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com.trolltech.qt.gui
Class QGradient

java.lang.Object
  extended by com.trolltech.qt.QSignalEmitter
      extended by com.trolltech.qt.QtJambiObject
          extended by com.trolltech.qt.gui.QGradient
All Implemented Interfaces:
QtJambiInterface
Direct Known Subclasses:
QConicalGradient, QLinearGradient, QRadialGradient

public abstract class QGradient
extends QtJambiObject

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

Qt currently supports three types of gradient fills:

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 is 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 specifiying 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.

See Also:
Gradients Demo, QBrush

Nested Class Summary
static class QGradient.CoordinateMode
          This enum specifies how gradient coordinates map to the paint device on which the gradient is used.
static class QGradient.Spread
          Specifies how the area outside the gradient area should be filled.
static class QGradient.Type
          Specifies the type of gradient.
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
QSignalEmitter.Signal0, QSignalEmitter.Signal1<A>, QSignalEmitter.Signal2<A,B>, QSignalEmitter.Signal3<A,B,C>, QSignalEmitter.Signal4<A,B,C,D>, QSignalEmitter.Signal5<A,B,C,D,E>, QSignalEmitter.Signal6<A,B,C,D,E,F>, QSignalEmitter.Signal7<A,B,C,D,E,F,G>, QSignalEmitter.Signal8<A,B,C,D,E,F,G,H>, QSignalEmitter.Signal9<A,B,C,D,E,F,G,H,I>
 
Constructor Summary
QGradient()
          
 
Method Summary
 QGradient.CoordinateMode coordinateMode()
          
 boolean equals(java.lang.Object other)
          
static QGradient fromNativePointer(QNativePointer nativePointer)
          This function returns the QGradient instance pointed to by nativePointer
static QNativePointer nativePointerArray(QGradient[] array)
          This function returns a QNativePointer that is pointing to the specified QGradient array.
 void setColorAt(double pos, QColor color)
          Creates a stop point at the given pos with the given color.
 void setCoordinateMode(QGradient.CoordinateMode mode)
          
 void setSpread(QGradient.Spread spread)
          Specifies the spread spread that should be used for this gradient.
 void setStops(java.util.List<QPair<java.lang.Double,QColor>> stops)
          Replaces the current set of stop points with the given stops.
 QGradient.Spread spread()
          Returns the spread method use by this gradient.
 java.util.List<QPair<java.lang.Double,QColor>> stops()
          Returns the stop points for this gradient.
 QGradient.Type type()
          Returns the type of gradient.
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread
 
Methods inherited from class java.lang.Object
clone, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Constructor Detail

QGradient

public QGradient()

Method Detail

coordinateMode

public final QGradient.CoordinateMode coordinateMode()

See Also:
setCoordinateMode

setColorAt

public final void setColorAt(double pos,
                             QColor color)

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

See Also:
setStops, stops

setCoordinateMode

public final void setCoordinateMode(QGradient.CoordinateMode mode)

See Also:
coordinateMode

setSpread

public final void setSpread(QGradient.Spread spread)

Specifies the spread spread that should be used for this gradient.

Note that this function only has effect for linear and radial gradients.

See Also:
spread

setStops

public final void setStops(java.util.List<QPair<java.lang.Double,QColor>> 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.


spread

public final QGradient.Spread spread()

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

See Also:
setSpread

stops

public final java.util.List<QPair<java.lang.Double,QColor>> stops()

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

public final QGradient.Type type()

Returns the type of gradient.


fromNativePointer

public static QGradient fromNativePointer(QNativePointer nativePointer)
This function returns the QGradient instance pointed to by nativePointer

Parameters:
nativePointer - the QNativePointer of which object should be returned.

nativePointerArray

public static QNativePointer nativePointerArray(QGradient[] array)
This function returns a QNativePointer that is pointing to the specified QGradient array.

Parameters:
array - the array that the returned pointer will point to.
Returns:
a QNativePointer that is pointing to the specified array.

equals

public boolean equals(java.lang.Object other)

Overrides:
equals in class java.lang.Object

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