using modified exiv2-ql (QL-Win/exiv2@cf560437bb) to detect Exif; switch from NConvert to Magick.NET

QuickLook.Plugin/QuickLook.Plugin.ImageViewer/Helper.cs

@@ -0,0 +1,41 @@
+// Copyright © 2020 Paddy Xu
+// 
+// This file is part of QuickLook program.
+// 
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+// 
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+using System.Reflection;
+using System.Windows.Media.Imaging;
+using QuickLook.Common.Helpers;
+
+namespace QuickLook.Plugin.ImageViewer
+{
+    internal class Helper
+    {
+        public static void DpiHack(BitmapSource img)
+        {
+            // a dirty hack... but is the fastest
+
+            var newDpiX = (double) DpiHelper.DefaultDpi * DpiHelper.GetCurrentScaleFactor().Horizontal;
+            var newDpiY = (double) DpiHelper.DefaultDpi * DpiHelper.GetCurrentScaleFactor().Vertical;
+
+            var dpiX = img.GetType().GetField("_dpiX",
+                BindingFlags.NonPublic | BindingFlags.Instance);
+            var dpiY = img.GetType().GetField("_dpiY",
+                BindingFlags.NonPublic | BindingFlags.Instance);
+            dpiX?.SetValue(img, newDpiX);
+            dpiY?.SetValue(img, newDpiY);
+        }
+    }
+}