Canvas Seems Buggy

HI , 

  Im trying to use the QtQuick.Canvas 

Canvas{

   id: mCanvas 

    onAvailableChanged:{

        if(available){

             var context= getContext('2d')

             context.drawImage(image, 0,0)  //works  here then i want to get the data that has been drawn 

             var data = context.getImageData(0,0,20,20) // returns   [object object] but when i check or serialize it only returns empty = {} 

             }

    }

}

Canvas{} = works 

but methods from there seems still buggy 

i tried getImageData, drawImage and putImageData , others are not yet tested 

drawImage works as expected but when using getImageData returns {} 

and unable to use putImageData due to CanvasImageData is unknown component , 

as per document CanvasImageData is part of QtQuick 

but Qt did not find it when trying to use it .

it says unknown component