) |
QRect | translated (int dx , int dy ) const |
QRect | translated (const QPoint & offset ) const |
QRect | transposed () const |
QRect | united (const QRect & rectangle ) const |
int | width () const |
int | x () const |
int | y () const |
QRect | operator& (const QRect & rectangle ) const |
QRect & | operator&= (const QRect & rectangle ) |
QRect & | operator+= (const QMargins & margins ) |
QRect & | operator-= (const QMargins & margins ) |
QRect | operator| (const QRect & rectangle ) const |
QRect & | operator|= (const QRect & rectangle ) |
bool | operator!= (const QRect & r1 , const QRect & r2 ) |
QRect | operator+ (const QRect & rectangle , const QMargins & margins ) |
QRect | operator+ (const QMargins & margins , const QRect & rectangle ) |
QRect | operator- (const QRect & lhs , const QMargins & rhs ) |
QDataStream & | operator<< (QDataStream & stream , const QRect & rectangle ) |
bool | operator== (const QRect & r1 , const QRect & r2 ) |
QDataStream & | operator>> (QDataStream & stream , QRect & rectangle ) |
QRect class defines a rectangle in the plane using integer precision.
A rectangle is normally expressed as a top-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 和 QSize . The following code creates two identical rectangles.
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 () 和 right () functions deviate from the true bottom-right corner of the rectangle.
QRect class provides a collection of functions that return the various rectangle coordinates, and enable manipulation of these. QRect also provides 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.
size () function returns the rectange's dimensions as a QSize . The dimensions can also be retrieved separately using the width () 和 height () functions. To manipulate the dimensions use the setSize (), setWidth () 或 setHeight () functions. Alternatively, the size can be changed by applying either of the functions setting the rectangle coordinates, for example, setBottom () 或 setRight ().
contains
() function tells whether a given point is inside the rectangle or not, and the
intersects
() 函数返回
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:
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intersected () | united () |
isEmpty
() 函数返回
true
if
left
() >
right
() 或
top
() >
bottom
(). Note that an empty rectangle is not valid: The
isValid
() 函数返回
true
if
left
() <=
right
()
and
top
() <=
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.
When using an 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.
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Logical representation | One pixel wide pen |
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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 provides functions to move the rectangle relative to the various coordinates.
For example the left (), setLeft () 和 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.
Note that for historical reasons the values returned by the bottom () 和 right () functions deviate from the true bottom-right corner of the rectangle: The right () 函数返回 left () + width () - 1 和 bottom () 函数返回 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 () 和 bottomLeft () functions, respectively, contain the same deviation from the true right and bottom edges.
We recommend that you use x () + width () 和 y () + height () to find the true bottom-right corner, and avoid right () 和 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 () 和 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.
此外, 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 () 和 setRect () function to manipulate the rectangle's coordinates and dimensions in one go.
QRect
is limited to the minimum and maximum values for the
int
type. Operations on a
QRect
that could potentially result in values outside this range will result in undefined behavior.
Constructs a null rectangle.
另请参阅 isNull ().
Constructs a rectangle with the given topLeft and bottomRight corners.
另请参阅 setTopLeft () 和 setBottomRight ().
Constructs a rectangle with the given topLeft corner and the given size .
另请参阅 setTopLeft () 和 setSize ().
Constructs a rectangle with ( x , y ) as its top-left corner and the given width and height .
另请参阅 setRect ().
添加 dx1 , dy1 , dx2 and dy2 respectively to the existing coordinates of the rectangle.
另请参阅 adjusted () 和 setRect ().
Returns a new rectangle with dx1 , dy1 , dx2 and dy2 added respectively to the existing coordinates of this rectangle.
另请参阅 adjust ().
Returns the y-coordinate of the rectangle's bottom edge.
Note that for historical reasons this function returns top () + height () - 1; use y () + height () to retrieve the true y-coordinate.
另请参阅 setBottom (), bottomLeft (),和 bottomRight ().
Returns the position of the rectangle's bottom-left corner. Note that for historical reasons this function returns QPoint ( left (), top () + height () - 1).
另请参阅 setBottomLeft (), bottom (),和 left ().
Returns the position of the rectangle's bottom-right corner.
Note that for historical reasons this function returns QPoint ( left () + width () -1, top () + height () - 1).
另请参阅 setBottomRight (), bottom (),和 right ().
Returns the center point of the rectangle.
另请参阅 moveCenter ().
返回
true
若给定
point
is inside or on the edge of the rectangle, otherwise returns
false
。若
proper
is true, this function only returns
true
若给定
point
is
inside
the rectangle (i.e., not on the edge).
另请参阅 intersects ().
这是重载函数。
返回
true
若给定
rectangle
is inside this rectangle. otherwise returns
false
。若
proper
is true, this function only returns
true
若
rectangle
is entirely inside this rectangle (not on the edge).
