Convert to binary and make basic call to findContours

Author: taylorjg

package.json

@@ -1,6 +1,6 @@
 {
   "name": "emscripten-opencv",
-  "version": "0.0.2",
+  "version": "0.0.3",
   "description": "Web app calling into C++ WebAssembly code that uses OpenCV",
   "scripts": {
     "build:wasm": "./build-wasm.sh",

src/hello.cpp

@@ -1,10 +1,12 @@
 #include <cstring>
+#include <vector>
 #include <opencv2/core/mat.hpp>
 #include <opencv2/imgcodecs.hpp>
 #include <opencv2/imgproc.hpp>
 #include <opencv2/opencv.hpp>
 #include <emscripten.h>
 
+using namespace std;
 using namespace cv;
 
 #ifdef __cplusplus
@@ -13,11 +15,34 @@ extern "C" {
 
 EMSCRIPTEN_KEEPALIVE
 uchar *processImage(uchar *array, int width, int height) {
+
   Mat mat(height, width, CV_8UC4, array);
+
   cvtColor(mat, mat, COLOR_RGBA2GRAY);
+
+  auto ksize = Size(5, 5);
+  auto sigmaX = 0;
+  GaussianBlur(mat, mat, ksize, sigmaX);
+
+  auto maxValue = 255;
+  auto adaptiveMethod = ADAPTIVE_THRESH_GAUSSIAN_C;
+  auto thresholdType = THRESH_BINARY_INV;
+  auto blockSize = 19;
+  auto C = 3;
+  adaptiveThreshold(mat, mat, maxValue, adaptiveMethod, thresholdType, blockSize, C);
+
+  vector<vector<Point>> contours;
+  vector<Vec4i> hierarchy;
+  auto mode = RETR_EXTERNAL;
+  auto method = CHAIN_APPROX_SIMPLE;
+  findContours(mat, contours, hierarchy, mode, method);
+
+  auto numContours = contours.size();
+  EM_ASM_(console.log(`numContours: ${$0}`), numContours);
+
   const int cb = width * height * mat.channels();
   uchar *array_copy = reinterpret_cast<uchar*>(malloc(cb));
-  std::memcpy(array_copy, mat.data, cb);
+  memcpy(array_copy, mat.data, cb);
   return array_copy;
 }