QGraphicsOpacityEffect Class
The QGraphicsOpacityEffect class provides an opacity effect. More...
| Header: | #include <QGraphicsOpacityEffect> |
| CMake: | find_package(Qt6 REQUIRED COMPONENTS Widgets) target_link_libraries(mytarget PRIVATE Qt6::Widgets) |
| qmake: | QT += widgets |
| Inherits: | QGraphicsEffect |
Properties
- opacity : qreal
- opacityMask : QBrush
Public Functions
| QGraphicsOpacityEffect(QObject *parent = nullptr) | |
| virtual | ~QGraphicsOpacityEffect() |
| 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) |
Reimplemented Protected Functions
| virtual void | draw(QPainter *painter) override |
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.
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.
Access functions:
| QBrush | opacityMask() const |
| void | setOpacityMask(const QBrush &mask) |
Notifier signal:
| void | opacityMaskChanged(const QBrush &mask) |
See also setOpacity().
Member Function Documentation
QGraphicsOpacityEffect::QGraphicsOpacityEffect(QObject *parent = nullptr)
Constructs a new QGraphicsOpacityEffect instance. The parent parameter is passed to QGraphicsEffect's constructor.
[virtual noexcept] QGraphicsOpacityEffect::~QGraphicsOpacityEffect()
Destroys the effect.
[override virtual protected] void QGraphicsOpacityEffect::draw(QPainter *painter)
Reimplements: QGraphicsEffect::draw(QPainter *painter).
[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.