Add documentation and example program for intersectConvexConvex

modules/imgproc/include/opencv2/imgproc.hpp

@@ -4149,7 +4149,23 @@ without self-intersections. Otherwise, the function output is undefined.
  */
 CV_EXPORTS_W bool isContourConvex( InputArray contour );
 
-//! finds intersection of two convex polygons
+/** @example samples/cpp/intersectExample.cpp
+Examples of how intersectConvexConvex works
+*/
+
+/** @brief Finds intersection of two convex polygons
+
+@param _p1 First polygon
+@param _p2 Second polygon
+@param _p12 Output polygon describing the intersecting area
+@param handleNested When true, an intersection is found if one of the polygons is fully enclosed in the other.
+When false, no intersection is found. If the polygons share a side or the vertex of one polygon lies on an edge
+of the other, they are not considered nested and an intersection will be found regardless of the value of handleNested.
+
+@returns Absolute value of area of intersecting polygon
+
+@note intersectConvexConvex doesn't confirm that both polygons are convex and will return invalid results if they aren't.
+ */
 CV_EXPORTS_W float intersectConvexConvex( InputArray _p1, InputArray _p2,
                                           OutputArray _p12, bool handleNested = true );