Lfb – 0.0: Feedback Theme Specification
Description: Reference for Lfb-0.0: Feedback Theme Specification

#### Feedback Theme Specification

# Overview

A feedback theme defines the kind of feedback that events (as described in the Event naming spec) will trigger.

The feedback daemon is responsible to select an appropriate feedback theme for a given device.

# Definitions

- Feedback: A feedback is something that notifies the user that s.th. happened (e.g. a played sound, the vibration of a haptic motor or led blinking).

- Feedback theme: A feedback theme is a set of feedbacks grouped by profiles. Each feedback is mapped to a single event.

- Feedback Profile: A feedback profile groups feedbacks by “noisiness”. The currently defined profiles names are full, quiet and silent. With full being the noisiest profile.

- Event: What the user should be notified about. The event names are built according to the Event naming spec.

# Implementation

When an application requests feedback for an event via the feedback daemon the daemon selects the provided feedback like this, capping the noisiness for each limit:

1. The currently selected profile provides the (global) upper limit for noisiness

2. Per application settings impose another upper limit

3. Per event noisiness is the last noisiness constraint

4. All feedback consistent with the resulting limit are selected and run to provide the feedback to the user

With the above a feedback theme in YAML format could look like:

    full:
        - event-name: phone-incoming-call
          type: Sound
          effect: phone-incoming-call
        - event-name: message-new-sms
        ...
    quiet:
        - event-name: phone-incoming-call
          type: Vibra
          duration: 0.5s
        - event-name: message-new-sms
        ...
    silent:
        - event-name: phone-incoming-call
          type: Led
          location: Front
          Color: Green
          Interval: 0.2s
        - event-name: message-new-sms
        ...

At the time of writing the theme format is daemon dependent. E.g. feedbackd uses a format similar to the above in JSON

# Recommendations

- The silent theme should not produce any audible feedback. This includes the buzzing of haptic motors.
- The quiet theme should not play any sounds. Haptic motors and LEDs can be used.
- The full feedback theme can use any available feedback mechanisms