Announcing Pebble SDK 2.0

Introducing Pebble SDK 2.0November 6th 2013

New Tools SDK Overhaul New APIs

A MAJOR UPDATE

If you are watching live, you can ask questions

On our IRC channel: #pebble on irc.freenode.net

During our AMA on Reddit at 12pm PST today

This is recorded and will be available on our YouTube channel and on the developer web site

Friendly warning: This presentation is mostly intended for developers

Introducing Pebble SDK 2.0

http://irc.freenode.net

New Tools

Improving the developer experience

CloudPebble Simplified build system

Deploying from the command line Application logs Documentation

Now open-sourced and hosted by Pebble Technology

CloudPebbleNew Tools

CloudPebbleNew Tools

No installation - From zero to first installed app in 60 seconds

One tool for all your Pebble development

Simplified build systemNew Tools

$ pebble new-project helloworldCreating new project hello-world$ cd helloworld$ pebble buildMemory usage:=============Total app footprint in RAM: 822 bytes / ~24kbFree RAM available (heap): 23754 bytes'build' finished successfully (0.351s)

Simplified build systemNew Tools

Use the Pebble mobile application to install and debug apps.

Developer ConnectionNew Tools

$ export PEBBLE_PHONE=192.168.1.42$ pebble install --logs[INFO ] Installation successful[INFO ] Enabling application logging...[INFO ] Displaying logs ... Ctrl-C to interrupt.[INFO ] D helloworld.c:58 Done initializing

Developer Connection

A very simple and reliable way to install and watch log messages

New Tools

We have re-written almost all of Pebble Documentation

Pebble documentation now includes: • A Getting Started Guide • Pebble Developer Guide with 11 chapters • Pebble Mobile Developer Guide • Pebble 2.0 Migration Guide • API Reference for Pebble, iOS and Android

DocumentationNew Tools

Improving the developer experience

CloudPebble Simplified build system

Deploying from the command line Application logs Documentation

New Tools

SDK Overhaul

Getting ready for bigger applications and an evolving SDK

Pebble 2.0 is a major evolution of Pebble 1.0 with lots of changes in the system and in the SDK

• Pebble 2.0 is not compatible with 1.0 apps

• Developers need to migrate their application to Pebble 2.0

SDK Overhaul

Refer to Pebble 2.0 Migration Guide http://developer.getpebble.com/2/guides/migration-guide.html

Migrating to Pebble 2.0

http://developer.getpebble.com/2/guides/migration-guide.html

Pebble application must provide some metadata through a JSON file in the project called appinfo.json

• Application name • UUID • Watchface / Watchapp • Resources • etc

SDK Overhaul Application metadata

In Pebble OS 2.0, all the SDK structures are opaque. This means we can change them without you having to recompile your apps.

You cannot allocate structures as global variables as you did in 1.0. You must use pointers and memory allocated dynamically by the system.

All calls to _init() functions become are replaced by _create() calls

SDK Overhaul Using pointers and dynamic memory

Window my_window;window_init(&my_window);

Window *my_window;my_window = window_create();becomes

• pbl_main() is now called main()

• PblTm is replaced by struct tm

• string_format_time() is replaced by strftime()

• Pebble does not support timezones yet but we introduce gmtime() and localtime() to prepare for timezone support.

• get_time() is replaced by localtime(time(NULL))

SDK Overhaul Getting closer to standards: C/UNIX

Pebble 2.0 relies heavily on Events. You register to events with _register functions.

All Pebble 1.x APIs have been updated: Timer, Tick, AppMessage, etc

SDK Overhaul Enforcing a subscription based Event system

PebbleAppHandlers handlers = { .timer_handler = &handle_timer };

timer = app_timer_register(1500, timer_callback, NULL);

becomes

Introducing two old friends: malloc() and free()

Each application has it’s own heap and is cleaned automatically

You can attach data to layers and windows (layer_create_with_data() and window_set_user_data())

Your total memory is ~24k. Your heap space is 24k minus app size.

