SpringBoardPlugins serve many purposes, but here is the two of them:
- Supporting “ZoomTouch”, the accessibility feature that magnifies the screen by two to five times.
- Supporting lock screen bundles, such as the Nike and iPod lockscreens. This is the basis of Cydget. See /System/Library/SpringBoardPlugins on TheiPhoneWiki for a list.
Lock screen bundles have been supported starting in 2.1, and ZoomTouch starting in 3.0.
Structure of ZoomTouch bundle
The ZoomTouch bundle must be named ZoomTouch.bundle. The principal class should implement the +disableZoom and +enableZoom methods.
ZoomTouch is the only non-lockscreen plugin. As such, it is hard-coded into SpringBoard.
... // Inside SpringBoard [(SpringBoard *)[UIApplication sharedApplication] setZoomTouchEnabled:YES]; ...
Structure of lock screen bundles
A lock screen bundle must have an extension of .bundle. The principle class should implement the +rootViewController method, and returns an SBAwayViewPluginController.
Enabling lock screen bundles
Lock screen bundles can be toggled using SpringBoardServices's SBEnableLockScreenBundle() function outside of SpringBoard, and SBAwayController's -enableLockScreenBundleWithName: and -disableLockScreenBundleWithName: within SpringBoard. When called outside of SpringBoard, the binary must have the com.apple.springboard.activateawayviewplugins entitlement.
- Apple - Accessibility - iPhone - Vision http://www.apple.com/accessibility/iphone/vision.html