About Me

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Senior Technical Talent Advisor and Community Development - A.I, Machine Learning and Data Science.

Director & Co-Founder @ www.Abso-Fashion-Lutely.co.uk
Director & Founder of Data Science & Big Data Analytics IT Job Board http://datasciencebigdataanalytics.jobboard.io/

Roles:

Data Scientist, Statistician, Insight Analyst, Chief Data Scientists, Data Architect, Data Engineer, Data Analyst, Statistics Consultant, Research Engineer, Quantitative Analyst, Developer, Engineer, Pre-Sales / Post Sales engineer, Sales Engineer, Software Engineer, Systems Engineer, Technical Evangelist, Client Services Engineer, Architects (Cloud, Solutions & Enterprise), Cloud & Big data Analytics, Microsoft Azure and consulting roles.

The above is not an exclusive list and I work on a diverse range of roles and technologies. Contact me:  0044 788 135 1363

I am currently studying with Udacity to further my career in Data Science, Big Data Analytics, Programming, Algorithms, Artificial Intelligence, Computer Science, Statistics, Physics, Psychology & Visualizing Algebra.

I specialise in the following:

• Talent Manager and also responsible for expanding our internal team; vetting, meeting & technically testing candidates
• Providing advice around legal, accounting and general recruitment to the community
• Utilising the latest social media strategies for recruitment Twitter,Github Etc ..
• Setting up interviews, negotiating extensions, offers & contracts
• Developing new relationships and bringing in new business
• Client & account management
• Attending and arranging technical conferences to better my understanding of the technologies and markets I specialise in

I own & run the following groups on LinkedIn:
• ASP.Net MVC 3, MVC 4 & MVC5 Ninjas
• Cloud & Big data
• Microsoft Azure Ninjas
• Data Scientist & Analytics UK
• HTML5 Ninjas
• Java Blackbelt
• Hadoop Experts UK & EMEA
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Friday, 13 January 2012

The Majority Of Web Developers Are Moving To HTML5

A survey has found that 75 percent of developers are using, or plan to use HTML5 for app developement

A new survey from Evans Data has confirmed that developers continue to flock to HTML5.
Indeed, Evans Data’s latest Global Development Survey indicates that although the HTML5 standard is still a work in progress, software developers are already committed to it.

De Facto Standard

The survey of more than 1,200 developers conducted worldwide in November and December 2011 showed current use of HTML at 43 percent in North America; 39 percent in the Europe, Middle East and Africa (EMEA) region; and an even greater 58 percent in the Asia Pacific (APAC) region. Adding in those planning to use HTML5 brought the totals to over three-quarters across the regions.
“There isn’t any question about the adoption of HTML5 – it’s already the de facto standard” said Janel Garvin, CEO of Evans Data, in a statement. “There is special strength in HTML5 for mobile and cross-platform mobile apps, which is the direction the industry is moving for client devices, and that has made it extremely attractive to developers everywhere in the world. We see the most strength in Asia, a region that is generally quick to adopt new technologies.”
The survey also showed that developers are more likely to use a standalone HTML5 editor in APAC and EMEA, while North Americans prefer to use the editor in their integrated development environment (IDE). When asked about importance in the development cycle, HTML5 came in 20 percent higher on average across regions than either Flash or Silverlight.
HTML5 has caught on quickly with developers, and vendors are providing support for it in their core products. Microsoft has embraced HTML5 for its Internet Explorer browser and Windows 8 operating system.

Flash Dies

In November, Adobe announced plans to halt development of Flash for mobile browsers. In its explanation for the change in direction, Adobe cited the popularity of HTML5.

In a 9 November blog post, Danny Winokur, vice president and general manager of interactive development at Adobe, said, “However, HTML5 is now universally supported on major mobile devices, in some cases exclusively. This makes HTML5 the best solution for creating and deploying content in the browser across mobile platforms. We are excited about this, and will continue our work with key players in the HTML community, including Google, Apple, Microsoft and RIM, to drive HTML5 innovation they can use to advance their mobile browsers.”

The Evans Data Global Development Survey series is conducted worldwide twice a year. The current survey includes sections on Platform Use and Migration, Agile Development, Embedded Systems, Cloud Development, Mobile Development, Distribution Channels, Security, and Technology Adoption.

