What is required to mirror the screen of your application on the iPad?

I'm very confused about the ability of the iPad to mirror the screen contents on an external display.

Until recently, this only worked for applications which supported it. I was never happy with the pe开发者_运维技巧rformance of these solutions in my app unless I use the non-AppStore-safe API UIGetScreenImage(). So I never shipped it to costumers.

What changed with the new iPad 2 and/or iOS 4.3? What is needed to mirror an app (please tick below)? And is there any impact on performance?

[ ] iPad 2
[ ] New HDMI adapter
[ ] iOS 4.3

The iPad 2 has a new, more powerful GPU inside it which allows for the mirroring of the display to an external monitor. This can be done using either the new HDMI output or the existing iPad VGA adapter. Nothing is required in the code of your application to support this.

However, if you had added external display support within your application using something similar to what's discussed in this question, that code will take precedence and your screen will not be mirrored. Application developers who wish to provide external displays on iPhone 4 and iPad may need to implement a preference to disable the custom video output on iPad 2 and newer devices if they want users to be able to mirror on the latter.

[X] iPad 2
[X] iOS 4.3

Mirroring works only on the iPad 2 and thus also only with iOS 4.3. But it also works with the old VGA adapter. Plus: It works right out of the box (or right out of the 30 Pin dock connector thing whatsoever)

However, you can also mirror the screen of iPad 1's using UIKit's UISCreen class (see the mirroredScreen property and its description)

Only the iPad 2 can mirror video (with iOS 4.3 of course). It will mirror video over HDMI or VGA, as per Apple's specs: http://www.apple.com/ipad/specs/