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# QRectF Class Reference

The QRectF class defines a rectangle in the plane using floating point coordinates for accuracy. More...

    #include <QRectF>

- List of all members, including inherited members

### Public Functions

- QRectF ()
- QRectF ( const QPointF & topLeft, const QSizeF & size )
- QRectF ( float x, float y, float width, float height )
- QRectF ( const QRect & rect )
- void addCoords ( float xp1, float yp1, float xp2, float yp2 )
- QRectF adjusted ( float xp1, float yp1, float xp2, float yp2 ) const
- QPointF center () const
- bool contains ( const QPointF & point ) const
- bool contains ( float x, float y ) const
- bool contains ( const QRectF & rectangle ) const
- void getCoords ( float * xp1, float * yp1, float * xp2, float * yp2 ) const
- void getRect ( float * x, float * y, float * w, float * h ) const
- float height () const
- QRectF intersect ( const QRectF & other ) const
- bool intersects ( const QRectF & rectangle ) const
- bool isEmpty () const
- bool isNull () const
- bool isValid () const
- void moveTo ( float x, float y )
- void moveTo ( const QPointF & pt )
- QRectF normalize () const
- QPointF origin () const
- void setCoords ( float xp1, float yp1, float xp2, float yp2 )
- void setHeight ( float height )
- void setRect ( float x, float y, float width, float height )
- void setSize ( const QSizeF & size )
- void setWidth ( float width )
- QSizeF size () const
- QRect toRect () const
- void translate ( float dx, float dy )
- void translate ( const QPointF & p )
- QRectF unite ( const QRectF & other ) const
- float width () const
- float x () const
- float y () const
- QRectF operator& ( const QRectF & other ) const
- QRectF & operator&= ( const QRectF & other )
- QRectF operator| ( const QRectF & other ) const
- QRectF & operator|= ( const QRectF & other )

### Related Non-Members

- bool operator!= ( const QRectF & r1, const QRectF & r2 )
- QDataStream & operator<< ( QDataStream & stream, const QRectF & rectangle )
- bool operator== ( const QRectF & r1, const QRectF & r2 )
- QDataStream & operator>> ( QDataStream & stream, QRectF & rectangle )

## Detailed Description

The QRectF class defines a rectangle in the plane using floating point coordinates for accuracy.

Rectangles are used throughout Qt to describe the area covered by visible items. They specify both the geometry of widgets and the extent of items that are painted using a QPainter. QRectF provides a variant of the QRect class that defines the position and dimension of the rectangle using `float` values for accuracy.

A rectangle is internally represented as the positions of its upper-left and bottom-right corners, but it is normally expressed as the position of its upper-left corner and a size.

Note that the size (width and height) of a rectangle might be different from what you expect. If the top-left corner and the bottom-right corner are the same, the height and the width of the rectangle will both be 1.

Generally, width = right - left + 1 and height = bottom - top + 1. We designed it this way to make it correspond to rectangular spaces used by drawing functions where the width and height denote a whole number of pixels. For example, drawing a rectangle with width and height 1 draws a single pixel.

The default coordinate system has origin (0, 0) in the top-left corner. The positive direction of the x axis is from left to right, and the positive direction of the y axis is from top to bottom.

A QRectF can be constructed with a set of floats specifying the coordinates of the top-left corner of the rectangle and its dimensions from two QPointF values, or from a QPointF and a QSizeF. After creation, the dimensions can be changed with setLeft(), setRight(), setTop(), and setBottom(), or by setting sizes with setWidth(), setHeight(), and setSize(). The dimensions can also be changed with the move functions, such as moveBy(), moveCenter(), and moveBottomRight(). You can also add coordinates to a rectangle with addCoords().

You can test to see if a rectangle contains a specific point with the contains() function. You can also test to see if two rectangles intersect with the intersects() function (see also intersect()). To get the bounding rectangle of two rectangles use unite().

See also QPointF and QSizeF.

