I have an issue with QGraphicsOpacityEffect::setOpacityMask(const QBrush & mask) the mask is a pixmap set with QBrush::(const QPixmap & pixmap) it contains a gradient Qt::black to Qt::transparent. On windows the black part is transparent and the transparent part is opaque with the mask applied, as it should be.

On Ubuntu Lucid 10.4 and also with maemo with the latest qtsdk-2010.04 and latest NokiaSDK black is not 100% transparent and transparent is not 100% opaque. It seems to be the default opacity value (0.7) that gets applied to the mask it self. I tried to fix it with setting opacity to (1.0) before and after setting the mask. Result is that the black area is as it should 100% transparent, but the transparent area is totally black with the mask applied.

QGraphicsOpacityEffect *effect_opacity = new QGraphicsOpacityEffect;
effect_opacity->setOpacityMask(QBrush(opacity_mask));
//effect_opacity->setOpacity(1.0);