Fix incorrect string format in js build script #26374
I accidentally met this small problem mentioned in https://github.com/opencv/opencv/pull/25084#discussion_r1710838120 when play with wasm build. It seems https://github.com/EDVTAZ didn't fix it yet, so I create this tiny pr.
Additionally, I remove a redundant argument in `add_argument` call. `'store_true'` already set the default, see https://docs.python.org/3/library/argparse.html#action.
### Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake
Split Javascript white-list to support contrib modules #25986
Single whitelist converted to several per-module json files. They are concatenated automatically and can be overriden by user config.
Related to https://github.com/opencv/opencv/pull/25656
### Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake
Fix OpenCV.js tests #25732
### Pull Request Readiness Checklist
* Firefox tests passed
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake
Add compatibility with latest (3.1.54) emsdk version #25084
### Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [ ] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake
### Details
I was following [this tutorial](https://docs.opencv.org/4.9.0/d4/da1/tutorial_js_setup.html) for building opencv with wasm target. The tutorial mentions that the last verified version of emscripten that is tested with opencv is 2.0.10, but I was curious if I could get it to work with more recent versions. I've run into a few issues with the latest version, for which fixes are included in this PR. I've found a few issues that have the same problems I encountered:
- https://github.com/opencv/opencv/issues/24620
- https://github.com/opencv/opencv/issues/20313
- https://stackoverflow.com/questions/77469603/custom-opencv-js-wasm-using-cv-matfromarray-results-in-cv-mat-is-not-a-co
- https://github.com/emscripten-core/emscripten/issues/14803
- https://github.com/opencv/opencv/issues/24572
- https://github.com/opencv/opencv/issues/19493#issuecomment-857167996
I used the docker image for building and comparing results with different emsdk versions. I tested by building with `--build_wasm` and `--build-test` flags and ran the tests in the browser. I addressed the following issues with newer versions of emscripten:
- In newer versions `EMSCRIPTEN` environemnt variable was stopped being set. I added support for deriving location based on the `EMSDK` environment variable, as suggested [here](https://github.com/emscripten-core/emscripten/issues/14803)
- In newer versions emcmake started passing `-DCMAKE...` arguments, however the opencv python script didn't know how to handle them. I added processing to the args that will forward all arguments to `cmake` that start with `-D`. I opted for this in hopes of being more futureproof, but another approach could be just ignoreing them, or explicitly forwarding them instead of matching anything starting with `-D`. These approches were suggested [here](https://github.com/opencv/opencv/issues/19493#issuecomment-855529448)
- With [version 3.1.31](https://github.com/emscripten-core/emscripten/blob/main/ChangeLog.md#3131---012623) some previously exported functions stopped being automatically exported. Because of this, `_free` and `_malloc` were no longer available and had to be explicitly exported because of breaking tests.
- With [version 3.1.42](https://github.com/emscripten-core/emscripten/compare/3.1.41...3.1.42#diff-e505aa80b2764c0197acfc9afd8179b3600f0ab5dd00ff77db01879a84515cdbL3875) the `post-js` code doesn't receive the module named as `EXPORT_NAME` anymore, but only as `moduleArg`/`Module`. This broke existing code in `helpers.js`, which was referencing exported functions through `cv.Mat`, etc. I changed all of these references to use `Module.Mat`, etc. If it is preferred, alternatively the `cv` variable could be reintroduced in `helper.js` as suggested [here](https://github.com/opencv/opencv/issues/24620)
With the above changes in place, I can successfully build and run tests with the latest emscripten/emsdk docker image (also with 2.0.10 and most of the other older tags, except for a few that contain transient issues like [this](https://github.com/emscripten-core/emscripten/issues/17700)).
This is my first time contributing to opencv, so I hope I got everything correct in this PR, but please let me know if I should change anything!
