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The QRectF class defines a rectangle in the plane using floating point coordinates for accuracy. More...
#include <QRectF>
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().
Constructs an invalid rectangle.
Constructs a rectangle with topLeft as the top-left corner and bottomRight as the bottom-right corner.
Constructs a rectangle with topLeft as the top-left corner and size as the rectangle size.
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);
Constructs a rectangle with floating point accuracy from the given rect.
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.
Returns the y-coordinate at the bottom edge of the rectangle.
See also setBottom(), top(), bottomLeft(), and bottomRight().
Returns the bottom-left position of the rectangle.
See also setBottomLeft(), moveBottomLeft(), topRight(), bottom(), and left().
Returns the bottom-right position of the rectangle.
See also setBottomRight(), moveBottomRight(), topLeft(), right(), and bottom().
Returns the center point of the rectangle.
See also moveCenter(), topLeft(), bottomRight(), topRight(), and bottomLeft().
Returns true if the given point is inside or on the edge of the rectangle; otherwise returns false.
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.
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().
Extracts the rectangle parameters as the top-left point *xp1, *yp1 and the bottom-right point *xp2, *yp2.
See also setCoords() and rect().
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().
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().
Returns the intersection of this rectangle and the other rectangle. r.intersect(s) is equivalent to r&s.
See also unite().
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().
Returns true if the rectangle is empty; otherwise returns false.
An empty rectangle has a left() > right() or top() > bottom().
An empty rectangle is not valid. isEmpty() == !isValid()
See also isNull(), isValid(), and normalize().
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, so that right() == left() - 1 and bottom() == top() - 1.
Note that if right() == left() and bottom() == top() then the rectangle has a width of 1 and a height of 1.
A null rectangle is also empty and invalid.
See also isEmpty() and isValid().
Returns true if the rectangle is valid; otherwise returns false.
A valid rectangle has a left() <= right() and top() <= bottom().
Note that non-trivial operations like intersections are not defined for invalid rectangles.
isValid() == !isEmpty()
See also isNull(), isEmpty(), and normalize().
Returns the x-coordinate at the left edge of the rectangle. Identical to x().
See also setLeft(), right(), topLeft(), and bottomLeft().
Moves the rectangle so that the y-coordinate of its bottom edge is at y. The size of the rectangle is unchanged.
See also bottom(), setBottom(), moveLeft(), moveTop(), and moveRight().
Moves the rectangle so that the position of its bottom-left corner lies at the given point. The size of the rectangle is unchanged.
See also bottomLeft(), setBottomLeft(), moveTopLeft(), moveBottomRight(), and moveTopRight().
Moves the rectangle so that the position of its bottom-right corner lies at the given point. The size of the rectangle is unchanged.
See also bottomRight(), setBottomRight(), moveTopLeft(), moveTopRight(), and moveBottomLeft().
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.
See also moveTopLeft().
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.
See also moveTopLeft().
Moves the rectangle so that the position of its center point lies at the point specified by p. The size of the rectangle is unchanged.
See also center(), moveTopLeft(), moveBottomRight(), moveTopRight(), and moveBottomLeft().
Moves the rectangle so that the x-coordinate of its left edge is at x. The size of the rectangle is unchanged.
See also left(), setLeft(), moveTop(), moveRight(), and moveBottom().
Moves the rectangle so that the x-coordinate of its right edge is at x. The size of the rectangle is unchanged.
See also right(), setRight(), moveLeft(), moveTop(), and moveBottom().
Moves the rectangle so that the y-coordinate of its top edge is at y. The size of the rectangle is unchanged.
See also top(), setTop(), moveLeft(), moveRight(), and moveBottom().
Moves the rectangle so that the position of its top-left corner lies at the given point. The size of the rectangle is unchanged.
See also topLeft(), setTopLeft(), moveBottomRight(), moveTopRight(), and moveBottomLeft().
Moves the rectangle so that the position of its top-right corner lies at the given point. The size of the rectangle is unchanged.
