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QGraphicsOpacityEffect Class Reference
[QtGui module]

The QGraphicsOpacityEffect class provides an opacity effect. More...

 #include <QGraphicsOpacityEffect>

Inherits QGraphicsEffect.

This class was introduced in Qt 4.6.

• List of all members, including inherited members

Properties

• opacity : qreal
• opacityMask : QBrush

• 1 property inherited from QGraphicsEffect
• 1 property inherited from QObject

Public Functions

• 3 public functions inherited from QGraphicsEffect
• 29 public functions inherited from QObject

Public Slots

• 2 public slots inherited from QGraphicsEffect
• 1 public slot inherited from QObject

Signals

• 1 signal inherited from QGraphicsEffect
• 1 signal inherited from QObject

Reimplemented Protected Functions

• 7 protected functions inherited from QGraphicsEffect
• 7 protected functions inherited from QObject

Additional Inherited Members

• 5 static public members inherited from QObject
• 7 protected functions inherited from QGraphicsEffect
• 7 protected functions inherited from QObject

Detailed Description

The QGraphicsOpacityEffect class provides an opacity effect.

An opacity effect renders the source with an opacity. This effect is useful for making the source semi-transparent, similar to a fade-in/fade-out sequence. The opacity can be modified using the setOpacity() function.

By default, the opacity is 0.7.

See also QGraphicsDropShadowEffect, QGraphicsBlurEffect, and QGraphicsColorizeEffect.

Property Documentation

opacity : qreal

This property holds the opacity of the effect.

The value should be in the range of 0.0 to 1.0, where 0.0 is fully transparent and 1.0 is fully opaque.

By default, the opacity is 0.7.

Access functions:

Notifier signal:

See also setOpacityMask().

opacityMask : QBrush

This property holds the opacity mask of the effect.

An opacity mask allows you apply opacity to portions of an element.

For example:

 ...
 QLinearGradient alphaGradient(rect.topLeft(), rect.bottomLeft());
 alphaGradient.setColorAt(0.0, Qt::transparent);
 alphaGradient.setColorAt(0.5, Qt::black);
 alphaGradient.setColorAt(1.0, Qt::transparent);
 QGraphicsOpacityEffect *effect = new QGraphicsOpacityEffect;
 effect->setOpacityMask(alphaGradient);
 ...

There is no opacity mask by default.

Access functions:

Notifier signal:

See also setOpacity().

Member Function Documentation

QGraphicsOpacityEffect::QGraphicsOpacityEffect ( QObject * parent = 0 )

Constructs a new QGraphicsOpacityEffect instance. The parent parameter is passed to QGraphicsEffect's constructor.

QGraphicsOpacityEffect::~QGraphicsOpacityEffect ()

Destroys the effect.

void QGraphicsOpacityEffect::draw ( QPainter * painter )   [virtual protected]

Reimplemented from QGraphicsEffect::draw().

void QGraphicsOpacityEffect::opacityChanged ( qreal opacity )   [signal]

This signal is emitted whenever the effect's opacity changes. The opacity parameter holds the effect's new opacity.

void QGraphicsOpacityEffect::opacityMaskChanged ( const QBrush & mask )   [signal]

This signal is emitted whenever the effect's opacity mask changes. The mask parameter holds the effect's new opacity mask.