[GSoC] OpenCV.js: Accelerate OpenCV.js DNN via WebNN
* Add WebNN backend for OpenCV DNN Module
Update dnn.cpp
Update dnn.cpp
Update dnn.cpp
Update dnn.cpp
Add WebNN head files into OpenCV 3rd partiy files
Create webnn.hpp
update cmake
Complete README and add OpenCVDetectWebNN.cmake file
add webnn.cpp
Modify webnn.cpp
Can successfully compile the codes for creating a MLContext
Update webnn.cpp
Update README.md
Update README.md
Update README.md
Update README.md
Update cmake files and
update README.md
Update OpenCVDetectWebNN.cmake and README.md
Update OpenCVDetectWebNN.cmake
Fix OpenCVDetectWebNN.cmake and update README.md
Add source webnn_cpp.cpp and libary libwebnn_proc.so
Update dnn.cpp
Update dnn.cpp
Update dnn.cpp
Update dnn.cpp
update dnn.cpp
update op_webnn
update op_webnn
Update op_webnn.hpp
update op_webnn.cpp & hpp
Update op_webnn.hpp
Update op_webnn
update the skeleton
Update op_webnn.cpp
Update op_webnn
Update op_webnn.cpp
Update op_webnn.cpp
Update op_webnn.hpp
update op_webnn
update op_webnn
Solved the problems of released variables.
Fixed the bugs in op_webnn.cpp
Implement op_webnn
Implement Relu by WebNN API
Update dnn.cpp for better test
Update elementwise_layers.cpp
Implement ReLU6
Update elementwise_layers.cpp
Implement SoftMax using WebNN API
Implement Reshape by WebNN API
Implement PermuteLayer by WebNN API
Implement PoolingLayer using WebNN API
Update pooling_layer.cpp
Update pooling_layer.cpp
Update pooling_layer.cpp
Update pooling_layer.cpp
Update pooling_layer.cpp
Update pooling_layer.cpp
Implement poolingLayer by WebNN API and add more detailed logs
Update dnn.cpp
Update dnn.cpp
Remove redundant codes and add more logs for poolingLayer
Add more logs in the pooling layer implementation
Fix the indent issue and resolve the compiling issue
Fix the build problems
Fix the build issue
FIx the build issue
Update dnn.cpp
Update dnn.cpp
* Fix the build issue
* Implement BatchNorm Layer by WebNN API
* Update convolution_layer.cpp
This is a temporary file for Conv2d layer implementation
* Integrate some general functions into op_webnn.cpp&hpp
* Update const_layer.cpp
* Update convolution_layer.cpp
Still have some bugs that should be fixed.
* Update conv2d layer and fc layer
still have some problems to be fixed.
* update constLayer, conv layer, fc layer
There are still some bugs to be fixed.
* Fix the build issue
* Update concat_layer.cpp
Still have some bugs to be fixed.
* Update conv2d layer, fully connected layer and const layer
* Update convolution_layer.cpp
* Add OpenCV.js DNN module WebNN Backend (both using webnn-polyfill and electron)
* Delete bib19450.aux
* Add WebNN backend for OpenCV DNN Module
Update dnn.cpp
Update dnn.cpp
Update dnn.cpp
Update dnn.cpp
Add WebNN head files into OpenCV 3rd partiy files
Create webnn.hpp
update cmake
Complete README and add OpenCVDetectWebNN.cmake file
add webnn.cpp
Modify webnn.cpp
Can successfully compile the codes for creating a MLContext
Update webnn.cpp
Update README.md
Update README.md
Update README.md
Update README.md
Update cmake files and
update README.md
Update OpenCVDetectWebNN.cmake and README.md
Update OpenCVDetectWebNN.cmake
Fix OpenCVDetectWebNN.cmake and update README.md
Add source webnn_cpp.cpp and libary libwebnn_proc.so
Update dnn.cpp
Update dnn.cpp
Update dnn.cpp
Update dnn.cpp
update dnn.cpp
update op_webnn
update op_webnn
Update op_webnn.hpp
update op_webnn.cpp & hpp
Update op_webnn.hpp
Update op_webnn
update the skeleton
Update op_webnn.cpp
Update op_webnn
Update op_webnn.cpp
Update op_webnn.cpp
Update op_webnn.hpp
update op_webnn
update op_webnn
Solved the problems of released variables.