Tuesday, 3 January 2012

How to create HTML5 applications on Windows Phone thanks to PhoneGap

We will first see in this article what the added values of PhoneGap for HTML5 applications are. We’ll then discover how to create our very first project where we will retrieve the accelerometer’s values from our JavaScript code. At last, we will review a complete HTML5 gaming sample almost ported as-is to PhoneGap to use the accelerometer available on the Windows Phones.  
  1. Introduction
  2. PhoneGap: a framework filling the gap
  3. Let’s create our first PhoneGap project
  4. Getting the accelerometer’s values from JavaScript
  5. Review of a complete sample with the HTML5 Platformer game
    1. Forcing the landscape orientation
    2. Handling various resolutions
    3. Loading the levels with calls to the file system instead of using XHR
    4. Modification of the gameplay to use the accelerometer
    5. Screenshots of the result and FPS on some phones
    6. Complete Visual Studio Solution to download
  6. Conclusion

Introduction

image
The Mango update for Windows Phone came with the support of HTML5 thanks to the embedded IE9 browser. As the desktop version, the mobile version of IE9 delivers hardware acceleration through the GPU of your Windows Phone. Thus, combined with JavaScript, IE9 can now serve as a base of interesting user’s experiences usually reserved to “native code”.
The Pros of using HTML5 as a development platform is a relative promise to easily re-use parts of the code on others compatibles platforms like Android or iOS. HTML5 has then driven a lot of interests from the mobiles developers’ ecosystem during the last months.
However, even if the HTML5/CSS3/SVG & JavaScript specifications have greatly evolved during the last months, they still lack some major features to build mobile applications. Indeed, a phone or a tablet exposes specific capabilities like: GPS, accelerometer, camera, sending SMS, accessing contacts, etc.
To have access to these capabilities from the JavaScript code, the W3C has been working now for a while on what we call “Device APIs” or DAP. Unfortunately, we can consider that no implementation currently exists of those specifications as this document seems to confirm: Standards for Web Applications on Mobile: November 2011 current state and roadmap . Mozilla has started an interesting work by more or less forking those specifications via what they call Web APIs to support their Boot To Gecko project. This is then a good news as a form of implementation seems to start with an on-going discussions with the W3C. However, even if things start to move slowly, we will probably have to wait for several years before having a stable official W3C specification implemented widely on all platforms.
So the question is: what should we do in the meantime? Can HTML5 really address those scenarios?

PhoneGap: a framework filling the gap


While waiting on real standardized specifications, we don’t have the choice: we need to create some bridges between JavaScript and the native code of the targeted platform to have access to its capabilities. The idea is then the following one: taking the native languages of each platform (C#, Objective-C and Java) and creating a framework with these languages that will expose interfaces to the JavaScript developer.
This is exactly what PhoneGap is doing. Let’s take the Windows Phone case which is the main topic of this article. A Windows Phone’s PhoneGap project is simply a Silverlight application hosting the WebBrowser control (and thus IE9) as well as a Silverlight Assembly written in C# which does the job to access to the accelerometer, GPS, contacts, camera and so on. In this way, as a JavaScript developer, you will use a DLL named WP7GapClassLib.dll (the PhoneGap core runtime) without even knowing it via the usage of the code embedded in the phonegap-1.3.0.js file. This DLL contains some C# code which does calls to the Silverlight runtime available on the phone. As the runtime has access to all the capabilities of the phone, the JavaScript will do also. The JavaScript library will then act as a gateway between both worlds. Moreover, the good point of using this library is that your code will most of the time works as-is on the PhoneGap versions of Android or iOS. PhoneGap offers then an interesting form of portability.
Please note by the way that the PhoneGap support for Windows Phone is now totally complete since the recent 1.3.0 version:

At last, PhoneGap offers also another interesting service. It embeds your .js, .css, .html, .png resources inside its projects to package it as a classical application. In summary, you can use PhoneGap to package your HTML5 application for the various applications' stores. This is for instance the case of the SujiQ Windows Phone application built using this approach.

Let’s create our first PhoneGap project

Prerequisites

Here are the very first steps you need to follow:
  1. Download the Windows Phone SDK: Windows Phone SDK
  2. Download the last version of Phone (1.3.0 today) on their site: http://phonegap.com/
  3. Unzip the downloaded file 
  4. Copy the PhoneGapStarter.zip and PhoneGapCustom.zip files into \Documents\Visual Studio 2010\Templates\ProjectTemplates

