You can change the settings of output media with the "Settings" dialog. Open this dialog by choosing "Settings..." from the "Edit" menu. There are three major sections:
Page Size lets you set the size of the 'logical' page. This is the size that the PostScript file works with.
Scaling lets you enlarge or reduce the 'logical' page to produce the actual output you see. This scaling happens conceptually after the page is printed. However, Ghostscript is aware of this final scaling and will adjust some parameters accordingly (such as halftone screen, or any other parameters that are in 'device coordinates').
Image Options let you select options that pertain to how the image is rendered and recorded.
For example, if you want to render a document that was designed for a Letter size paper, but you want the output to be reduced to half size, then choose "US Letter" for the Page Size and "Half" for the Scaling.
There are too many controls and options in this dialog to discuss here: Turn on balloon help and explore it!
The options apply to all devices (see below), except Image Options which only apply to the 'mac' device.
