Merge pull request #27599 from chacha21:drawing_stack_alloc

optimize some drawing with stack allocation #27599

Some drawings can try a stack allocation instead of a std::vector

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [X] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake

modules/imgproc/src/drawing.cpp

@@ -2034,9 +2034,12 @@ void fillPoly( InputOutputArray _img, const Point** pts, const int* npts, int nc
     edges.reserve( total + 1 );
     for (i = 0; i < ncontours; i++)
     {
-        if (npts[i] > 0 && pts[i])
+        const Point* currentContour = pts[i];
+        const int currentContourLength = npts[i];
+        if ( (currentContourLength > 0) && currentContour )
         {
-            std::vector<Point2l> _pts(pts[i], pts[i] + npts[i]);
+            AutoBuffer<Point2l> _pts(currentContourLength);
+            std::copy(currentContour, currentContour+currentContourLength, _pts.data());
             CollectPolyEdges(img, _pts.data(), npts[i], edges, buf, line_type, shift, offset);
         }
     }
@@ -2063,8 +2066,11 @@ void polylines( InputOutputArray _img, const Point* const* pts, const int* npts,
 
     for( int i = 0; i < ncontours; i++ )
     {
-        std::vector<Point2l> _pts(pts[i], pts[i]+npts[i]);
-        PolyLine( img, _pts.data(), npts[i], isClosed, buf, thickness, line_type, shift );
+        const Point* currentContour = pts[i];
+        const int currentContourLength = npts[i];
+        AutoBuffer<Point2l> _pts(currentContourLength);
+        std::copy(currentContour, currentContour+currentContourLength, _pts.data());
+        PolyLine( img, _pts.data(), currentContourLength, isClosed, buf, thickness, line_type, shift );
     }
 }