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Category: 3rd party

Fire on High or Framebuffer in Rocky.js

By , 02/11/2016 10:23 PM

First things first. DISCLAMER: Everything described here is a hack upon a crude hack and most likely, barring a divine intervention, won’t work in final product. And I apologize in advance to Pebble dev team if my attempts at “hacking” seem silly. Now to business. Pebble SDK offers very cool framebuffer API that allows developers to address display memory of the watch directly. This makes possible creation of many cool special effects (matter of fact EffectLayer library uses framebuffer extensively).
Rocky.js is JavaScript incarnation of Pebble SDK and it made me wonder whether it offers framebuffer access. Turned out it is hidden, but it’s there. At least at the latest commit at the time of this article it is. If you take a look at source file html-bindings.js you will see that binding function looks something like this:

Rocky.bindCanvas = function(canvas, options) {
  var framebufferPixels = new Uint8Array(module.HEAPU8.buffer,
                                         canvasW * canvasH);


  var binding = {



  return binding;

Continue reading 'Fire on High or Framebuffer in Rocky.js'»

Persistent configs in Rocky.js watchfaces

By , 02/09/2016 10:56 PM

Rocky.JS is the first step in Pebble journey to run JavaScript directly on the watches (unlike Pebble.JS which runs on your phone). Previously I described how to convert a simple watchface from C to Rocky.js. But that was a static watchface with unchangeable settings.

Here I will show how to create a configurable watchface in Rocky.js similarly how classic SDK faces can be configured. You will be able to reuse your existing config page – and if it was set to work with Pebble emulator as well as real watch – you will reuse it without any changes at all.

First let’s review how classic Pebble SDK calls config page. In PKJS (JavaScript) portion of Pebble code usually there’s a piece like this:

  function(e) {

If user requests config of face/app – this event fires and opens page with configurable options from specified URL. After user modifies settings usually “Save” button is clicked on that page and code similar to this executes:

$('#xbtnSave').click(function () {
   var location = (decodeURIComponent(getURLVariable('return_to')) || 
                   "pebblejs://close#") + 
   document.location = location;

Here, first we determine which location to redirect config page to. If parameter "return_to” is passed in query string (here custom function getURLVariable() is used to extract individual parameters – look it up), so if this parameter is passed – it means config page is called form the emulator and we use it for redirection. Otherwise we use standard "pebblejs://close#" URL to save settings into real watch. We also take settings object which has our collective options combined, convert it to string and add to the URL as a parameter. Page then is redirected to resulting URL and Pebble emulator or real watch takes care of processing parameters.

So, how can we (re)use it in a Rocky.js watchface? Continue reading 'Persistent configs in Rocky.js watchfaces'»

Restore natural picture look on Samsung smart TV

By , 02/02/2016 10:04 PM

I really like my new smart TV from Samsung it has tons of bells and whistles. But one thing I noticed – no matter what I watch – series or movies, streaming or broadcast – picture has a “teleplay” feeling – like the action is happening on stage in the theater. If you recall what later Twilight Zone episodes look like you’d know what I am talking about. Maybe it’s supposed to look like this, but I like “film” feeling more. So I found a setting that restores natural picture look:

Go to your TV menu, then select Picture -> Picture Options -> Auto Motion Plus and turn it off.

Fix Roku problem connecting to 802.11ac 5Ghz WiFi

By , 01/30/2016 2:15 PM

I recently got a Roku 4 – at the time of this post the latest and greatest streaming players from Roku family. It comes with many bells and whistles – including ability to connect to 5Ghz WiFi networks. But for the life of me – it could not connect to mine. Player was seeing the SSID of the network, able to connect to wireless, but chocked on joining to LAN. Extensive chat with support lead nowhere – they wanted me to change WAN DNS and many other hoops that achieved nothing. For the record – my router is a dual-band one, and Roku had no problems connecting to 2.4Ghz band. But Internet speed falls dramatically over 2.4Ghz connection and I needed 5Ghz.

Finally I found one thing that worked.
AC Network
AC connection has 3 bandwidth modes: 20Mhz, 40Mhz, and 80Mhz. My router was set to 80Mhz to take full advantage of 1300 speed. None of my devices had problem with this (including, I might add, my previous Roku 3 player). But apparently Roku 4 couldn’t handle it. But as soon as I switched bandwidth to 40Mhz – boom, instant connection.

