QML is clever enough to re-evaluate the function when item.rotation or dimensions change.

In D9460#182139, @dvratil wrote:

QML is clever enough to re-evaluate the function when item.rotation or dimensions change.

Not if it's within _transformedSize()

In D9460#182151, @apol wrote:

In D9460#182139, @dvratil wrote:

QML is clever enough to re-evaluate the function when item.rotation or dimensions change.

Not if it's within _transformedSize()

It actually does, since the function depends on the object. Try running this and resize the window:

import QtQuick 2.0

Rectangle {
    id: root
    anchors.fill: parent
    color: "red"

    function f(item) {
        if (item.width > 1000) {
            console.log("Wide");
        } else {
            console.log("Narrow");
        }
        return 0
    }

    rotation: f(root)
}