File->New project

Once the previous steps are done, you will be able to create your first PhoneGap project. Start Visual Studio 2010, select the “Visual C#” templates and filter them via the “Gap” keyword. You should then see a new type of project named PhoneGapStarter:
image
Name your project “MyFirstPhoneGapProject”. Once done, you will find the files I was talking about before in the Solution Explorer:
image
You just now have to insert your HTML5 application into the “www” directory.
Here are several tips I’d like to share with you about this default project template:
- never ever touch the phonegap-1.3.0.js file if you’d like to keep a portable code on other versions of PhoneGap
- all files you will add inside the “www” directory must be set as “Content” in the properties window 
- instead of the WP7GapClassLib.dll binary file, you can add a reference to the WP7GapClassLib.csproj C# project available in the “Windows Phone\framework” directory of the downloaded PhoneGap archive. It will help you debugging or discovering the native code of the PhoneGap library if needed.
Ok, let’s now start by doing something normally impossible by default with IE9 Mango: accessing to the accelerometer’s values from JavaScript.

Getting the accelerometer’s values from JavaScript

We’re going to see here how to get the values sent back by the accelerometer (of the emulator or the real device) in a very simple way.
Open the “index.html” page and change its default body by this one:
<body>
    <h1>Accelerometer sample</h1>
    <div id="valueX"></div>
    <div id="valueY"></div>
    <div id="valueZ"></div>
</body>
We will simply use 3 <div> tags to display the current X, Y & Z values of the accelerometer.
Next step is to change the last default <script> block by this one:
<script type="text/javascript">
    document.addEventListener("deviceready", onDeviceReady, false);

    // variable to output the current x, y & z values of the accelerometer
    var valueX;
    var valueY;
    var valueZ;

    // when PhoneGap tells us everything is ready, start watching the accelerometer
    function onDeviceReady() {
        valueX = document.getElementById("valueX");
        valueY = document.getElementById("valueY");
        valueZ = document.getElementById("valueZ");
        startWatch();
    }

    // start monitoring the state of the accelerometer
    function startWatch() {
        var options = { frequency: 500 };
        navigator.accelerometer.watchAcceleration(onSuccess, onError, options);
    }

    // if the z-axis has moved outside of our sensitivity threshold, move the aarvark's head in the appropriate direction
    function onSuccess(acceleration) {
        valueX.innerHTML = "X: " + acceleration.x;
        valueY.innerHTML = "Y: " + acceleration.y;
        valueZ.innerHTML = "Z: " + acceleration.z;
    }

    function onError() {
        alert('onError!');
    }
</script>
Well the code is relatively self-explicit I think. The very first thing to note is that you need to wait for the “deviceready” event raised by PhoneGap to be sure to be in a stable state. You then need to subscribe to this event. In our case, we will be call-backed into the OnDeviceReady() function. This function is getting the references to the 3 <div> tags and then asks to be notified by any changes done inside the accelerometer every 500ms with the startWatch() function. The notifications will be sent to the onSuccess() function that will have access to the acceleration object containing the x, y & z values. You’ll find the complete documentation on the PhoneGap site: PhoneGap Documentation - API Reference - Accelerometer
This is all you need to do on the JavaScript side. However, to make it works, you need to specify in the project’s properties that you want to request access to the device’s sensor. The capabilities needed for the proper execution of our application are listed inside the WMAppManifest.xml file available in the “Properties” directory. By default, since 1.3.0, PhoneGap is listing the strict minimum capabilities:
<Capabilities>
  <Capability Name="ID_CAP_IDENTITY_DEVICE" />
  <Capability Name="ID_CAP_IDENTITY_USER" />
  <Capability Name="ID_CAP_LOCATION" />
  <Capability Name="ID_CAP_NETWORKING" />
  <Capability Name="ID_CAP_WEBBROWSERCOMPONENT" />
</Capabilities>
It’s then up to you to add the capabilities you need for your PhoneGap application. In our case, we need to add this line:
<Capability Name="ID_CAP_SENSORS" />
To be allowed to access to the accelerometer. You’ll find the complete list of all available capabilities here:  Application Manifest File for Windows Phone
Ok, we’re logically ready to test that inside the emulator as a first phase. Press on the magical “F5” key and let’s have a look to the result:
image
By moving the virtual phone in the emulator on the right, you should see the values of the accelerometer updated. Congratulations!
You can download the complete source code of this first solution here: http://david.blob.core.windows.net/html5/MyFirstPhoneGapProject.zip

