Add Java and Python code for the following imgproc tutorials: Finding contours...

Add Java and Python code for the following imgproc tutorials: Finding contours in your image, Convex Hull, Creating Bounding boxes and circles for contours, Creating Bounding rotated boxes and ellipses for contours, Image Moments, Point Polygon Test.

doc/tutorials/imgproc/shapedescriptors/bounding_rects_circles/bounding_rects_circles.markdown

@@ -15,55 +15,167 @@ Theory
 Code
 ----
 
+@add_toggle_cpp
 This tutorial code's is shown lines below. You can also download it from
 [here](https://github.com/opencv/opencv/tree/3.4/samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp)
 @include samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp
+@end_toggle
+
+@add_toggle_java
+This tutorial code's is shown lines below. You can also download it from
+[here](https://github.com/opencv/opencv/tree/3.4/samples/java/tutorial_code/ShapeDescriptors/bounding_rects_circles/GeneralContoursDemo1.java)
+@include samples/java/tutorial_code/ShapeDescriptors/bounding_rects_circles/GeneralContoursDemo1.java
+@end_toggle
+
+@add_toggle_python
+This tutorial code's is shown lines below. You can also download it from
+[here](https://github.com/opencv/opencv/tree/3.4/samples/python/tutorial_code/ShapeDescriptors/bounding_rects_circles/generalContours_demo1.py)
+@include samples/python/tutorial_code/ShapeDescriptors/bounding_rects_circles/generalContours_demo1.py
+@end_toggle
 
 Explanation
 -----------
 
 The main function is rather simple, as follows from the comments we do the following:
--#  Open the image, convert it into grayscale and blur it to get rid of the noise.
-    @snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp setup
--# Create a window with header "Source" and display the source file in it.
-    @snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp createWindow
--# Create a trackbar on the source_window and assign a callback function to it
+-   Open the image, convert it into grayscale and blur it to get rid of the noise.
+
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp setup
+@end_toggle
+
+@add_toggle_java
+@snippet samples/java/tutorial_code/ShapeDescriptors/bounding_rects_circles/GeneralContoursDemo1.java setup
+@end_toggle
+
+@add_toggle_python
+@snippet samples/python/tutorial_code/ShapeDescriptors/bounding_rects_circles/generalContours_demo1.py setup
+@end_toggle
+
+-  Create a window with header "Source" and display the source file in it.
+
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp createWindow
+@end_toggle
+
+@add_toggle_java
+@snippet samples/java/tutorial_code/ShapeDescriptors/bounding_rects_circles/GeneralContoursDemo1.java createWindow
+@end_toggle
+
+@add_toggle_python
+@snippet samples/python/tutorial_code/ShapeDescriptors/bounding_rects_circles/generalContours_demo1.py createWindow
+@end_toggle
+
+-  Create a trackbar on the `source_window` and assign a callback function to it.
    In general callback functions are used to react to some kind of signal, in our
    case it's trackbar's state change.
-   @snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp taskbar
--# Explicit one-time call of `thresh_callback` is necessary to display
+   Explicit one-time call of `thresh_callback` is necessary to display
    the "Contours" window simultaniously with the "Source" window.
-   @snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp callback00
--# Wait for user to close the windows.
-   @snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp waitForIt
 
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp trackbar
+@end_toggle
 
-The callback function `thresh_callback` does all the interesting job.
+@add_toggle_java
+@snippet samples/java/tutorial_code/ShapeDescriptors/bounding_rects_circles/GeneralContoursDemo1.java trackbar
+@end_toggle
 
+@add_toggle_python
+@snippet samples/python/tutorial_code/ShapeDescriptors/bounding_rects_circles/generalContours_demo1.py trackbar
+@end_toggle
 
--# Writes to `threshold_output` the threshold of the grayscale picture (you can check out about thresholding @ref tutorial_threshold "here").
-   @snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp threshold
--# Finds contours and saves them to the vectors `contour` and `hierarchy`.
-    @snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp findContours
--# For every found contour we now apply approximation to polygons
-   with accuracy +-3 and stating that the curve must me closed.
+The callback function does all the interesting job.
 
-   After that we find a bounding rect for every polygon and save it to `boundRect`.
+-  Use @ref cv::Canny to detect edges in the images.
+
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp Canny
+@end_toggle
+
+@add_toggle_java
+@snippet samples/java/tutorial_code/ShapeDescriptors/bounding_rects_circles/GeneralContoursDemo1.java Canny
+@end_toggle
+
+@add_toggle_python
+@snippet samples/python/tutorial_code/ShapeDescriptors/bounding_rects_circles/generalContours_demo1.py Canny
+@end_toggle
+
+-  Finds contours and saves them to the vectors `contour` and `hierarchy`.
+
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp findContours
+@end_toggle
 
+@add_toggle_java
+@snippet samples/java/tutorial_code/ShapeDescriptors/bounding_rects_circles/GeneralContoursDemo1.java findContours
+@end_toggle
+
+@add_toggle_python
+@snippet samples/python/tutorial_code/ShapeDescriptors/bounding_rects_circles/generalContours_demo1.py findContours
+@end_toggle
+
+-  For every found contour we now apply approximation to polygons
+   with accuracy +-3 and stating that the curve must be closed.
+   After that we find a bounding rect for every polygon and save it to `boundRect`.
    At last we find a minimum enclosing circle for every polygon and
    save it to `center` and `radius` vectors.
-   @snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp allthework
+
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp allthework
+@end_toggle
+
+@add_toggle_java
+@snippet samples/java/tutorial_code/ShapeDescriptors/bounding_rects_circles/GeneralContoursDemo1.java allthework
+@end_toggle
+
+@add_toggle_python
+@snippet samples/python/tutorial_code/ShapeDescriptors/bounding_rects_circles/generalContours_demo1.py allthework
+@end_toggle
 
 We found everything we need, all we have to do is to draw.
 
--# Create new Mat of unsigned 8-bit chars, filled with zeros.
+-  Create new Mat of unsigned 8-bit chars, filled with zeros.
    It will contain all the drawings we are going to make (rects and circles).
-   @snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp zeroMat
--# For every contour: pick a random color, draw the contour, the bounding rectangle and
-   the minimal enclosing circle with it,
-   @snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp forContour
--# Display the results: create a new window "Contours" and show everything we added to drawings on it.
-   @snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp showDrawings
+
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp zeroMat
+@end_toggle
+
+@add_toggle_java
+@snippet samples/java/tutorial_code/ShapeDescriptors/bounding_rects_circles/GeneralContoursDemo1.java zeroMat
+@end_toggle
+
+@add_toggle_python
+@snippet samples/python/tutorial_code/ShapeDescriptors/bounding_rects_circles/generalContours_demo1.py zeroMat
+@end_toggle
+
+-  For every contour: pick a random color, draw the contour, the bounding rectangle and
+   the minimal enclosing circle with it.
+
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp forContour
+@end_toggle
+
+@add_toggle_java
+@snippet samples/java/tutorial_code/ShapeDescriptors/bounding_rects_circles/GeneralContoursDemo1.java forContour
+@end_toggle
+
+@add_toggle_python
+@snippet samples/python/tutorial_code/ShapeDescriptors/bounding_rects_circles/generalContours_demo1.py forContour
+@end_toggle
+
+-  Display the results: create a new window "Contours" and show everything we added to drawings on it.
+
+@add_toggle_cpp
+@snippet samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp showDrawings
+@end_toggle
+
+@add_toggle_java
+@snippet samples/java/tutorial_code/ShapeDescriptors/bounding_rects_circles/GeneralContoursDemo1.java showDrawings
+@end_toggle
+
+@add_toggle_python
+@snippet samples/python/tutorial_code/ShapeDescriptors/bounding_rects_circles/generalContours_demo1.py showDrawings
+@end_toggle
 
 Result
 ------

doc/tutorials/imgproc/shapedescriptors/bounding_rotated_ellipses/bounding_rotated_ellipses.markdown

@@ -15,9 +15,23 @@ Theory
 Code
 ----
 
+@add_toggle_cpp
 This tutorial code's is shown lines below. You can also download it from
 [here](https://github.com/opencv/opencv/tree/3.4/samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo2.cpp)
 @include samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo2.cpp
+@end_toggle
+
+@add_toggle_java
+This tutorial code's is shown lines below. You can also download it from
+[here](https://github.com/opencv/opencv/tree/3.4/samples/java/tutorial_code/ShapeDescriptors/bounding_rotated_ellipses/GeneralContoursDemo2.java)
+@include samples/java/tutorial_code/ShapeDescriptors/bounding_rotated_ellipses/GeneralContoursDemo2.java
+@end_toggle
+
+@add_toggle_python
+This tutorial code's is shown lines below. You can also download it from
+[here](https://github.com/opencv/opencv/tree/3.4/samples/python/tutorial_code/ShapeDescriptors/bounding_rotated_ellipses/generalContours_demo2.py)
+@include samples/python/tutorial_code/ShapeDescriptors/bounding_rotated_ellipses/generalContours_demo2.py
+@end_toggle
 
 Explanation
 -----------

doc/tutorials/imgproc/shapedescriptors/find_contours/find_contours.markdown

@@ -15,9 +15,23 @@ Theory
 Code
 ----
 
+@add_toggle_cpp
 This tutorial code's is shown lines below. You can also download it from
 [here](https://github.com/opencv/opencv/tree/3.4/samples/cpp/tutorial_code/ShapeDescriptors/findContours_demo.cpp)
 @include samples/cpp/tutorial_code/ShapeDescriptors/findContours_demo.cpp
+@end_toggle
+
+@add_toggle_java
+This tutorial code's is shown lines below. You can also download it from
+[here](https://github.com/opencv/opencv/tree/3.4/samples/java/tutorial_code/ShapeDescriptors/find_contours/FindContoursDemo.java)
+@include samples/java/tutorial_code/ShapeDescriptors/find_contours/FindContoursDemo.java
+@end_toggle
+
+@add_toggle_python
+This tutorial code's is shown lines below. You can also download it from
+[here](https://github.com/opencv/opencv/tree/3.4/samples/python/tutorial_code/ShapeDescriptors/find_contours/findContours_demo.py)
+@include samples/python/tutorial_code/ShapeDescriptors/find_contours/findContours_demo.py
+@end_toggle
 
 Explanation
 -----------

doc/tutorials/imgproc/shapedescriptors/hull/hull.markdown

@@ -14,10 +14,23 @@ Theory
 Code
 ----
 
+@add_toggle_cpp
 This tutorial code's is shown lines below. You can also download it from
 [here](https://github.com/opencv/opencv/tree/3.4/samples/cpp/tutorial_code/ShapeDescriptors/hull_demo.cpp)
-
 @include samples/cpp/tutorial_code/ShapeDescriptors/hull_demo.cpp
+@end_toggle
+
+@add_toggle_java
+This tutorial code's is shown lines below. You can also download it from
+[here](https://github.com/opencv/opencv/tree/3.4/samples/java/tutorial_code/ShapeDescriptors/hull/HullDemo.java)
+@include samples/java/tutorial_code/ShapeDescriptors/hull/HullDemo.java
+@end_toggle
+
+@add_toggle_python
+This tutorial code's is shown lines below. You can also download it from
+[here](https://github.com/opencv/opencv/tree/3.4/samples/python/tutorial_code/ShapeDescriptors/hull/hull_demo.py)
+@include samples/python/tutorial_code/ShapeDescriptors/hull/hull_demo.py
+@end_toggle
 
 Explanation
 -----------

doc/tutorials/imgproc/shapedescriptors/moments/moments.markdown

@@ -16,9 +16,23 @@ Theory
 Code
 ----
 
+@add_toggle_cpp
 This tutorial code's is shown lines below. You can also download it from
 [here](https://github.com/opencv/opencv/tree/3.4/samples/cpp/tutorial_code/ShapeDescriptors/moments_demo.cpp)
 @include samples/cpp/tutorial_code/ShapeDescriptors/moments_demo.cpp
+@end_toggle
+
+@add_toggle_java
+This tutorial code's is shown lines below. You can also download it from
+[here](https://github.com/opencv/opencv/tree/3.4/samples/java/tutorial_code/ShapeDescriptors/moments/MomentsDemo.java)
+@include samples/java/tutorial_code/ShapeDescriptors/moments/MomentsDemo.java
+@end_toggle
+
+@add_toggle_python
+This tutorial code's is shown lines below. You can also download it from
+[here](https://github.com/opencv/opencv/tree/3.4/samples/python/tutorial_code/ShapeDescriptors/moments/moments_demo.py)
+@include samples/python/tutorial_code/ShapeDescriptors/moments/moments_demo.py
+@end_toggle
 
