threeMF Evaluation Project

First please read this blog post to know what this repository is about and how you can take part in this little framework evaluation. Afterwards please follow the implementation instructions below.

PLEASE NOTICE: The framework may report a connection refused error in some cases. Restarting the app on both devices will help until the problem is fixed.

Project

This application is called MultiAirCam and uses 3MF to share camera images between n iPhones and m iPads. These devices should find each other automatically via 3MF and iPads should subscribe to all iPhone cameras and display live preview data of what the camera is recording. Small images captured from the camera are transmitted to each subscribed iPad. All the camera recording is ready to use, no effort in this direction has to be made!

Each iPhone provides two services, one for sharing live preview images from their cameras as publish subscribe command. The second service is a request response command allowing iPads to execute one of three different actions at each connected iPhone.

• Turn their flash on or off (MACCameraActionToggleFlash)
• Toggle between back-facing and front-facing camera (MACCameraActionToggleCamera)
• Request a still shot image (MACCameraActionTakePicture)

3MF enables these devices to publish services (Commands) and share arbitrary data between each other with very little code. These devices find each other automatically on the local network and check their capabilities to talk with each other.

For more information on 3MF please read this blog post, the 3MF Wiki, the code documentation or have a look at the existing sample applications.

Tasks for this evaluation

1. Fork this project
2. Read about creating Custom, Publish Subscribe and Request Response Commands
3. Build the project and replace all warnings with the necessary 3MF code.
   • While building the app please write a diary, take down your thoughts which can point out where improvements should be made (or record some audio, everything helps). Simply create a text document and take down your thoughts after every step marked in the sample project and the time it took you to perform the step. You can copy your diary into the survey at the end of the evaluation.
   • Take down the time it takes you to do the evaluation
   • Use the sample applications for further insights
4. Push your code back to your Github fork
5. And finally it would be very kind if you fill out this survey

threeMF-eval is not an working application out of the box and prepared with placeholders for an implementation with 3MF. #warning directives are used all over to indicate where additions have to be made.

Implementation Instructions

The project is divided into two view controllers, first the MACCameraListViewController which is the controller running on iPads displaying all iPhones in range. The second controller is MACCameraViewController containing all code for the iPhone. Both controllers are a subclass of MACViewController adding some convenience code and most importantly defining the TMFConnector property. Beside the 3MF commands, these are the only classes to change.

Two files for the planned commands already exist MACPreviewCommand and MACCameraActionCommand (but without any class definitions).

Step 1 - The Connector

Start with the initialization of the [MACViewController tmf] property in [MACViewController init].

Step 2 - Commands

Camera Action Command

This command should follow the request response pattern. Provide the command create a corresponding arguments class defining a MACCameraAction property and implementing the - (id)initWithAction:(MACCameraAction)action method.

Camera Preview Command

This command should follow the publish subscribe pattern. Provide the command and create a corresponding arguments class. This command sends small image frames to subscribers and therefore we can subclass TMFImageCommand and TMFImageCommandArguments.

Step 3 - iPhone Controller

The MACCameraViewController is defined to run on iPhones which are the providers for our commands.

1. Add an ivar for each command to MACCameraViewController
2. Create both commands in viewDidLoad and provide the code below each warning in the MACCameraActionCommand receive block.
3. Publish both commands in viewDidAppear
4. Activate the code in connector:didAddSubscriber:toCommand
5. Activate the code in connector:didRemoveSubscriber:fromCommand
6. Create preview arguments and send them in cameraPreviewImageCaptured:image:

Step 4 - iPad Controller

The MACCameraListViewController is defined to run on iPads which are subscribers for our commands.

1. Start discovery for providers with our two commands in viewWillAppear: and use self as delegate.
2. Subscribe to the preview command and update the cameras preview image like in the given example (comment in code).
3. Execute all camera action commands and save the resulting image of MACCameraActionTakePicture to the photos album with UIImageWriteToSavedPhotosAlbum([UIImage imageWithData:response[@"image"]], nil, nil, nil);