Fix #750 making it compatible with Opencv4.4

Author: wandenberg

.travis.yml

@@ -10,7 +10,7 @@ env:
     - OPENCV4NODEJS_DISABLE_AUTOBUILD=1
     - LATEST_STABLE_NODEJS_VERSION=12
     - OPENCV3_LATEST=3.4.6
-    - OPENCV4_LATEST=4.1.0
+    - OPENCV4_LATEST=4.4.0
 
 matrix:
   include:

appveyor.yml

@@ -15,7 +15,7 @@ init:
 # what combinations to test
 environment:
   OPENCV3_LATEST: 3.4.6
-  OPENCV4_LATEST: 4.1.0
+  OPENCV4_LATEST: 4.4.0
   PYTHON_VERSION: 2.7
   PYTHON: "C:\\Python27-x64"
   # use self build
@@ -28,6 +28,9 @@ environment:
     - nodejs_version: 12
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
       OPENCV_VERSION: "%OPENCV3_LATEST%"
+    - nodejs_version: 12
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      OPENCV_VERSION: 4.1.0
     - nodejs_version: 12
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
       OPENCV_VERSION: "%OPENCV4_LATEST%"

cc/xfeatures2d/SIFTDetector.h

@@ -6,7 +6,11 @@
 #ifndef __FF_SIFTDETECTOR_H__
 #define __FF_SIFTDETECTOR_H__
 
+#if CV_VERSION_GREATER_EQUAL(4, 4, 0)
+class SIFTDetector : public FeatureDetector, public FF::ObjectWrapTemplate<SIFTDetector, cv::Ptr<cv::SIFT>> {
+#else
 class SIFTDetector : public FeatureDetector, public FF::ObjectWrapTemplate<SIFTDetector, cv::Ptr<cv::xfeatures2d::SIFT>> {
+#endif
 public:
 	static Nan::Persistent<v8::FunctionTemplate> constructor;
 
@@ -47,7 +51,11 @@ class SIFTDetector : public FeatureDetector, public FF::ObjectWrapTemplate<SIFTD
 			auto sigma = opt<FF::DoubleConverter>("sigma", 1.6);
 
 			executeBinding = [=]() {
+			#if CV_VERSION_GREATER_EQUAL(4, 4, 0)
+				return cv::SIFT::create(
+			#else
 				return cv::xfeatures2d::SIFT::create(
+			#endif
 					nFeatures->ref(),
 					nOctaveLayers->ref(),
 					contrastThreshold->ref(),
@@ -67,4 +75,4 @@ class SIFTDetector : public FeatureDetector, public FF::ObjectWrapTemplate<SIFTD
 	};
 };
 
-#endif
+#endif