 Explanation
 -----------

doc/tutorials/imgproc/shapedescriptors/point_polygon_test/point_polygon_test.markdown

@@ -14,9 +14,23 @@ Theory
 Code
 ----
 
+@add_toggle_cpp
 This tutorial code's is shown lines below. You can also download it from
 [here](https://github.com/opencv/opencv/tree/3.4/samples/cpp/tutorial_code/ShapeDescriptors/pointPolygonTest_demo.cpp)
 @include samples/cpp/tutorial_code/ShapeDescriptors/pointPolygonTest_demo.cpp
+@end_toggle
+
+@add_toggle_java
+This tutorial code's is shown lines below. You can also download it from
+[here](https://github.com/opencv/opencv/tree/3.4/samples/java/tutorial_code/ShapeDescriptors/point_polygon_test/PointPolygonTestDemo.java)
+@include samples/java/tutorial_code/ShapeDescriptors/point_polygon_test/PointPolygonTestDemo.java
+@end_toggle
+
+@add_toggle_python
+This tutorial code's is shown lines below. You can also download it from
+[here](https://github.com/opencv/opencv/tree/3.4/samples/python/tutorial_code/ShapeDescriptors/point_polygon_test/pointPolygonTest_demo.py)
+@include samples/python/tutorial_code/ShapeDescriptors/point_polygon_test/pointPolygonTest_demo.py
+@end_toggle
 
 Explanation
 -----------

doc/tutorials/imgproc/table_of_content_imgproc.markdown

@@ -225,6 +225,8 @@ In this section you will learn about the image processing (manipulation) functio
 
 -   @subpage tutorial_find_contours
 
+    *Languages:* C++, Java, Python
+
     *Compatibility:* \> OpenCV 2.0
 
     *Author:* Ana Huamán
@@ -233,6 +235,8 @@ In this section you will learn about the image processing (manipulation) functio
 
 -    @subpage tutorial_hull
 
+    *Languages:* C++, Java, Python
+
     *Compatibility:* \> OpenCV 2.0
 
     *Author:* Ana Huamán
@@ -241,6 +245,8 @@ In this section you will learn about the image processing (manipulation) functio
 
 -   @subpage tutorial_bounding_rects_circles
 
+    *Languages:* C++, Java, Python
+
     *Compatibility:* \> OpenCV 2.0
 
     *Author:* Ana Huamán
@@ -249,6 +255,8 @@ In this section you will learn about the image processing (manipulation) functio
 
 -   @subpage tutorial_bounding_rotated_ellipses
 
+    *Languages:* C++, Java, Python
+
     *Compatibility:* \> OpenCV 2.0
 
     *Author:* Ana Huamán
@@ -257,6 +265,8 @@ In this section you will learn about the image processing (manipulation) functio
 
 -   @subpage tutorial_moments
 
+    *Languages:* C++, Java, Python
+
     *Compatibility:* \> OpenCV 2.0
 
     *Author:* Ana Huamán
@@ -265,6 +275,8 @@ In this section you will learn about the image processing (manipulation) functio
 
 -   @subpage tutorial_point_polygon_test
 
+    *Languages:* C++, Java, Python
+
     *Compatibility:* \> OpenCV 2.0
 
     *Author:* Ana Huamán

samples/cpp/tutorial_code/ShapeDescriptors/findContours_demo.cpp

@@ -12,9 +12,8 @@
 using namespace cv;
 using namespace std;
 
-Mat src; Mat src_gray;
+Mat src_gray;
 int thresh = 100;
-int max_thresh = 255;
 RNG rng(12345);
 
 /// Function header
@@ -25,34 +24,31 @@ void thresh_callback(int, void* );
  */
 int main( int argc, char** argv )
 {
-  /// Load source image
-  String imageName("../data/happyfish.jpg"); // by default
-  if (argc > 1)
-  {
-    imageName = argv[1];
-  }
-  src = imread(imageName, IMREAD_COLOR);
+    /// Load source image
+    CommandLineParser parser( argc, argv, "{@input | ../data/HappyFish.jpg | input image}" );
+    Mat src = imread( parser.get<String>( "@input" ) );
+    if( src.empty() )
+    {
+      cout << "Could not open or find the image!\n" << endl;
+      cout << "Usage: " << argv[0] << " <Input image>" << endl;
+      return -1;
+    }
 
-  if (src.empty())
-  {
-    cerr << "No image supplied ..." << endl;
-    return -1;
-  }
+    /// Convert image to gray and blur it
+    cvtColor( src, src_gray, COLOR_BGR2GRAY );
+    blur( src_gray, src_gray, Size(3,3) );
 
-  /// Convert image to gray and blur it
-  cvtColor( src, src_gray, COLOR_BGR2GRAY );
-  blur( src_gray, src_gray, Size(3,3) );
+    /// Create Window
+    const char* source_window = "Source";
+    namedWindow( source_window );
+    imshow( source_window, src );
 
-  /// Create Window
-  const char* source_window = "Source";
-  namedWindow( source_window, WINDOW_AUTOSIZE );
-  imshow( source_window, src );
+    const int max_thresh = 255;
+    createTrackbar( "Canny thresh:", source_window, &thresh, max_thresh, thresh_callback );
+    thresh_callback( 0, 0 );
 
-  createTrackbar( " Canny thresh:", "Source", &thresh, max_thresh, thresh_callback );
-  thresh_callback( 0, 0 );
-
-  waitKey(0);
-  return(0);
+    waitKey();
+    return 0;
 }
 
 /**
@@ -60,24 +56,23 @@ int main( int argc, char** argv )
  */
 void thresh_callback(int, void* )
 {
-  Mat canny_output;
-  vector<vector<Point> > contours;
-  vector<Vec4i> hierarchy;
+    /// Detect edges using Canny
+    Mat canny_output;
+    Canny( src_gray, canny_output, thresh, thresh*2 );
 
-  /// Detect edges using canny
-  Canny( src_gray, canny_output, thresh, thresh*2, 3 );
-  /// Find contours
-  findContours( canny_output, contours, hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0) );
+    /// Find contours
+    vector<vector<Point> > contours;
+    vector<Vec4i> hierarchy;
+    findContours( canny_output, contours, hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE );
 
-  /// Draw contours
-  Mat drawing = Mat::zeros( canny_output.size(), CV_8UC3 );
-  for( size_t i = 0; i< contours.size(); i++ )
-     {
-       Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) );
-       drawContours( drawing, contours, (int)i, color, 2, 8, hierarchy, 0, Point() );
-     }
+    /// Draw contours
+    Mat drawing = Mat::zeros( canny_output.size(), CV_8UC3 );
+    for( size_t i = 0; i< contours.size(); i++ )
+    {
+        Scalar color = Scalar( rng.uniform(0, 256), rng.uniform(0,256), rng.uniform(0,256) );
+        drawContours( drawing, contours, (int)i, color, 2, LINE_8, hierarchy, 0 );
+    }
 
-  /// Show in a window
-  namedWindow( "Contours", WINDOW_AUTOSIZE );
-  imshow( "Contours", drawing );
+    /// Show in a window
+    imshow( "Contours", drawing );
 }

samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo1.cpp

@@ -12,9 +12,8 @@
 using namespace cv;
 using namespace std;
 
-Mat src; Mat src_gray;
+Mat src_gray;
 int thresh = 100;
-int max_thresh = 255;
 RNG rng(12345);
 
 /// Function header
@@ -25,42 +24,37 @@ void thresh_callback(int, void* );
  */
 int main( int argc, char** argv )
 {
-  //![setup]
-  /// Load source image
-  CommandLineParser parser( argc, argv, "{@input | ../data/stuff.jpg | input image}" );
-  src = imread( parser.get<String>( "@input" ), IMREAD_COLOR );
-  if( src.empty() )
+    //! [setup]
+    /// Load source image
+    CommandLineParser parser( argc, argv, "{@input | ../data/stuff.jpg | input image}" );
+    Mat src = imread( parser.get<String>( "@input" ) );
+    if( src.empty() )
     {
-      cout << "Could not open or find the image!\n" << endl;
-      cout << "usage: " << argv[0] << " <Input image>" << endl;
-      return -1;
+        cout << "Could not open or find the image!\n" << endl;
+        cout << "usage: " << argv[0] << " <Input image>" << endl;
+        return -1;
     }
 
-  /// Convert image to gray and blur it
-  cvtColor( src, src_gray, COLOR_BGR2GRAY );
-  blur( src_gray, src_gray, Size(3,3) );
-  //![setup]
-
-  //![createWindow]
-  /// Create Window
-  const char* source_window = "Source";
-  namedWindow( source_window, WINDOW_AUTOSIZE );
-  imshow( source_window, src );
-  //![createWindow]
-
-  //![taskbar]
-  createTrackbar( " Threshold:", "Source", &thresh, max_thresh, thresh_callback );
-  //![taskbar]
-
-  //![callback00]
-  thresh_callback( 0, 0 );
-  //![callback00]
-
-  //![waitForIt]
-  waitKey(0);
-  //![waitForIt]
-
-  return(0);
+    /// Convert image to gray and blur it
+    cvtColor( src, src_gray, COLOR_BGR2GRAY );
+    blur( src_gray, src_gray, Size(3,3) );
+    //! [setup]
+
+    //! [createWindow]
+    /// Create Window
+    const char* source_window = "Source";
+    namedWindow( source_window );
+    imshow( source_window, src );
+    //! [createWindow]
+
+    //! [trackbar]
+    const int max_thresh = 255;
+    createTrackbar( "Canny thresh:", source_window, &thresh, max_thresh, thresh_callback );
+    thresh_callback( 0, 0 );
+    //! [trackbar]
+
+    waitKey();
+    return 0;
 }
 
 /**
@@ -68,53 +62,50 @@ int main( int argc, char** argv )
  */
 void thresh_callback(int, void* )
 {
-  Mat threshold_output;
-  vector<vector<Point> > contours;
-  vector<Vec4i> hierarchy;
-
-  //![threshold]
-  /// Detect edges using Threshold
-  threshold( src_gray, threshold_output, thresh, 255, THRESH_BINARY );
-  //![threshold]
-
-  //![findContours]
-  /// Find contours
-  findContours( threshold_output, contours, hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0) );
-  //![findContours]
-
-  /// Approximate contours to polygons + get bounding rects and circles
-  vector<vector<Point> > contours_poly( contours.size() );
-  vector<Rect> boundRect( contours.size() );
-  vector<Point2f>center( contours.size() );
-  vector<float>radius( contours.size() );
-
-  //![allthework]
-  for( size_t i = 0; i < contours.size(); i++ )
-  {
-    approxPolyDP( contours[i], contours_poly[i], 3, true );
-    boundRect[i] = boundingRect( contours_poly[i] );
-    minEnclosingCircle( contours_poly[i], center[i], radius[i] );
-  }
-  //![allthework]
-
-  //![zeroMat]
-  /// Draw polygonal contour + bonding rects + circles
-  Mat drawing = Mat::zeros( threshold_output.size(), CV_8UC3 );
-  //![zeroMat]
-
-  //![forContour]
-  for( size_t i = 0; i< contours.size(); i++ )
-  {
-    Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) );
-    drawContours( drawing, contours_poly, (int)i, color, 1, 8, vector<Vec4i>(), 0, Point() );
-    rectangle( drawing, boundRect[i].tl(), boundRect[i].br(), color, 2, 8, 0 );
-    circle( drawing, center[i], (int)radius[i], color, 2, 8, 0 );
-  }
-  //![forContour]
-
-  //![showDrawings]
-  /// Show in a window
-  namedWindow( "Contours", WINDOW_AUTOSIZE );
-  imshow( "Contours", drawing );
-  //![showDrawings]
+    //! [Canny]
+    /// Detect edges using Canny
+    Mat canny_output;
+    Canny( src_gray, canny_output, thresh, thresh*2 );
+    //! [Canny]
+
+    //! [findContours]
+    /// Find contours
+    vector<vector<Point> > contours;
+    findContours( canny_output, contours, RETR_TREE, CHAIN_APPROX_SIMPLE );
+    //! [findContours]
+
+    //! [allthework]
+    /// Approximate contours to polygons + get bounding rects and circles
+    vector<vector<Point> > contours_poly( contours.size() );
+    vector<Rect> boundRect( contours.size() );
+    vector<Point2f>centers( contours.size() );
+    vector<float>radius( contours.size() );
+
+    for( size_t i = 0; i < contours.size(); i++ )
+    {
+        approxPolyDP( contours[i], contours_poly[i], 3, true );
+        boundRect[i] = boundingRect( contours_poly[i] );
+        minEnclosingCircle( contours_poly[i], centers[i], radius[i] );
+    }
+    //! [allthework]
+
+    //! [zeroMat]
+    Mat drawing = Mat::zeros( canny_output.size(), CV_8UC3 );
+    //! [zeroMat]
+
+    //! [forContour]
+    /// Draw polygonal contour + bonding rects + circles
+    for( size_t i = 0; i< contours.size(); i++ )
+    {
+        Scalar color = Scalar( rng.uniform(0, 256), rng.uniform(0,256), rng.uniform(0,256) );
+        drawContours( drawing, contours_poly, (int)i, color );
+        rectangle( drawing, boundRect[i].tl(), boundRect[i].br(), color, 2 );
+        circle( drawing, centers[i], (int)radius[i], color, 2 );
+    }
+    //! [forContour]
+
+    //! [showDrawings]
+    /// Show in a window
+    imshow( "Contours", drawing );
+    //! [showDrawings]
 }

samples/cpp/tutorial_code/ShapeDescriptors/generalContours_demo2.cpp

@@ -12,9 +12,8 @@
 using namespace cv;
 using namespace std;
 
