COMP: Add explicit QByteArray to "const char*" conversion for DCMTK compatibility

This change ensures backward compatibility while preparing for future updates to DCMTK,
specifically commit DCMTK/dcmtk@1ebac2d0f ("Replaced the data type of parameter 'filename'.", 2024-02-20).
In this update, the parameter type changes from `const char *` to `const OFFilename`.

QByteArray only provides an explicit conversion to `const char *`, but not directly to
`const OFFilename` (which can be constructed from `const char *`). This explicit conversion
allows seamless integration with both the current and updated DCMTK codebase.

Author: jcfr

Libs/DICOM/Core/ctkDICOMDatabase.cpp

@@ -2433,7 +2433,7 @@ bool ctkDICOMDatabase::storeThumbnailFile(const QString &originalFilePath,
   }
   else
   {
-    DicomImage dcmImage(QDir::toNativeSeparators(originalFilePath).toUtf8());
+    DicomImage dcmImage(QDir::toNativeSeparators(originalFilePath).toUtf8().data());
     return d->ThumbnailGenerator->generateThumbnail(&dcmImage, thumbnailPath, backgroundColor);
   }
 }

Libs/DICOM/Core/ctkDICOMThumbnailGenerator.cpp

@@ -176,7 +176,7 @@ bool ctkDICOMThumbnailGenerator::generateThumbnail(DicomImage *dcmImage, QImage&
   /* create output buffer for DicomImage class */
   QByteArray buffer;
   /* copy header to output buffer and resize it for pixel data */
-  buffer.append(header.toUtf8());
+  buffer.append(header.toUtf8().data());
   buffer.resize(length);
 
   /* render pixel data to buffer */
@@ -211,14 +211,14 @@ bool ctkDICOMThumbnailGenerator::generateThumbnail(DicomImage *dcmImage, const Q
 //------------------------------------------------------------------------------
 bool ctkDICOMThumbnailGenerator::generateThumbnail(const QString& dcmImagePath, QImage& image)
 {
-  DicomImage dcmImage(QDir::toNativeSeparators(dcmImagePath).toUtf8());
+  DicomImage dcmImage(QDir::toNativeSeparators(dcmImagePath).toUtf8().data());
   return this->generateThumbnail(&dcmImage, image);
 }
 
 //------------------------------------------------------------------------------
 bool ctkDICOMThumbnailGenerator::generateThumbnail(const QString& dcmImagePath, const QString& thumbnailPath)
 {
-  DicomImage dcmImage(QDir::toNativeSeparators(dcmImagePath).toUtf8());
+  DicomImage dcmImage(QDir::toNativeSeparators(dcmImagePath).toUtf8().data());
   return this->generateThumbnail(&dcmImage, thumbnailPath);
 }
 

Libs/DICOM/Widgets/Testing/Cpp/ctkDICOMImageTest1.cpp

@@ -54,7 +54,7 @@ int ctkDICOMImageTest1( int argc, char * argv [] )
 
   QString dicomFilePath(arguments.at(0));
 
-  DicomImage dcmtkImage(QDir::toNativeSeparators(dicomFilePath).toUtf8());
+  DicomImage dcmtkImage(QDir::toNativeSeparators(dicomFilePath).toUtf8().data());
   ctkDICOMImage ctkImage(&dcmtkImage);
 
   QLabel qtImage;

Libs/DICOM/Widgets/Testing/Cpp/ctkDICOMItemViewTest1.cpp

@@ -55,7 +55,7 @@ int ctkDICOMItemViewTest1( int argc, char * argv [] )
 
   QString dicomFilePath(arguments.at(0));
 
-  DicomImage img(QDir::toNativeSeparators(dicomFilePath).toUtf8());
+  DicomImage img(QDir::toNativeSeparators(dicomFilePath).toUtf8().data());
   QImage image;
   QImage image2(200, 200, QImage::Format_RGB32);