Merge pull request #13481 from dkurt:fix_13227

* Fix drawMatches and drawKeypoints for BGRA input images

* keep BGRA too

* Combine different input types for drawMatches test

modules/features2d/src/draw.cpp

@@ -95,9 +95,9 @@ void drawKeypoints( InputArray image, const std::vector<KeyPoint>& keypoints, In
 
     if( !(flags & DrawMatchesFlags::DRAW_OVER_OUTIMG) )
     {
-        if( image.type() == CV_8UC3 )
+        if (image.type() == CV_8UC3 || image.type() == CV_8UC4)
         {
-            image.copyTo( outImage );
+            image.copyTo(outImage);
         }
         else if( image.type() == CV_8UC1 )
         {
@@ -105,7 +105,7 @@ void drawKeypoints( InputArray image, const std::vector<KeyPoint>& keypoints, In
         }
         else
         {
-            CV_Error( Error::StsBadArg, "Incorrect type of input image.\n" );
+            CV_Error( Error::StsBadArg, "Incorrect type of input image: " + typeToString(image.type()) );
         }
     }
 
@@ -122,6 +122,25 @@ void drawKeypoints( InputArray image, const std::vector<KeyPoint>& keypoints, In
     }
 }
 
+static void _prepareImage(InputArray src, const Mat& dst)
+{
+    CV_CheckType(src.type(), src.type() == CV_8UC1 || src.type() == CV_8UC3 || src.type() == CV_8UC4, "Unsupported source image");
+    CV_CheckType(dst.type(), dst.type() == CV_8UC3 || dst.type() == CV_8UC4, "Unsupported destination image");
+    const int src_cn = src.channels();
+    const int dst_cn = dst.channels();
+
+    if (src_cn == dst_cn)
+        src.copyTo(dst);
+    else if (src_cn == 1)
+        cvtColor(src, dst, dst_cn == 3 ? COLOR_GRAY2BGR : COLOR_GRAY2BGRA);
+    else if (src_cn == 3 && dst_cn == 4)
+        cvtColor(src, dst, COLOR_BGR2BGRA);
+    else if (src_cn == 4 && dst_cn == 3)
+        cvtColor(src, dst, COLOR_BGRA2BGR);
+    else
+        CV_Error(Error::StsInternal, "");
+}
+
 static void _prepareImgAndDrawKeypoints( InputArray img1, const std::vector<KeyPoint>& keypoints1,
                                          InputArray img2, const std::vector<KeyPoint>& keypoints2,
                                          InputOutputArray _outImg, Mat& outImg1, Mat& outImg2,
@@ -140,21 +159,16 @@ static void _prepareImgAndDrawKeypoints( InputArray img1, const std::vector<KeyP
     }
     else
     {
-        _outImg.create( size, CV_MAKETYPE(img1.depth(), 3) );
+        const int cn1 = img1.channels(), cn2 = img2.channels();
+        const int out_cn = std::max(3, std::max(cn1, cn2));
+        _outImg.create(size, CV_MAKETYPE(img1.depth(), out_cn));
         outImg = _outImg.getMat();
         outImg = Scalar::all(0);
         outImg1 = outImg( Rect(0, 0, img1size.width, img1size.height) );
         outImg2 = outImg( Rect(img1size.width, 0, img2size.width, img2size.height) );
 
-        if( img1.type() == CV_8U )
-            cvtColor( img1, outImg1, COLOR_GRAY2BGR );
-        else
-            img1.copyTo( outImg1 );
-
-        if( img2.type() == CV_8U )
-            cvtColor( img2, outImg2, COLOR_GRAY2BGR );
-        else
-            img2.copyTo( outImg2 );
+        _prepareImage(img1, outImg1);
+        _prepareImage(img2, outImg2);
     }
 