这是重载函数。
返回
true
if the point (
x
,
y
) is inside this rectangle, otherwise returns
false
.
这是重载函数。
返回
true
if the point (
x
,
y
) is inside or on the edge of the rectangle, otherwise returns
false
。若
proper
is true, this function only returns
true
if the point is entirely inside the rectangle(not on the edge).
Extracts the position of the rectangle's top-left corner to * x1 and * y1 , and the position of the bottom-right corner to * x2 and * y2 .
另请参阅 setCoords () 和 getRect ().
Extracts the position of the rectangle's top-left corner to * x and * y , and its dimensions to * width and * height .
另请参阅 setRect () 和 getCoords ().
Returns the height of the rectangle.
另请参阅 setHeight (), width (),和 size ().
Returns the intersection of this rectangle and the given
rectangle
。注意
r.intersected(s)
相当于
r & s
.
This function was introduced in Qt 4.2.
另请参阅 intersects (), united (),和 operator&= ().
返回
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
.
The intersection rectangle can be retrieved using the intersected () 函数。
另请参阅 contains ().
返回
true
if the rectangle is empty, otherwise returns
false
.
An empty rectangle has a left () > right () 或 top () > bottom (). An empty rectangle is not valid (i.e., isEmpty() == ! isValid ()).
使用 normalized () function to retrieve a rectangle where the corners are swapped.
另请参阅 isNull (), isValid (),和 normalized ().
返回
true
if the rectangle is a null rectangle, otherwise returns
false
.
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.
返回
true
if the rectangle is valid, otherwise returns
false
.
A valid rectangle has a left () <= right () 和 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 ()).
另请参阅 isNull (), isEmpty (),和 normalized ().
Returns the x-coordinate of the rectangle's left edge. Equivalent to x ().
另请参阅 setLeft (), topLeft (),和 bottomLeft ().
Returns a rectangle grown by the margins .
This function was introduced in Qt 5.1.
另请参阅 operator+= (), marginsRemoved (),和 operator-= ().
移除 margins from the rectangle, shrinking it.
This function was introduced in Qt 5.1.
另请参阅 marginsAdded (), operator+= (),和 operator-= ().
Moves the rectangle vertically, leaving the rectangle's bottom edge at the given y coordinate. The rectangle's size is unchanged.
另请参阅 bottom (), setBottom (),和 moveTop ().
Moves the rectangle, leaving the bottom-left corner at the given position . The rectangle's size is unchanged.
另请参阅 setBottomLeft (), moveBottom (),和 moveLeft ().
Moves the rectangle, leaving the bottom-right corner at the given position . The rectangle's size is unchanged.
另请参阅 setBottomRight (), moveRight (),和 moveBottom ().
Moves the rectangle, leaving the center point at the given position . The rectangle's size is unchanged.
另请参阅 center ().
Moves the rectangle horizontally, leaving the rectangle's left edge at the given x coordinate. The rectangle's size is unchanged.
另请参阅 left (), setLeft (),和 moveRight ().
Moves the rectangle horizontally, leaving the rectangle's right edge at the given x coordinate. The rectangle's size is unchanged.
另请参阅 right (), setRight (),和 moveLeft ().
Moves the rectangle, leaving the top-left corner at the given position ( x , y ). The rectangle's size is unchanged.
另请参阅 translate () 和 moveTopLeft ().
Moves the rectangle, leaving the top-left corner at the given position .
Moves the rectangle vertically, leaving the rectangle's top edge at the given y coordinate. The rectangle's size is unchanged.
另请参阅 top (), setTop (),和 moveBottom ().
Moves the rectangle, leaving the top-left corner at the given position . The rectangle's size is unchanged.
另请参阅 setTopLeft (), moveTop (),和 moveLeft ().
Moves the rectangle, leaving the top-right corner at the given position . The rectangle's size is unchanged.
另请参阅 setTopRight (), moveTop (),和 moveRight ().
Returns a normalized rectangle; i.e., a rectangle that has a non-negative width and height.
若 width () < 0 the function swaps the left and right corners, and it swaps the top and bottom corners if height () < 0.
Returns the x-coordinate of the rectangle's right edge.
Note that for historical reasons this function returns left () + width () - 1; use x () + width () to retrieve the true x-coordinate.
另请参阅 setRight (), topRight (),和 bottomRight ().
Sets the bottom edge of the rectangle to the given y coordinate. May change the height, but will never change the top edge of the rectangle.
另请参阅 bottom () 和 moveBottom ().
Set the bottom-left corner of the rectangle to the given position . May change the size, but will never change the top-right corner of the rectangle.
另请参阅 bottomLeft () 和 moveBottomLeft ().
Set the bottom-right corner of the rectangle to the given position . May change the size, but will never change the top-left corner of the rectangle.
另请参阅 bottomRight () 和 moveBottomRight ().
Sets the coordinates of the rectangle's top-left corner to ( x1 , y1 ), and the coordinates of its bottom-right corner to ( x2 , y2 ).