Streaming doesn’t suffer from this change, but it does lower LAN speed, so I’d like alternative solution from Roku if possible. Is this a known issue? Would an update fix it?

UPDATE 2016-02-01: Found a better workaround with the help of this awesome device.
WUMC710 is a bridge between 4 Gigabit Ethernet connections and full 802.11ac WiFi. And it has no problem with 80Mhz channel. So I basically tell Roku it has a wired connection (and it does to the bridge) and the bridge has beautiful wireless connection to my router. You can grab the WUMC710 pretty cheap (I got mine for $10) and besides not having to slowdown your main network it makes actual Roku internet Speed much faster. Shame Roku’s own WiFi is not on par, but hopefully it will catch on

Fixing problem with Yahoo geolocation service

By , 01/25/2016 5:04 PM

Recently two Pebble watchfaces I’ve developed based on Paul Joel designes: Clean&Smart and Cobblestyle began to experience weather update issues – as in “weather was not updated at all”. Looking into the issue I found a weird thing: If you set your location manually – weather worked. But automatic weather based on phone location did not.

The way automatic location works is pretty straighforward. First this function is called to determine location:

function getLocation() {
    {timeout: 15000, maximumAge: 60000}

It uses phone location services (GPS, if its available, otherwise network-based location). In case of success it calls locationSuccess function. And in my tests it always called it, so location was determined successfully. Continue reading 'Fixing problem with Yahoo geolocation service'»

Solved: Issue with Pebble framebuffer after notification is dismissed

By , 01/08/2016 1:15 PM

Effect Layer Issue I’ve encountered a weird issue while working with EffectLayer Library (a visual effect library for Pebble smartwatch). In this particular watchface called Clean & Smart I used “invert” effect which inverts colors of the watchface should the user choose that option in settings. It was working fine when option changed when watchface was loaded/unload and behaved weirdly only in one particular scenario: when you would receive a notification (email, text etc.) and then dismiss it. Upon coming back from notification to watchface invert effect would only partially cover the watchface (as seen on the screenshot).
I don’t know exactly what was happening, but had a theory. Continue reading 'Solved: Issue with Pebble framebuffer after notification is dismissed'»

How to make your Pebble smartwatch really tick

By , 08/18/2015 1:28 PM

“Tick tock, goes the clock, And Now what shall we play?”.

Pebble smartwatch is an amazing piece of hardware with no less amazing software to support it. Pebble appstore boasts huge variety of watchfaces from intricately carved art pieces to simplicity personified. And the apps, my gods the apps! You want to track your sleep, count swimming stokes, automate your home – Pebble can do all those things and more. But something was missing. Something that ordinary mechanical clocks could do since the dawn of time.

Tick tock, goes the clock, And then what shall we see?
Continue reading 'How to make your Pebble smartwatch really tick'»

Sprite animation on original classic Pebble smartwatch

By , 07/20/2015 2:08 PM

SDK 3.x for Pebble Time smartwatch offers cool and very convenient set of functions to create animation from your existing GIF or MP4 via APNG support. APNG is an obscure “Animated PNG” format (at the time of the post only Mozilla Firefox supports it) but it’s very powerful and can store animation in much more compressed format than traditional animated GIF, so Pebble chose it for a reason. So if you have a GIF, convert it to APNG with Gif2Apng (or if you have a video, convert MP4 to GIF first and then to APNG) and you’re ready to use it on Pebble Time. Just keep the size in check, since Pebble has to load entire APNG sequence in memory, try not to go overboard. The first video is showing animation from my “Vortex” watchface using this approach on Pebble Time.

But what about original classic Pebbles? Eventually they will get firmware 3.x and SDK 3.x support and with that APNG functions among other advantages, but at the time of this writing it is still hazy when this is going to happen. But where there’s a will there’s a way – you can still use your MP4/GIF source for animation it’s just a bit more tricky. Instead of dealing with a single APNG file as your resource and relying on Pebble firmware to draw the frames you will need to help it a little.

