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//! [0]
MyGraphicsOpacityEffect::draw(QPainter *painter, QGraphicsEffectSource *source)
{
// Fully opaque; draw directly without going through a pixmap.
if (qFuzzyCompare(m_opacity, 1)) {
source->draw(painter);
return;
}
...
}
//! [0]
//! [1]
MyGraphicsEffect::draw(QPainter *painter, QGraphicsEffectSource *source)
{
...
QPoint offset;
if (source->isPixmap()) {
// No point in drawing in device coordinates (pixmap will be scaled anyways).
const QPixmap pixmap = source->pixmap(Qt::LogicalCoordinates, &offset);
...
painter->drawPixmap(offset, pixmap);
} else {
// Draw pixmap in device coordinates to avoid pixmap scaling;
const QPixmap pixmap = source->pixmap(Qt::DeviceCoordinates, &offset);
painter->setWorldTransform(QTransform());
...
painter->drawPixmap(offset, pixmap);
}
...
}
//! [1]
//! [2]
...
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);
...
//! [2]
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