-Mat src; Mat src_gray;
+Mat src_gray;
 int thresh = 100;
-int max_thresh = 255;
 RNG rng(12345);
 
 /// Function header
@@ -25,30 +24,31 @@ void thresh_callback(int, void* );
  */
 int main( int argc, char** argv )
 {
-  /// Load source image and convert it to gray
-  CommandLineParser parser( argc, argv, "{@input | ../data/stuff.jpg | input image}" );
-  src = imread( parser.get<String>( "@input" ), IMREAD_COLOR );
-  if( src.empty() )
+    /// Load source image and convert it to gray
+    CommandLineParser parser( argc, argv, "{@input | ../data/stuff.jpg | input image}" );
+    Mat src = imread( parser.get<String>( "@input" ) );
+    if( src.empty() )
     {
-      cout << "Could not open or find the image!\n" << endl;
-      cout << "Usage: " << argv[0] << " <Input image>" << endl;
-      return -1;
+        cout << "Could not open or find the image!\n" << endl;
+        cout << "Usage: " << argv[0] << " <Input image>" << endl;
+        return -1;
     }
 
-  /// Convert image to gray and blur it
-  cvtColor( src, src_gray, COLOR_BGR2GRAY );
-  blur( src_gray, src_gray, Size(3,3) );
+    /// Convert image to gray and blur it
+    cvtColor( src, src_gray, COLOR_BGR2GRAY );
+    blur( src_gray, src_gray, Size(3,3) );
 
-  /// Create Window
-  const char* source_window = "Source";
-  namedWindow( source_window, WINDOW_AUTOSIZE );
-  imshow( source_window, src );
+    /// Create Window
+    const char* source_window = "Source";
+    namedWindow( source_window );
+    imshow( source_window, src );
 
-  createTrackbar( " Threshold:", "Source", &thresh, max_thresh, thresh_callback );
-  thresh_callback( 0, 0 );
+    const int max_thresh = 255;
+    createTrackbar( "Canny thresh:", source_window, &thresh, max_thresh, thresh_callback );
+    thresh_callback( 0, 0 );
 
-  waitKey(0);
-  return(0);
+    waitKey();
+    return 0;
 }
 
 /**
@@ -56,41 +56,43 @@ int main( int argc, char** argv )
  */
 void thresh_callback(int, void* )
 {
-  Mat threshold_output;
-  vector<vector<Point> > contours;
-  vector<Vec4i> hierarchy;
+    /// Detect edges using Canny
+    Mat canny_output;
+    Canny( src_gray, canny_output, thresh, thresh*2 );
+    /// Find contours
+    vector<vector<Point> > contours;
+    findContours( canny_output, contours, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0) );
 
-  /// Detect edges using Threshold
-  threshold( src_gray, threshold_output, thresh, 255, THRESH_BINARY );
-  /// Find contours
-  findContours( threshold_output, contours, hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0) );
-
-  /// Find the rotated rectangles and ellipses for each contour
-  vector<RotatedRect> minRect( contours.size() );
-  vector<RotatedRect> minEllipse( contours.size() );
-
-  for( size_t i = 0; i < contours.size(); i++ )
-     { minRect[i] = minAreaRect( contours[i] );
-       if( contours[i].size() > 5 )
-         { minEllipse[i] = fitEllipse( contours[i] ); }
-     }
+    /// Find the rotated rectangles and ellipses for each contour
+    vector<RotatedRect> minRect( contours.size() );
+    vector<RotatedRect> minEllipse( contours.size() );
+    for( size_t i = 0; i < contours.size(); i++ )
+    {
+        minRect[i] = minAreaRect( contours[i] );
+        if( contours[i].size() > 5 )
+        {
+            minEllipse[i] = fitEllipse( contours[i] );
+        }
+    }
 
-  /// Draw contours + rotated rects + ellipses
-  Mat drawing = Mat::zeros( threshold_output.size(), CV_8UC3 );
-  for( size_t i = 0; i< contours.size(); i++ )
-     {
-       Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) );
-       // contour
-       drawContours( drawing, contours, (int)i, color, 1, 8, vector<Vec4i>(), 0, Point() );
-       // ellipse
-       ellipse( drawing, minEllipse[i], color, 2, 8 );
-       // rotated rectangle
-       Point2f rect_points[4]; minRect[i].points( rect_points );
-       for( int j = 0; j < 4; j++ )
-          line( drawing, rect_points[j], rect_points[(j+1)%4], color, 1, 8 );
-     }
+    /// Draw contours + rotated rects + ellipses
+    Mat drawing = Mat::zeros( canny_output.size(), CV_8UC3 );
+    for( size_t i = 0; i< contours.size(); i++ )
+    {
+        Scalar color = Scalar( rng.uniform(0, 256), rng.uniform(0,256), rng.uniform(0,256) );
+        // contour
+        drawContours( drawing, contours, (int)i, color );
+        // ellipse
+        ellipse( drawing, minEllipse[i], color, 2 );
+        // rotated rectangle
+        Point2f rect_points[4];
+        minRect[i].points( rect_points );
+        for ( int j = 0; j < 4; j++ )
+        {
+            line( drawing, rect_points[j], rect_points[(j+1)%4], color );
+        }
+    }
 
-  /// Show in a window
-  namedWindow( "Contours", WINDOW_AUTOSIZE );
-  imshow( "Contours", drawing );
+    /// Show in a window
+    imshow( "Contours", drawing );
 }

samples/cpp/tutorial_code/ShapeDescriptors/hull_demo.cpp

@@ -12,9 +12,8 @@
 using namespace cv;
 using namespace std;
 
-Mat src; Mat src_gray;
+Mat src_gray;
 int thresh = 100;
-int max_thresh = 255;
 RNG rng(12345);
 
 /// Function header
@@ -25,30 +24,31 @@ void thresh_callback(int, void* );
  */
 int main( int argc, char** argv )
 {
-  /// Load source image and convert it to gray
-  CommandLineParser parser( argc, argv, "{@input | ../data/stuff.jpg | input image}" );
-  src = imread( parser.get<String>( "@input" ), IMREAD_COLOR );
-  if( src.empty() )
-  {
-    cout << "Could not open or find the image!\n" << endl;
-    cout << "Usage: " << argv[0] << " <Input image>" << endl;
-    return -1;
-  }
+    /// Load source image and convert it to gray
+    CommandLineParser parser( argc, argv, "{@input | ../data/stuff.jpg | input image}" );
+    Mat src = imread( parser.get<String>( "@input" ) );
+    if( src.empty() )
+    {
+        cout << "Could not open or find the image!\n" << endl;
+        cout << "Usage: " << argv[0] << " <Input image>" << endl;
+        return -1;
+    }
 
-  /// Convert image to gray and blur it
-  cvtColor( src, src_gray, COLOR_BGR2GRAY );
-  blur( src_gray, src_gray, Size(3,3) );
+    /// Convert image to gray and blur it
+    cvtColor( src, src_gray, COLOR_BGR2GRAY );
+    blur( src_gray, src_gray, Size(3,3) );
 
-  /// Create Window
-  const char* source_window = "Source";
-  namedWindow( source_window, WINDOW_AUTOSIZE );
-  imshow( source_window, src );
+    /// Create Window
+    const char* source_window = "Source";
+    namedWindow( source_window );
+    imshow( source_window, src );
 
-  createTrackbar( " Threshold:", "Source", &thresh, max_thresh, thresh_callback );
-  thresh_callback( 0, 0 );
+    const int max_thresh = 255;
+    createTrackbar( "Canny thresh:", source_window, &thresh, max_thresh, thresh_callback );
+    thresh_callback( 0, 0 );
 
-  waitKey(0);
-  return(0);
+    waitKey();
+    return 0;
 }
 
 /**
@@ -56,31 +56,30 @@ int main( int argc, char** argv )
  */
 void thresh_callback(int, void* )
 {
-  Mat threshold_output;
-  vector<vector<Point> > contours;
-  vector<Vec4i> hierarchy;
+    /// Detect edges using Canny
+    Mat canny_output;
+    Canny( src_gray, canny_output, thresh, thresh*2 );
 
-  /// Detect edges using Threshold
-  threshold( src_gray, threshold_output, thresh, 255, THRESH_BINARY );
+    /// Find contours
+    vector<vector<Point> > contours;
+    findContours( canny_output, contours, RETR_TREE, CHAIN_APPROX_SIMPLE );
 
-  /// Find contours
-  findContours( threshold_output, contours, hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0) );
+    /// Find the convex hull object for each contour
+    vector<vector<Point> >hull( contours.size() );
+    for( size_t i = 0; i < contours.size(); i++ )
+    {
+        convexHull( contours[i], hull[i] );
+    }
 
-  /// Find the convex hull object for each contour
-  vector<vector<Point> >hull( contours.size() );
-  for( size_t i = 0; i < contours.size(); i++ )
-     {   convexHull( contours[i], hull[i], false ); }
+    /// Draw contours + hull results
+    Mat drawing = Mat::zeros( canny_output.size(), CV_8UC3 );
+    for( size_t i = 0; i< contours.size(); i++ )
+    {
+        Scalar color = Scalar( rng.uniform(0, 256), rng.uniform(0,256), rng.uniform(0,256) );
+        drawContours( drawing, contours, (int)i, color );
+        drawContours( drawing, hull, (int)i, color );
+    }
 
-  /// Draw contours + hull results
-  Mat drawing = Mat::zeros( threshold_output.size(), CV_8UC3 );
-  for( size_t i = 0; i< contours.size(); i++ )
-     {
-       Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) );
-       drawContours( drawing, contours, (int)i, color, 1, 8, vector<Vec4i>(), 0, Point() );
-       drawContours( drawing, hull, (int)i, color, 1, 8, vector<Vec4i>(), 0, Point() );
-     }
-
-  /// Show in a window
-  namedWindow( "Hull demo", WINDOW_AUTOSIZE );
-  imshow( "Hull demo", drawing );
+    /// Show in a window
+    imshow( "Hull demo", drawing );
 }

samples/cpp/tutorial_code/ShapeDescriptors/moments_demo.cpp

@@ -8,13 +8,13 @@
 #include "opencv2/highgui.hpp"
 #include "opencv2/imgproc.hpp"
 #include <iostream>
+#include <iomanip>
 
 using namespace cv;
 using namespace std;
 
-Mat src; Mat src_gray;
+Mat src_gray;
 int thresh = 100;
-int max_thresh = 255;
 RNG rng(12345);
 
