CopperSpice API  1.7.2
QGradient Class Reference

The QGradient class is used in combination with QBrush to specify gradient fills. More...

Inheritance diagram for QGradient:
QConicalGradient QLinearGradient QRadialGradient

Public Types

enum  CoordinateMode
 
enum  Spread
 
enum  Type
 

Public Methods

CoordinateMode coordinateMode () const
 
InterpolationMode interpolationMode () const
 
bool operator!= (const QGradient &gradient) const
 
bool operator== (const QGradient &gradient) const
 
void setColorAt (qreal position, const QColor &color)
 
void setCoordinateMode (CoordinateMode mode)
 
void setInterpolationMode (InterpolationMode mode)
 
void setSpread (Spread spread)
 
void setStops (const QGradientStops &stops)
 
Spread spread () const
 
QGradientStops stops () const
 
Type type () const
 

Friends

class QBrush
 
class QConicalGradient
 
class QLinearGradient
 
class QRadialGradient
 

Related Functions

These are not member functions

typedef QGradientStop
 
typedef QGradientStops
 

Detailed Description

The QGradient class is used in combination with QBrush to specify gradient fills.

CopperSpice currently supports three types of gradient fills:

  • Linear gradients interpolate colors between start and end points.
  • Simple radial gradients interpolate colors between a focal point and end points on a circle surrounding it.
  • Extended radial gradients interpolate colors between a center and a focal circle.
  • Conical gradients interpolate colors around a center point.

A gradient's type can be retrieved using the type() function. Each of the types is represented by a subclass of QGradient:

QLinearGradientQRadialGradientQConicalGradient

The colors in a gradient are defined using stop points of the QGradientStop type; i.e., a position and a color. Use the setColorAt() function to define a single stop point. Alternatively, use the setStops() function to define several stop points in one go. Note that the latter function replaces the current set of stop points.

It is the gradient's complete set of stop points (accessible through the stops() function) 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.

A diagonal linear gradient from black at (100, 100) to white at (200, 200) could be specified like this:

QLinearGradient linearGrad(QPointF(100, 100), QPointF(200, 200));
linearGrad.setColorAt(0, Qt::black);
linearGrad.setColorAt(1, Qt::white);

A gradient can have an arbitrary number of stop points. The following would create a radial gradient starting with red in the center, blue and then green on the edges:

QRadialGradient radialGrad(QPointF(100, 100), 100);
radialGrad.setColorAt(0, Qt::red);
radialGrad.setColorAt(0.5, Qt::blue);
radialGrad.setColorAt(1, Qt::green);

It is possible to repeat or reflect the gradient outside its area by specifying the spread method using the setSpread() function. The default is to pad the outside area with the color at the closest stop point. The currently set spread method can be retrieved using the spread() function. The QGradient::Spread enum defines three different methods:

PadSpreadRepeatSpreadReflectSpread

Note that the setSpread() function only has effect for linear and radial gradients. The reason is that the conical gradient is closed by definition, i.e. the conical gradient fills the entire circle from 0 - 360 degrees, while the boundary of a radial or a linear gradient can be specified through its radius or final stop points, respectively.

The gradient coordinates can be specified in logical coordinates, relative to device coordinates, or relative to object bounding box coordinates. The coordinate mode can be set using the setCoordinateMode() function. The default is LogicalMode, where the gradient coordinates are specified in the same way as the object coordinates. To retrieve the currently set coordinate mode use coordinateMode().

See also
QBrush

Member Enumeration Documentation

This enum specifies how gradient coordinates map to the paint device on which the gradient is used.

ConstantValueDescription
QGradient::LogicalMode0This is the default mode. The gradient coordinates are specified logical space just like the object coordinates.
QGradient::StretchToDeviceMode1In this mode the gradient coordinates are relative to the bounding rectangle of the paint device, with (0,0) in the top left corner, and (1,1) in the bottom right corner of the paint device.
QGradient::ObjectBoundingMode2In this mode the gradient coordinates are relative to the bounding rectangle of the object being drawn, with (0,0) in the top left corner, and (1,1) in the bottom right corner of the object's bounding rectangle.

Specifies how the area outside the gradient area should be filled.

ConstantValueDescription
QGradient::PadSpread0The area is filled with the closest stop color. This is the default.
QGradient::RepeatSpread2The gradient is repeated outside the gradient area.
QGradient::ReflectSpread1The gradient is reflected outside the gradient area.
See also
spread(), setSpread()

Specifies the type of gradient.

ConstantValueDescription
QGradient::LinearGradient0Interpolates colors between start and end points (QLinearGradient).
QGradient::RadialGradient1Interpolate colors between a focal point and end points on a circle surrounding it (QRadialGradient).
QGradient::ConicalGradient2Interpolate colors around a center point (QConicalGradient).
QGradient::NoGradient3No gradient is used.
See also
type()

Method Documentation

CoordinateMode QGradient::coordinateMode ( ) const

Returns the coordinate mode of this gradient. The default mode is LogicalMode.

See also
setCoordinateMode()
InterpolationMode QGradient::interpolationMode ( ) const

Property documentation pending.

bool QGradient::operator!= ( const QGradient &  gradient) const
inline

Returns true if the gradient is the same as the other gradient specified, otherwise returns false.

See also
operator==()
bool QGradient::operator== ( const QGradient &  gradient) const

Returns true if the gradient is the same as the other gradient specified, otherwise returns false.

See also
operator!=()
void QGradient::setColorAt ( qreal  position,
const QColor color 
)

Creates a stop point at the given position with the given color. The given position must be in the range 0 to 1.

See also
setStops(), stops()
void QGradient::setCoordinateMode ( CoordinateMode  mode)

Sets the coordinate mode of this gradient to mode. The default mode is LogicalMode.

See also
coordinateMode()
void QGradient::setInterpolationMode ( InterpolationMode  mode)

Property documentation pending.

void QGradient::setSpread ( Spread  spread)
inline

Specifies the spread method that should be used for this gradient. This method only has effect for linear and radial gradients.

See also
spread()
void QGradient::setStops ( const QGradientStops stops)

Replaces the current set of stop points with the given stops. The positions of the points must be in the range 0 to 1, and must be sorted with the lowest point first.

See also
setColorAt(), stops()
Spread QGradient::spread ( ) const
inline

Returns the spread method use by this gradient. The default is PadSpread.

See also
setSpread()
QGradientStops QGradient::stops ( ) const

Returns the stop points for this gradient.

If no stop points have been specified, a gradient of black at 0 to white at 1 is used.

See also
setStops(), setColorAt()
Type QGradient::type ( ) const
inline

Returns the type of gradient.

Friends And Related Function Documentation

typedef QGradientStop ( )
related

Typedef for QPair<qreal, QColor>.

typedef QGradientStops ( )
related

Typedef for QVector<QGradientStop>.