But, on resize, even though boundingbox is large enough to show text but text becomes hidden. Text visibility becomes inconsistent. I started to look into QTextDocument pointer returned from document() function. I think in QTextDocument also may need some changes for bounding box. Is this approach correct or you have any different idea ?

Is there any function in QGraphicsTextItem, QTextDocument or QAbstractTextDocumentLayout which can change bounding-rect x and y values ?

Is that what you question is? Then, yes, subclass QGraphicsTextItem and override QRectF QGraphicsTextItem::boundingRect() const to return whatever you want. It has always been the case that you can do do this for any QGraphicsItem if you need to specify a bounding rectangle different from the shape's rectangle.

There's no direct equivalent. You have setTextWidth that allows you to influence that dimension and the height will be adapted.

If you want more control like "forcing the text within the bound of a particular rectangle, you'll have to implement that yourself.

Let's say a QGraphicsRectItem is at (x,y) position. When QGraphicsRectItem gets resized, i get new bounding box value. This boundingbox value is given to setRect() of QGraphicsRectItem, to make it larger/smaller. I don't change (x,y) position of the rectangle.

Assume i resize using top-left corner of QGraphicsRectItem. In this case, position of item changes along with resize. Here also, i can set boundingbox value to setRect() function which resize and changes position of item.

I want QGraphicsRectItem setRect() equivalent for QGraphicsTextItem

Then how do i move QGraphicsTextItem to new position ?

I don't really understand what you are asking, but every graphics item inherits void QGraphicsItem::setPos(const QPointF &pos).