Fixed the bugs in op_webnn.cpp
Implement op_webnn
Implement Relu by WebNN API
Update dnn.cpp for better test
Update elementwise_layers.cpp
Implement ReLU6
Update elementwise_layers.cpp
Implement SoftMax using WebNN API
Implement Reshape by WebNN API
Implement PermuteLayer by WebNN API
Implement PoolingLayer using WebNN API
Update pooling_layer.cpp
Update pooling_layer.cpp
Update pooling_layer.cpp
Update pooling_layer.cpp
Update pooling_layer.cpp
Update pooling_layer.cpp
Implement poolingLayer by WebNN API and add more detailed logs
Update dnn.cpp
Update dnn.cpp
Remove redundant codes and add more logs for poolingLayer
Add more logs in the pooling layer implementation
Fix the indent issue and resolve the compiling issue
Fix the build problems
Fix the build issue
FIx the build issue
Update dnn.cpp
Update dnn.cpp
* Fix the build issue
* Implement BatchNorm Layer by WebNN API
* Update convolution_layer.cpp
This is a temporary file for Conv2d layer implementation
* Integrate some general functions into op_webnn.cpp&hpp
* Update const_layer.cpp
* Update convolution_layer.cpp
Still have some bugs that should be fixed.
* Update conv2d layer and fc layer
still have some problems to be fixed.
* update constLayer, conv layer, fc layer
There are still some bugs to be fixed.
* Update conv2d layer, fully connected layer and const layer
* Update convolution_layer.cpp
* Add OpenCV.js DNN module WebNN Backend (both using webnn-polyfill and electron)
* Update dnn.cpp
* Fix Error in dnn.cpp
* Resolve duplication in conditions in convolution_layer.cpp
* Fixed the issues in the comments
* Fix building issue
* Update tutorial
* Fixed comments
* Address the comments
* Update CMakeLists.txt
* Offer more accurate perf test on native
* Add better perf tests for both native and web
* Modify per tests for better results
* Use more latest version of Electron
* Support latest WebNN Clamp op
* Add definition of HAVE_WEBNN macro
* Support group convolution
* Implement Scale_layer using WebNN
* Add Softmax option for native classification example
* Fix comments
* Fix comments
[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
[GSoC 2019] Improve the performance of JavaScript version of OpenCV (OpenCV.js)
* [GSoC 2019]
Improve the performance of JavaScript version of OpenCV (OpenCV.js):
1. Create the base of OpenCV.js performance test:
This perf test is based on benchmark.js(https://benchmarkjs.com). And first add `cvtColor`, `Resize`, `Threshold` into it.
2. Optimize the OpenCV.js performance by WASM threads:
This optimization is based on Web Worker API and SharedArrayBuffer, so it can be only used in browser.
3. Optimize the OpenCV.js performance by WASM SIMD:
Add WASM SIMD backend for OpenCV Universal Intrinsics. It's experimental as WASM SIMD is still in development.
* [GSoC2019]
1. use short license header
2. fix documentation node issue
3. remove the unused `hasSIMD128()` api
* [GSoC2019]
1. fix emscripten define
2. use fallback function for f16
* [GSoC2019]
Fix rebase issue
* Enable Javascript bindings for photo module.
1. Enable the build flag in build_js.py.
2. Append js into WRAP list of photo’s CMakefiles.txt
3. Add photo module's API into JS API whitelist (embindgen.py)
Exposing the HDR imaging part of photo module.
[TODO]
Add tests
Fix opencv/doc/js_tutorials/
* [WIP] TODO: Add tests
* Remove TonemapDurand: algorithm patented in US, so moved to opencv_contrib
* Fix ningxin's comment: expose the base class.
* Add some more simple binding tests.
