From 088b44bdeb31d780defc23304e4cc0aac1ac1c30 Mon Sep 17 00:00:00 2001
From: Max Ehrlich <max.ehr@gmail.com>
Date: Tue, 20 Jan 2015 10:19:28 -0500
Subject: [PATCH] Added drawChessboardCorners

---
 src/Calib3D.cc | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/Calib3D.h  |  2 ++
 2 files changed, 72 insertions(+)

diff --git a/src/Calib3D.cc b/src/Calib3D.cc
index 240c431..512b524 100644
--- a/src/Calib3D.cc
+++ b/src/Calib3D.cc
@@ -8,6 +8,7 @@ void Calib3D::Init(Handle<Object> target)
     NanAssignPersistent(inner, obj);
 
     NODE_SET_METHOD(obj, "findChessboardCorners", FindChessboardCorners);
+    NODE_SET_METHOD(obj, "drawChessboardCorners", DrawChessboardCorners);
 
     target->Set(NanNew("calib3d"), obj);
 }
@@ -86,3 +87,72 @@ NAN_METHOD(Calib3D::FindChessboardCorners)
     }
 
 };
+
+// cv::drawChessboardCorners
+NAN_METHOD(Calib3D::DrawChessboardCorners)
+{
+    NanEscapableScope();
+
+    try {
+        // Get the arguments
+
+        // 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 is the corners array
+        std::vector<cv::Point2f> corners;
+        if(args[2]->IsArray()) {
+            Local<Array> cornersArray = Local<Array>::Cast(args[2]);
+
+            for(unsigned int i = 0; i < cornersArray->Length(); i++)
+            {
+                Local<Object> pt = cornersArray->Get(i)->ToObject();
+                corners.push_back(cv::Point2f(pt->Get(NanNew<String>("x"))->ToNumber()->Value(),
+                                              pt->Get(NanNew<String>("y"))->ToNumber()->Value()));
+            }
+        } else {
+            JSTHROW_TYPE("Must pass corners array");
+        }
+
+        // Arg 3, pattern found boolean
+        bool patternWasFound = args[3]->ToBoolean()->Value();
+
+        // Final argument is the callback
+        REQ_FUN_ARG(4, cb);
+
+        // Draw the corners
+        cv::drawChessboardCorners(mat, patternSize, corners, patternWasFound);
+
+        // Make the callback arguments (same image that was passed, now with corners drawn on it)
+        Local<Value> argv[2];
+        argv[0] = NanNull();
+        argv[1] = args[0];
+
+        // 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/Calib3D.h b/src/Calib3D.h
index e8bba46..14ecc99 100644
--- a/src/Calib3D.h
+++ b/src/Calib3D.h
@@ -10,6 +10,8 @@ public:
     static void Init(Handle<Object> target);
 
     static NAN_METHOD(FindChessboardCorners);
+
+    static NAN_METHOD(DrawChessboardCorners);
 };
 
 #endif