From 97715a8048aa8be714451d578cc29cbf0190eff6 Mon Sep 17 00:00:00 2001
From: Max Ehrlich <max.ehr@gmail.com>
Date: Mon, 19 Jan 2015 15:15:05 -0500
Subject: [PATCH] Added findChessboardCorners function

---
 src/OpenCV.cc | 94 +++++++++++++++++++++++++++++++++++++++++++++------
 src/OpenCV.h  |  3 +-
 2 files changed, 86 insertions(+), 11 deletions(-)

diff --git a/src/OpenCV.cc b/src/OpenCV.cc
index 4ed6c43..24f594b 100755
--- a/src/OpenCV.cc
+++ b/src/OpenCV.cc
@@ -5,48 +5,49 @@
 void
 OpenCV::Init(Handle<Object> target) {
   NanScope();
-  
+
   // Version string.
   char out [21];
   int n = sprintf(out, "%i.%i", CV_MAJOR_VERSION, CV_MINOR_VERSION);
   target->Set(NanNew<String>("version"), NanNew<String>(out, n));
 
   NODE_SET_METHOD(target, "readImage", ReadImage);
+  NODE_SET_METHOD(target, "findChessboardCorners", FindChessboardCorners);
 
-}  
+}
 
 
 NAN_METHOD(OpenCV::ReadImage) {
   NanEscapableScope();
 
   try{
-    
+
     Local<Object> im_h = NanNew(Matrix::constructor)->GetFunction()->NewInstance();
     Matrix *img = ObjectWrap::Unwrap<Matrix>(im_h);
-    
+
     cv::Mat mat;
 
     REQ_FUN_ARG(1, cb);
-    
+
     if (args[0]->IsNumber() && args[1]->IsNumber()){
       int width, height;
 
       width = args[0]->Uint32Value();
-      height = args[1]->Uint32Value();    
+      height = args[1]->Uint32Value();
       mat = *(new cv::Mat(width, height, CV_64FC1));
 
     } else if (args[0]->IsString()) {
-      
+
       std::string filename = std::string(*NanAsciiString(args[0]->ToString()));
       mat = cv::imread(filename);
 
     } else if (Buffer::HasInstance(args[0])){
      	uint8_t *buf = (uint8_t *) Buffer::Data(args[0]->ToObject());
      	unsigned len = Buffer::Length(args[0]->ToObject());
-      
+
   	 	cv::Mat *mbuf = new cv::Mat(len, 1, CV_64FC1, buf);
       mat = cv::imdecode(*mbuf, -1);
-            
+
       if (mat.empty()){
         NanThrowTypeError("Error loading file");
       }
@@ -74,4 +75,77 @@ NAN_METHOD(OpenCV::ReadImage) {
       NanThrowError(err_msg);
       NanReturnUndefined();
   }
-};    
+};
+
+NAN_METHOD(OpenCV::FindChessboardCorners) {
+    NanEscapableScope();
+
+    try {
+        // Get the arguments from javascript
+
+        // Arg 0 is the image
+        Matrix* m = ObjectWrap::Unwrap<Matrix>(args[0]->ToObject());
+        cv::Mat mat = m->mat;
+
+        // Arg 1 is the pattern size
+        cv::Size patternSize;
+        if (args[1]->IsArray()) {
+            Local<Object> v8sz = args[1]->ToObject();
+
+            patternSize = cv::Size(v8sz->Get(0)->IntegerValue(), v8sz->Get(1)->IntegerValue());
+        } else {
+            JSTHROW_TYPE("Must pass pattern size");
+        }
+
+        // Arg 2 would normally be the flags, ignoring this for now and using the default flags
+
+        // Final argument is the callback function
+        REQ_FUN_ARG(2, cb);
+
+        // Find the corners
+        std::vector<cv::Point2f> corners;
+        bool found = cv::findChessboardCorners(mat, patternSize, corners);
+
+        // Make the callback arguments
+        Local<Value> argv[2];
+
+        argv[0] = NanNull();
+        argv[1] = NanNull(); // This will be replaced by the corners array if corners were found
+
+        // Further processing if we found corners
+        Local<Array> cornersArray;
+        if(found)
+        {
+            // Convert the return value to a javascript array
+            cornersArray = Array::New(corners.size());
+            for(int i = 0; i < corners.size(); i++)
+            {
+                Local<Object> point_data = NanNew<Object>();
+                point_data->Set(NanNew<String>("x"), NanNew<Number>(corners[i].x));
+                point_data->Set(NanNew<String>("y"), NanNew<Number>(corners[i].y));
+
+                cornersArray->Set(Number::New(i), point_data);
+            }
+
+            argv[1] = cornersArray;
+        }
+
+        // Callback
+        TryCatch try_catch;
+
+        cb->Call(NanGetCurrentContext()->Global(), 2, argv);
+
+        if(try_catch.HasCaught()) {
+            FatalException(try_catch);
+        }
+
+        NanReturnUndefined();
+
+
+    } catch (cv::Exception &e) {
+        const char *err_msg = e.what();
+        NanThrowError(err_msg);
+        NanReturnUndefined();
+    }
+
+};
diff --git a/src/OpenCV.h b/src/OpenCV.h
index ea1ca83..b8a53ab 100755
--- a/src/OpenCV.h
+++ b/src/OpenCV.h
@@ -50,9 +50,10 @@ class OpenCV: public node::ObjectWrap{
     static void Init(Handle<Object> target);
 
     static NAN_METHOD(ReadImage);
+
+    static NAN_METHOD(FindChessboardCorners);
 };
 
 
 
 #endif
-