Also expose process function
* js: update build script
- support emscipten 1.38.12 (wasm is ON by default)
- verbose build messages
* js: use builtin Math functions
* js: disable tracing code completelly
GSoC 2017: Improve and Extend the JavaScript Bindings for OpenCV (#9466)
* Initial support for build with emscripten
mkdir build_js
cd build_js
cmake -D CMAKE_TOOLCHAIN_FILE=/path/to/emsdk/emsdk-portable/emscripten/master/cmake/Modules/Platform/Emscripten.cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=/usr/local ..
* Add js module
The output is build/bin/opencv_js.js
* Fix opencv2/calib3d.hpp not found issue
* Add module name
Usage:
var cv = cv();
* Add total memory as 128MB and allow growth
* Add compilation flags for emscripten
* Use EMSCRIPTEN build target
* Disable js module for non emscripten build
* Bind the preload file path to root
Usage:
face_cascade.load('haarcascade_frontalface_default.xml');
* add test folder
* fix test files
* Copy js module test to bin
* Support to run tests on Node.js
Fix tests to import cv Module when runtime is node.
Add tests.js to use qunit to auto run tests.
Modify umd wrapper to support Module is not defined.
Usage:
node tests.js
* Support UMD and file system
Wrap the opencv_js.js to opencv.js by UMD wrapper
Use emscripten file system API to load files instead of generating data file or
embedding them. It supports both browser and node.js usages.
* Fix incorrect module name in tests
* Add package.json to add dependence of qunit
* Add js_tutorials folder and a intro page of opencv.js
Enable BUILD_DOCS in CMakeLists.txt.
Add new folder of js_tutorials in folder opencv/doc.
Imitate the tutorials of OpenCV-Python to create a intro page of opencv.js and a setup guide
* Import and use binding gen from opencvjs project
* Modify the embindgen.py to pass the build and test
* Add classes and functions white list
* Consolidate hdr_parser.py (#31)
Use hdr_parser.py of python module
Add js flag to support js binding generator.
* Use emscripten::vecFromJSArray for input vector param
Fix part of #23
* Fix test cases after #34Fix#39
* Expose groupRectangles and CascadeClassifier.empty
* Add js highgui tutorials
add tutorials of imread&imshow and createTrackbar in doc/js_tutorials/js_gui folder
add interactive tutorial webpage for imread&imshow and createTrackbar in doc/js_tutorials/js_interactive_tutorials folder, and some images needed.
change doc/CMakeLists.txt to copy the interactive tutorial webpage and opencv.js to the tutorials' destination folder
* rm useless annotation in doc/CMakeLists.txt
* fix some nonstandard indentation and space
* add check if canvas is valid
* Expose BackgroundSubtractorMOG2
Fix#43
* Fix build of js doc
Limit copy_js_interactive_tutorials for doxygen build
Add dep to opencv.js
Fix#53
* Implement cv.imread & cv.imshow and insert interactive pages in tutorials (#55)
* add helper.js
* delete ALL in add target copy_js_interactive_tutorials to avoid dependence error
* Insert interactive pages in tutorials
insert the old interactive pages in markdown by using \htmlonly and \endhtmlonly command.
delete the useless interactive page
rename js_interactive_tutorials to js_assets to put some images needed in
* fix the depends of the target doxygen
add opencv.js to depends and delete the useless target of copy_js_assets
* change filename helper.js to helpers.js
* disable button or trankbar before opencv.js is ready
* Expose CV_64F
Fix#65
* improve cv.imshow to display different types as native imshow
* add utils.js to reuse functions and update tutorials
* Make doxygen depend on bin/opencv.js
* Fix memory issue of matFromArray
Fix#37
* Merge pull request from ganwenyao/tutorial_18
* Add notes for ganwenyao/tutorial_18
* Modifying for ganwenyao/tutorial_18
* Change Mat constructor with data to 5 parameters
* Mat supports constructor with Scalar
Fix#60
* update cv.imread cause the memory issue of matFromArray has been fixed
* fix canvas name and default input image
* Expose cv::Moments
Fix#85
* Add -Wno-missing-prototypes for emscripten build
* fix canvas name
* add tutorial of video input and output
* Expose enums as emscripten consts
Fix#72
* update the tutorial to use Mat constructor with Scalar and change lena.jpg
* Exclude cv::Mat for vecFromJSArray
Fix#82
* Add unit tests for cv.moments
* Fix the unit tests.
