[solved] How to work with masks in QPainter?

sheepy

Hello,
I'm using Qt.5.3 and want to work with masks on a QImage to fill a region with a specific color.

My mask is a 1Bit QImage (Mono).

i thought, that i can handle this like:

@
QPainter overlayPainter(&overlayClusters);
QPixmap pixmap = QPixmap::fromImage(maskForegroundByUser);
overlayPainter.setClipRegion(QRegion(pixmap));
overlayPainter.fillRect(overlayClusters.rect(),brush);
@

but i can't create a QRegion from a QPixmap.

Can someone help me?

//EDIT
This solution works and has good performance:
@
QPainter overlayPainter(&image);
QBitmap bitmap = QBitmap::fromImage(mask); //mask is a QImage with the format Mono
QRegion regionMask(bitmap);
overlayPainter.setClipRegion(regionMask);
overlayPainter.setCompositionMode(QPainter::CompositionMode_SourceOver);
QBrush brush(Qt::blue,Qt::SolidPattern);
overlayPainter.fillRect(image.rect(),brush);
@
Greetings

SGaist

Hi,

I haven't played with mask yet, but from the doc you can make a QBitmap from your maskForegroundByUser to use with setClipRegion

Hope it helps

sheepy

Thanks,
I thought about it, too. Now I see, that the QBitmap have a finction called "fromImage()".

That works!

SGaist

Good !

Since your mask is working now, please update the thread title prepending [solved] so other forum users may know a solution has been found :)