Pebble SDK includes tool to help you manage your memory:

SDK Overhaul Dynamic Memory

$ pebble build Memory usage: ============= Total app footprint in RAM: 822 bytes / ~24kb Free RAM available (heap): 23754 bytes !$ pebble logs ... [INFO ] I Heap Usage for <Template App>: Available <23200B> Used <2344B> Still allocated <0B>

Use pebble convert-project to generate the new appinfo.json file

Rename pbl_main() into main()

Use pointers to structures instead of statically allocated structures

Use the SDK APIs to allocate memory and initialize the structs

Check the other APIs for changes

SDK Overhaul Migration in a nutshell

Refer to Pebble 2.0 Migration Guide http://developer.getpebble.com/2/guides/migration-guide.html

http://developer.getpebble.com/2/guides/migration-guide.html

Getting ready for bigger applications and an evolving SDK

SDK Overhaul

New Frameworks Event Services

A unique design pattern that communicates with Pebble OS subsystems


The App Focus Service lets you know when your app is covered by a modal window

typedef void (*AppFocusHandler)(bool in_focus);!void app_focus_service_subscribe(AppFocusHandler handler);void app_focus_service_unsubscribe();


The Bluetooth Connection Service lets you know when the watch is connected to the phone

typedef void (*BluetoothConnectionHandler)(bool connected);void bluetooth_connection_service_subscribe(BluetoothConnectionHandler handler);void bluetooth_connection_service_unsubscribe(void);!bool bluetooth_connection_service_peek(void);


The Battery State Service can let you know when the watch is plugged or unplugged

typedef struct { uint8_t charge_percent; bool is_charging; bool is_plugged;} BatteryChargeState; !typedef void (*BatteryStateHandler)(BatteryChargeState charge);void battery_state_service_subscribe(BatteryStateHandler handler);void battery_state_service_unsubscribe();!void battery_state_service_peek(void);


A unique design pattern that communicates with Pebble OS subsystems

Bluetooth, App Focus, Battery Status

Refer to Pebble 2.0 Event Services Guide http://developer.getpebble.com/2/guides/event-service-guide.html

http://developer.getpebble.com/2/guides/event-service-guide.html

New Frameworks Accelerometer

Let’s shake things up ...

The Accelerometer framework is designed with all use cases in mind: user interaction for watchfaces, games, activity monitor, etc


Hardware accelerometer !

Able to detect taps Perform measurements at a given frequency

Store samples to save CPU time


The simplest way to use the accelerometer is to register for tap events

Those events are generated by the hardware and use very little energyvoid accel_tap_handler(AccelAxisType axism int32_t direction) { // Process tap on ACCEL_AXIS_X, ACCEL_AXIS_Y or ACCEL_AXIS_Z}!void handle_init() { accel_tap_service_subscribe(&accel_tap_handler);}!void handle_deinit() { accel_tap_service_unsubscribe(); }

You can register to receive raw events one at a time


void accel_data_handler(AccelData *data, uint32_t num_samples) {process_sample(&data);

}!void handle_init() { accel_data_service_subscribe(1, &accel_data_handler);}!void handle_deinit() { accel_data_service_unsubscribe(); }

The accelerometer API also supports storing samples on the hardware

void accel_data_handler(AccelData *data, uint32_t num_samples) { // Process 10 events - every 1 second}!void handle_init() { accel_data_service_subscribe(10, &accel_data_handler); accel_service_set_sampling_rate(ACCEL_SAMPLING_10HZ);}


You can also peek at the accelerometer when updating your UI This is the strategy we recommend for game developers


void tick_handler() { AccelData data; accel_service_peek(&data);}!void handle_init() { accel_data_service_subscribe(0, NULL);}void handle_deinit() { accel_data_service_unsubscribe(); };


The Accelerometer Service

Tap events - Regular measures - Batch processing - Real time processing

Refer to Pebble 2.0 Accelerometer Guide http://developer.getpebble.com/2/guides/accelerometer.html

http://developer.getpebble.com/2/guides/accelerometer.html

New Frameworks Data Logging

A better way to transfer data

The data logging service is a transparent buffer between your watch app and your phone that reliably and efficiently carries your data.