 /// Function header
@@ -25,31 +25,32 @@ void thresh_callback(int, void* );
  */
 int main( int argc, char** argv )
 {
-  /// Load source image and convert it to gray
-  CommandLineParser parser( argc, argv, "{@input | ../data/stuff.jpg | input image}" );
-  src = imread( parser.get<String>( "@input" ), IMREAD_COLOR );
-
-  if( src.empty() )
-  {
-      cout << "Could not open or find the image!\n" << endl;
-      cout << "usage: " << argv[0] << " <Input image>" << endl;
-      exit(0);
-  }
-
-  /// Convert image to gray and blur it
-  cvtColor( src, src_gray, COLOR_BGR2GRAY );
-  blur( src_gray, src_gray, Size(3,3) );
-
-  /// Create Window
-  const char* source_window = "Source";
-  namedWindow( source_window, WINDOW_AUTOSIZE );
-  imshow( source_window, src );
-
-  createTrackbar( " Canny thresh:", "Source", &thresh, max_thresh, thresh_callback );
-  thresh_callback( 0, 0 );
-
-  waitKey(0);
-  return(0);
+    /// Load source image
+    CommandLineParser parser( argc, argv, "{@input | ../data/stuff.jpg | input image}" );
+    Mat src = imread( parser.get<String>( "@input" ) );
+
+    if( src.empty() )
+    {
+        cout << "Could not open or find the image!\n" << endl;
+        cout << "usage: " << argv[0] << " <Input image>" << endl;
+        return -1;
+    }
+
+    /// Convert image to gray and blur it
+    cvtColor( src, src_gray, COLOR_BGR2GRAY );
+    blur( src_gray, src_gray, Size(3,3) );
+
+    /// Create Window
+    const char* source_window = "Source";
+    namedWindow( source_window );
+    imshow( source_window, src );
+
+    const int max_thresh = 255;
+    createTrackbar( "Canny thresh:", source_window, &thresh, max_thresh, thresh_callback );
+    thresh_callback( 0, 0 );
+
+    waitKey();
+    return 0;
 }
 
 /**
@@ -57,44 +58,47 @@ int main( int argc, char** argv )
  */
 void thresh_callback(int, void* )
 {
-  Mat canny_output;
-  vector<vector<Point> > contours;
-
-  /// Detect edges using canny
-  Canny( src_gray, canny_output, thresh, thresh*2, 3 );
-  /// Find contours
-  findContours( canny_output, contours, RETR_TREE, CHAIN_APPROX_SIMPLE );
-
-  /// Get the moments
-  vector<Moments> mu(contours.size() );
-  for( size_t i = 0; i < contours.size(); i++ )
-     { mu[i] = moments( contours[i], false ); }
-
-  ///  Get the mass centers:
-  vector<Point2f> mc( contours.size() );
-  for( size_t i = 0; i < contours.size(); i++ )
-     { mc[i] = Point2f( static_cast<float>(mu[i].m10/mu[i].m00) , static_cast<float>(mu[i].m01/mu[i].m00) ); }
-
-  /// Draw contours
-  Mat drawing = Mat::zeros( canny_output.size(), CV_8UC3 );
-  for( size_t i = 0; i< contours.size(); i++ )
-     {
-       Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) );
-       drawContours( drawing, contours, (int)i, color, 2, LINE_8 );
-       circle( drawing, mc[i], 4, color, -1, 8, 0 );
-     }
-
-  /// Show in a window
-  namedWindow( "Contours", WINDOW_AUTOSIZE );
-  imshow( "Contours", drawing );
-
-  /// Calculate the area with the moments 00 and compare with the result of the OpenCV function
-  printf("\t Info: Area and Contour Length \n");
-  for( size_t i = 0; i< contours.size(); i++ )
-     {
-       printf(" * Contour[%d] - Area (M_00) = %.2f - Area OpenCV: %.2f - Length: %.2f \n", (int)i, mu[i].m00, contourArea(contours[i]), arcLength( contours[i], true ) );
-       Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) );
-       drawContours( drawing, contours, (int)i, color, 2, LINE_8 );
-       circle( drawing, mc[i], 4, color, -1, 8, 0 );
-     }
+    /// Detect edges using canny
+    Mat canny_output;
+    Canny( src_gray, canny_output, thresh, thresh*2, 3 );
+    /// Find contours
+    vector<vector<Point> > contours;
+    findContours( canny_output, contours, RETR_TREE, CHAIN_APPROX_SIMPLE );
+
+    /// Get the moments
+    vector<Moments> mu(contours.size() );
+    for( size_t i = 0; i < contours.size(); i++ )
+    {
+        mu[i] = moments( contours[i] );
+    }
+
+    ///  Get the mass centers
+    vector<Point2f> mc( contours.size() );
+    for( size_t i = 0; i < contours.size(); i++ )
+    {
+        //add 1e-5 to avoid division by zero
+        mc[i] = Point2f( static_cast<float>(mu[i].m10 / (mu[i].m00 + 1e-5)),
+                         static_cast<float>(mu[i].m01 / (mu[i].m00 + 1e-5)) );
+        cout << "mc[" << i << "]=" << mc[i] << endl;
+    }
+
+    /// Draw contours
+    Mat drawing = Mat::zeros( canny_output.size(), CV_8UC3 );
+    for( size_t i = 0; i< contours.size(); i++ )
+    {
+        Scalar color = Scalar( rng.uniform(0, 256), rng.uniform(0,256), rng.uniform(0,256) );
+        drawContours( drawing, contours, (int)i, color, 2 );
+        circle( drawing, mc[i], 4, color, -1 );
+    }
+
+    /// Show in a window
+    imshow( "Contours", drawing );
+
+    /// Calculate the area with the moments 00 and compare with the result of the OpenCV function
+    cout << "\t Info: Area and Contour Length \n";
+    for( size_t i = 0; i < contours.size(); i++ )
+    {
+        cout << " * Contour[" << i << "] - Area (M_00) = " << std::fixed << std::setprecision(2) << mu[i].m00
+             << " - Area OpenCV: " << contourArea(contours[i]) << " - Length: " << arcLength( contours[i], true ) << endl;
+    }
 }

samples/cpp/tutorial_code/ShapeDescriptors/pointPolygonTest_demo.cpp

@@ -16,60 +16,71 @@ using namespace std;
  */
 int main( void )
 {
-  /// Create an image
-  const int r = 100;
-  Mat src = Mat::zeros( Size( 4*r, 4*r ), CV_8UC1 );
+    /// Create an image
+    const int r = 100;
+    Mat src = Mat::zeros( Size( 4*r, 4*r ), CV_8U );
 
-  /// Create a sequence of points to make a contour:
-  vector<Point2f> vert(6);
+    /// Create a sequence of points to make a contour
+    vector<Point2f> vert(6);
+    vert[0] = Point( 3*r/2, static_cast<int>(1.34*r) );
+    vert[1] = Point( 1*r, 2*r );
+    vert[2] = Point( 3*r/2, static_cast<int>(2.866*r) );
+    vert[3] = Point( 5*r/2, static_cast<int>(2.866*r) );
+    vert[4] = Point( 3*r, 2*r );
+    vert[5] = Point( 5*r/2, static_cast<int>(1.34*r) );
 
-  vert[0] = Point( 3*r/2, static_cast<int>(1.34*r) );
-  vert[1] = Point( 1*r, 2*r );
-  vert[2] = Point( 3*r/2, static_cast<int>(2.866*r) );
-  vert[3] = Point( 5*r/2, static_cast<int>(2.866*r) );
-  vert[4] = Point( 3*r, 2*r );
-  vert[5] = Point( 5*r/2, static_cast<int>(1.34*r) );
+    /// Draw it in src
+    for( int i = 0; i < 6; i++ )
+    {
+        line( src, vert[i],  vert[(i+1)%6], Scalar( 255 ), 3 );
+    }
 
-  /// Draw it in src
-  for( int j = 0; j < 6; j++ )
-     { line( src, vert[j],  vert[(j+1)%6], Scalar( 255 ), 3, 8 ); }
+    /// Get the contours
+    vector<vector<Point> > contours;
+    findContours( src, contours, RETR_TREE, CHAIN_APPROX_SIMPLE);
 
-  /// Get the contours
-  vector<vector<Point> > contours;
+    /// Calculate the distances to the contour
+    Mat raw_dist( src.size(), CV_32F );
+    for( int i = 0; i < src.rows; i++ )
+    {
+        for( int j = 0; j < src.cols; j++ )
+        {
+            raw_dist.at<float>(i,j) = (float)pointPolygonTest( contours[0], Point2f((float)j, (float)i), true );
+        }
+    }
 
-  findContours( src, contours, RETR_TREE, CHAIN_APPROX_SIMPLE);
+    double minVal, maxVal;
+    minMaxLoc( raw_dist, &minVal, &maxVal );
+    minVal = abs(minVal);
+    maxVal = abs(maxVal);
 
-  /// Calculate the distances to the contour
-  Mat raw_dist( src.size(), CV_32FC1 );
-
-  for( int j = 0; j < src.rows; j++ )
-     { for( int i = 0; i < src.cols; i++ )
-          { raw_dist.at<float>(j,i) = (float)pointPolygonTest( contours[0], Point2f((float)i,(float)j), true ); }
-     }
-
-  double minVal; double maxVal;
-  minMaxLoc( raw_dist, &minVal, &maxVal, 0, 0, Mat() );
-  minVal = abs(minVal); maxVal = abs(maxVal);
-
-  /// Depicting the  distances graphically
-  Mat drawing = Mat::zeros( src.size(), CV_8UC3 );
-
-  for( int j = 0; j < src.rows; j++ )
-     { for( int i = 0; i < src.cols; i++ )
-          {
-            if( raw_dist.at<float>(j,i) < 0 )
-              { drawing.at<Vec3b>(j,i)[0] = (uchar)(255 - abs(raw_dist.at<float>(j,i))*255/minVal); }
-            else if( raw_dist.at<float>(j,i) > 0 )
-              { drawing.at<Vec3b>(j,i)[2] = (uchar)(255 - raw_dist.at<float>(j,i)*255/maxVal); }
+    /// Depicting the  distances graphically
+    Mat drawing = Mat::zeros( src.size(), CV_8UC3 );
+    for( int i = 0; i < src.rows; i++ )
+    {
+        for( int j = 0; j < src.cols; j++ )
+        {
+            if( raw_dist.at<float>(i,j) < 0 )
+            {
+                drawing.at<Vec3b>(i,j)[0] = (uchar)(255 - abs(raw_dist.at<float>(i,j)) * 255 / minVal);
+            }
+            else if( raw_dist.at<float>(i,j) > 0 )
+            {
+                drawing.at<Vec3b>(i,j)[2] = (uchar)(255 - raw_dist.at<float>(i,j) * 255 / maxVal);
+            }
             else
-              { drawing.at<Vec3b>(j,i)[0] = 255; drawing.at<Vec3b>(j,i)[1] = 255; drawing.at<Vec3b>(j,i)[2] = 255; }
-          }
-     }
+            {
+                drawing.at<Vec3b>(i,j)[0] = 255;
+                drawing.at<Vec3b>(i,j)[1] = 255;
+                drawing.at<Vec3b>(i,j)[2] = 255;
+            }
+        }
+    }
 
-  /// Show your results
-  imshow( "Source", src );
-  imshow( "Distance", drawing );
+    /// Show your results
+    imshow( "Source", src );
+    imshow( "Distance", drawing );
 
-  waitKey(0);
-  return(0);
+    waitKey();
+    return 0;
 }

samples/java/tutorial_code/ShapeDescriptors/bounding_rects_circles/GeneralContoursDemo1.java

