Among the many new Leopard features are three new iTunes visualizers—Lathe, Jelly, and Stix (choose View -> Visualizer to select a visualizer, then press Command-T to activate the visualizer). Unlike the previous iTunes visualizers, there’s no hidden “H for help” feature to show you these visualizers’ new tricks. But that doesn’t mean they don’t have any tricks.
All three of the new visualizers will display an album info overlay when you press I, and you can see the current frame rate by pressing F. If you’re using Lathe, that’s about it for the special features. Stix has a couple of minor tricks up its sleeve; press the Up Arrow once to add a second (mirror image) stick, and the Down Arrow seems to cycle through a few available speeds. Jelly, though, has the most hidden features. Press the Up or Down Arrow to cycle between seven different jelly styles. If you see one you like, press M to lock it (otherwise iTunes will automatically cycle between all seven styles). When in lock mode, the arrow keys won’t do anything; press M again to unlock Jelly, and you can then use the arrow keys again.
Press and hold 1 or 2, and the center of the current jelly will move farther away or much closer to your viewpoint. Press and hold any combination of 8, 9, and 0 (zero), and you’ll add an extra “glow” to certain areas of the jelly. Press and hold all three, and you may wish you were wearing sunglasses at your desk. All of these number key effects are temporary; they stop as soon as you release the keys.
As a side note/hint, these visualizers are actually Quartz Composer compositions. Quartz Composer is a tool that can create some amazingly interesting visuals, all without writing any code. (Many of the OS X screen savers are also Quartz Composer documents.) You’ll find the Lathe, Jelly, and Stix visualizers in the /System -> Library -> Compositions folder; if you have the Developer Tools installed, double-click one and it will open in Quartz Composer (assuming, again, you have the Developer Tools installed). Here’s what a visualizer looks like when seen in its “code’ form; this happens to be Jelly:
(For a closer view of the visualizer, click the above image to view a portion of it at 100-percent zoom; it’s really got an interesting user interface.)
Because you can open the visualizer in Quartz Composer, this means you can also create your own iTunes visualizers by modifying those provided by Apple. First create a folder named Compositions in your user’s Library folder. Open another Finder window, and copy Lathe.qtz, Jelly.qtz, and Stix.qtz out of the System -> Library Compositions folder into the one you just created. Rename them in the Finder; add “modified” or “version 2” or whatever to their filenames, just so you know you’re working on your copies. Now double-click one of your local copies to open it in Quartz Composer…and that’s where this hint ends!
From here on, you’re on your own, mostly, but here are a couple small tips to get you started. First, use the Viewer button on the right side of the toolbar to see your visualizer in real time. Second, select Editor -> Edit Information, and change the value in the Name field to whatever you like—this is the name that will be visible in iTunes. Finally, all the good info is hiding in the Inspector; press Command-I to display it. Now start double-clicking on elements, and you’ll find values in the Inspector you can change—and the results of your changes will be immediately visible in the Inspector. When you’re done, save your work, launch iTunes, and select your modified visualizer in the View -> Visualizer sub-menu. If you’re really interested in Quartz Composer, Apple has a detailed user manual available online (also as a PDF from that link). Have fun!