Move scaleImage() in Utils

1 files changed, 28 insertions, 0 deletions

diff --git a/include/Utils.h b/include/Utils.h

index 30e592cd..fa825b7c 100644
--- a/include/Utils.h
+++ b/include/Utils.h
@@ -26,4 +26,32 @@ firstChar(const QString &input);
 //! Get a human readable file size with the appropriate units attached.
 QString
 humanReadableFileSize(uint64_t bytes);
+
+//! Scale down an image to fit to the given width & height limitations.
+template<class ImageType>
+ImageType
+scaleDown(uint64_t max_width, uint64_t max_height, const ImageType &source)
+{
+        if (source.isNull())
+                return source;
+
+        auto width_ratio  = (double)max_width / (double)source.width();
+        auto height_ratio = (double)max_height / (double)source.height();
+
+        auto min_aspect_ratio = std::min(width_ratio, height_ratio);
+
+        int final_width  = 0;
+        int final_height = 0;
+
+        if (min_aspect_ratio > 1) {
+                final_width  = source.width();
+                final_height = source.height();
+        } else {
+                final_width  = source.width() * min_aspect_ratio;
+                final_height = source.height() * min_aspect_ratio;
+        }
+
+        return source.scaled(
+          final_width, final_height, Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
+}
 }