QML, How to tell the Item rendered size after scale - qt

Question

So I have an Image inside a Flickable. I want to know the size of the image after the scale is applied so that I can assign it to the Flickable's contentWidth and contentHeight. Is there a way to get the size after the scale has been applied?
Flickable{
contentWidth: target.width
contentHeight: target.height
Image{
id: target
horizontalAlignment: Image.AlignLeft
verticalAlignment: Image.AlignTop
fillMode: Image.PreserveAspectFit
scale: slider_bar.value
source: "/image.png"
}
}
Slider{
id: slider_bar
from: 0
to : 2
value: 1
}
Another example is where I want to make the rect_1 large and the rect_2 to stay to the right of it. When running the following rect_1 resizes but rect_2 does not move.
Rectangle{
id:rect_1
height: 100
width: 100
scale: slider_bar.value
transformOrigin: Item.TopLeft
color: "green"
}
Rectangle{
id: rect_2
anchors.left: rect_1.right
height: 100
width: 100
color:"red"
}
Slider{
id: slider_bar
from: 0
to : 2
value: 1
}
I could do something like
ScaledItem.qml
Item{
height: implicitHeight
width:implicitWidth
implicitHeight: childrenRect.height * scale
implicitWidth: childrenRect.width * scale
scale:1
}
then
ScaledItem{
scale: slider_bar.value
transformOrigin: Item.TopLeft
id:rect_1
Rectangle{
height: 100
width: 100
color: "green"
}
}
Rectangle{
anchors.left: rect_1.right
height: 100
width: 100
color:"red"
}
Slider{
id: slider_bar
from: 0
to : 2
value: 1
}