This sample page is a simple app using the GeoExt printing control to test installation of the GeoServer printing module. This module wraps the Mapfish print module. See also the GeoServer Manual for more information about the manual. If the viewer on this page fails to load, then you have not properly installed the extension.
The rectangle and handles on the map can be used to change center, scale and rotation. Dragging one of the handles will change the scale. Dragging the corner handles on their edges will rotate the extent, if supported by the layout. Holding the SHIFT key will constrain rotation to 45° steps.
See http://dev.geoext.org/extensions/geoext.ux/ux/SimplePrint/examples/SimplePrint.js for the source code.