Hi Riccardo, Fredrik has answered this one on techbase:
http://techbase.kde.org/Development/Tutorials/Graphics/Performance#QPainter::setOpacity.28.29 Regards, Robert. 2008/9/20 Riccardo Iaconelli <[EMAIL PROTECTED]>: > hello, > so, I have the following code: > > QPixmap temp = *d->p; > QPainter p(&temp); > p.setCompositionMode(QPainter::CompositionMode_Source); > p.drawPixmap(0, 0, *d->p); > p.setCompositionMode(QPainter::CompositionMode_DestinationIn); > p.fillRect(temp.rect(), QColor(0, 0, 0, qreal(d->frame)*5.0/100.0)); > p.end(); > painter->drawPixmap(d->optV4.rect, temp); > > where d->p is a cached pixmap of an expensive operation obtained through > manipuladig a QImage, and shouldn't be changed for this reason. > I was wondering if that's the best approach (which requires a pixmap copy) or > it's faster to call painter->setOpacity and then drawPixmap. > > As my knowledge of the inner Qt painting system is not so wide, I'm asking > here. =) > > if you have questions, or need more code, please ask. > > Bye, > -Riccardo > p.s. aye, that's raptor code, if someone wants more context (not sure if it's > needed) > -- > GPG key: > 3D0F6376 > When encrypting, please encrypt also for this subkey: > 9EBD7FE1 > ----- > Pace Peace Paix Paz Frieden Pax Pokój Friður Fred Béke 和平 > Hasiti Lapé Hetep Malu Mир Wolakota Santiphap Irini Peoch שלום > Shanti Vrede Baris Rój Mír Taika Rongo Sulh Mir Py'guapy 평화 > > _______________________________________________ > Plasma-devel mailing list > Plasma-devel@kde.org > https://mail.kde.org/mailman/listinfo/plasma-devel > _______________________________________________ Plasma-devel mailing list Plasma-devel@kde.org https://mail.kde.org/mailman/listinfo/plasma-devel
