Unsolved QML and cpp:QQuickPaintedItem paint pincharea on android

[zenghsing]

I want to use the most simple code to implement multi-touch for resizing and moving my object.
QQ.qml

QuickPaintedStitch{//here and
        id:widgetStitch
        //anchors.fill:parent
        x:0
        z:-1
        y:imgTop.height
        width: parent.width
        height: parent.height-y-imgThreadBackground.height
        //objectName:"mPreviewStitch"
        PinchArea{
            anchors.fill: parent
            pinch.target:widgetStitch
            pinch.minimumScale: 1
            pinch.maximumScale: 3
            pinch.dragAxis: Pinch.XAndYAxis
            onPinchUpdated:
            {
                widgetStitch.setCanRePaint(false);
            }
        }
    }

quickpaintedstitch.cpp for widgetStitch
/*
I find the strange thing will occur when I only use the code of "bCanRePaint=true" after using pincharea.

Hence, I add the code of "bCanRePaint=false " for pincharea.

But there are another strange thing will occur when I only use the code after using pincharea.

The image will be trimed for the top part when I move the image up to down by using two finger.

(
I capture a screenshot in below link.

In my screenshot ,
the top row is move my image from top to down by using two fingers and

the bottom row is move my image from down to top by using two fingers.
)
https://drive.google.com/file/d/0ByVRIO9rYFrJQU91ZVZnSDZTa0U/view?usp=sharing
Why?

*/

void QuickPaintedStitch::paint(QPainter *painter)
{
    if(bCanRePaint){
        QPainterPath BodyPath;
        BodyPath.addRect(0, 0, this->width(), this->height());
        if(gClass.getBShowMessage()){
            painter->fillPath(BodyPath, QBrush(Qt::yellow));
            painter->fillRect(this->x(),this->y(),this->width(),this->height(),Qt::yellow);
        }
        this->DrawHoop(painter);
        this->GraphicsData_Draw(painter);
        if(connectData.stitchFile!=0 && bPreviouStitchIconFinised==false){
            bPreviouStitchIconFinised=true;
            emit sendStitchIconFinished();
        }
        painter->end();
    }else{
      QRect imgRect=  QRect((this->width() - this->connectData.EmbImage->width()) / 2, (this->height() - this->connectData.EmbImage->height()) / 2,
                       this->connectData.EmbImage->width(), this->connectData.EmbImage->height());
        painter->drawImage(imgRect, *this->connectData.EmbImage);

    }

}

[zenghsing]

@zenghsing
There are something I found.

1.I find the trimmed area is
because of "this->height() < this->connectData.EmbImage->height()".
EX:
this->height()=400
this->connectData.EmbImage->height()=410
Then the top pixels will being delete...

2.The resize center always being in the center of object.
How to set resized center to the center OF MY TWO FINGERS ?