Issues with phones using French locale

If you’re testing the very same code on your phone configured to use a French local (as mine for instance! Clignement d'œil), you will have the feeling that the application doesn’t work at all…which is indeed the case. I’ve then spent some time debugging the code and I’ve discovered that the following exception was raised inside phonegap-1.3.0.js:
"Error in success callback: Accelerometer = Syntax error"
After dumping the values, I’ve seen that the error was due to a tentative of de-serialization of the following bad formatted JSON string:
"{\"x\":0,00472,\"y\":-0,19879,\"z\":-0,98115}" whereas the proper EN-US is the following one: "{\"x\":0.00472,\"y\":-0.19879,\"z\":-0.98115}"
Yes, we’re using a coma in France as a numeric separator. Clignement d'œil
2 solutions to solve this problem:
1 – The lazy one: switch your phone into EN-US (I know, this is not a solution!)
2 – Fix the problem that comes from the C# code. For that, replace the following code from the Accelometer.cs file of the WP7GalClassLib library:
/// <summary>
/// Formats current coordinates into JSON format
/// </summary>
/// <returns>Coordinates in JSON format</returns>
private string GetCurrentAccelerationFormatted()
{
    string resultCoordinates = String.Format("\"x\":{0},\"y\":{1},\"z\":{2}",
                    accelerometer.CurrentValue.Acceleration.X.ToString("0.00000"),
                    accelerometer.CurrentValue.Acceleration.Y.ToString("0.00000"),
                    accelerometer.CurrentValue.Acceleration.Z.ToString("0.00000"));
    resultCoordinates = "{" + resultCoordinates + "}";
    return resultCoordinates;
}
By this one:
private string GetCurrentAccelerationFormatted()
{
    string resultCoordinates = String.Format("\"x\":{0},\"y\":{1},\"z\":{2}",
             accelerometer.CurrentValue.Acceleration.X.ToString("0.00000", CultureInfo.InvariantCulture),
             accelerometer.CurrentValue.Acceleration.Y.ToString("0.00000", CultureInfo.InvariantCulture),
             accelerometer.CurrentValue.Acceleration.Z.ToString("0.00000", CultureInfo.InvariantCulture));
    resultCoordinates = "{" + resultCoordinates + "}";
    return resultCoordinates;
}
And the sample will now work with all locales. I’ve filled a bug on this topic here: https://issues.apache.org/jira/browse/CB-141 suggesting the same solution that will normally be shipped with the next version (2.0.0).
By the way, you’re maybe wondering how I’ve managed to debug the JavaScript part of my PhoneGap project? Well, you can simply use the wonderful jsConsole project. If you want to know more about that, please read one of my colleague’s article: jsConsole Remote Debugging in IE9 on Windows Phone Mango

Review of a complete sample with the HTML5 Platformer game

Let’s now review a more complex sample. My idea was to start from the game I’ve written before. It’s exposed in this article: HTML5 Platformer: the complete port of the XNA game to <canvas> with EaselJS . I wanted to see what I should do to make it works on the phone.
First step is to simply copy/paste the different .js, .png, .css files into the “www” directory and to mark them as “Content”. Here are the others steps to follow.

Forcing the landscape orientation

The game has to be played in landscape mode. I’ve then forced this orientation. I’ve also remove the information bar on the side (the System Tray). For that, you need to open the MainPage.xaml file and change these properties:
SupportedOrientations="Landscape" Orientation="Landscape" shell:SystemTray.IsVisible="False"

Handling various resolutions

As my main goal was to build a game that could run on the highest number of devices, I need to handle a lot of different resolutions.
For that, I’ve slightly modified the initial code of the Platformer you can download in the other article. The game is now capable on running at any resolution by applying a rescale ratio on the images and sprites to draw. Everything is being redrawn based on a specific ratio that came from the Windows Phone (800x480) which is the 100% ratio. You can test this version in your desktop browser here: HTML5 Platformer ReScale and try to dynamically resize the browser window. Moreover, if your screen resolution has a 16/9 aspect ratio, press the F11 key to play in fullscreen! The experience in this mode is really cool as you can see in this screenshot:
image
We’re letting the browser taking care of the anti-aliasing during this scaling operation. Based on the browser you’ll use, you will notice also that the performance could vary a lot related to the size of the window you’ll have. On my machine, IE9/IE10 seems relatively indifferent to the fullscreen mode or small resolutions by maintaining a stable 60 fps framerate.

