The QGraphicsOpacityEffect class provides an opacity effect. More...
#include <QGraphicsOpacityEffect>
Inherits: QGraphicsEffect.
This class was introduced in Qt 4.6.
QGraphicsOpacityEffect ( QObject * parent = 0 ) | |
~QGraphicsOpacityEffect () | |
qreal | opacity () const |
QBrush | opacityMask () const |
void | setOpacity ( qreal opacity ) |
void | setOpacityMask ( const QBrush & mask ) |
void | opacityChanged ( qreal opacity ) |
void | opacityMaskChanged ( const QBrush & mask ) |
virtual void | draw ( QPainter * painter ) |
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.
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().
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().
Constructs a new QGraphicsOpacityEffect instance. The parent parameter is passed to QGraphicsEffect's constructor.
Destroys the effect.
Reimplemented from QGraphicsEffect::draw().
This signal is emitted whenever the effect's opacity changes. The opacity parameter holds the effect's new opacity.
This signal is emitted whenever the effect's opacity mask changes. The mask parameter holds the effect's new opacity mask.