I resolved it.

It because of RenderTarget.

I rollback it to default value.

@mdma2
Can you post the full code of this short example, so that it can be tried out immediately using simple copy/paste...

As I now understand it there is no easy way to recognize gestures inside the c++ part of a Qt Quick 'QQuickPaintedItem' inherited class, is that correct?

I need both pan and pinch in my c++ class so if i dont want to write my own recognition code should I then inherit my class from both 'QQuickPaintedItem', PinchArea and Flickable? that doesn't seem right? (besides that they are declared in private header files like qquickpincharea_p.h)

found the same request (also without an statisfying answer here:
https://forum.qt.io/topic/61108/recognize-arbitrary-gestures-in-qt5-like-gesturearea-in-qt4 )

Hi @gs_chris It looks very close to the warning here.

Warning: Resizing a framebuffer object is a costly operation, avoid using the QQuickPaintedItem::FramebufferObject render target if the item gets resized often.

@benlau said:

Finally , I can not find any way to fix with QQuickPaintedItem. I just changed to use QQuickItem.

Hi, thank you for your response. Since you used QQuickItem instead, did you used updatePaintNode() in painting and didn't used QPainter?

Can you please provide me a simple code in implementing QQuickItem?
Actually, I tried creating rectangles using QSGGoemetryNode however i can't find any example on how to draw text using QSG without using QPainter.
Sorry i'm still new to integrating c++ in QML. TIA.

@p3c0 nice job!