Using doc-view-mode on Mac OS X

Included with emacs 23 is a new feature called DocView, which lets you view PDF, PS, and DVI files (via conversion to PNG) directly in emacs. However, it does not work on Mac OS X out of the box. If you try to open a PDF, you get an error of the form "No PNG support available or some conversion utility for pdf files is missing."

There seems to be little information on the web about this, but if you read the file header, it tells you what you need:

doc-view.el requires GNU Emacs 22.1 or newer. You also need Ghostscript, `dvipdf' (comes with Ghostscript) or `dvipdfm' (comes with teTeX or TeXLive) and `pdftotext', which comes with xpdf (http://www.foolabs.com/xpdf/) or poppler (http://poppler.freedesktop.org/).

You can install these via MacPorts:

sudo port install ghostscript xpdf

Then you must restart emacs to get DocView to register the availability of the new commands.