+import java.awt.BorderLayout;
+import java.awt.Container;
+import java.awt.Image;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+import javax.swing.BoxLayout;
+import javax.swing.ImageIcon;
+import javax.swing.JFrame;
+import javax.swing.JLabel;
+import javax.swing.JPanel;
+import javax.swing.JSlider;
+import javax.swing.event.ChangeEvent;
+import javax.swing.event.ChangeListener;
+
+import org.opencv.core.Core;
+import org.opencv.core.CvType;
+import org.opencv.core.Mat;
+import org.opencv.core.MatOfPoint;
+import org.opencv.core.MatOfPoint2f;
+import org.opencv.core.Point;
+import org.opencv.core.Rect;
+import org.opencv.core.Scalar;
+import org.opencv.core.Size;
+import org.opencv.highgui.HighGui;
+import org.opencv.imgcodecs.Imgcodecs;
+import org.opencv.imgproc.Imgproc;
+
+class GeneralContours1 {
+    private Mat srcGray = new Mat();
+    private JFrame frame;
+    private JLabel imgSrcLabel;
+    private JLabel imgContoursLabel;
+    private static final int MAX_THRESHOLD = 255;
+    private int threshold = 100;
+    private Random rng = new Random(12345);
+
+    public GeneralContours1(String[] args) {
+        //! [setup]
+        /// Load source image
+        String filename = args.length > 0 ? args[0] : "../data/stuff.jpg";
+        Mat src = Imgcodecs.imread(filename);
+        if (src.empty()) {
+            System.err.println("Cannot read image: " + filename);
+            System.exit(0);
+        }
+
+        /// Convert image to gray and blur it
+        Imgproc.cvtColor(src, srcGray, Imgproc.COLOR_BGR2GRAY);
+        Imgproc.blur(srcGray, srcGray, new Size(3, 3));
+        //! [setup]
+
+        //! [createWindow]
+        // Create and set up the window.
+        frame = new JFrame("Creating Bounding boxes and circles for contours demo");
+        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        // Set up the content pane.
+        Image img = HighGui.toBufferedImage(src);
+        addComponentsToPane(frame.getContentPane(), img);
+        //! [createWindow]
+        // Use the content pane's default BorderLayout. No need for
+        // setLayout(new BorderLayout());
+        // Display the window.
+        frame.pack();
+        frame.setVisible(true);
+        update();
+    }
+
+    private void addComponentsToPane(Container pane, Image img) {
+        if (!(pane.getLayout() instanceof BorderLayout)) {
+            pane.add(new JLabel("Container doesn't use BorderLayout!"));
+            return;
+        }
+
+        JPanel sliderPanel = new JPanel();
+        sliderPanel.setLayout(new BoxLayout(sliderPanel, BoxLayout.PAGE_AXIS));
+
+        //! [trackbar]
+        sliderPanel.add(new JLabel("Canny threshold: "));
+        JSlider slider = new JSlider(0, MAX_THRESHOLD, threshold);
+        slider.setMajorTickSpacing(20);
+        slider.setMinorTickSpacing(10);
+        slider.setPaintTicks(true);
+        slider.setPaintLabels(true);
+        slider.addChangeListener(new ChangeListener() {
+            @Override
+            public void stateChanged(ChangeEvent e) {
+                JSlider source = (JSlider) e.getSource();
+                threshold = source.getValue();
+                update();
+            }
+        });
+        //! [trackbar]
+        sliderPanel.add(slider);
+        pane.add(sliderPanel, BorderLayout.PAGE_START);
+
+        JPanel imgPanel = new JPanel();
+        imgSrcLabel = new JLabel(new ImageIcon(img));
+        imgPanel.add(imgSrcLabel);
+
+        Mat blackImg = Mat.zeros(srcGray.size(), CvType.CV_8U);
+        imgContoursLabel = new JLabel(new ImageIcon(HighGui.toBufferedImage(blackImg)));
+        imgPanel.add(imgContoursLabel);
+
+        pane.add(imgPanel, BorderLayout.CENTER);
+    }
+
+    private void update() {
+        //! [Canny]
+        /// Detect edges using Canny
+        Mat cannyOutput = new Mat();
+        Imgproc.Canny(srcGray, cannyOutput, threshold, threshold * 2);
+        //! [Canny]
+
+        //! [findContours]
+        /// Find contours
+        List<MatOfPoint> contours = new ArrayList<>();
+        Mat hierarchy = new Mat();
+        Imgproc.findContours(cannyOutput, contours, hierarchy, Imgproc.RETR_TREE, Imgproc.CHAIN_APPROX_SIMPLE);
+        //! [findContours]
+
+        //! [allthework]
+        /// Approximate contours to polygons + get bounding rects and circles
+        MatOfPoint2f[] contoursPoly  = new MatOfPoint2f[contours.size()];
+        Rect[] boundRect = new Rect[contours.size()];
+        Point[] centers = new Point[contours.size()];
+        float[][] radius = new float[contours.size()][1];
+
+        for (int i = 0; i < contours.size(); i++) {
+            contoursPoly[i] = new MatOfPoint2f();
+            Imgproc.approxPolyDP(new MatOfPoint2f(contours.get(i).toArray()), contoursPoly[i], 3, true);
+            boundRect[i] = Imgproc.boundingRect(new MatOfPoint(contoursPoly[i].toArray()));
+            centers[i] = new Point();
+            Imgproc.minEnclosingCircle(contoursPoly[i], centers[i], radius[i]);
+        }
+        //! [allthework]
+
+        //! [zeroMat]
+        Mat drawing = Mat.zeros(cannyOutput.size(), CvType.CV_8UC3);
+        //! [zeroMat]
+        //! [forContour]
+        /// Draw polygonal contour + bonding rects + circles
+        List<MatOfPoint> contoursPolyList = new ArrayList<>(contoursPoly.length);
+        for (MatOfPoint2f poly : contoursPoly) {
+            contoursPolyList.add(new MatOfPoint(poly.toArray()));
+        }
+
+        for (int i = 0; i < contours.size(); i++) {
+            Scalar color = new Scalar(rng.nextInt(256), rng.nextInt(256), rng.nextInt(256));
+            Imgproc.drawContours(drawing, contoursPolyList, i, color);
+            Imgproc.rectangle(drawing, boundRect[i].tl(), boundRect[i].br(), color, 2);
+            Imgproc.circle(drawing, centers[i], (int) radius[i][0], color, 2);
+        }
+        //! [forContour]
+
+        //! [showDrawings]
+        /// Show in a window
+        imgContoursLabel.setIcon(new ImageIcon(HighGui.toBufferedImage(drawing)));
+        frame.repaint();
+        //! [showDrawings]
+    }
+}
+
+public class GeneralContoursDemo1 {
+    public static void main(String[] args) {
+        // Load the native OpenCV library
+        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
+
+        // Schedule a job for the event dispatch thread:
+        // creating and showing this application's GUI.
+        javax.swing.SwingUtilities.invokeLater(new Runnable() {
+            @Override
+            public void run() {
+                new GeneralContours1(args);
+            }
+        });
+    }
+}

samples/java/tutorial_code/ShapeDescriptors/bounding_rotated_ellipses/GeneralContoursDemo2.java

+import java.awt.BorderLayout;
+import java.awt.Container;
+import java.awt.Image;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+import javax.swing.BoxLayout;
+import javax.swing.ImageIcon;
+import javax.swing.JFrame;
+import javax.swing.JLabel;
+import javax.swing.JPanel;
+import javax.swing.JSlider;
+import javax.swing.event.ChangeEvent;
+import javax.swing.event.ChangeListener;
+
+import org.opencv.core.Core;
+import org.opencv.core.CvType;
+import org.opencv.core.Mat;
+import org.opencv.core.MatOfPoint;
+import org.opencv.core.MatOfPoint2f;
+import org.opencv.core.Point;
+import org.opencv.core.RotatedRect;
+import org.opencv.core.Scalar;
+import org.opencv.core.Size;
+import org.opencv.highgui.HighGui;
+import org.opencv.imgcodecs.Imgcodecs;
+import org.opencv.imgproc.Imgproc;
+
+class GeneralContours2 {
+    private Mat srcGray = new Mat();
+    private JFrame frame;
+    private JLabel imgSrcLabel;
+    private JLabel imgContoursLabel;
+    private static final int MAX_THRESHOLD = 255;
+    private int threshold = 100;
+    private Random rng = new Random(12345);
+
+    public GeneralContours2(String[] args) {
+        //! [setup]
+        /// Load source image
+        String filename = args.length > 0 ? args[0] : "../data/stuff.jpg";
+        Mat src = Imgcodecs.imread(filename);
+        if (src.empty()) {
+            System.err.println("Cannot read image: " + filename);
+            System.exit(0);
+        }
+
+        /// Convert image to gray and blur it
+        Imgproc.cvtColor(src, srcGray, Imgproc.COLOR_BGR2GRAY);
+        Imgproc.blur(srcGray, srcGray, new Size(3, 3));
+        //! [setup]
+
+        //! [createWindow]
+        // Create and set up the window.
+        frame = new JFrame("Creating Bounding rotated boxes and ellipses for contours demo");
+        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        // Set up the content pane.
+        Image img = HighGui.toBufferedImage(src);
+        addComponentsToPane(frame.getContentPane(), img);
+        //! [createWindow]
+        // Use the content pane's default BorderLayout. No need for
+        // setLayout(new BorderLayout());
+        // Display the window.
+        frame.pack();
+        frame.setVisible(true);
+        update();
+    }
+
+    private void addComponentsToPane(Container pane, Image img) {
+        if (!(pane.getLayout() instanceof BorderLayout)) {
+            pane.add(new JLabel("Container doesn't use BorderLayout!"));
+            return;
+        }
+
+        JPanel sliderPanel = new JPanel();
+        sliderPanel.setLayout(new BoxLayout(sliderPanel, BoxLayout.PAGE_AXIS));
+
+        //! [trackbar]
+        sliderPanel.add(new JLabel("Canny threshold: "));
+        JSlider slider = new JSlider(0, MAX_THRESHOLD, threshold);
+        slider.setMajorTickSpacing(20);
+        slider.setMinorTickSpacing(10);
+        slider.setPaintTicks(true);
+        slider.setPaintLabels(true);
+        slider.addChangeListener(new ChangeListener() {
+            @Override
+            public void stateChanged(ChangeEvent e) {
+                JSlider source = (JSlider) e.getSource();
+                threshold = source.getValue();
+                update();
+            }
+        });
+        //! [trackbar]
+        sliderPanel.add(slider);
+        pane.add(sliderPanel, BorderLayout.PAGE_START);
+
+        JPanel imgPanel = new JPanel();
+        imgSrcLabel = new JLabel(new ImageIcon(img));
+        imgPanel.add(imgSrcLabel);
+
+        Mat blackImg = Mat.zeros(srcGray.size(), CvType.CV_8U);
+        imgContoursLabel = new JLabel(new ImageIcon(HighGui.toBufferedImage(blackImg)));
+        imgPanel.add(imgContoursLabel);
+
+        pane.add(imgPanel, BorderLayout.CENTER);
+    }
+
+    private void update() {
+        //! [Canny]
+        /// Detect edges using Canny
+        Mat cannyOutput = new Mat();
+        Imgproc.Canny(srcGray, cannyOutput, threshold, threshold * 2);
+        //! [Canny]
+
+        //! [findContours]
+        /// Find contours
+        List<MatOfPoint> contours = new ArrayList<>();
+        Mat hierarchy = new Mat();
+        Imgproc.findContours(cannyOutput, contours, hierarchy, Imgproc.RETR_TREE, Imgproc.CHAIN_APPROX_SIMPLE);
+        //! [findContours]
+
+        /// Find the rotated rectangles and ellipses for each contour
+        RotatedRect[] minRect = new RotatedRect[contours.size()];
+        RotatedRect[] minEllipse = new RotatedRect[contours.size()];
+        for (int i = 0; i < contours.size(); i++) {
+            minRect[i] = Imgproc.minAreaRect(new MatOfPoint2f(contours.get(i).toArray()));
+            minEllipse[i] = new RotatedRect();
+            if (contours.get(i).rows() > 5) {
+                minEllipse[i] = Imgproc.fitEllipse(new MatOfPoint2f(contours.get(i).toArray()));
+            }
+        }
+
+        //! [zeroMat]
+        /// Draw contours + rotated rects + ellipses
+        Mat drawing = Mat.zeros(cannyOutput.size(), CvType.CV_8UC3);
+        //! [zeroMat]
+        //! [forContour]
+        for (int i = 0; i < contours.size(); i++) {
+            Scalar color = new Scalar(rng.nextInt(256), rng.nextInt(256), rng.nextInt(256));
+            // contour
+            Imgproc.drawContours(drawing, contours, i, color);
+            // ellipse
+            Imgproc.ellipse(drawing, minEllipse[i], color, 2);
+            // rotated rectangle
+            Point[] rectPoints = new Point[4];
+            minRect[i].points(rectPoints);
+            for (int j = 0; j < 4; j++) {
+                Imgproc.line(drawing, rectPoints[j], rectPoints[(j+1) % 4], color);
+            }
+        }
+        //! [forContour]
+
+        //! [showDrawings]
+        /// Show in a window
+        imgContoursLabel.setIcon(new ImageIcon(HighGui.toBufferedImage(drawing)));
+        frame.repaint();
+        //! [showDrawings]
+    }
+}
+
+public class GeneralContoursDemo2 {
+    public static void main(String[] args) {
+        // Load the native OpenCV library
+        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
+
+        // Schedule a job for the event dispatch thread:
+        // creating and showing this application's GUI.
+        javax.swing.SwingUtilities.invokeLater(new Runnable() {
+            @Override
+            public void run() {
+                new GeneralContours2(args);
+            }
+        });
+    }
+}

