I am not able to see any image with following code

Qt Enthusiast

Hi All
I have following code ,

class myModel: public QAbstractItemModel {
}

2 ) QtreeView is using this model

QVariant myModel::data() {
case Qt::DecorationRole:
if (index.column() == 0) {
QPixmap pixmap(10,10);
/* icon for transparent color*/
pixmap.fill(QColor(0,0,0,0));
QIcon icon(pixmap);
return icon;
}
}

If my QtreeView has white background , I cannot see anything . Could you let me know why I cannot see anything ., I have to have transparent color image box on white background .What to do ?

raven-worx

@Qt-Enthusiast said in I am not able to see any image with following code:

If my QtreeView has white background , I cannot see anything

what does that mean? What are you expecting?
You fill it transparent on purpose :)

Qt Enthusiast

I wanted to see some box with a boundary and white background like a transparent box

raven-worx

@Qt-Enthusiast
then you need to draw a border inside the transparent pixmap?

Qt Enthusiast

can u please code ?

raven-worx

@Qt-Enthusiast

const int QSize iconSize(10,10);

QPixmap pixmap(iconSize);
pixmap.fill(Qt::transparent);

QPen pen(Qt::red, 1.0);

QPainter p(&pixmap);
p.setBrush( Qt::NoBrush );
p.setPen( pen );
const int correctionTopLeft = qFloor( pen.width()/2.0 );
const int correctionBottomRight = -qCeil( pen.width()/2.0 );
p.drawRect( QRect(QPoint(0,0),iconSize).adjusted(correctionTopLeft,correctionTopLeft,correctionBottomRight,correctionBottomRight) );
p.end();
...

But i suggest instead of doing the painting every time the decoration role is requested you should use a PNG file instead or at least create the Ppxmap only once and cache/re-use it when needed.