We’re spending a few weeks letting some of the marquee features of Mac OS X “Leopard” out of the bag.  This week I get to describe to you my favorite (and to date most used) facet of the latest and greatest update to the Mac operating system.  It’s called Quick Look.

In many ways it’s the simplest of the new features, but underlying Quick Look’s simple interface are two of Leopard’s powerful “core technologies” – Core Graphics and Core Animation.  These core technologies leverage the power of modern graphics processing units (GPUs).  We used to call them “video cards” or “video RAM”, but today’s GPUs are little computers unto themselves with both processors and memory.  The job of the GPU is to take over intensive image and video processing tasks to free up the computer’s main processor(s) to handle the heavy number crunching.  All right, that’s enough techno babble.  Let’s get back to the Leopard feature at hand.

Quick Look, as the name implies, gives Leopard users the ability to see the contents of almost any file on their Mac, without having to open the application that created it or is otherwise used to view it.  Here’s how it works.

Simply select a file in any of Leopard’s four view modes (you remember – Icon, List, Column, and Cover Flow) by single-clicking it.  Double-clicking the file would, of course, open the file in the application that created it, or is otherwise used to view it.  But that’s so 2005, so Windows Vista, so outdated, so arcane.  So, you single-click to select the file, then either press the Space Bar or click the Cover Flow button in the Finder window toolbar.

Voila!  The file “opens” in a floating window, which can be moved around on the desktop and resized.  There’s even a button on the window to show the contents in full screen mode.  If you select multiple files and invoke Quick Look, you can choose to see small thumbnails of the files on an Index Sheet and then select an individual file for closer inspection.  Scroll through MS Word or PDF documents with multiple pages.  Scrub through full-screen video and audio files to move forward or back in a movie or song.  Click a “Play” button and run a full-screen slideshow of a group of selected images.  Step through a Keynote or PowerPoint presentation, or scroll through an Excel or Numbers spreadsheet.  All without opening the associated application.

If you’re using Quick Look to view a text or PDF file containing a URL, clicking the link opens Safari and displays the web page.  Nice.

To close the Quick Look window, simply press the Space Bar again.  If you want to open the file fully in it’s associated application, simply double-click the file in the Quick Look window. 

Quick Look uses a plug-in architecture, so it’s extensible (a techie term for “you can make it do more stuff later”).  In other words, developers can add Quick Look capability to other applications and file formats.  Quick Look is already built into Apple’s Mail application.  Click one button and see all the attached files in an email, then click another button to put, say, all the images into iPhoto.  Cool.

Speaking of formats, Quick Look already has built-in coverage for virtually any type of image file, text file (including MS Word), presentation, video, or audio file you may use or stumble upon.  Having said that, I found that Quick Look currently won’t display the contents of AppleWorks documents (which would be nice if it did) or RealPlayer media files (which is just as well).