samples/java/tutorial_code/ShapeDescriptors/find_contours/FindContoursDemo.java

+import java.awt.BorderLayout;
+import java.awt.Container;
+import java.awt.Image;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+import javax.swing.BoxLayout;
+import javax.swing.ImageIcon;
+import javax.swing.JFrame;
+import javax.swing.JLabel;
+import javax.swing.JPanel;
+import javax.swing.JSlider;
+import javax.swing.event.ChangeEvent;
+import javax.swing.event.ChangeListener;
+
+import org.opencv.core.Core;
+import org.opencv.core.CvType;
+import org.opencv.core.Mat;
+import org.opencv.core.MatOfPoint;
+import org.opencv.core.Point;
+import org.opencv.core.Scalar;
+import org.opencv.core.Size;
+import org.opencv.highgui.HighGui;
+import org.opencv.imgcodecs.Imgcodecs;
+import org.opencv.imgproc.Imgproc;
+
+class FindContours {
+    private Mat srcGray = new Mat();
+    private JFrame frame;
+    private JLabel imgSrcLabel;
+    private JLabel imgContoursLabel;
+    private static final int MAX_THRESHOLD = 255;
+    private int threshold = 100;
+    private Random rng = new Random(12345);
+
+    public FindContours(String[] args) {
+        /// Load source image
+        String filename = args.length > 0 ? args[0] : "../data/HappyFish.jpg";
+        Mat src = Imgcodecs.imread(filename);
+        if (src.empty()) {
+            System.err.println("Cannot read image: " + filename);
+            System.exit(0);
+        }
+
+        /// Convert image to gray and blur it
+        Imgproc.cvtColor(src, srcGray, Imgproc.COLOR_BGR2GRAY);
+        Imgproc.blur(srcGray, srcGray, new Size(3, 3));
+
+        // Create and set up the window.
+        frame = new JFrame("Finding contours in your image demo");
+        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        // Set up the content pane.
+        Image img = HighGui.toBufferedImage(src);
+        addComponentsToPane(frame.getContentPane(), img);
+        // Use the content pane's default BorderLayout. No need for
+        // setLayout(new BorderLayout());
+        // Display the window.
+        frame.pack();
+        frame.setVisible(true);
+        update();
+    }
+
+    private void addComponentsToPane(Container pane, Image img) {
+        if (!(pane.getLayout() instanceof BorderLayout)) {
+            pane.add(new JLabel("Container doesn't use BorderLayout!"));
+            return;
+        }
+
+        JPanel sliderPanel = new JPanel();
+        sliderPanel.setLayout(new BoxLayout(sliderPanel, BoxLayout.PAGE_AXIS));
+
+        sliderPanel.add(new JLabel("Canny threshold: "));
+        JSlider slider = new JSlider(0, MAX_THRESHOLD, threshold);
+        slider.setMajorTickSpacing(20);
+        slider.setMinorTickSpacing(10);
+        slider.setPaintTicks(true);
+        slider.setPaintLabels(true);
+        slider.addChangeListener(new ChangeListener() {
+            @Override
+            public void stateChanged(ChangeEvent e) {
+                JSlider source = (JSlider) e.getSource();
+                threshold = source.getValue();
+                update();
+            }
+        });
+        sliderPanel.add(slider);
+        pane.add(sliderPanel, BorderLayout.PAGE_START);
+
+        JPanel imgPanel = new JPanel();
+        imgSrcLabel = new JLabel(new ImageIcon(img));
+        imgPanel.add(imgSrcLabel);
+
+        Mat blackImg = Mat.zeros(srcGray.size(), CvType.CV_8U);
+        imgContoursLabel = new JLabel(new ImageIcon(HighGui.toBufferedImage(blackImg)));
+        imgPanel.add(imgContoursLabel);
+
+        pane.add(imgPanel, BorderLayout.CENTER);
+    }
+
+    private void update() {
+        /// Detect edges using Canny
+        Mat cannyOutput = new Mat();
+        Imgproc.Canny(srcGray, cannyOutput, threshold, threshold * 2);
+
+        /// Find contours
+        List<MatOfPoint> contours = new ArrayList<>();
+        Mat hierarchy = new Mat();
+        Imgproc.findContours(cannyOutput, contours, hierarchy, Imgproc.RETR_TREE, Imgproc.CHAIN_APPROX_SIMPLE);
+
+        /// Draw contours
+        Mat drawing = Mat.zeros(cannyOutput.size(), CvType.CV_8UC3);
+        for (int i = 0; i < contours.size(); i++) {
+            Scalar color = new Scalar(rng.nextInt(256), rng.nextInt(256), rng.nextInt(256));
+            Imgproc.drawContours(drawing, contours, i, color, 2, Core.LINE_8, hierarchy, 0, new Point());
+        }
+
+        imgContoursLabel.setIcon(new ImageIcon(HighGui.toBufferedImage(drawing)));
+        frame.repaint();
+    }
+}
+
+public class FindContoursDemo {
+    public static void main(String[] args) {
+        // Load the native OpenCV library
+        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
+
+        // Schedule a job for the event dispatch thread:
+        // creating and showing this application's GUI.
+        javax.swing.SwingUtilities.invokeLater(new Runnable() {
+            @Override
+            public void run() {
+                new FindContours(args);
+            }
+        });
+    }
+}

samples/java/tutorial_code/ShapeDescriptors/hull/HullDemo.java

+import java.awt.BorderLayout;
+import java.awt.Container;
+import java.awt.Image;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+import javax.swing.BoxLayout;
+import javax.swing.ImageIcon;
+import javax.swing.JFrame;
+import javax.swing.JLabel;
+import javax.swing.JPanel;
+import javax.swing.JSlider;
+import javax.swing.event.ChangeEvent;
+import javax.swing.event.ChangeListener;
+
+import org.opencv.core.Core;
+import org.opencv.core.CvType;
+import org.opencv.core.Mat;
+import org.opencv.core.MatOfInt;
+import org.opencv.core.MatOfPoint;
+import org.opencv.core.Point;
+import org.opencv.core.Scalar;
+import org.opencv.core.Size;
+import org.opencv.highgui.HighGui;
+import org.opencv.imgcodecs.Imgcodecs;
+import org.opencv.imgproc.Imgproc;
+
+class Hull {
+    private Mat srcGray = new Mat();
+    private JFrame frame;
+    private JLabel imgSrcLabel;
+    private JLabel imgContoursLabel;
+    private static final int MAX_THRESHOLD = 255;
+    private int threshold = 100;
+    private Random rng = new Random(12345);
+
+    public Hull(String[] args) {
+        /// Load source image
+        String filename = args.length > 0 ? args[0] : "../data/stuff.jpg";
+        Mat src = Imgcodecs.imread(filename);
+        if (src.empty()) {
+            System.err.println("Cannot read image: " + filename);
+            System.exit(0);
+        }
+
+        /// Convert image to gray and blur it
+        Imgproc.cvtColor(src, srcGray, Imgproc.COLOR_BGR2GRAY);
+        Imgproc.blur(srcGray, srcGray, new Size(3, 3));
+
+        // Create and set up the window.
+        frame = new JFrame("Convex Hull demo");
+        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        // Set up the content pane.
+        Image img = HighGui.toBufferedImage(src);
+        addComponentsToPane(frame.getContentPane(), img);
+        // Use the content pane's default BorderLayout. No need for
+        // setLayout(new BorderLayout());
+        // Display the window.
+        frame.pack();
+        frame.setVisible(true);
+        update();
+    }
+
+    private void addComponentsToPane(Container pane, Image img) {
+        if (!(pane.getLayout() instanceof BorderLayout)) {
+            pane.add(new JLabel("Container doesn't use BorderLayout!"));
+            return;
+        }
+
+        JPanel sliderPanel = new JPanel();
+        sliderPanel.setLayout(new BoxLayout(sliderPanel, BoxLayout.PAGE_AXIS));
+
+        sliderPanel.add(new JLabel("Canny threshold: "));
+        JSlider slider = new JSlider(0, MAX_THRESHOLD, threshold);
+        slider.setMajorTickSpacing(20);
+        slider.setMinorTickSpacing(10);
+        slider.setPaintTicks(true);
+        slider.setPaintLabels(true);
+        slider.addChangeListener(new ChangeListener() {
+            @Override
+            public void stateChanged(ChangeEvent e) {
+                JSlider source = (JSlider) e.getSource();
+                threshold = source.getValue();
+                update();
+            }
+        });
+        sliderPanel.add(slider);
+        pane.add(sliderPanel, BorderLayout.PAGE_START);
+
+        JPanel imgPanel = new JPanel();
+        imgSrcLabel = new JLabel(new ImageIcon(img));
+        imgPanel.add(imgSrcLabel);
+
+        Mat blackImg = Mat.zeros(srcGray.size(), CvType.CV_8U);
+        imgContoursLabel = new JLabel(new ImageIcon(HighGui.toBufferedImage(blackImg)));
+        imgPanel.add(imgContoursLabel);
+
+        pane.add(imgPanel, BorderLayout.CENTER);
+    }
+
+    private void update() {
+        /// Detect edges using Canny
+        Mat cannyOutput = new Mat();
+        Imgproc.Canny(srcGray, cannyOutput, threshold, threshold * 2);
+
+        /// Find contours
+        List<MatOfPoint> contours = new ArrayList<>();
+        Mat hierarchy = new Mat();
+        Imgproc.findContours(cannyOutput, contours, hierarchy, Imgproc.RETR_TREE, Imgproc.CHAIN_APPROX_SIMPLE);
+
+        /// Find the convex hull object for each contour
+        List<MatOfPoint> hullList = new ArrayList<>();
+        for (MatOfPoint contour : contours) {
+            MatOfInt hull = new MatOfInt();
+            Imgproc.convexHull(contour, hull);
+
+            Point[] contourArray = contour.toArray();
+            Point[] hullPoints = new Point[hull.rows()];
+            List<Integer> hullContourIdxList = hull.toList();
+            for (int i = 0; i < hullContourIdxList.size(); i++) {
+                hullPoints[i] = contourArray[hullContourIdxList.get(i)];
+            }
+            hullList.add(new MatOfPoint(hullPoints));
+        }
+
+        /// Draw contours + hull results
+        Mat drawing = Mat.zeros(cannyOutput.size(), CvType.CV_8UC3);
+        for (int i = 0; i < contours.size(); i++) {
+            Scalar color = new Scalar(rng.nextInt(256), rng.nextInt(256), rng.nextInt(256));
+            Imgproc.drawContours(drawing, contours, i, color);
+            Imgproc.drawContours(drawing, hullList, i, color );
+        }
+
+        imgContoursLabel.setIcon(new ImageIcon(HighGui.toBufferedImage(drawing)));
+        frame.repaint();
+    }
+}
+
+public class HullDemo {
+    public static void main(String[] args) {
+        // Load the native OpenCV library
+        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
+
+        // Schedule a job for the event dispatch thread:
+        // creating and showing this application's GUI.
+        javax.swing.SwingUtilities.invokeLater(new Runnable() {
+            @Override
+            public void run() {
+                new Hull(args);
+            }
+        });
+    }
+}

