QGraphicsOpacityEffect Class

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

Header:	#include <QGraphicsOpacityEffect>
qmake:	QT += widgets
Since:	Qt 4.6
Inherits:	QGraphicsEffect

This class was introduced in Qt 4.6.

List of all members, including inherited members

Properties

opacity : qreal
opacityMask : QBrush

Public Functions

qreal	opacity() const
QBrush	opacityMask() const

Public Slots

void	setOpacity(qreal opacity)
void	setOpacityMask(const QBrush &mask)

Signals

void	opacityChanged(qreal opacity)
void	opacityMaskChanged(const QBrush &mask)

Detailed Description

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.

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:

qreal	opacity() const
void	setOpacity(qreal opacity)

Notifier signal:

void	opacityChanged(qreal opacity)

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.