## Member Function Documentation

### QRectF::QRectF ()

Constructs an invalid rectangle.

### QRectF::QRectF ( const QPointF & topLeft, const QSizeF & size )

Constructs a rectangle with topLeft as the top-left corner and size as the rectangle size.

### QRectF::QRectF ( float x, float y, float width, float height )

Constructs a rectangle with the top-left corner at (x, y) and dimensions specified by the width and height.

Example (creates three identical rectangles):

        QRectF r1(QPoint(100,200), QPoint(110,215));
        QRectF r2(QPoint(100,200), QSize(11,16));
        QRectF r3(100, 200, 11, 16);

### QRectF::QRectF ( const QRect & rect )

Constructs a rectangle with floating point accuracy from the given rect.

### void QRectF::addCoords ( float xp1, float yp1, float xp2, float yp2 )

Adds (xp1, yp1) to the existing position of the rectangle's top-left corner, and (xp2, yp2) to the position of its bottom-right corner.

### QRectF QRectF::adjusted ( float xp1, float yp1, float xp2, float yp2 ) const

Returns a new rectangle with (xp1, yp1) added to the existing position of the rectangle's top-left corner, and (xp2, yp2) added to the position of its bottom-right corner.

### QPointF QRectF::center () const

Returns the center point of the rectangle.

See also moveCenter(), topLeft(), bottomRight(), topRight(), and bottomLeft().

### bool QRectF::contains ( const QPointF & point ) const

Returns true if the given point is inside or on the edge of the rectangle; otherwise returns false.

### bool QRectF::contains ( float x, float y ) const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Returns true if the point (x, y) is inside this rectangle; otherwise returns false.

### bool QRectF::contains ( const QRectF & rectangle ) const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Returns true if the given rectangle is inside this rectangle; otherwise returns false.

See also unite(), intersect(), and intersects().

### void QRectF::getCoords ( float * xp1, float * yp1, float * xp2, float * yp2 ) const

Extracts the rectangle parameters as the top-left point `*`xp1, `*`yp1 and the bottom-right point `*`xp2, `*`yp2.

See also setCoords() and rect().

### void QRectF::getRect ( float * x, float * y, float * w, float * h ) const

Extracts the position of the rectangle's top-left corner to `*`x, `*`y, its width to `*`w, and its height to `*`h.

See also setRect() and coords().

### float QRectF::height () const

Returns the height of the rectangle. The height includes both the top and bottom edges; i.e. height = bottom - top + 1.

See also width(), size(), and setHeight().

### QRectF QRectF::intersect ( const QRectF & other ) const

Returns the intersection of this rectangle and the other rectangle. `r.intersect(s)` is equivalent to `r&s`.

See also unite().

### bool QRectF::intersects ( const QRectF & rectangle ) const

Returns true if this rectangle intersects with the given rectangle (there is at least one pixel that is within both rectangles); otherwise returns false.

See also intersect() and contains().

### bool QRectF::isEmpty () const

Returns true if the rectangle is empty; otherwise returns false.

An empty rectangle has a width() <= 0 or height() <= 0.

An empty rectangle is not valid. `isEmpty() == !isValid()`

See also isNull(), isValid(), and normalize().

### bool QRectF::isNull () const

Returns true if the rectangle is a null rectangle; otherwise returns false.

A null rectangle has both the width and the height set to 0.

A null rectangle is also empty and invalid.

See also isEmpty() and isValid().

### bool QRectF::isValid () const

Returns true if the rectangle is valid; otherwise returns false.

A valid rectangle has a width() > 0 and height() > 0.

Note that non-trivial operations like intersections are not defined for invalid rectangles.

`isValid() == !isEmpty()`

See also isNull(), isEmpty(), and normalize().

### void QRectF::moveTo ( float x, float y )

Moves the top left corner of the rectangle to x and y, without changing the rectangles size.

### void QRectF::moveTo ( const QPointF & pt )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Moves the top left corner of the rectangle to pt, without changing the rectangles size.