Loading the levels with calls to the file system instead of using XHR

In the initial code, the .TXT files linked to the each level were stored on the web server and downloaded via XmlHttpRequest calls. As we’re now running everything client-side in offline mode, XHR local calls are not very appropriated. I’ve then replaced the initial code of the PlatformerGame.prototype.LoadNextLevel function by this one:
PlatformerGame.prototype.LoadNextLevel = function () {
    this.levelIndex = (this.levelIndex + 1) % numberOfLevels;

    // Searching where we are currently hosted
    var nextFileName = "app/www/assets/levels/" + this.levelIndex + ".txt";
    try {
        var instance = this;
        window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, gotFS, fail);

        function gotFS(fileSystem) {
            fileSystem.root.getFile(nextFileName, null, gotFileEntry, fail);
        }

        function gotFileEntry(fileEntry) {
            fileEntry.file(gotFile, fail);
        }

        function gotFile(file) {
            readAsText(file);
        }

        function readAsText(file) {
            var reader = new FileReader();
            reader.onloadend = function (evt) {
                instance.LoadThisTextLevel(evt.target.result.replace(/[\n\r\t]/g, ''));
            };
            reader.readAsText(file);
        }

        function fail(evt) {
            console.log(evt.target.error.code);
        }
    }
    catch (e) {
        console.log("Error loading level: " + e.message);
        // Probably an access denied if you try to run from the file:// context
        // Loading the hard coded error level to have at least something to play with
        this.LoadThisTextLevel(hardcodedErrorTextLevel);
    }
};
I’ve just re-used the code available in the PhoneGap documentation: FileReader . As you can see, you have a full access to the Windows Phone file system from JavaScript with PhoneGap.
Cool tip: to help you debugging what’s really stored in the Isolated Storage of the phone or not, you should have a look to this awesome tool: IsoStoreSpy written by Samuel Blanchard.

Modification of the gameplay to use the accelerometer

Well, last part is just to mix all parts of this article to obtain the final result. For that, I’ve added the following code into the constructor of the Player object in the Player.js file:
var options = { frequency: 500 };
var that = this;

navigator.accelerometer.watchAcceleration(
    function (accelerometer) { that.moveDirectionAccel(accelerometer); },
    function () { console.log("Error with accelerometer"); }, 
    options);
Here is the function that will be call-backed during the accelerometer variations:
Player.prototype.moveDirectionAccel = function(acceleration) {
    var accelValue = -acceleration.y;

    // Move the player with accelerometer
    if (Math.abs(accelValue) > 0.15) {
        // set our movement speed
        this.direction = Math.clamp(accelValue * this.AccelerometerScale, -1, 1);
    }
    else {
        this.direction = 0;
    }
};
I’ve also added an handler on the “onmousedown” event on the canvas to jump when the user tap on the screen.

Screenshots of the result and FPS on some phones

First, let’s review the result within the Windows Phone emulator:
image
We have a framerate varying from 54 to 60 fps on my machine. On a real device, the framerate differs logically between models. Let’s take the first game level. On the LG E900, the framerate is around 22 fps. On the HTC Radar, it’s around 31 fps. On the Nokia Lumia 800, it’s around 42 fps.
DSCF4677
The gameplay could then be not very convincing in most cases. Indeed, I’m using a fullscreen canvas to draw the whole game. This is not a very good idea for the mobile limited power CPU, even if the Nokia seems powerful enough to handle this approach. A better methodology could be to cut the screen stage into various little canvas that will then be moved by modifying the CSS properties on them. This is what has been done for the HTML5 version of Angry Birds for instance. Some JS gaming frameworks start to think about handling this complexity for you. The idea would then be to code the game once with high level APIs and the framework could switch between a full frame canvas or various little canvas moved via CSS based on the performance.
Well, you’ll get it: the HTML5 gaming experience on mobile is currently just at its beginning. But its future looks very promising!

Complete Visual Studio Solution to download

You’ll find the complete source code of the HTML5 Platformer for PhoneGap here: HTML5GapPlatformer.zip

Other useful resources

Conclusion

PhoneGap offers interesting perspectives to help you writing applications on the phone. It lets you using your existing skills in JavaScript, HTML and CSS. PhoneGap won’t necessary cover all the scenarios currently available with the native development stack (Silverlight or XNA). But this could be something to have a look to if you’d like to capitalize on the HTML skills of one of your team. You will have to pay attention to properly identify the kind of project to work on.
You can also think about mixing both environments to create hybrid experiences: the main branch would be written using “HTML5” and some specific parts into native code. Using this idea, some plug-ins have been created to push a bit further the integration into the Metro UI: PhoneGap Plug-ins for Windows Phone . You’ll find for instance one of them allowing a JavaScript code to update the Tiles.
At last, PhoneGap and HTML5 could allow a relative portability to other platforms… with some limitations. But this is a vast subject with passionate debates that would need a complete dedicated article.