Finish ImageViewer; mouse drag to scroll

QuickLook.Plugin.ImageViewer/Plugin.cs

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+using System;
+using System.IO;
+using System.Windows;
+using System.Windows.Media.Imaging;
+
+namespace QuickLook.Plugin.ImageViewer
+{
+    public class Plugin : IViewer
+    {
+        private ImagePanel _ip;
+        private BitmapDecoder decoder;
+
+        public int Priority { get; }
+
+        public bool CanHandle(string path)
+        {
+            // TODO: determine file type by content
+
+            if (Directory.Exists(path))
+                return false;
+
+            switch (Path.GetExtension(path).ToLower())
+            {
+                case ".bmp":
+                case ".gif":
+                case ".ico":
+                case ".jpg":
+                case ".png":
+                case ".wdp":
+                case ".tiff":
+                    return true;
+
+                default:
+                    return false;
+            }
+        }
+
+        public void Prepare(string path, ViewContentContainer container)
+        {
+            decoder = BitmapDecoder.Create(new Uri(path), BitmapCreateOptions.None, BitmapCacheOption.None);
+            var frame = decoder.Frames[0];
+
+            container.SetPreferedSizeFit(new Size {Width = frame.Width, Height = frame.Height}, 0.6);
+        }
+
+        public void View(string path, ViewContentContainer container)
+        {
+            _ip = new ImagePanel(path);
+
+            container.SetContent(_ip);
+            container.Title = $"{Path.GetFileName(path)}";
+        }
+
+        public void Close()
+        {
+        }
+    }
+}