### QRectF QRectF::normalize () const

Returns a normalized rectangle; i.e. a rectangle that has a non-negative width and height.

It swaps left and right if width() < 0, and swaps top and bottom if height() < 0.

See also isValid().

### QPointF QRectF::origin () const

### void QRectF::setCoords ( float xp1, float yp1, float xp2, float yp2 )

Sets the position of the rectangle's top-left corner to (xp1, yp1), and the position of its bottom-right corner to (xp2, yp2).

See also coords() and setRect().

### void QRectF::setHeight ( float height )

Sets the height of the rectangle. The top edge is not moved, but the bottom edge may be moved.

See also height(), setTop(), setBottom(), and setSize().

### void QRectF::setRect ( float x, float y, float width, float height )

Sets the position of the rectangle's top-left corner to (x, y), and resizes it to the specified width and height.

See also rect() and setCoords().

### void QRectF::setSize ( const QSizeF & size )

Sets the size of the rectangle to size. The top-left corner is not moved.

See also size(), setWidth(), and setHeight().

### void QRectF::setWidth ( float width )

Sets the width of the rectangle. If the width is different to the old width, only the rectangle's right edge is moved. The left edge is not moved.

See also width(), setLeft(), setRight(), and setSize().

### QSizeF QRectF::size () const

Returns the size of the rectangle to floating point accuracy.

See also width() and height().

### QRect QRectF::toRect () const

Returns a rectangle with integer precision. Note that the coordinates in the returned rectangle are less precise than those in the floating point rectangle.

### void QRectF::translate ( float dx, float dy )

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 downwards.

### void QRectF::translate ( const QPointF & p )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Moves the rectangle p.x() along the x axis and p.y() along the y axis, relative to the current position. Positive values move the rectangle to the right and downwards.

### QRectF QRectF::unite ( const QRectF & other ) const

Returns the bounding rectangle of this rectangle and the other rectangle. `r.unite(s)` is equivalent to `r|s`.

See also intersect().

### float QRectF::width () const

Returns the width of the rectangle. The width includes both the left and right edges; i.e. width = right - left + 1.

See also height(), size(), and setHeight().

### float QRectF::x () const

Returns the x-coordinate at the left edge of the rectangle. Identical to left().

See also left(), y(), and setX().

### float QRectF::y () const

Returns the y-coordinate at the top edge of the rectangle. Identical to top().

See also top(), x(), and setY().

### QRectF QRectF::operator& ( const QRectF & other ) const

Returns the intersection of this rectangle and the other rectangle.

Returns an empty rectangle if there is no intersection.

See also operator&=(), operator|(), isEmpty(), intersects(), and contains().

### QRectF & QRectF::operator&= ( const QRectF & other )

Intersects this rectangle with the other rectangle, and returns the result.

See also operator|=().

### QRectF QRectF::operator| ( const QRectF & other ) const

Returns the bounding rectangle of this rectangle and the other rectangle.

The bounding rectangle of a non-empty rectangle and an empty (or invalid) rectangle is defined to be the non-empty rectangle.

See also operator|=(), operator&(), intersects(), and contains().

### QRectF & QRectF::operator|= ( const QRectF & other )

Unites this rectangle with the other rectangle, and returns the result.

See also operator&=().

## Related Non-Members

### bool operator!= ( const QRectF & r1, const QRectF & r2 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Returns true if the rectangles r1 and r2 are different; otherwise returns false.

### QDataStream & operator<< ( QDataStream & stream, const QRectF & rectangle )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Writes the rectangle to the stream, and returns a reference to the stream.

See also Format of the QDataStream operators.

### bool operator== ( const QRectF & r1, const QRectF & r2 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Returns true if the rectangles r1 and r2 are equal; otherwise returns false.

### QDataStream & operator>> ( QDataStream & stream, QRectF & rectangle )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Reads a rectangle from the stream, and returns a reference to the stream.

See also Format of the QDataStream operators.