* add checkbox and stop button
* add adapter.js to make sure compatibility fo video tutorials
* Support default parameters with function overloading
* modify enums to constants
* Use https URL for MathJax.js
Fix#109
* Comment out the debug print in embindgen.py
* Expose RotatedRect
Fix#96
* replace enum with constants and improve onload function
* delete some useless paras cause #105 fixed this
* Modify const name
* Modify Contour Properties
* tutorials for imgprc2 and objdec
* Expose more functions for img proc tutorials
Fix#76
* Expose polylines for video analysis tutorial
Fix#121
* Expose constants for default parameters of img proc tutorials
Fix#122
* Fix wrong parameter types of Mat.copyTo
Fix#87
* Support default parameters of mat.convertTo
Fix#123
* Support default parameters for external constructors
Fix#131
* Revert "Expose polylines for video analysis tutorial"
This reverts commit 3ce7615652e510d30e3c0014706ac38c98883189.
Fix#121
* Support cv.minMaxLoc
Fix#127
* Expose cv.minEnclosingCircle
Fix#126
* Add video analysis tutorials
add three video tutorials, Meanshift and Camshift, Optical Flow Background Subtraction
add cup.mp4 and box.mp4 for demo in tutorials
* improve image processing tutorials
* repalce console.warn with throw to throw exception
* add try-catch to throw exception in code demo
* Change mat.size() return value to JS Array object
Fix#140
* add a note about different channels order between canvas and native opencv
* add a note about how to capture video from video files
* Binding cv.Scalar to JS array
Fix#147
* Add JS cv.Scalar object into helpers.js
* Update Install OpenCV-JavaScript tutorial page
Fix#44
* Update the OpenCV-JavaScript introduction page
Fix#44
* add cv.VideoCapture and read() function
* set the size of the hidden canvas same as the video
* Add Using OpenCV-JavaScript tutorial page
Fix#44
* fix some bad code style
* Update tutorials after 8/2 sync meeting
Changes include:
- Use OpenCV.js name instead of OpenCV-JavaScript
- Put using OpenCV.js ahead of build OpenCV.js
- Refine usage and introduction page
- Muted the video in tutorials
* Fix a typo in introduction page
* use cv.VideoCapture and its read() function to read video
* replace OpenCV-JavaScript with OpenCV.js
* Use onload of async script in js_usage tutorial
* add more info about mat.data
* Change Size to value_object
* Integrate Moh and Sajjad's editing into introduction page
* Change Point to value_object
* Change Rect to value_object with helper object
* Add helper objects for Point and Size
* Change RotatedRect to value_object with helpers
* Change MinMaxLoc and Circle to value_object
* Change TermCriteria to value_object
* Fix core_bindings.cpp for MinMaxLoc and Circle
* Remove unused types
* Change meanShift and CamShift to return Rect
* Change methods of RotatedRect to static
* Change mat.data from methods to property
Fix#75 and #77
* support img id and element in cv.imread
* Change mat.size to property and add mat.step
Fix#163
* Add matFromArray and matFromImageData as JS helpers
Fix#79, #78
* Lower camel case for Mat element getters
Fix#81
* Mat.getRoiRect and tests
Fix#86
* Support type for Mat.ptr
Fix#83
* Name changing of Mat element getters
'getUcharAt` -> 'ucharAt'
* fix code style and args names
* Fix helpers.js due to cv.Mat API update
* Fix opencv.js usage tutorial
* Fix a typo of js_setup
* Change Moments to value_object
* Add Range as value_object
Fix#171
* Support Mat.diag and Mat.isContinous
Fix#84 and #89
* Support Mat.setTo
Fix#88
* Apply edits to js_intro
* Apply edits to js_usage
* Apply edits to js_setup
* update tutorials to apply data type change
* Modify tutorials
* add core tutorials
* delete MatVector elements and delete useless set operation
* add tutorials_objdec_camera
* Add instructions for WebAssembly
