* fixed antialiased line rendering to process image border correctly

* fixed warning on Windows

* imgproc(test): circle drawing regression

* fixed issue with Mat reshape in decodeMulti()

* added test for decodeMulti

* used assign

* Update py_thresholding.markdown

* 📝 Update py_thresholding.markdown

* added note about BORDER_TYPE in separable filters; fixed SGBMStereo description

* added # to BORDER_ constants to generate hyperlinks

Fix compilation errors on GLES platforms

* Do not include glx.h when using GLES

GL/glx.h is included on all LINUX plattforms, which is wrong
for a number of reasons:

- GL_PERSPECTIVE_CORRECTION_HINT is defined in GL/gl.h, so we
  want gl.h not glx.h, the latter just includes the former
- GL/gl.h is a Desktop GL header, and should not be included
  on GLES plattforms
- GL/gl.h is already included via QtOpenGL ->
  QtGui/qopengl.h on desktop plattforms

This fixes a problem when Qt is compiled with GLES, which
is often done on ARM platforms where desktop GL is not or
only poorly supported (e.g. slow due to emulation).

Fixes part of #9171.

* Only set GL_PERSPECTIVE_CORRECTION_HINT when GL version defines it

GL_PERSPECTIVE_CORRECTION_HINT does not exist in GLES 2.0/3.x,
and has been deprecated in OpenGL 3.0 core profiles.

Fixes part of #9171.

* Add python version of panorama_stitching_rotating_camera and perspective_correction

* Updated code

* added in the docs

* added python code in the docs

* docs change

* Add java tutorial as well

* Add toggle in documentation

* Added the link for Java code

* format code

* Refactored code

This is a correction of the previously missleading documentation and a warning related to a common calibration failure described in issue 15992

* corrected incorrect description of failed calibration state.

see issue 15992

* calib3d: apply suggestions from code review by catree

* Fix bug 16410 and add test

* imgproc(connectedcomponents): avoid manual uninitialized allocations

* imgproc(connectedcomponents): force 'odd' chunk range size

* imgproc(connectedcomponents): reuse stripeFirstLabel{4/8}Connectivity

* imgproc(connectedcomponents): extend fix from PR14964

Just like with the other headers in the rest of the file.

See e.g. https://stackoverflow.com/questions/36831465/what-difference-does-it-make-when-i-include-limits-or-limits-h-in-my-c-cod
for the reasons, the most important one being that limits.h does not respect
namespaces, which can make problems for downstream consumers of cvdef.h.

  generalize constraints to 'wa' for VSX registers

backporting of commit f163778d

QR-Code detector : multiple detection

* change in qr-codes detection

* change in qr-codes detection

* change in test

* change in test

* add multiple detection

* multiple detection

* multiple detect

* add parallel implementation

* add functional for performance tests

* change in test

* add perftest

* returned implementation for 1 qr-code, added support for vector<Mat> and vector<vector<Point2f>> in MultipleDetectAndDecode

* deleted all lambda expressions

* changing in triangle sort

* fixed warnings

* fixed errors

* add java and python tests

* change in java tests

* change in java and python tests

* change in perf test

* change in qrcode.cpp

* add spaces

* change in qrcode.cpp

* change in qrcode.cpp

* change in qrcode.cpp

* change in java tests

* change in java tests

* solved problems

* solved problems

* change in java and python tests

* change in python tests

* change in python tests

* change in python tests

* change in methods name

* deleted sample qrcode_multi, change in qrcode.cpp

* change in perf tests

* change in objdetect.hpp

* deleted code duplication in sample qrcode.cpp

* returned spaces

* added spaces

* deleted draw function

* change in qrcode.cpp

* change in qrcode.cpp

* deleted all draw functions

* objdetect(QR): extractVerticalLines

* objdetect(QR): whitespaces

* objdetect(QR): simplify operations, avoid duplicated code

* change in interface, additional checks in java and python tests, added new key in sample for saving original image from camera

* fix warnings and errors in python test

* fix

* write in file with space key

* solved error with empty mat check in python test

* correct path to test image

* deleted spaces

* solved error with check empty mat in python tests

* added check of empty vector of points

* samples: rework qrcode.cpp

* objdetect(QR): fix API, input parameters must be first

* objdetect(QR): test/fix points layout