remove unnecessary buffer copies

modules/photo/src/seamless_cloning_impl.cpp

@@ -50,7 +50,20 @@ void Cloning::computeGradientX( const Mat &img, Mat &gx)
     Mat kernel = Mat::zeros(1, 3, CV_8S);
     kernel.at<char>(0,2) = 1;
     kernel.at<char>(0,1) = -1;
-    filter2D(img, gx, CV_32F, kernel);
+
+    if(img.channels() == 3)
+    {
+        filter2D(img, gx, CV_32F, kernel);
+    }
+    else if (img.channels() == 1)
+    {
+        Mat tmp[3];
+        for(int chan = 0 ; chan < 3 ; ++chan)
+        {
+            filter2D(img, tmp[chan], CV_32F, kernel);
+        }
+        merge(tmp, 3, gx);
+    }
 }
 
 void Cloning::computeGradientY( const Mat &img, Mat &gy)
@@ -58,7 +71,20 @@ void Cloning::computeGradientY( const Mat &img, Mat &gy)
     Mat kernel = Mat::zeros(3, 1, CV_8S);
     kernel.at<char>(2,0) = 1;
     kernel.at<char>(1,0) = -1;
-    filter2D(img, gy, CV_32F, kernel);
+
+    if(img.channels() == 3)
+    {
+        filter2D(img, gy, CV_32F, kernel);
+    }
+    else if (img.channels() == 1)
+    {
+        Mat tmp[3];
+        for(int chan = 0 ; chan < 3 ; ++chan)
+        {
+            filter2D(img, tmp[chan], CV_32F, kernel);
+        }
+        merge(tmp, 3, gy);
+    }
 }
 
 void Cloning::computeLaplacianX( const Mat &img, Mat &laplacianX)
@@ -365,18 +391,10 @@ void Cloning::normalClone(const Mat &destination, const Mat &patch, const Mat &b
 
         case MONOCHROME_TRANSFER:
             Mat gray = Mat(patch.size(),CV_8UC1);
-            Mat gray8 = Mat(patch.size(),CV_8UC3);
             cvtColor(patch, gray, COLOR_BGR2GRAY );
-            vector <Mat> temp;
-            split(destination,temp);
-            gray.copyTo(temp[2]);
-            gray.copyTo(temp[1]);
-            gray.copyTo(temp[0]);
-
-            merge(temp,gray8);
 
-            computeGradientX(gray8,patchGradientX);
-            computeGradientY(gray8,patchGradientY);
+            computeGradientX(gray,patchGradientX);
+            computeGradientY(gray,patchGradientY);
 
             arrayProduct(patchGradientX, binaryMaskFloat, patchGradientX);
             arrayProduct(patchGradientY, binaryMaskFloat, patchGradientY);