Your watchapp creates one or multiple data logging sessions and pushes data to those sessions.

Using PebbleKit iOS and Android, your mobile app gets events when new data is available for download.

Your data is managed by Pebble OS: saved on the watch filesystem, persisted if the user moves to another app, transferred in batches.


You create a spool with a call to data_logging_create ()

DataSpoolRef my_data_spool;!void handle_init() { logging_session = data_logging_create( /* tag */ 42, /* data type */ DATA_LOGGING_BYTE_ARRAY, /* length */ sizeof(AccelData), /* resume */ true );}


Use data_logging_log() to add data to the spool

New Frameworks

void accel_data_handler(AccelData *data, uint32_t num_samples) { DataLoggingResult r = data_logging_log(logging_session, data, num_samples);}

Data Logging

Finally, use data_logging_finish() when you are done

New Frameworks

void handle_deinit() { data_logging_finish(logging_session);}

Data Logging

You register to data spooling on iOS by providing a delegate to the dataLoggingService

New Frameworks

[[[PBPebbleCentral defaultCentral] dataLoggingService] setDelegate:self];

Data Logging - iOS

The delegate implements methods to consume the data

New Frameworks

- (BOOL)dataLoggingService:(PBDataLoggingService *)service hasUInt32s:(const UInt32 [])data numberOfItems:(UInt16)numberOfItems forDataLoggingSession:(PBDataLoggingSessionMetadata *)sessionMetadata {

// Return YES when the data has been processed.}!- (void)dataLoggingService:(PBDataLoggingService *)service sessionDidFinish:(PBDataLoggingSessionMetadata *)sessionMetadata { // Session closed.}

Data Logging - iOS


A better way to transfer data

The data logging service is a transparent buffer between your watch app and your phone that reliably and efficiently carries your data.

Refer to the Ocean Data Survey example Examples/data-logging-demo

New Frameworks Persistent Storage

Store data on the watch

Persistent storage is perfect to save user settings, cache data from the phone app, high scores, etc

Every application get its own persistent storage space. Its size is limited to 4kB.

Each value is associated to a uint32_t key.

Persistent storage supports saving integers, strings and byte arrays.

The maximum size of byte arrays and strings is defined by PERSIST_DATA_MAX_LENGTH (currently set to 256 bytes)


To write data in persistent storage, call one of the persist_write functions:

You should check the return value for error codes (anything but 0 is bad news)


void handle_deinit() { persist_write_bool(TRUTH_KEY, true); persist_write_int(DOUGLAS_KEY, 42); persist_write_string(USERNAME_KEY, “thomas”); uint8_t byte_array[42]; persist_write_data(DATA_KEY, sizeof(byte_array), byte_array);}

The function persist_exists(key) returns a boolean indicating if the key exists or not.

To read data from persistent storage, use the persist_read functions


void handle_init() { bool truth = persist_read_bool(TRUTH_KEY); int douglas_value = persist_read_int(DOUGLAS_KEY);

char username[20];persist_read_string(USERNAME_KEY, 20, username);

uint8_t byte_array[42]; persist_read_data(DATA_KEY, sizeof(byte_array), byte_array);}

You can use persist_delete() to remove a key from persistent storage



Store data on the watch

Persistent storage is perfect to save user settings, cache data from the phone app, high scores, etc

Refer to Pebble Persistent Storage Guide http://developer.getpebble.com/2/guides/persistent-storage.html

http://developer.getpebble.com/2/guides/persistent-storage.html

New Frameworks PebbleKit JavaScript

Expand the reach of your Pebble apps with JavaScript logic running on the phone

Make http calls on the phone, process the reply and send it to your watchapp.