* apply tech writer's feedbacks into tutorials
* Organize white list by modules
* Change size to method and bind to MatExpr.size()
Fix#177
* improve tutorials
* Modify core tutorials
* add params list and explanations for OpenCV.js functions
* remove face_profile from Face Detection in Video Capture
* Add demos link
* Change Gui to GUI
* Update js_intro based on Moh and Sajjad's edits
* Fixup for 3.3.0 rebase
* Update js_intro per Moh's suggestion
* Update contributors list per Moh's idea
* add adapter.js in video_display tutorial
* Change Mat.getRoiRect to Mat.roi
Fix#194
* Remove unnecessary files for test
Fix#192
* Licenses updated to UC BSD 3-Clause
* Apply OpenCV coding style for C++ files
* Add OpenCV license for python and js files
* Fix coding style issue in helpers.js
* Remove unused test_commons.js
* Fix coding style of test_imgproc.js
* Fix coding style of test_mat.js
* Fix space before semicolon
* Fix coding style of test_objdetect.js
* Fix coding style of tests.js
* Fix coding style of test_utils.js
* Fix coding style of test_video.js
* Fix failures of node.js tests
* Add eslint rule config and fix eslint errors
* Add eslint config for js/src and fix eslint errors
* Clean up the opencv.js dependencies
Fix#186
* Fix build issue for python generator
* Fix doxygen buildbot failure
* delete trailing whitespace, blank line at EOF and replace tab with space
* Fix tutorial_js_root reference issue for non opencv.js build
* replace the file with small size
* Initial commit of build_js.py
* Move the js build configurations to build script
* Add wasm build support
* Update OpenCV.js build tutorial by using script
* Fix global var issue in tests
* Add a README.md for build_js.py
* Copy the haar cascade files from data dir for tutorials
* Not use memory init file
* Disable debug print for modules/js/CMakeLists.txt
* Check files when build done
* Fix image name in js_gradients tutorial
* Fix image load issue in js_trackbar tutorial
* Find the opencv source directory via relative path by default
* Make the cmake args based on build_doc option
* Fix a typo in js_setup.markdown
* Fix make failure issue on config generated by build_js.py
* Eliminate js branch of hdr_parser.py
* Extract examples from js_basic_ops tutorial
* Fix coding style of utils.js
* Improve examples error handling
Handle:
1. opencv.js loading errors
2. script errors (Error)
3. cv::Exception
Fix#217
* Add enable_exception option into build_js.py
* Support print exception for exception catching disabled build
* Extract example from js_usage tutorial
* Avoid copying .eslintrc.json when building doc
Fix#223
* Revert to use onload as opencv.js ready event
* Use 4 spaces indention for js examples
* embed html in tutorials with iframe tag
* Revert to use onload as opencv.js ready event
* Extract examples from js_video_display tutorial
* Implement Utils object
* modify core imgprc and face_detection tutorials
* Fix examples of js_gui tutorials
* Fix coding style of utils.js
* Modify tutorials
* Extract example from js_face_detection_camera tutorial
* Disable new-cap check in eslint
* Extract examples from js_meanshift tutorial
* Extract examples from video tutorials
* Remove new-cap declaration and update grammer in comments
* Change textarea width to 100 to align with eslint config
* Fix printError issue when opencv.js loading fails
* Remove BUILD_opencv_js dependency for doc build
Fix#213
* Expose cv::getBuildInformation
* Dump opencv build info when opencv.js loaded for live examples
* Make the button to stand out in js live examples
Fix#235
* Style for disabled button
* Add js_imgproc_camera.html example
* Fix coding style of imgproc_camera example
* Add js_imgproc_camera tutorial
* Remove link to opencv.js demos
* doc: copy opencv.js on build, use absolute paths for assets
* doc: reuse existed file box.mp4
