Qt 4.3: QRadialGradient Class Reference

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# QRadialGradient Class Reference
[QtGui module]

The QRadialGradient class is used in combination with QBrush to specify a radial gradient brush. More...

     #include <QRadialGradient>

Inherits QGradient.

- List of all members, including inherited members

### Public Functions

- QRadialGradient ()
- QRadialGradient ( const QPointF & center, qreal radius, const QPointF & focalPoint )
- QRadialGradient ( qreal cx, qreal cy, qreal radius, qreal fx, qreal fy )
- QRadialGradient ( const QPointF & center, qreal radius )
- QRadialGradient ( qreal cx, qreal cy, qreal radius )
- QPointF center () const
- QPointF focalPoint () const
- qreal radius () const
- void setCenter ( const QPointF & center )
- void setCenter ( qreal x, qreal y )
- void setFocalPoint ( const QPointF & focalPoint )
- void setFocalPoint ( qreal x, qreal y )
- void setRadius ( qreal radius )

- 8 public functions inherited from QGradient

## Detailed Description

The QRadialGradient class is used in combination with QBrush to specify a radial gradient brush.

Radial gradients interpolate colors between a focal point and end points on a circle surrounding it. Outside the end points the gradient is either padded, reflected or repeated depending on the currently set spread method:

PadSpread (default) | ReflectSpread | RepeatSpread

The colors in a gradient is defined using stop points of the QGradientStop type, i.e. a position and a color. Use the QGradient::setColorAt() or the QGradient::setStops() function to define the stop points. It is the gradient's complete set of stop points that describes how the gradient area should be filled. If no stop points have been specified, a gradient of black at 0 to white at 1 is used.

In addition to the functions inherited from QGradient, the QRadialGradient class provides the center(), focalPoint() and radius() functions returning the gradient's center, focal point and radius respectively.

See also QLinearGradient, QConicalGradient, and The Gradients Demo.

## Member Function Documentation

### QRadialGradient::QRadialGradient ()

Constructs a radial gradient with the center and focal point at (0, 0) with a radius of 1.

### QRadialGradient::QRadialGradient ( const QPointF & center, qreal radius, const QPointF & focalPoint )

Constructs a radial gradient with the given center, radius and focalPoint.

See also QGradient::setColorAt() and QGradient::setStops().

### QRadialGradient::QRadialGradient ( qreal cx, qreal cy, qreal radius, qreal fx, qreal fy )

Constructs a radial gradient with the given center (cx, cy), radius and focal point (fx, fy).

See also QGradient::setColorAt() and QGradient::setStops().

### QRadialGradient::QRadialGradient ( const QPointF & center, qreal radius )

Constructs a radial gradient with the given center, radius and the focal point in the circle center.

See also QGradient::setColorAt() and QGradient::setStops().

### QRadialGradient::QRadialGradient ( qreal cx, qreal cy, qreal radius )

Constructs a radial gradient with the center at (cx, cy) and the specified radius. The focal point lies at the center of the circle.

See also QGradient::setColorAt() and QGradient::setStops().

### QPointF QRadialGradient::center () const

Returns the center of this radial gradient in logical coordinates.

See also setCenter() and QGradient::stops().

### QPointF QRadialGradient::focalPoint () const

Returns the focal point of this radial gradient in logical coordinates.

See also setFocalPoint() and QGradient::stops().

### qreal QRadialGradient::radius () const

Returns the radius of this radial gradient in logical coordinates.

See also setRadius() and QGradient::stops().

### void QRadialGradient::setCenter ( const QPointF & center )

Sets the center of this radial gradient in logical coordinates to center.

This function was introduced in Qt 4.2.

See also center().

### void QRadialGradient::setCenter ( qreal x, qreal y )

This is an overloaded member function, provided for convenience.

Sets the center of this radial gradient in logical coordinates to (x, y).

This function was introduced in Qt 4.2.

See also center().

### void QRadialGradient::setFocalPoint ( const QPointF & focalPoint )

Sets the focal point of this radial gradient in logical coordinates to focalPoint.

This function was introduced in Qt 4.2.

See also focalPoint().

### void QRadialGradient::setFocalPoint ( qreal x, qreal y )

This is an overloaded member function, provided for convenience.

Sets the focal point of this radial gradient in logical coordinates to (x, y).

This function was introduced in Qt 4.2.

See also focalPoint().

### void QRadialGradient::setRadius ( qreal radius )

Sets the radius of this radial gradient in logical coordinates to radius

This function was introduced in Qt 4.2.

See also radius().