Index

Symbols

@ (at) symbol, 53, 65

^ (caret), 85

+ (plus sign), 137

A

acceleration

detecting shakes with, 683-686

locating “up,” 668-672

basic orientation, 671-672

calculating relative angle, 671

catching acceleration events, 669

retrieving current accelerometer angle synchronously, 670

moving onscreen objects, 672-676

accelerometer key, 663

accelerometer:didAccelerate: method, 668

AccelerometerHelper, 683-686

accessing AVFoundation camera, 359-368

building camera helper, 367-368

camera previews, 364

establishing camera session, 361-363

EXIF, 365

image geometry, 365-367

laying out camera previews, 364-365

querying and retrieving camera, 360-361

requiring cameras, 360

switching cameras, 363

accounts, GitHub

action sheets. See also alerts

creating, 646-648

displaying text in, 648-649