Use lossless format to get sharper project preview images

opengisch · Jan 13, 2024 · 0147c41 · 0147c41
1 parent b2d24bc
commit 0147c41
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Showing 2 changed files with 13 additions and 4 deletions.
diff --git a/src/core/projectsimageprovider.cpp b/src/core/projectsimageprovider.cpp
@@ -27,6 +27,15 @@ QImage ProjectsImageProvider::requestImage( const QString &id, QSize *size, cons
 {
   // the id is passed on as an encoded URL string which needs decoding
   const QString path = QUrl::fromPercentEncoding( id.toUtf8() );
-  const QString previewPath = QStringLiteral( "%1.jpg" ).arg( path );
-  return QFileInfo::exists( previewPath ) ? QImage( previewPath ) : QImage();
+  const QString previewPath = QStringLiteral( "%1.png" ).arg( path );
+
+  if ( QFileInfo::exists( previewPath ) )
+    return QImage( previewPath );
+
+  // Fallback to jpg generated by older QField versions
+  const QString previewPathJpg = QStringLiteral( "%1.jpg" ).arg( path );
+  if ( QFileInfo::exists( previewPathJpg ) )
+    return QImage( previewPathJpg );
+
+  return QImage();
 }
diff --git a/src/core/qgismobileapp.cpp b/src/core/qgismobileapp.cpp
@@ -667,7 +667,7 @@ void QgisMobileapp::onMapCanvasRefreshed()
   disconnect( mMapCanvas, &QgsQuickMapCanvasMap::mapCanvasRefreshed, this, &QgisMobileapp::onMapCanvasRefreshed );
   if ( !mProjectFilePath.isEmpty() )
   {
-    if ( !QFileInfo::exists( QStringLiteral( "%1.jpg" ).arg( mProjectFilePath ) ) )
+    if ( !QFileInfo::exists( QStringLiteral( "%1.png" ).arg( mProjectFilePath ) ) )
     {
       saveProjectPreviewImage();
     }
@@ -1371,7 +1371,7 @@ void QgisMobileapp::saveProjectPreviewImage()
       const int pixels = std::min( grab.width(), grab.height() );
       const QRect rect( ( grab.width() - pixels ) / 2, ( grab.height() - pixels ) / 2, pixels, pixels );
       const QImage img = grab.copy( rect );
-      img.save( QStringLiteral( "%1.jpg" ).arg( mProjectFilePath ) );
+      img.save( QStringLiteral( "%1.png" ).arg( mProjectFilePath ) );
     }
   }
 }