colinta / avclub

I've been pouring over the AVCam sample code from Apple, and I think I've finally gotten my head around it enough to generalize it and, I hope, repackage it for our benefit!

You can setup an AVCaptureSession with video, multiple cameras, and still image capabilities. You can also easily have touch-to-focus and flash-on-picture features. Just by implementing a few actions and delegate methods. I'm calling it "AVClub".

Really, the code is largely unchanged from the sample code - if you've seen it, I just moved more code into the Manager class, and renamed "AVCamManager" to "AVClub", since that's the central "wrapper" class.

This tool - and AVFoundation in general - is much more low level than the UIImagePickerController (see Camera Programming Topics for iOS). If you're looking for an easy off-the-shelf solution, use BubbleWrap::Camera or an instance of UIImagePickerController.

Working with AVFoundation is like holding a dozen loose wires, plugging them all into each other, and hoping that a photo or video comes out the end. If it goes wrong, lemme know.

The basic process is this:

Create a view-finder, for where you want the preview image to appear. Or don't, it's optional.

1. Create a "club" - AVClub.new.
2. Assign your controller as the delegate - club.delegate = self.
3. When you're ready, pass the view-finder to AVClub: club.startInView(viewfinder_view). You can start and stop the session by calling club.stopSession ; club.startSession

def viewDidLoad
  @video_view = UIView.alloc.initWithFrame([[10, 10], [100, 100]])  # an AVCaptureVideoPreviewLayer will be added to this view
  club = AVClub.new
  club.delegate = self
  club.startInView(@video_view)
end

You might have noticed that AVClub uses camelCased method names, rather than the more rubyesque snake_case. This is to distinguish it as an Objective-C class. However, for convenience, there is an included AVClubController class that is a Ruby class, and so uses snake_case. It adds two methods you can use or refer to: start_in_view(viewfinder) (it just passes it on to the AVClub object, @club) and rotate_camera_to(orientation:duration:).

# this method creates the club, assigns it to self.club, and assigns the
# viewFinderView that you pass to self.viewFinderView
def viewWillAppear(animated)
  self.start_in_view(view)
end

# you have to tell AVClub to rotate the image using rotate_camera_to()
def willRotateToInterfaceOrientation(to_interface_orientation, duration:duration)
  # you'll need to adjust the frame yourself!

  case to_interface_orientation
  when UIInterfaceOrientationLandscapeLeft
    new_frame = CGRect.new([0, 0], [480, 320])
  when UIInterfaceOrientationLandscapeRight
    new_frame = CGRect.new([0, 0], [480, 320])
  when UIInterfaceOrientationPortrait
    new_frame = CGRect.new([0, 0], [320, 480])
  when UIInterfaceOrientationPortraitUpsideDown
    new_frame = CGRect.new([0, 0], [320, 480])
  end

  rotate_camera_to(new_frame, orientation: to_interface_orientation, duration:duration)
end