Initiates semantic zoom on the custom control.
This method has no parameters.
On Windows the method does not return a value.
On Windows Phone 8.1, this method returns a Promise object. The control implementing the zoomable view interface is responsible for animating the incoming/outgoing content. The Promise object returned by beginZoom is the promise for that animation, and completes when the animation finishes.
Zooms in or out depending on the value of zoomedOut (defined by configureForZoom).
When calling this method, ensure that:
- Content within the control is not cropped.
- The pages specified by the value of prefetchedPages (defined by configureForZoom) are visible.
- Unnecessary UI controls (such as scroll bars) are hidden.
Minimum WinJS version