function zoomIn( 
   factor : number
) : (Any);

var resultVar = instanceOfPageView.zoomIn(number);

Parameters

factor

Use this parameter to indicate how much to zoom in on the image. The value should be greater than 1 because 1 indicates no zooming. A value of 2 indicates the image should double in size. Typically, you should use a value between 1.25 and 1.75.

Zooms in on the current image, while keeping the portion of the image at the center of the viewer remaining in the same location.

Reference