Add support for saving embedded album covers

Fixes #286

src/core/utilities.cpp

@@ -57,7 +57,7 @@
 #include <QtEvents>
 #include <QMessageBox>
 #include <QNetworkInterface>
-#include <QImageReader>
+#include <QMimeDatabase>
 #include <QtDebug>
 #if QT_VERSION >= QT_VERSION_CHECK(5, 10, 0)
 #  include <QRandomGenerator>
@@ -102,9 +102,6 @@
 
 namespace Utilities {
 
-QStringList kSupportedImageMimeTypes;
-QStringList kSupportedImageFormats;
-
 static QString tr(const char *str) {
   return QCoreApplication::translate("", str);
 }
@@ -945,41 +942,23 @@ bool IsColorDark(const QColor &color) {
   return ((30 * color.red() + 59 * color.green() + 11 * color.blue()) / 100) <= 130;
 }
 
-QStringList SupportedImageMimeTypes() {
+QByteArray ReadDataFromFile(const QString &filename) {
 
-  if (kSupportedImageMimeTypes.isEmpty()) {
-    for (const QByteArray &mimetype : QImageReader::supportedMimeTypes()) {
-      kSupportedImageMimeTypes << mimetype;
-    }
+  QFile file(filename);
+  QByteArray data;
+  if (file.open(QIODevice::ReadOnly)) {
+    data = file.readAll();
+    file.close();
   }
-
-  return kSupportedImageMimeTypes;
+  return data;
 
 }
 
-QStringList SupportedImageFormats() {
+QString MimeTypeFromData(const QByteArray &data) {
 
-  if (kSupportedImageFormats.isEmpty()) {
-    for (const QByteArray &filetype : QImageReader::supportedImageFormats()) {
-      kSupportedImageFormats << filetype;
-    }
-  }
+  if (data.isEmpty()) return QString();
 
-  return kSupportedImageFormats;
-
-}
-
-QList<QByteArray> ImageFormatsForMimeType(const QByteArray &mimetype) {
-
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 12, 0))
-  return QImageReader::imageFormatsForMimeType(mimetype);
-#else
-  if (mimetype == "image/bmp") return QList<QByteArray>() << "BMP";
-  else if (mimetype == "image/gif") return QList<QByteArray>() << "GIF";
-  else if (mimetype == "image/jpeg") return QList<QByteArray>() << "JPG";
-  else if (mimetype == "image/png") return QList<QByteArray>() << "PNG";
-  else return QList<QByteArray>();
-#endif
+  return QMimeDatabase().mimeTypeForData(data).name();
 
 }