add class methods for frame

src/utility.cpp

- #include "utility.h"
+#include "utility.h"
 
 using namespace cv;
 using namespace std;
@@ -28,6 +28,17 @@ utility::Frame& utility::Frame::convertColor(int code) {
 	cvtColor(*this, *this, code);
 	return *this;
 }
+utility::Frame utility::Frame::difference(Frame& f) {
+	return Frame(utility::difference(*this, f));
+}
+utility::Frame& utility::Frame::crop(Size rect_size, Point2f center) {
+	cv::getRectSubPix(*this, rect_size, center, *this);
+	return *this;
+}
+utility::Frame& utility::Frame::warp(cv::Mat rotationMatrix) {
+	cv::warpAffine(*this, *this, rotationMatrix, this->size(), INTER_CUBIC);
+	return *this;
+}
 
 void utility::detectShape(Ptr<GeneralizedHoughGuil> alg, Mat templateShape, int posThresh, vector<Vec4f> &positivePositions, Mat &positiveVotes, vector<Vec4f> &negativePositions, Mat &negativeVotes, Mat processingArea) {
 

src/utility.h

@@ -23,8 +23,12 @@ namespace utility {
 		Frame clone() const;
 		Frame& downsample(int factor);
 		Frame& convertColor(int code);
+		Frame difference(Frame& f);
+		Frame& crop(Size rect_size, Point2f center);
+		Frame& warp(cv::Mat rotationMatrix);
 	};
 
+
 	/**
 	 * @brief Detects a given shape in an image, using a the OpenCV algorithm GeneralizedHoughGuil.
 	 *
@@ -73,5 +77,4 @@ namespace utility {
 	 * @return cv::Mat A black and white frame, where black pixels represent a difference, while white pixels represent an equality.
 	 */
 	cv::Mat difference(cv::Mat &prevFrame, cv::Mat &currentFrame);
-
 }