     // draw keypoints

modules/features2d/test/test_drawing.cpp

+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+//
+// Copyright (C) 2018, Intel Corporation, all rights reserved.
+// Third party copyrights are property of their respective owners.
+#include "test_precomp.hpp"
+
+namespace opencv_test { namespace {
+
+static
+Mat getReference_DrawKeypoint(int cn)
+{
+    static Mat ref = (Mat_<uint8_t>(11, 11) <<
+        1,   1,   1,   1,   1,   1,   1,   1,   1,   1,   1,
+        1,   1,   1,   1,  15,  54,  15,   1,   1,   1,   1,
+        1,   1,   1,  76, 217, 217, 221,  81,   1,   1,   1,
+        1,   1, 100, 224, 111,  57, 115, 225, 101,   1,   1,
+        1,  44, 215, 100,   1,   1,   1, 101, 214,  44,   1,
+        1,  54, 212,  57,   1,   1,   1,  55, 212,  55,   1,
+        1,  40, 215, 104,   1,   1,   1, 105, 215,  40,   1,
+        1,   1, 102, 221, 111,  55, 115, 222, 103,   1,   1,
+        1,   1,   1,  76, 218, 217, 220,  81,   1,   1,   1,
+        1,   1,   1,   1,  15,  55,  15,   1,   1,   1,   1,
+        1,   1,   1,   1,   1,   1,   1,   1,   1,   1,   1);
+    Mat res;
+    cvtColor(ref, res, (cn == 4) ? COLOR_GRAY2BGRA : COLOR_GRAY2BGR);
+    return res;
+}
+
+typedef testing::TestWithParam<MatType> Features2D_drawKeypoints;
+TEST_P(Features2D_drawKeypoints, Accuracy)
+{
+    const int cn = CV_MAT_CN(GetParam());
+    Mat inpImg(11, 11, GetParam(), Scalar(1, 1, 1, 255)), outImg;
+
+    std::vector<KeyPoint> keypoints(1, KeyPoint(5, 5, 1));
+    drawKeypoints(inpImg, keypoints, outImg, Scalar::all(255));
+    ASSERT_EQ(outImg.channels(), (cn == 4) ? 4 : 3);
+
+    Mat ref_ = getReference_DrawKeypoint(cn);
+    EXPECT_EQ(0, cv::norm(outImg, ref_, NORM_INF));
+}
+INSTANTIATE_TEST_CASE_P(/**/, Features2D_drawKeypoints, Values(CV_8UC1, CV_8UC3, CV_8UC4));
+
+typedef testing::TestWithParam<tuple<MatType, MatType> > Features2D_drawMatches;
+TEST_P(Features2D_drawMatches, Accuracy)
+{
+    Mat inpImg1(11, 11, get<0>(GetParam()), Scalar(1, 1, 1, 255));
+    Mat inpImg2(11, 11, get<1>(GetParam()), Scalar(2, 2, 2, 255)), outImg2, outImg;
+
+    std::vector<KeyPoint> keypoints(1, KeyPoint(5, 5, 1));
+
+    // Get outImg2 using drawKeypoints assuming that it works correctly (see the test above).
+    drawKeypoints(inpImg2, keypoints, outImg2, Scalar::all(255));
+    ASSERT_EQ(outImg2.channels(), (inpImg2.channels() == 4) ? 4 : 3);
+
+    // Merge both references.
+    const int cn = max(3, max(inpImg1.channels(), inpImg2.channels()));
+    if (cn == 4 && outImg2.channels() == 3)
+        cvtColor(outImg2, outImg2, COLOR_BGR2BGRA);
+    Mat ref_ = getReference_DrawKeypoint(cn);
+    Mat concattedRef;
+    hconcat(ref_, outImg2, concattedRef);
+
+    std::vector<DMatch> matches;
+    drawMatches(inpImg1, keypoints, inpImg2, keypoints, matches, outImg,
+                Scalar::all(255), Scalar::all(255));
+    ASSERT_EQ(outImg.channels(), cn);
+
+    EXPECT_EQ(0, cv::norm(outImg, concattedRef, NORM_INF));
+}
+INSTANTIATE_TEST_CASE_P(/**/, Features2D_drawMatches, Combine(
+    Values(CV_8UC1, CV_8UC3, CV_8UC4),
+    Values(CV_8UC1, CV_8UC3, CV_8UC4)
+));
+
+}} // namespace