QGraphicsOpacityEffect Class

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

This class was introduced in Qt 4.6.

• List of all members, including inherited members

Properties

• opacity : qreal
• opacityMask : QBrush

Public Functions

Public Slots

Signals

Reimplemented Protected Functions

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.

See also QGraphicsDropShadowEffect, QGraphicsBlurEffect, and QGraphicsColorizeEffect.

...
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);
...

Member Function Documentation

QGraphicsOpacityEffect::QGraphicsOpacityEffect(QObject *parent = nullptr)

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

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

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

Note: Notifier signal for property opacity.

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

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

Note: Notifier signal for property opacityMask.

[virtual] QGraphicsOpacityEffect::~QGraphicsOpacityEffect()

Destroys the effect.

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

Reimplements: QGraphicsEffect::draw(QPainter *painter).