Merge pull request #462 from kobigurk:master

modules/highgui/src/grfmt_tiff.cpp

@@ -101,6 +101,11 @@ bool TiffDecoder::checkSignature( const std::string& signature ) const
         memcmp(signature.c_str(), fmtSignTiffMM, 4) == 0);
 }
 
+int TiffDecoder::normalizeChannelsNumber(int channels) const
+{
+    return channels > 4 ? 4 : channels;
+}
+
 ImageDecoder TiffDecoder::newDecoder() const
 {
     return new TiffDecoder;
@@ -133,10 +138,11 @@ bool TiffDecoder::readHeader()
                 (ncn != 1 && ncn != 3 && ncn != 4)))
                 bpp = 8;
 
+            int wanted_channels = normalizeChannelsNumber(ncn);
             switch(bpp)
             {
                 case 8:
-                    m_type = CV_MAKETYPE(CV_8U, photometric > 1 ? 3 : 1);
+                    m_type = CV_MAKETYPE(CV_8U, photometric > 1 ? wanted_channels : 1);
                     break;
                 case 16:
                     m_type = CV_MAKETYPE(CV_16U, photometric > 1 ? 3 : 1);
@@ -185,6 +191,7 @@ bool  TiffDecoder::readData( Mat& img )
         TIFFGetField( tif, TIFFTAG_SAMPLESPERPIXEL, &ncn );
         const int bitsPerByte = 8;
         int dst_bpp = (int)(img.elemSize1() * bitsPerByte);
+        int wanted_channels = normalizeChannelsNumber(img.channels());
 
         if(dst_bpp == 8)
         {
@@ -248,9 +255,20 @@ bool  TiffDecoder::readData( Mat& img )
 
                             for( i = 0; i < tile_height; i++ )
                                 if( color )
-                                    icvCvt_BGRA2BGR_8u_C4C3R( buffer + i*tile_width*4, 0,
+                                {
+                                    if (wanted_channels == 4)
+                                    {
+                                        icvCvt_BGRA2RGBA_8u_C4R( buffer + i*tile_width*4, 0,
+                                                             data + x*4 + img.step*(tile_height - i - 1), 0,
+                                                             cvSize(tile_width,1) );
+                                    }
+                                    else
+                                    {
+                                        icvCvt_BGRA2BGR_8u_C4C3R( buffer + i*tile_width*4, 0,
                                                              data + x*3 + img.step*(tile_height - i - 1), 0,
                                                              cvSize(tile_width,1), 2 );
+                                    }
+                                }
                                 else
                                     icvCvt_BGRA2Gray_8u_C4C1R( buffer + i*tile_width*4, 0,
                                                               data + x + img.step*(tile_height - i - 1), 0,

modules/highgui/src/grfmt_tiff.hpp

@@ -107,6 +107,7 @@ public:
 
 protected:
     void* m_tif;
+    int normalizeChannelsNumber(int channels) const;
 };
 
 #endif

modules/highgui/test/test_grfmt.cpp

@@ -99,8 +99,11 @@ public:
                 {
                     if(ext_from_int(ext).empty())
                         continue;
-                    for (int num_channels = 1; num_channels <= 3; num_channels+=2)
+                    for (int num_channels = 1; num_channels <= 4; num_channels++)
                     {
+                        if (num_channels == 2) continue;
+                        if (num_channels == 4 && ext!=3 /*TIFF*/) continue;
+
                         ts->printf(ts->LOG, "image type depth:%d   channels:%d   ext: %s\n", CV_8U, num_channels, ext_from_int(ext).c_str());
                         Mat img(img_r * k, img_c * k, CV_MAKETYPE(CV_8U, num_channels), Scalar::all(0));
                         circle(img, Point2i((img_c * k) / 2, (img_r * k) / 2), std::min((img_r * k), (img_c * k)) / 4 , Scalar::all(255));
@@ -116,6 +119,7 @@ public:
 
                         CV_Assert(img.size() == img_test.size());
                         CV_Assert(img.type() == img_test.type());
+                        CV_Assert(num_channels == img_test.channels());
 
                         double n = norm(img, img_test);
                         if ( n > 1.0)