[G-API] Implement render using stateful kernel

* Implement render using stateful kernel

* Move freetype to backends folder

* Fix freetype compilation

* Fix freetype smoke test

* Fix comments

* Refactoring

[G-API] Wrap cv::gapi::infer<Generic> into python

* Introduce generic infer

* Move Generic to infer.hpp

* Removew num_outs

* Fix windows warnings

* Fix comments to review

* Fix doxygen

* Add comment

* Fix comments to review

* Wrap inference to python

* Add default ctor to Params

* Add test

* Fix clang build

* Implement GInferInputs/GInferOutputs as Pimpl

* Add checkIEtarget to infer test

* Fix path

* Supress warning

* Use getAvailableDevices insted of checkIETarget

* Move PyParams to bindings_ie

* Add namespace

* Update CMakeLists.txt

* stitching: add WAVE_CORRECT_AUTO

* stitching: use CV_EXPORTS

Detection and decoding of curved QR-codes

* temp changes for curved qrcodes

* added api for curved qr code decoding

* fixed prototypes

* refactored curved qr code decoding

* refactored curved qr code decoding 2nd part

* refactored curved qr code decoding 3rd part

* refactored curved qr code decoding 4th part

* added tests for curved qr code decoding

* refactored curved qr code decoding 5th part

Add support for Swift version independence

* Build for distribution (Swift version independence) when new Xcode build system is available

* Add module map and set "Defines Modules" flag

* support similarity masks

* add test for similarity threshold

* short license in test

* use UMat in buildSimilarityMask

* fix win32 warnings

* fix test indentation

* fix umat/mat sync

* no in-place argument for erode/dilate

Fixes two errors when building with the options WITH_CUDA=ON and BUILD_CUDA_STUBS=ON on a machine without CUDA.

In the cudaarithm module, make sure cuda_runtime.h only gets included when CUDA is installed.

In the stitching module, don't assume that cuda is present just because cudaarithm and cudawarping are present (as is the case when building with the above options).

test by projecting and reprojecting back random points

This sample models the Text Detection demo from OMZ:
https://github.com/openvinotoolkit/open_model_zoo/tree/2020.4/demos/text_detection_demo

Also: renamed cv::gapi::size() to cv::gapi::streaming::size()

Univ Intrinsics implementation of Add, Sub, Absdiff kernels

* Add, sub, absdiff kernels optimization

* avoid unused conditions

* add conditions for tail processing

[G-API]: Introduce RMat serialization API

* Introduce RMat serialization API

* Fix RunArgs deserialization

* Address review comments

* Export operators for GRunArg serialization

* Fix warning and add handling for RMat in bind()

* Update CMakeLists.txt

* G-API: RMat S11N -- probably fix the Windows warning

* add HEVC(H.265) codec to iOS,Mac VideoWriter

* Update cap_avfoundation_mac.mm

add CV_FOURCC('h','v','c','1') for HEVC codec

* Update cap_avfoundation.mm

add CV_FOURCC('h','v','c','1') for HEVC codec

* feat: add availability check for HEVC codec on iOS and OS X
Co-authored-by: NVadim Levin <vadim.levin@xperience.ai>

Add support thread-local directx (OpenCL interop) initialization

* support thread-local directx (OpenCL interop) initialization

* reflect reviews

* Remove verbose function prototype declarations

* Countermeasures for VC warnings. (declaration of 'platform' hides class member)

* core(directx): remove internal stuff from public headers

[GSoC] OpenCV.js: WASM SIMD optimization 2.0

* gsoc_2020_simd Add perf test for filter2d

* add perf test for kernel scharr and kernel gaussianBlur

* add perf test for blur, medianBlur, erode, dilate

* fix the errors for the opencv PR robot

fix the trailing whitespace.

* add perf tests for kernel remap, warpAffine, warpPersepective, pyrDown

* fix a bug in  modules/js/perf/perf_imgproc/perf_remap.js

* add function smoothBorder in helpfun.js and remove replicated function in perf test of warpAffine and warpPrespective

* fix the trailing white space issues

* add OpenCV.js loader

* Implement the Loader with help of WebAssembly Feature Detection, remove trailing whitespaces

* modify the explantion for loader in js_setup.markdown and fix bug in loader.js