samples/java/tutorial_code/ShapeDescriptors/moments/MomentsDemo.java

+import java.awt.BorderLayout;
+import java.awt.Container;
+import java.awt.Image;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+import javax.swing.BoxLayout;
+import javax.swing.ImageIcon;
+import javax.swing.JFrame;
+import javax.swing.JLabel;
+import javax.swing.JPanel;
+import javax.swing.JSlider;
+import javax.swing.event.ChangeEvent;
+import javax.swing.event.ChangeListener;
+
+import org.opencv.core.Core;
+import org.opencv.core.CvType;
+import org.opencv.core.Mat;
+import org.opencv.core.MatOfPoint;
+import org.opencv.core.MatOfPoint2f;
+import org.opencv.core.Point;
+import org.opencv.core.Scalar;
+import org.opencv.core.Size;
+import org.opencv.highgui.HighGui;
+import org.opencv.imgcodecs.Imgcodecs;
+import org.opencv.imgproc.Imgproc;
+import org.opencv.imgproc.Moments;
+
+class MomentsClass {
+    private Mat srcGray = new Mat();
+    private JFrame frame;
+    private JLabel imgSrcLabel;
+    private JLabel imgContoursLabel;
+    private static final int MAX_THRESHOLD = 255;
+    private int threshold = 100;
+    private Random rng = new Random(12345);
+
+    public MomentsClass(String[] args) {
+        //! [setup]
+        /// Load source image
+        String filename = args.length > 0 ? args[0] : "../data/stuff.jpg";
+        Mat src = Imgcodecs.imread(filename);
+        if (src.empty()) {
+            System.err.println("Cannot read image: " + filename);
+            System.exit(0);
+        }
+
+        /// Convert image to gray and blur it
+        Imgproc.cvtColor(src, srcGray, Imgproc.COLOR_BGR2GRAY);
+        Imgproc.blur(srcGray, srcGray, new Size(3, 3));
+        //! [setup]
+
+        //! [createWindow]
+        // Create and set up the window.
+        frame = new JFrame("Image Moments demo");
+        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        // Set up the content pane.
+        Image img = HighGui.toBufferedImage(src);
+        addComponentsToPane(frame.getContentPane(), img);
+        //! [createWindow]
+        // Use the content pane's default BorderLayout. No need for
+        // setLayout(new BorderLayout());
+        // Display the window.
+        frame.pack();
+        frame.setVisible(true);
+        update();
+    }
+
+    private void addComponentsToPane(Container pane, Image img) {
+        if (!(pane.getLayout() instanceof BorderLayout)) {
+            pane.add(new JLabel("Container doesn't use BorderLayout!"));
+            return;
+        }
+
+        JPanel sliderPanel = new JPanel();
+        sliderPanel.setLayout(new BoxLayout(sliderPanel, BoxLayout.PAGE_AXIS));
+
+        //! [trackbar]
+        sliderPanel.add(new JLabel("Canny threshold: "));
+        JSlider slider = new JSlider(0, MAX_THRESHOLD, threshold);
+        slider.setMajorTickSpacing(20);
+        slider.setMinorTickSpacing(10);
+        slider.setPaintTicks(true);
+        slider.setPaintLabels(true);
+        slider.addChangeListener(new ChangeListener() {
+            @Override
+            public void stateChanged(ChangeEvent e) {
+                JSlider source = (JSlider) e.getSource();
+                threshold = source.getValue();
+                update();
+            }
+        });
+        //! [trackbar]
+        sliderPanel.add(slider);
+        pane.add(sliderPanel, BorderLayout.PAGE_START);
+
+        JPanel imgPanel = new JPanel();
+        imgSrcLabel = new JLabel(new ImageIcon(img));
+        imgPanel.add(imgSrcLabel);
+
+        Mat blackImg = Mat.zeros(srcGray.size(), CvType.CV_8U);
+        imgContoursLabel = new JLabel(new ImageIcon(HighGui.toBufferedImage(blackImg)));
+        imgPanel.add(imgContoursLabel);
+
+        pane.add(imgPanel, BorderLayout.CENTER);
+    }
+
+    private void update() {
+        //! [Canny]
+        /// Detect edges using Canny
+        Mat cannyOutput = new Mat();
+        Imgproc.Canny(srcGray, cannyOutput, threshold, threshold * 2);
+        //! [Canny]
+
+        //! [findContours]
+        /// Find contours
+        List<MatOfPoint> contours = new ArrayList<>();
+        Mat hierarchy = new Mat();
+        Imgproc.findContours(cannyOutput, contours, hierarchy, Imgproc.RETR_TREE, Imgproc.CHAIN_APPROX_SIMPLE);
+        //! [findContours]
+
+        /// Get the moments
+        List<Moments> mu = new ArrayList<>(contours.size());
+        for (int i = 0; i < contours.size(); i++) {
+            mu.add(Imgproc.moments(contours.get(i)));
+        }
+
+        /// Get the mass centers
+        List<Point> mc = new ArrayList<>(contours.size());
+        for (int i = 0; i < contours.size(); i++) {
+            //add 1e-5 to avoid division by zero
+            mc.add(new Point(mu.get(i).m10 / (mu.get(i).m00 + 1e-5), mu.get(i).m01 / (mu.get(i).m00 + 1e-5)));
+        }
+
+        //! [zeroMat]
+        /// Draw contours
+        Mat drawing = Mat.zeros(cannyOutput.size(), CvType.CV_8UC3);
+        //! [zeroMat]
+        //! [forContour]
+        for (int i = 0; i < contours.size(); i++) {
+            Scalar color = new Scalar(rng.nextInt(256), rng.nextInt(256), rng.nextInt(256));
+            Imgproc.drawContours(drawing, contours, i, color, 2);
+            Imgproc.circle(drawing, mc.get(i), 4, color, -1);
+        }
+        //! [forContour]
+
+        //! [showDrawings]
+        /// Show in a window
+        imgContoursLabel.setIcon(new ImageIcon(HighGui.toBufferedImage(drawing)));
+        frame.repaint();
+        //! [showDrawings]
+
+        /// Calculate the area with the moments 00 and compare with the result of the OpenCV function
+        System.out.println("\t Info: Area and Contour Length \n");
+        for (int i = 0; i < contours.size(); i++) {
+            System.out.format(" * Contour[%d] - Area (M_00) = %.2f - Area OpenCV: %.2f - Length: %.2f\n", i,
+                    mu.get(i).m00, Imgproc.contourArea(contours.get(i)),
+                    Imgproc.arcLength(new MatOfPoint2f(contours.get(i).toArray()), true));
+        }
+    }
+}
+
+public class MomentsDemo {
+    public static void main(String[] args) {
+        // Load the native OpenCV library
+        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
+
+        // Schedule a job for the event dispatch thread:
+        // creating and showing this application's GUI.
+        javax.swing.SwingUtilities.invokeLater(new Runnable() {
+            @Override
+            public void run() {
+                new MomentsClass(args);
+            }
+        });
+    }
+}

samples/java/tutorial_code/ShapeDescriptors/point_polygon_test/PointPolygonTestDemo.java

+import java.util.ArrayList;
+import java.util.List;
+
+import org.opencv.core.Core;
+import org.opencv.core.Core.MinMaxLocResult;
+import org.opencv.core.CvType;
+import org.opencv.core.Mat;
+import org.opencv.core.MatOfPoint;
+import org.opencv.core.MatOfPoint2f;
+import org.opencv.core.Point;
+import org.opencv.core.Scalar;
+import org.opencv.core.Size;
+import org.opencv.highgui.HighGui;
+import org.opencv.imgproc.Imgproc;
+
+class PointPolygonTest {
+    public void run() {
+        /// Create an image
+        int r = 100;
+        Mat src = Mat.zeros(new Size(4 * r, 4 * r), CvType.CV_8U);
+
+        /// Create a sequence of points to make a contour
+        List<Point> vert = new ArrayList<>(6);
+        vert.add(new Point(3 * r / 2, 1.34 * r));
+        vert.add(new Point(1 * r, 2 * r));
+        vert.add(new Point(3 * r / 2, 2.866 * r));
+        vert.add(new Point(5 * r / 2, 2.866 * r));
+        vert.add(new Point(3 * r, 2 * r));
+        vert.add(new Point(5 * r / 2, 1.34 * r));
+
+        /// Draw it in src
+        for (int i = 0; i < 6; i++) {
+            Imgproc.line(src, vert.get(i), vert.get((i + 1) % 6), new Scalar(255), 3);
+        }
+
+        /// Get the contours
+        List<MatOfPoint> contours = new ArrayList<>();
+        Mat hierarchy = new Mat();
+        Imgproc.findContours(src, contours, hierarchy, Imgproc.RETR_TREE, Imgproc.CHAIN_APPROX_SIMPLE);
+
+        /// Calculate the distances to the contour
+        Mat rawDist = new Mat(src.size(), CvType.CV_32F);
+        float[] rawDistData = new float[(int) (rawDist.total() * rawDist.channels())];
+        for (int i = 0; i < src.rows(); i++) {
+            for (int j = 0; j < src.cols(); j++) {
+                rawDistData[i * src.cols() + j] = (float) Imgproc
+                        .pointPolygonTest(new MatOfPoint2f(contours.get(0).toArray()), new Point(j, i), true);
+            }
+        }
+        rawDist.put(0, 0, rawDistData);
+
+        MinMaxLocResult res = Core.minMaxLoc(rawDist);
+        double minVal = Math.abs(res.minVal);
+        double maxVal = Math.abs(res.maxVal);
+
+        /// Depicting the distances graphically
+        Mat drawing = Mat.zeros(src.size(), CvType.CV_8UC3);
+        byte[] drawingData = new byte[(int) (drawing.total() * drawing.channels())];
+        for (int i = 0; i < src.rows(); i++) {
+            for (int j = 0; j < src.cols(); j++) {
+                if (rawDistData[i * src.cols() + j] < 0) {
+                    drawingData[(i * src.cols() + j) * 3] =
+                            (byte) (255 - Math.abs(rawDistData[i * src.cols() + j]) * 255 / minVal);
+                } else if (rawDistData[i * src.cols() + j] > 0) {
+                    drawingData[(i * src.cols() + j) * 3 + 2] =
+                            (byte) (255 - rawDistData[i * src.cols() + j] * 255 / maxVal);
+                } else {
+                    drawingData[(i * src.cols() + j) * 3] = (byte) 255;
+                    drawingData[(i * src.cols() + j) * 3 + 1] = (byte) 255;
+                    drawingData[(i * src.cols() + j) * 3 + 2] = (byte) 255;
+                }
+            }
+        }
+        drawing.put(0, 0, drawingData);
+
+        /// Show your results
+        HighGui.imshow("Source", src);
+        HighGui.imshow("Distance", drawing);
+
+        HighGui.waitKey();
+        System.exit(0);
+    }
+}
+
+public class PointPolygonTestDemo {
+    public static void main(String[] args) {
+        // Load the native OpenCV library
+        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
+
+        new PointPolygonTest().run();
+    }
+
+}

samples/python/tutorial_code/ShapeDescriptors/bounding_rects_circles/generalContours_demo1.py

+from __future__ import print_function
+import cv2 as cv
+import numpy as np
+import argparse
+import random as rng
+
+rng.seed(12345)
+
+def thresh_callback(val):
+    threshold = val
+
+    ## [Canny]
+    # Detect edges using Canny
+    canny_output = cv.Canny(src_gray, threshold, threshold * 2)
+    ## [Canny]
+
+    ## [findContours]
+    # Find contours
+    _, contours, _ = cv.findContours(canny_output, cv.RETR_TREE, cv.CHAIN_APPROX_SIMPLE)
+    ## [findContours]
+
+    ## [allthework]
+    # Approximate contours to polygons + get bounding rects and circles
+    contours_poly = [None]*len(contours)
+    boundRect = [None]*len(contours)
+    centers = [None]*len(contours)
+    radius = [None]*len(contours)
+    for i in range(len(contours)):
+        contours_poly[i] = cv.approxPolyDP(contours[i], 3, True)
+        boundRect[i] = cv.boundingRect(contours_poly[i])
+        centers[i], radius[i] = cv.minEnclosingCircle(contours_poly[i])
+    ## [allthework]
+
+    ## [zeroMat]
+    drawing = np.zeros((canny_output.shape[0], canny_output.shape[1], 3), dtype=np.uint8)
+    ## [zeroMat]
+
+    ## [forContour]
+    # Draw polygonal contour + bonding rects + circles
+    for i in range(len(contours)):
+        color = (rng.randint(0,256), rng.randint(0,256), rng.randint(0,256))
+        cv.drawContours(drawing, contours_poly, i, color)
+        cv.rectangle(drawing, (int(boundRect[i][0]), int(boundRect[i][1])), \
+          (int(boundRect[i][0]+boundRect[i][2]), int(boundRect[i][1]+boundRect[i][3])), color, 2)
+        cv.circle(drawing, (int(centers[i][0]), int(centers[i][1])), int(radius[i]), color, 2)
+    ## [forContour]
+
+    ## [showDrawings]
+    # Show in a window
+    cv.imshow('Contours', drawing)
+    ## [showDrawings]
+
+## [setup]
+# Load source image
+parser = argparse.ArgumentParser(description='Code for Creating Bounding boxes and circles for contours tutorial.')
+parser.add_argument('--input', help='Path to input image.', default='../data/stuff.jpg')
+args = parser.parse_args()
+
+src = cv.imread(args.input)
+if src is None:
+    print('Could not open or find the image:', args.input)
+    exit(0)
+
+# Convert image to gray and blur it
+src_gray = cv.cvtColor(src, cv.COLOR_BGR2GRAY)
+src_gray = cv.blur(src_gray, (3,3))
+## [setup]
+
+## [createWindow]
+# Create Window
+source_window = 'Source'
+cv.namedWindow(source_window)
+cv.imshow(source_window, src)
+## [createWindow]
+## [trackbar]
+max_thresh = 255
+thresh = 100 # initial threshold
+cv.createTrackbar('Canny thresh:', source_window, thresh, max_thresh, thresh_callback)
+thresh_callback(thresh)
+## [trackbar]
+
+cv.waitKey()

samples/python/tutorial_code/ShapeDescriptors/bounding_rotated_ellipses/generalContours_demo2.py