See also topRight(), setTopRight(), moveTopLeft(), moveBottomRight(), and moveBottomLeft().
Returns a normalized rectangle; i.e. a rectangle that has a non-negative width and height.
It swaps left and right if left() > right(), and swaps top and bottom if top() > bottom().
See also isValid().
Returns a reference to the height of the rectangle.
See also rLeft(), rTop(), and rWidth().
Returns a reference to the x-coordinate at the left edge of the rectangle.
See also rTop(), rWidth(), and rHeight().
Returns a reference to the y-coordinate at the top edge of the rectangle.
See also rLeft(), rWidth(), and rHeight().
Returns a reference to the width of the rectangle.
See also rLeft(), rTop(), and rHeight().
Returns the x-coordinate at the right edge of the rectangle.
See also setRight(), left(), topRight(), and bottomRight().
Sets the y-coordinate of the rectangle's bottom edge to y. The rectangle's height may change, but its top edge is not moved.
See also bottom(), setTop(), and setHeight().
Sets the position of the rectangle's bottom-left corner to lie at the given point. The size of the rectangle may change. The rectangle's top and right edges are not moved.
See also bottomLeft(), moveBottomLeft(), setTopLeft(), setBottomRight(), and setTopRight().
Sets the position of the rectangle's bottom-right corner to lie at the given point. The size of the rectangle may change. The rectangle's top and left edges are not moved.
See also bottomRight(), moveBottomRight(), setTopLeft(), setTopRight(), and setBottomLeft().
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().
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().
Sets the x-coordinate of the rectangle's left edge to x. The rectangle's width may change, but its right edge is not moved.
Identical to setX().
See also left(), setTop(), and setWidth().
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().
Sets the x-coordinate of the rectangle's right edge to x. The rectangle's width may change, but its left edge is not moved.
See also right(), setLeft(), and setWidth().
Sets the size of the rectangle to size. The top-left corner is not moved.
See also size(), setWidth(), and setHeight().
Sets the y-coordinate of the rectangle's top edge to y. The rectangle's height may change, but its bottom edge is not moved.
Identical to setY().
See also top(), setBottom(), and setHeight().
Sets the position of the rectangle's top-left corner to lie at the given point. The size of the rectangle may change. The rectangle's bottom and right edges are not moved.
See also topLeft(), moveTopLeft(), setBottomRight(), setTopRight(), and setBottomLeft().
Sets the position of the rectangle's top-right corner to lie at the given point. The size of the rectangle may change. The rectangle's bottom and left edges are not moved.
See also topRight(), moveTopRight(), setTopLeft(), setBottomRight(), and setBottomLeft().
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().
Sets the x-coordinate of the rectangle's left edge to x. The rectangle's width may change, but its right edge is not moved.
Identical to setLeft().
Sets the y-coordinate of the rectangle's top edge to y. The rectangle's height may change, but its bottom edge is not moved.
Identical to setTop().
Returns the size of the rectangle to floating point accuracy.
See also width() and height().
Returns a rectangle with integer precision. Note that the coordinates in the returned rectangle are less precise than those in the floating point rectangle.
Returns the y-coordinate at the top edge of the rectangle. Identical to y().
See also setTop(), bottom(), topLeft(), and topRight().
Returns the top-left position of the rectangle.
See also setTopLeft(), moveTopLeft(), bottomRight(), left(), and top().
Returns the top-right position of the rectangle.
See also setTopRight(), moveTopRight(), bottomLeft(), top(), and right().
Returns the bounding rectangle of this rectangle and the other rectangle. r.unite(s) is equivalent to r|s.
See also intersect().
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().
Returns the x-coordinate at the left edge of the rectangle. Identical to left().
See also left(), y(), and setX().
Returns the y-coordinate at the top edge of the rectangle. Identical to top().
See also top(), x(), and setY().
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().
Intersects this rectangle with the other rectangle, and returns the result.
See also operator|=().
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().
Unites this rectangle with the other rectangle, and returns the result.
See also operator&=().
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.
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.
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.
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.
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