Customers of the iPad VGA Adapter may be confused with its actual capabilities. Unlike a MacBook or a Mac desktop machine, the iPad with a VGA Adapter won't let the iPad mirror its screen to an external display. At the same time, there are interesting new applications that let Mac users put a part of their desktop on an iPad. On his blog, developer Matt Gemmell reminds readers of the confusion. It's not like Steve Jobs' keynotes where the entire iPad screen is shown on the overhead projector. Instead, it's all about the app showing what it wants to show.
Apps that want to support external display via the adapter must explicitly do so; the developer has to write code to support it. There are some standard iPhone OS-supplied APIs which will automatically do the right thing (such as video playback via standard controllers), but generally you won’t see anything on your external display unless the app you’re using has taken steps to put something there. That's the “bad” (though surely not surprising) news.So, it's up to developers and the application what will be displayed on the external display. If it's a video app, only the video may be presented. The controls, of course, will be visible (and useable) on the iPad. In the other direction, I recently purchased Avatron Software's interesting Air Display, a combination of an iPad app and Mac application that makes the iPad a peripheral of a Mac desktop or MacBook, in this case an extension of the Mac display. The software uses WiFi to link the displays. Avatron has lots of ideas for its use:
Some great uses for Air Display: Fill your iPad screen with your utility apps, like iChat, Mail, iCal, and Calculator. Graphic designers: Make Photoshop and Illustrator usable on your laptop by putting your tool palettes on the iPad screen. Musicians: Use your iPad as the ultimate control surface for Logic or Pro Tools. Programmers: Use the extra display area for such auxiliary development tools as Console, Terminal, and the Debugger. Business professionals: Move all of your iWork and Office palettes and inspector windows onto the iPad, and let your document fill the screen.It works. After downloading both Mac and iPad apps, I was able quickly to link up the displays. I moved my iChat Buddy List over to the iPad. It took my finger input as a click to initiate a chat; the chat window came up on my MacBook Pro display. Check Out: Apps that turn your iPhone/iPod Touch into an external peripheral I could move windows across the gap between the displays, even though the iPad was placed on its back on the desk. It's all virtual.