+from __future__ import print_function
+import cv2 as cv
+import numpy as np
+import argparse
+import random as rng
+
+rng.seed(12345)
+
+def thresh_callback(val):
+    threshold = val
+
+    ## [Canny]
+    # Detect edges using Canny
+    canny_output = cv.Canny(src_gray, threshold, threshold * 2)
+    ## [Canny]
+
+    ## [findContours]
+    # Find contours
+    _, contours, _ = cv.findContours(canny_output, cv.RETR_TREE, cv.CHAIN_APPROX_SIMPLE)
+    ## [findContours]
+
+    # Find the rotated rectangles and ellipses for each contour
+    minRect = [None]*len(contours)
+    minEllipse = [None]*len(contours)
+    for i in range(len(contours)):
+        minRect[i] = cv.minAreaRect(contours[i])
+        if contours[i].shape[0] > 5:
+            minEllipse[i] = cv.fitEllipse(contours[i])
+
+    # Draw contours + rotated rects + ellipses
+    ## [zeroMat]
+    drawing = np.zeros((canny_output.shape[0], canny_output.shape[1], 3), dtype=np.uint8)
+    ## [zeroMat]
+    ## [forContour]
+    for i in range(len(contours)):
+        color = (rng.randint(0,256), rng.randint(0,256), rng.randint(0,256))
+        # contour
+        cv.drawContours(drawing, contours, i, color)
+        # ellipse
+        if contours[i].shape[0] > 5:
+            cv.ellipse(drawing, minEllipse[i], color, 2)
+        # rotated rectangle
+        box = cv.boxPoints(minRect[i])
+        box = np.intp(box) #np.intp: Integer used for indexing (same as C ssize_t; normally either int32 or int64)
+        cv.drawContours(drawing, [box], 0, color)
+    ## [forContour]
+
+    ## [showDrawings]
+    # Show in a window
+    cv.imshow('Contours', drawing)
+    ## [showDrawings]
+
+## [setup]
+# Load source image
+parser = argparse.ArgumentParser(description='Code for Creating Bounding rotated boxes and ellipses for contours tutorial.')
+parser.add_argument('--input', help='Path to input image.', default='../data/stuff.jpg')
+args = parser.parse_args()
+
+src = cv.imread(args.input)
+if src is None:
+    print('Could not open or find the image:', args.input)
+    exit(0)
+
+# Convert image to gray and blur it
+src_gray = cv.cvtColor(src, cv.COLOR_BGR2GRAY)
+src_gray = cv.blur(src_gray, (3,3))
+## [setup]
+
+## [createWindow]
+# Create Window
+source_window = 'Source'
+cv.namedWindow(source_window)
+cv.imshow(source_window, src)
+## [createWindow]
+## [trackbar]
+max_thresh = 255
+thresh = 100 # initial threshold
+cv.createTrackbar('Canny Thresh:', source_window, thresh, max_thresh, thresh_callback)
+thresh_callback(thresh)
+## [trackbar]
+
+cv.waitKey()

samples/python/tutorial_code/ShapeDescriptors/find_contours/findContours_demo.py

+from __future__ import print_function
+import cv2 as cv
+import numpy as np
+import argparse
+import random as rng
+
+rng.seed(12345)
+
+def thresh_callback(val):
+    threshold = val
+
+    # Detect edges using Canny
+    canny_output = cv.Canny(src_gray, threshold, threshold * 2)
+
+    # Find contours
+    _, contours, hierarchy = cv.findContours(canny_output, cv.RETR_TREE, cv.CHAIN_APPROX_SIMPLE)
+
+    # Draw contours
+    drawing = np.zeros((canny_output.shape[0], canny_output.shape[1], 3), dtype=np.uint8)
+    for i in range(len(contours)):
+        color = (rng.randint(0,256), rng.randint(0,256), rng.randint(0,256))
+        cv.drawContours(drawing, contours, i, color, 2, cv.LINE_8, hierarchy, 0)
+
+    # Show in a window
+    cv.imshow('Contours', drawing)
+
+# Load source image
+parser = argparse.ArgumentParser(description='Code for Finding contours in your image tutorial.')
+parser.add_argument('--input', help='Path to input image.', default='../data/HappyFish.jpg')
+args = parser.parse_args()
+
+src = cv.imread(args.input)
+if src is None:
+    print('Could not open or find the image:', args.input)
+    exit(0)
+
+# Convert image to gray and blur it
+src_gray = cv.cvtColor(src, cv.COLOR_BGR2GRAY)
+src_gray = cv.blur(src_gray, (3,3))
+
+# Create Window
+source_window = 'Source'
+cv.namedWindow(source_window)
+cv.imshow(source_window, src)
+max_thresh = 255
+thresh = 100 # initial threshold
+cv.createTrackbar('Canny Thresh:', source_window, thresh, max_thresh, thresh_callback)
+thresh_callback(thresh)
+
+cv.waitKey()

samples/python/tutorial_code/ShapeDescriptors/hull/hull_demo.py

+from __future__ import print_function
+import cv2 as cv
+import numpy as np
+import argparse
+import random as rng
+
+rng.seed(12345)
+
+def thresh_callback(val):
+    threshold = val
+
+    # Detect edges using Canny
+    canny_output = cv.Canny(src_gray, threshold, threshold * 2)
+
+    # Find contours
+    _, contours, _ = cv.findContours(canny_output, cv.RETR_TREE, cv.CHAIN_APPROX_SIMPLE)
+
+    # Find the convex hull object for each contour
+    hull_list = []
+    for i in range(len(contours)):
+        hull = cv.convexHull(contours[i])
+        hull_list.append(hull)
+
+    # Draw contours + hull results
+    drawing = np.zeros((canny_output.shape[0], canny_output.shape[1], 3), dtype=np.uint8)
+    for i in range(len(contours)):
+        color = (rng.randint(0,256), rng.randint(0,256), rng.randint(0,256))
+        cv.drawContours(drawing, contours, i, color)
+        cv.drawContours(drawing, hull_list, i, color)
+
+    # Show in a window
+    cv.imshow('Contours', drawing)
+
+# Load source image
+parser = argparse.ArgumentParser(description='Code for Convex Hull tutorial.')
+parser.add_argument('--input', help='Path to input image.', default='../data/stuff.jpg')
+args = parser.parse_args()
+
+src = cv.imread(args.input)
+if src is None:
+    print('Could not open or find the image:', args.input)
+    exit(0)
+
+# Convert image to gray and blur it
+src_gray = cv.cvtColor(src, cv.COLOR_BGR2GRAY)
+src_gray = cv.blur(src_gray, (3,3))
+
+# Create Window
+source_window = 'Source'
+cv.namedWindow(source_window)
+cv.imshow(source_window, src)
+max_thresh = 255
+thresh = 100 # initial threshold
+cv.createTrackbar('Canny thresh:', source_window, thresh, max_thresh, thresh_callback)
+thresh_callback(thresh)
+
+cv.waitKey()

samples/python/tutorial_code/ShapeDescriptors/moments/moments_demo.py

+from __future__ import print_function
+from __future__ import division
+import cv2 as cv
+import numpy as np
+import argparse
+import random as rng
+
+rng.seed(12345)
+
+def thresh_callback(val):
+    threshold = val
+
+    ## [Canny]
+    # Detect edges using Canny
+    canny_output = cv.Canny(src_gray, threshold, threshold * 2)
+    ## [Canny]
+
+    ## [findContours]
+    # Find contours
+    _, contours, _ = cv.findContours(canny_output, cv.RETR_TREE, cv.CHAIN_APPROX_SIMPLE)
+    ## [findContours]
+
+    # Get the moments
+    mu = [None]*len(contours)
+    for i in range(len(contours)):
+        mu[i] = cv.moments(contours[i])
+
+    # Get the mass centers
+    mc = [None]*len(contours)
+    for i in range(len(contours)):
+        # add 1e-5 to avoid division by zero
+        mc[i] = (mu[i]['m10'] / (mu[i]['m00'] + 1e-5), mu[i]['m01'] / (mu[i]['m00'] + 1e-5))
+
+    # Draw contours
+    ## [zeroMat]
+    drawing = np.zeros((canny_output.shape[0], canny_output.shape[1], 3), dtype=np.uint8)
+    ## [zeroMat]
+    ## [forContour]
+    for i in range(len(contours)):
+        color = (rng.randint(0,256), rng.randint(0,256), rng.randint(0,256))
+        cv.drawContours(drawing, contours, i, color, 2)
+        cv.circle(drawing, (int(mc[i][0]), int(mc[i][1])), 4, color, -1)
+    ## [forContour]
+
+    ## [showDrawings]
+    # Show in a window
+    cv.imshow('Contours', drawing)
+    ## [showDrawings]
+
+    # Calculate the area with the moments 00 and compare with the result of the OpenCV function
+    for i in range(len(contours)):
+        print(' * Contour[%d] - Area (M_00) = %.2f - Area OpenCV: %.2f - Length: %.2f' % (i, mu[i]['m00'], cv.contourArea(contours[i]), cv.arcLength(contours[i], True)))
+
+## [setup]
+# Load source image
+parser = argparse.ArgumentParser(description='Code for Image Moments tutorial.')
+parser.add_argument('--input', help='Path to input image.', default='../data/stuff.jpg')
+args = parser.parse_args()
+
+src = cv.imread(args.input)
+if src is None:
+    print('Could not open or find the image:', args.input)
+    exit(0)
+
+# Convert image to gray and blur it
+src_gray = cv.cvtColor(src, cv.COLOR_BGR2GRAY)
+src_gray = cv.blur(src_gray, (3,3))
+## [setup]
+
+## [createWindow]
+# Create Window
+source_window = 'Source'
+cv.namedWindow(source_window)
+cv.imshow(source_window, src)
+## [createWindow]
+## [trackbar]
+max_thresh = 255
+thresh = 100 # initial threshold
+cv.createTrackbar('Canny Thresh:', source_window, thresh, max_thresh, thresh_callback)
+thresh_callback(thresh)
+## [trackbar]
+
+cv.waitKey()

samples/python/tutorial_code/ShapeDescriptors/point_polygon_test/pointPolygonTest_demo.py

+from __future__ import print_function
+from __future__ import division
+import cv2 as cv
+import numpy as np
+
+# Create an image
+r = 100
+src = np.zeros((4*r, 4*r), dtype=np.uint8)
+
+# Create a sequence of points to make a contour
+vert = [None]*6
+vert[0] = (3*r//2, int(1.34*r))
+vert[1] = (1*r, 2*r)
+vert[2] = (3*r//2, int(2.866*r))
+vert[3] = (5*r//2, int(2.866*r))
+vert[4] = (3*r, 2*r)
+vert[5] = (5*r//2, int(1.34*r))
+
+# Draw it in src
+for i in range(6):
+    cv.line(src, vert[i],  vert[(i+1)%6], ( 255 ), 3)
+
+# Get the contours
+_, contours, _ = cv.findContours(src, cv.RETR_TREE, cv.CHAIN_APPROX_SIMPLE)
+
+# Calculate the distances to the contour
+raw_dist = np.empty(src.shape, dtype=np.float32)
+for i in range(src.shape[0]):
+    for j in range(src.shape[1]):
+        raw_dist[i,j] = cv.pointPolygonTest(contours[0], (j,i), True)
+
+minVal, maxVal, _, _ = cv.minMaxLoc(raw_dist)
+minVal = abs(minVal)
+maxVal = abs(maxVal)
+
+# Depicting the  distances graphically
+drawing = np.zeros((src.shape[0], src.shape[1], 3), dtype=np.uint8)
+for i in range(src.shape[0]):
+    for j in range(src.shape[1]):
+        if raw_dist[i,j] < 0:
+            drawing[i,j,0] = 255 - abs(raw_dist[i,j]) * 255 / minVal
+        elif raw_dist[i,j] > 0:
+            drawing[i,j,2] = 255 - raw_dist[i,j] * 255 / maxVal
+        else:
+            drawing[i,j,0] = 255
+            drawing[i,j,1] = 255
+            drawing[i,j,2] = 255
+
+cv.imshow('Source', src)
+cv.imshow('Distance', drawing)
+cv.waitKey()