First you will need to split your source into individual frames, for example using this service. Yes, you will be dealing with individual frames, so don’t go creating a Hollywood blockbuster. But don’t fret, it’s a bit more manual work, but you won’t have to hand-crank the moving pictures all the way.
Continue reading 'Sprite animation on original classic Pebble smartwatch'»

EffectLayers gets (long overdue) remove function

By , 07/09/2015 4:50 PM

EffectLayer for Pebble Smartwatch is a library that allows you to easily add special effects to your watchfaces or watch apps. You can even add multiple effects (up to 4 by default) to a single layer. But up until now you couldn’t easily remove added effect.

This feature could be useful when you need to add/remove an effect on the fly. For example user can choose to turn off or on color inversion from watchface config, so instead of creating/showing/destroying/hiding entire layer you can simple add/remove inversion effect.

Another use case is where you need to swap effects, for example remove 90-degree rotation clockwise and add 90-degree rotation counter-clockwise.

Well now you can, the library now has effect_layer_remove_effect function. What it does is simple removes last added effect. The effect showing in the demo above is achieved by this block of code:

switch (anim_count) {
   case 0:
      effect_layer_add_effect(effect_layer, effect_invert, NULL);
   case 1:
      effect_layer_add_effect(effect_layer, effect_rotate_90_degrees, (void *)true);
   case 2:
      effect_layer_add_effect(effect_layer, effect_mirror_vertical, NULL);
   case 3:
if (anim_count == 4)  anim_count = 0;

It is called every time animation movement is initiated for the layer. Layer is moved 4 times in this demo:

  • On 1st call – inversion effect is added to the layer
  • On 2nd call – last added effect (inversion) is removed and 90-degree rotation added
  • On 3rd call – 90-degree rotation removed and vertical mirror effect is added
  • On 4th call – effect is removed so now layer has no effects.

Combined the chain produced the effect shown in the animation above.

Ideally library should have “insert” and “remove_at” function to be able to insert and remove effects from arbitrary index (and not only the end of effect chain). Stay tuned.

Useful Links

“Background” vibes on Pebble smartwatch

By , 05/21/2015 4:17 PM

Matt Thompson from Pebble G+ community asked a question that got me curious: Is there a way to buzz Pebble vibe at regular intervals in the background, while a regular watchface is displayed in foreground?

Besides running a normal app, Pebble has 2 ways to run code in the background: background worker and Wakeup API.

Background worker can truly run in the background, but has no access to UI (and vibes are considered UI) as well as other limitations. Besides you can have only one background worker, so for example if you’re running MisFit app and want to run another background app – you’re out of luck.

WakeUp API has the ability to act as a timer in the background and launch your app when timer countdown finished. Interesting thing is – if your app doesn’t have any UI (windows) – it exits right away, so from the user’s point of view – it didn’t even ran – then point in the watch interface remains the same (if you’re looking at a watchface, or at settings etc. – you remain at the same spot).

We can use this to wake the app, buzz the vibe, reschedule wakeup time and exit. User will just hear a buzz with no visual indication that something was launched. Here’s a basic code to achieve this:

static uint32_t const segments[] = {1000, 500, 1000, 500, 1000};  

static void init(void) {

  wakeup_schedule(time(NULL) + 60, 0, false);
  VibePattern pat = {
    .durations = segments,
    .num_segments = ARRAY_LENGTH(segments),

int main(void) {

This is pretty straightforward. Line 01 declares an array for custom vibe pattern (3 one-second buzzes separated by half-a-second silence) Line 05 subscribes to WakeUp event. Ordinary you need to specify a callback function as a parameter, but our entire code runs in the Init, so we don’t use it here. Line 06 schedules app wake-up in 60 seconds. Line 08 cancels any current vibes in case any are still running. Lines 10-13 prepare structure for custom vibe sequence and Line 14 runs the vibes.

That’s it. When you launch the app – it schedules its own wakeup, buzzes the vibe and exits immediately. You’re free to do what you want – set a watchface, run another app etc. When time comes – the app wakes up, buzzes the vibe, schedules next wakeup and exits without interfering with whatever user is doing. Etc. Etc. Etc.

Just remember that the only way to stop it is delete the app from the watch and wait for the current buzz sequence to finish.

Useful Links

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