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| title | author | tags | |
|---|---|---|---|
| 4.2-beta4 SDK - Emery Edition! | jonb |
|
We're incredibly excited to announce the first public beta of the Pebble SDK 4.2. This is the first time that developers can experience the new 'Emery' platform which is specifically created for the upcoming Pebble Time 2.
All About Those Pixels
The new display on the Pebble Time 2 is almost 53% physically larger, and the Pixels per inch (PPI) has been increased from 182 PPI to 202 PPI. This is a massive 200x228 pixels, compared to 144x168 on the Pebble Time Steel, that's an 88% increase in the total amount of pixels!.
Take a look at our {% guide_link tools-and-resources/hardware-information "Hardware guide" %} for further information about the specifications of the Pebble Time 2.
Watchfaces and watchapps that have not been updated for the Emery platform will run in Bezel Mode. This means they will appear centered on screen at their original resolution (144x168), but due to the change in PPI, they appear slightly smaller.
Left: Pebble Time Steel, Middle: Pebble Time 2 -
Bezel Mode, Right: Optimized for Pebble Time 2.
Concentricity
Watchface
The increased number of pixels would immediately make you think that you can just add more elements to your watchface design, but due to the increase in PPI, existing elements and fonts may feel slightly smaller than expected when viewed on an actual device.
The image below simulates how the PPI difference makes a bezel mode application feel smaller on the Pebble Time 2.
Left: Pebble Time Steel, Right: Pebble Time 2 - Bezel Mode.
We've now seen that the increased amount of pixels doesn't necessarily equate to bigger text on our devices, due to the change in PPI, that's why we've created the new ContentSize API.
Introducing the ContentSize API
All existing Pebble smartwatches provide the ability for users to change the size of text for notifications and some system UI components using Settings > Notifications > Text Size.
The new ContentSize API now exposes this setting to developers, in order for them to adapt their application design and layout based on this user preference.
In the previous section, we saw how the PPI increase on Pebble Time 2 affected the relative size of a watchface. In the image below you can see precisely how text sizes are affected by the PPI change.
Yellow: Pebble Time Steel, Green: Pebble Time 2.
To negate the effects of this reduced font size, the Emery platform uses larger fonts by default. Developers can use the ContentSize API to match this behaviour within their own applications.
The following table explains how the text size setting affects the content size on each platform:
| Platform | Text Size: Small | Text Size: Medium | Text Size: Large |
|---|---|---|---|
| Aplite, Basalt, Chalk, Diorite | ContentSize: Small | ContentSize: Medium | ContentSize: Large |
| Emery | ContentSize: Medium | ContentSize: Large | ContentSize: Extra Large |
Developers should aim to implement designs which adapt to the capabilities of the device, but also the accessibility requirements of the user. The ContentSize API satisfies both of these goals.
For more information, read the {% guide_link user-interfaces/content-size "ContentSize guide" %}.
New for Rocky.js
With the release of SDK 4.2, we're extremely proud to announce that Rocky.js watchfaces can be published into the Pebble appstore! As usual, don't publish apps with the beta SDK into the appstore, please wait for the final release.
In addition to finalizing the memory contract for Rocky.js apps, we've also added a few new APIs to work with:
Memory Pressure
The memorypressure event has been added to allow developers to handle the
situations which occur when the amount of memory available to their application
has changed. Initially we've only implemented the high memory pressure level,
which occurs right before your application is about to be terminated, due to a
lack of memory. If you can free sufficient memory within the callback for this
event, your application will continue to run. Please refer to the Rocky.js
documentation and the memory
pressure example application.
UserPreferences
The first watchface setting exposed in the new UserPreferences object is
contentSize. This exposes the new
ContentSize
API to Rocky.js watchface
developers. Find out more in the Rocky.js
UserPreferences documentation.
What's Next
Check out the release notes for a full list of changes and fixes that were included in SDK 4.2-beta4.
Let us know on [Twitter]({{ site.links.twitter }}) if you built something cool using the new APIs! We'd love to hear about your experiences with the SDK.
Happy Hacking!
Team Pebble