Send notification. Use the phone GPS. Use a webview in the phone to provide a configuration

screen to your application.

Add a pebble-js-app.js file in your project

Or use pebble new-project --javascript

When Pebble mobile application installs your pbw, the JS is extracted and saved on the phone.

Your JavaScript code is started with your watchapp/watchface and will run as long as your app is in the foreground on Pebble.



Pebble sandbox provides API to receive messages from the watch, make http requests, send new messages to the watch, etc.

On the watch, AppMessage APIs are used to receive and send data.

PebbleKit JS is completely independent of the platform (iOS, Android).

The sandbox provides a Pebble.addEventListener function to register for events.

A ‘ready’ event is fired when your JavaScript is ready to execute.

PebbleEventListener.addEventListener("ready", function(e) { startRemoteRequest(); }});


Your JavaScript code can send notifications to the watch: Pebble.showSimpleNotificationOnPebble(title, text)

You can also use the standard console.log() calls to log messages to the Pebble console.


Your JS code can also process messages coming from the watch through the ‘appmessage’ event.

PebbleEventListener.addEventListener("appmessage", function(e) { var temperatureRequest = e.payload.temperatureRequest; if (temperatureRequest) { fetchWeather(); }});


To send messages to the watch, use Pebble.sendAppMessage()

PebbleKit JS automatically transforms JS dictionaries to Pebble’s Dictionary


Pebble.sendAppMessage({ "icon": ICON_SUNNY, "temperature": "28oC"});

The Pebble JavaScript sandbox provides the standard XMLHttpRequest method to make http calls.

var req = new XMLHttpRequest();req.open('GET', 'http://api.openweathermap.org/data/2.1/find/city?lat=37.830310&lon=-122.270831&cnt=1', true);req.onload = function(e) { if (req.readyState == 4 && req.status == 200) { if(req.status == 200) { var response = JSON.parse(req.responseText); var temperature = result.list[0].main.temp; var icon = result.list[0].main.icon; Pebble.sendAppMessage({ "icon":icon, "temperature":temperature + "\u00B0C"}); } else { console.log("Error"); } }}req.send(null);


http://api.openweathermap.org/data/2.1/find/city?lat=37.830310&lon=-122.270831&cnt=1'

Pebble sandbox provides several standard APIs:

• HTML5 Geolocation API through navigator.geolocation • Local Storage APIs through window.localStorage


Your application can show a Configure button on the phone screen

When the user clicks on this button, the configure event is fired

The html page can return information: document.location.href = “pebblejs:///close#some-data-set”

Pebble.addEventListener("showConfiguration", function() { console.log("showing configuration"); Pebble.openURL('http://assets.getpebble.com.s3-website-us-east-1.amazonaws.com/pebble-js/configurable.html');});Pebble.addEventListener("webviewclosed", function(e) { console.log("configuration closed");});


pebblejs:///close#some-data-set%E2%80%9D


Expand the reach of your watchapp with JavaScript logic running on the phone

Make http calls on the phone, process the reply and send it to your watchapp.

Send notification. Use the phone GPS. Use a webview in the phone to provide a configuration

screen to your application.

Refer to Pebble JavaScript Guide http://developer.getpebble.com/2/guides/javascript-guide.html

http://developer.getpebble.com/2/guides/javascript-guide.html

WRAPPING UP

Updated Tools SDK Overhaul New Frameworks

pebble

Developer Connection

App Metadata

Following Standards

Events based APIs

Dynamic Memory

2.0 Migration Guide

Event Service

Accelerometer

Data Logging

Persistent Storage

PebbleKit JS

Cloud Pebble

Documentation

Application logs

Downloading the new SDK !

Available now on http://developer.getpebble.com/2/

http://developer.getpebble.com/2/

ENJOY!

Questions? !

#pebble on irc.freenode.net AMA on reddit

http://irc.freenode.net