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Tuesday, 29 October 2013

Samsung Pen Package – Some Fundamentals

This is in continuation from my previous post. Samsung’s latest devices (Samsung Galaxy Note 3 and the Galaxy Note 10.1 (2014 edition) tablet) are unique with the introduction of the S Pen. The focus of the Samsung SmartApp Challenge that is currently open expects developers to use the pen and the look packages that are part of the Samsung Mobile SDK briefed in my earlier two posts.
In this post I would like to dive a bit deeper on the pen package and in a subsequent post on the look package. We will see what are they, as we go along.

S Pen is opening up a new horizon to Smartphones that support it. In fact I would not be surprised if Samsung soon open sources this project for encouraging wider adoption.

First, what is an S Pen?
Note that S Pen is an innovative stylus-type input device that comes with the Galaxy Note range of devices. It seems to have started off with the idea of making drawing or writing easy on smartphone where a finger touch doesn’t provide a great experience. It is not a capacitive stylus that typically phones came with but uses the Wacom’s EMR (Electro-Magnetic Resonance) patented Technology. For more on the technology behind the S Pen, you can read this article on the XDA Developers Forum or the ‘Android Authority’ post.
The tip of an S Pen allows for its usage in apps that need sensitivity to pressure applied and precision. The side buttons provide for press and release events based on which actions can be initiated.

In order to support developers to build apps for the S Pen, a pen package has been introduced as part of the Samsung Mobile SDK.

Next, what is the Pen package?
It is a package that allows developers to write applications that can take hand-written inputs. It allows the use of a pen, finger or any other kind of input tools or virtual pens to aid precise user input in the most natural way possible. It feels like you are actually writing or drawing on the device and would you call that a luxury? I am sure it is an understatement for thos who use their devices extensively for all day to day activities. J

The pen package enables to
  • ·      Draw using a pen/finger
  • ·      Change user preferences for pens, erasers and text
  • ·      Edit and save the inputs
  • ·      Undo or redo thus managing history of inputs
  • ·      Support both touch and hover events

A few words about the architecture of the pen package before we look at snippets of program using the package:

 This diagram is taken from the Samsung documentation.

As you can see the pen package is a layer over the Android platform using which many applications can be developed like the S-Note or S-Planner etc.

The pen core is organized into various packages with clear separation of responsibilities.  The relevant methods that can be used to develop apps have been made ‘public’ through what is shown as the ‘Pen API’.  It also provides a whole host of listeners that help in handling the touch, the hover, the zoom, the long press, the replay and the text change actions, to name a few.

The Engine provides the core of the package. It a way of managing the runtime objects and extensions to the Android view, line a canvas, text area, multi view, a context menu etc., that can take in inputs from the pen or a finger.

The Model module is literally the model of the pen package.  It gives APIs to save a pen document and retrieve it.  It could be a note that is to be saved and retrieved or a page with a set of strokes to be maintained in the history or even a image, a stroke or a text box with support for all text formatting – these could be persisted and retrieved.

The Setting module is one that helps in understand whether the device support s pen and manage the settings on the pen, eraser and text -  a small utility package.

The UI Control module consists of the various classes that help in managing the UI layouts and associated context menu.

The Plug-in module has a recognition class that allows for signature, text, shape and equation recognition that can be used for very interesting apps. The S pen Object Runtime allows developers to embed video clips or special text box as sandbox.

In order to start developing using the pen package, you need to download the Samsung Mobile SDK. It looks like that the programs need to be tested on a real device and are not supported on an emulator. I did try enabling on the emulator as given in the article on ‘Testing S Pen Apps on an Emulator’. However it seems that it works with what is called the S Pen SDK and not with the pen package, which is the focus of the developer challenge.

Now, unzip the Mobile SDK and you will find a folder by name libs. In libs, you find pen folder in which you have 2 jar files – “pen-v1.0.0.jar” and “sdk-v1.0.0.jar”.  Both of these need to be copied into your Android project libs folder and you are ready to create a pen based app.

You can start with a simple hello world program:

In the onCreate() method, you will have to check the support for the s pen feature first:

boolean isSpenFeatureEnabled = false;
Spen spenPackage = new Spen();
try {
      isSpenFeatureEnabled = spenPackage.isFeatureEnabled(Spen.DEVICE_PEN);
     } catch (SsdkUnsupportedException e) {
        //Handle the exception here   
     } catch (Exception e1) {
         Toast.makeText(mContext, "Cannot initialize Spen.",

Once this basic and essential check is done, let us create a SpenSurfaceView and add it to a relative layout:

RelativeLayout spenViewLayout =
            (RelativeLayout) findViewById(;
        mSpenSurfaceView = new SpenSurfaceView(mContext);
        if (mSpenSurfaceView == null) {
            Toast.makeText(mContext, "Cannot create new SpenView.",

The next thing you need to do is a SpenNoteDoc which holds a SpenPageDoc within it and voila, you are ready with the first Spen app J

Display display = getWindowManager().getDefaultDisplay();
Rect rect = new Rect();
try {
     mSpenNoteDoc =
     new SpenNoteDoc(mContext, rect.width(), rect.height());
     } catch (IOException e) {
        Toast.makeText(mContext, "Cannot create new NoteDoc.",
     } catch (Exception e) {

        mSpenPageDoc = mSpenNoteDoc.appendPage();
        mSpenSurfaceView.setPageDoc(mSpenPageDoc, true);

Note that when you create a SpenNotedoc, you make it as big as the display size that is available.
Then you create a SpenPageDoc and append it to SpenNoteDoc and could optional set parameters like the background and clear the history, if any.
And finally in the onDestroy() method ensure that you clean up after yourself as shown:
    protected void onDestroy() {

        if(mSpenSurfaceView != null) {
            mSpenSurfaceView = null;

        if(mSpenNoteDoc != null) {
            try {
            } catch (Exception e) {
            mSpenNoteDoc = null;

And you are done!!  With this you have created the first pen app with a canvas that takes the written input from a pen or a finger J

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