Deleting old tutorial files and put them in folders

doc/tutorials/HighGUI/Adding_Trackbars/Adding_Trackbars.rst

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+.. _Adding_Trackbars:
+
+Adding a Trackbar to our applications!
+***************************************
+
+* In the previous tutorials (about *linear blending* and the *brightness and contrast adjustments*) you might have noted that we needed to give some **input** to our programs, such as :math:`\alpha` and :math:`beta`. We accomplished that by entering this data using the Terminal
+
+* Well, it is time to use some fancy GUI tools. OpenCV provides some GUI utilities (*highgui.h*) for you. An example of this is a **Trackbar** 
+
+  .. image:: images/Adding_Trackbars_Tutorial_Trackbar.png
+     :alt: Trackbar example
+     :align: center 
+
+* In this tutorial we will just modify our two previous programs so that they get the input information from the trackbar.
+
+
+Goals
+======
+
+In this tutorial you will learn how to:
+
+* Add a Trackbar in an OpenCV window by using  :create_trackbar:`createTrackbar <>` 
+
+Code
+=====
+
+Let's modify the program made in the tutorial :ref:`Adding_Images`. We will let the user enter the :math:`\alpha` value by using the Trackbar.
+
+.. code-block:: cpp
+
+   #include <cv.h>
+   #include <highgui.h>
+
+   using namespace cv;
+
+   /// Global Variables 
+   const int alpha_slider_max = 100;
+   int alpha_slider; 
+   double alpha;
+   double beta;  
+
+   /// Matrices to store images 
+   Mat src1;
+   Mat src2;
+   Mat dst;
+
+   /**
+    * @function on_trackbar
+    * @brief Callback for trackbar
+    */
+   void on_trackbar( int, void* )
+   { 
+    alpha = (double) alpha_slider/alpha_slider_max ;
+    beta = ( 1.0 - alpha );
+
+    addWeighted( src1, alpha, src2, beta, 0.0, dst);
+  
+    imshow( "Linear Blend", dst );
+   }
+
+   int main( int argc, char** argv )
+   {
+    /// Read image ( same size, same type )
+    src1 = imread("../../images/LinuxLogo.jpg");
+    src2 = imread("../../images/WindowsLogo.jpg");
+
+    if( !src1.data ) { printf("Error loading src1 \n"); return -1; }
+    if( !src2.data ) { printf("Error loading src2 \n"); return -1; }
+
+    /// Initialize values 
+    alpha_slider = 0;
+
+    /// Create Windows
+    namedWindow("Linear Blend", 1);
+
+    /// Create Trackbars
+    char TrackbarName[50];
+    sprintf( TrackbarName, "Alpha x %d", alpha_slider_max ); 
+
+    createTrackbar( TrackbarName, "Linear Blend", &alpha_slider, alpha_slider_max, on_trackbar );
+
+    /// Show some stuff
+    on_trackbar( alpha_slider, 0 );
+  
+    /// Wait until user press some key
+    waitKey(0);
+    return 0;
+   }
+
+
+Explanation
+============
+
+We only analyze the code that is related to Trackbar:
+
+#. First, we load 02 images, which are going to be blended.
+
+   .. code-block:: cpp
+
+      src1 = imread("../../images/LinuxLogo.jpg");
+      src2 = imread("../../images/WindowsLogo.jpg");
+
+#. To create a trackbar, first we have to create the window in which it is going to be located. So:
+
+   .. code-block:: cpp
+
+      namedWindow("Linear Blend", 1);
+
+#. Now we can create the Trackbar:
+
+   .. code-block:: cpp
+
+      createTrackbar( TrackbarName, "Linear Blend", &alpha_slider, alpha_slider_max, on_trackbar );
+
+   Note the following:
+   
+   * Our Trackbar has a label **TrackbarName**
+   * The Trackbar is located in the window named **"Linear Blend"**
+   * The Trackbar values will be in the range from :math:`0` to **alpha_slider_max** (the minimum limit is always **zero**).
+   * The numerical value of Trackbar is stored in **alpha_slider**
+   * Whenever the user moves the Trackbar, the callback function **on_trackbar** is called
+
+#. Finally, we have to define the callback function **on_trackbar**
+
+   .. code-block:: cpp
+
+      void on_trackbar( int, void* )
+      { 
+       alpha = (double) alpha_slider/alpha_slider_max ;
+       beta = ( 1.0 - alpha );
+
+       addWeighted( src1, alpha, src2, beta, 0.0, dst);
+  
+       imshow( "Linear Blend", dst );
+      }
+
+   Note that:
+ 
+   * We use the value of **alpha_slider** (integer) to get a double value for **alpha**. 
+   * **alpha_slider** is updated each time the trackbar is displaced by the user.
+   * We define *src1*, *src2*, *dist*, *alpha*, *alpha_slider* and *beta* as global  variables, so they can be used everywhere.
+ 
+Result
+=======
+
+* Our program produces the following output:
+
+  .. image:: images/Adding_Trackbars_Tutorial_Result_0.png
+     :alt: Adding Trackbars - Windows Linux
+     :align: center 
+
+* As a manner of practice, you can also add 02 trackbars for the program made in :ref:`Basic_Linear_Transform`. One trackbar to set :math:`\alpha` and another for :math:`\beta`. The output might look like:
+
+  .. image:: images/Adding_Trackbars_Tutorial_Result_1.png
+     :alt: Adding Trackbars - Lena
+     :height: 500px
+     :align: center 
+
+
+
+
+