how to disable pinch/zoom resizing of full screen browser?

How can I prevent pinch/zoom from resizing a fullscreen browser? I'd like to disable both operations so the browser always occupies the full screen (like a kiosk) and pinch/zoom only work within web pages that support them such as map sites. Any suggestions? Note that my screen size is 800x600 so I set the minimum contents width to 800 below.

import QtQuick 2.0
import QtWebKit 3.0
import QtQuick.Controls 1.3
import QtWebKit.experimental 1.0
ApplicationWindow {
visible: true
visibility: "Maximized"
WebView {
anchors.fill: parent
experimental.preferredMinimumContentsWidth: 800
experimental.preferences.fullScreenEnabled: true
experimental.preferences.developerExtrasEnabled: true
url: "file:///path/to/index.html"
}
}