added drawMatches function to features2d and documentation on this

doc/cv_feature_detection.tex

@@ -1957,4 +1957,72 @@ protected:
 };
 \end{lstlisting}
 
+\cvCppFunc{drawMatches}
+This function draws matches of keypints from two images on output image. 
+Match is a line connecting two keypoints (circles).
+
+\cvdefCpp{
+void drawMatches( const Mat\& img1, const Mat\& img2,
+		  const vector<KeyPoint>\& keypoints1, const vector<KeyPoint>\& keypoints2,
+		  const vector<int>\& matches, const vector<char>\& mask, Mat\& outImg,
+		  const Scalar\& matchColor = Scalar::all(-1), 
+		  const Scalar\& singlePointColor = Scalar::all(-1),
+		  int flags = DrawMatchesFlags::DEFAULT );
+}
+
+\begin{description}
+\cvarg{img1}{First sourse image.}
+\end{description}
+
+\begin{description}
+\cvarg{img1}{Second sourse image.}
+\end{description}
+
+\begin{description}
+\cvarg{keypoints1}{Keypoints from first sourse image.}
+\end{description}
+
+\begin{description}
+\cvarg{keypoints2}{Keypoints from second sourse image.}
+\end{description}
+
+\begin{description}
+\cvarg{matches}{Matches from first image to second one, i.e. keypoints1[i] has corresponding point keypoints2[matches[i]]}
+\end{description}
+
+\begin{description}
+\cvarg{mask}{Mask determining which matches will be drawn. If mask is empty all matches will be drawn. }
+\end{description}
+
+\begin{description}
+\cvarg{outImg}{Output image. Its content depends on \texttt{flags} value what is drawn in output image. See below possible \texttt{flags} bit values. }
+\end{description}
+
+\begin{description}
+\cvarg{matchColor}{Color of matches (lines and connected keypoints). If \texttt{matchColor}==Scalar::all(-1) color will be generated randomly.}
+\end{description}
+
+\begin{description}
+\cvarg{singlePointColor}{Color of single keypoints (circles), i.e. keypoints not having the matches. If \texttt{singlePointColor}==Scalar::all(-1) color will be generated randomly.}
+\end{description}
+
+\begin{description}
+\cvarg{flags}{Each bit of \texttt{flags} sets some feature of drawing. Possible \texttt{flags} bit values is defined by DrawMatchesFlags, see below. }
+\end{description}
+
+\begin{lstlisting}
+struct DrawMatchesFlags
+{
+    enum{ DEFAULT = 0, // Output image matrix will be created (Mat::create),
+                       // i.e. existing memory of output image will be reused. 
+                       // Two source image, matches and single keypoints will be drawn.
+          DRAW_OVER_OUTIMG = 1, // Output image matrix will not be created (Mat::create).
+                                // Matches will be drawn on existing content 
+				// of output image.
+          NOT_DRAW_SINGLE_POINTS = 2 // Single keypoints will not be drawn.
+        };
+};
+
+\end{lstlisting}
+
 \fi