另请参阅 getCoords () 和 setRect ().
Sets the height of the rectangle to the given height . The bottom edge is changed, but not the top one.
Sets the left edge of the rectangle to the given x coordinate. May change the width, but will never change the right edge of the rectangle.
相当于 setX ().
Sets the coordinates of the rectangle's top-left corner to ( x , y ), and its size to the given width and height .
另请参阅 getRect () 和 setCoords ().
Sets the right edge of the rectangle to the given x coordinate. May change the width, but will never change the left edge of the rectangle.
Sets the size of the rectangle to the given size . The top-left corner is not moved.
另请参阅 size (), setWidth (),和 setHeight ().
Sets the top edge of the rectangle to the given y coordinate. May change the height, but will never change the bottom edge of the rectangle.
相当于 setY ().
Set the top-left corner of the rectangle to the given position . May change the size, but will never change the bottom-right corner of the rectangle.
另请参阅 topLeft () 和 moveTopLeft ().
Set the top-right corner of the rectangle to the given position . May change the size, but will never change the bottom-left corner of the rectangle.
另请参阅 topRight () 和 moveTopRight ().
Sets the width of the rectangle to the given width . The right edge is changed, but not the left one.
Sets the left edge of the rectangle to the given x coordinate. May change the width, but will never change the right edge of the rectangle.
相当于 setLeft ().
另请参阅 x (), setY (),和 setTopLeft ().
Sets the top edge of the rectangle to the given y coordinate. May change the height, but will never change the bottom edge of the rectangle.
相当于 setTop ().
另请参阅 y (), setX (),和 setTopLeft ().
Returns the size of the rectangle.
另请参阅 setSize (), width (),和 height ().
Creates a CGRect from a QRect .
This function was introduced in Qt 5.8.
另请参阅 QRectF::fromCGRect ().
Returns the y-coordinate of the rectangle's top edge. Equivalent to y ().
另请参阅 setTop (), topLeft (),和 topRight ().
Returns the position of the rectangle's top-left corner.
另请参阅 setTopLeft (), top (),和 left ().
Returns the position of the rectangle's top-right corner.
Note that for historical reasons this function returns QPoint ( left () + width () -1, top ()).
另请参阅 setTopRight (), top (),和 right ().
Moves the rectangle dx along the x axis and dy along the y axis, relative to the current position. Positive values move the rectangle to the right and down.
另请参阅 moveTopLeft (), moveTo (),和 translated ().
这是重载函数。
Moves the rectangle offset . x() along the x axis and offset . y() along the y axis, relative to the current position.
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. Positive values move the rectangle to the right and down.
另请参阅 translate ().
这是重载函数。
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.
Returns a copy of the rectangle that has its width and height exchanged:
QRect r = {15, 51, 42, 24}; r = r.transposed(); // r == {15, 51, 24, 42}
This function was introduced in Qt 5.7.
另请参阅 QSize::transposed ().
Returns the bounding rectangle of this rectangle and the given rectangle .
This function was introduced in Qt 4.2.
另请参阅 intersected ().
Returns the width of the rectangle.
另请参阅 setWidth (), height (),和 size ().
Returns the x-coordinate of the rectangle's left edge. Equivalent to left ().
另请参阅 setX (), y (),和 topLeft ().
Returns the y-coordinate of the rectangle's top edge. Equivalent to top ().
另请参阅 setY (), x (),和 topLeft ().
Returns the intersection of this rectangle and the given rectangle . Returns an empty rectangle if there is no intersection.
另请参阅 operator&= () 和 intersected ().
Intersects this rectangle with the given rectangle .
另请参阅 intersected () 和 operator& ().
添加 margins to the rectangle, growing it.
This function was introduced in Qt 5.1.
另请参阅 marginsAdded (), marginsRemoved (),和 operator-= ().
Returns a rectangle shrunk by the margins .
This function was introduced in Qt 5.1.
另请参阅 marginsRemoved (), operator+= (),和 marginsAdded ().
Returns the bounding rectangle of this rectangle and the given rectangle .
另请参阅 operator|= () 和 united ().
Unites this rectangle with the given rectangle .
返回
true
if the rectangles
r1
and
r2
are different, otherwise returns
false
.
返回 rectangle grown by the margins .
This function was introduced in Qt 5.1.
这是重载函数。
返回 rectangle grown by the margins .
This function was introduced in Qt 5.1.
返回 lhs rectangle shrunk by the rhs margins.
This function was introduced in Qt 5.3.
写入给定 rectangle 到给定 stream , and returns a reference to the stream.
另请参阅 序列化 Qt 数据类型 .
返回
true
if the rectangles
r1
and
r2
are equal, otherwise returns
false
.
Reads a rectangle from the given stream into the given rectangle , and returns a reference to the stream.
另请参阅 序列化 Qt 数据类型 .