Add experimental support for WebAssembly

README.md

@@ -3,6 +3,11 @@
 This is a JavaScript binding that exposes OpenCV library to the web. This project is made possible by support of Intel corporation. Currently, this is based on OpenCV 3.1.0.
 
 ### How to Build
+
+You can build two different versions of OpenCV.js: asm.js or WebAssembly (experimental). If you want to build the later, you will need the "incoming" version of Emscripten.
+
+#### asm.js version (default)
+
 1. Get the source code
 
   ```
@@ -23,19 +28,44 @@ This is a JavaScript binding that exposes OpenCV library to the web. This projec
 3. Patch Emscripten & Rebuild.
 
   ```
-  patch -p1 < PATH/TO/patch_emscripten_master.diff
-  ```
-4. Rebuild emscripten
-  ```
+  patch -p1 < PATH/TO/patch_emscripten.diff -d emscripten/master
   ./emsdk install sdk-master-64bit --shallow
   ```
 
-5. Compile OpenCV and generate bindings by executing make.py script.
+4. Compile OpenCV and generate bindings by executing make.py script.
 
   ```
     python make.py
   ```
 
+#### WebAssembly version (experimental)
+
+1. Get the source code (just like above)
+
+2. Install the "incoming" branch of emscripten. You can obtain emscripten by using [Emscripten SDK](https://kripken.github.io/emscripten-site/docs/getting_started/downloads.html).
+At the time of writing, the current version of Emscripten does not support WebAssembly yet, so you will need to install the "incoming" branch.
+
+  ```
+  ./emsdk update
+  ./emsdk install sdk-incoming-64bit --shallow
+  ./emsdk activate sdk-incoming-64bit
+  source ./emsdk_env.sh
+  ```
+3. Patch Emscripten & Rebuild.
+
+  ```
+  patch -p1 < PATH/TO/patch_emscripten.diff -d emscripten/incoming
+  ./emsdk install sdk-incoming-64bit --shallow
+  ```
+
+4. Compile OpenCV and generate bindings by executing make.py script.
+
+  ```
+    python make.py --wasm
+  ```
+
+
+
 ### Tests
 Test suite contains several tests and examples demonstrating how the API can be used. Run the tests by launching test/tests.html file usig a browser.
 

bindings.cpp

@@ -247,6 +247,15 @@ EMSCRIPTEN_BINDINGS(Utils) {
         .element(&Point2f::x)
         .element(&Point2f::y);
 
+    value_array<Size2f>("Size2f")
+        .element(&Size2f::height)
+        .element(&Size2f::width);
+
+    value_object<RotatedRect>("RotatedRect")
+        .field("angle", &RotatedRect::angle)
+        .field("center", &RotatedRect::center)
+        .field("size", &RotatedRect::size);
+
     emscripten::class_<cv::Rect_<int>> ("Rect")
         .constructor<>()
         .constructor<const cv::Point_<int>&, const cv::Size_<int>&>()
@@ -437,6 +446,10 @@ namespace Wrappers {
         return cv::adaptiveThreshold(arg1, arg2, arg3, arg4, arg5, arg6, arg7);
     }
 
+    void magnitudeThreshold_wrapper(const cv::Mat& arg1, const cv::Mat& arg2, cv::Mat& arg3, double thresh, double minValue, double maxValue ){
+        return cv::magnitudeThreshold(arg1, arg2, arg3, thresh, minValue, maxValue);
+    }
+
     void add_wrapper(const cv::Mat& arg1, const cv::Mat& arg2, cv::Mat& arg3, const cv::Mat& arg4, int arg5) {
         return cv::add(arg1, arg2, arg3, arg4, arg5);
     }
@@ -2458,6 +2471,8 @@ EMSCRIPTEN_BINDINGS(testBinding) {
 
     function("adaptiveThreshold", select_overload<void(const cv::Mat&, cv::Mat&, double, int, int, int, double)>(&Wrappers::adaptiveThreshold_wrapper));
 
+    function("magnitudeThreshold", select_overload<void(const cv::Mat&, const cv::Mat&, cv::Mat&, double, double, double)>(&Wrappers::magnitudeThreshold_wrapper));
+
     function("add", select_overload<void(const cv::Mat&, const cv::Mat&, cv::Mat&, const cv::Mat&, int)>(&Wrappers::add_wrapper));
 
     function("addWeighted", select_overload<void(const cv::Mat&, double, const cv::Mat&, double, double, cv::Mat&, int)>(&Wrappers::addWeighted_wrapper));

make.py

@@ -1,7 +1,14 @@
 #!/usr/bin/python
 import os, sys, re, json, shutil
+import argparse
 from subprocess import Popen, PIPE, STDOUT
 
+
+#   parse the command-line options
+parser = argparse.ArgumentParser()
+parser.add_argument( "--wasm", action="store_true", help="Create a .wasm file (WebAssembly format, experimental) instead of asm.js format." )
+clArguments = parser.parse_args()
+
 # Startup
 exec(open(os.path.expanduser('~/.emscripten'), 'r').read())
 
@@ -184,8 +191,15 @@ def stage(text):
     assert os.path.exists('bindings.bc')
 
     stage('Building OpenCV.js')
-    opencv = os.path.join('..', '..', 'build', 'cv.js')
-    data = os.path.join('..', '..', 'build', 'cv.data')
+
+    if clArguments.wasm:
+        emcc_args += "-s WASM=1".split( " " )
+        basename = "cv-wasm"
+    else:
+        basename = "cv"
+
+    destFiles = [ os.path.join('..', '..', 'build', basename + ext ) for ext in [ ".js", ".data", ".wasm" ] ]
+    opencv = destFiles[0]
 
     tests = os.path.join('..', '..', 'test')
 
@@ -245,10 +259,9 @@ def stage(text):
 }));
 """ % (out,)).lstrip())
 
-
-    shutil.copy2(opencv, tests)
-    if os.path.exists(data):
-        shutil.copy2(data, tests)
+    for f in destFiles:
+        if os.path.exists(f):
+            shutil.copy2(f, tests)
 
 finally:
     os.chdir(this_dir)

patch_emscripten_master.diff → patch_emscripten.diff

@@ -1,5 +1,5 @@
---- ./emscripten/master/system/include/emscripten/bind.h	2016-12-20 13:05:20.498980029 -0800
-+++ ./emscripten/master/system/include/emscripten/bind.h	2016-12-20 13:12:11.599146929 -0800
+--- ./system/include/emscripten/bind.h	2016-12-20 13:05:20.498980029 -0800
++++ ./system/include/emscripten/bind.h	2016-12-20 13:12:11.599146929 -0800
 @@ -999,7 +999,7 @@
          };
      }
@@ -54,8 +54,8 @@
          template<typename WrapperType>
          val wrapped_extend(const std::string& name, const val& properties) {
 
---- ./emscripten/master/src/embind/embind.js	2016-12-20 13:05:20.498980029 -0800
-+++ ./emscripten/master/src/embind/embind.js	2016-12-20 13:12:11.599146929 -0800
+--- ./src/embind/embind.js	2016-12-20 13:05:20.498980029 -0800
++++ ./src/embind/embind.js	2016-12-20 13:12:11.599146929 -0800
 @@ -2077,6 +2077,7 @@
              var invokerArgsArray = [argTypes[0] /* return value */, null /* no class 'this'*/].concat(argTypes.slice(1) /* actual params */);
              var func = craftInvokerFunction(humanName, invokerArgsArray, null /* no class 'this'*/, rawInvoker, fn);