Fix #337: Exif rotation is broken in WPF

Author: xupefei

QuickLook.Plugin/QuickLook.Plugin.ImageViewer/AnimatedImage/NativeImageProvider.cs

@@ -40,6 +40,8 @@ public override Task<BitmapSource> GetThumbnail(Size size, Size fullSize)
                                                Math.Min(size.Width / 2 / fullSize.Width,
                                                    size.Height / 2 / fullSize.Height));
             var decodeHeight = (int) Math.Round(fullSize.Height / fullSize.Width * decodeWidth);
+            var orientation = Meta.GetOrientation();
+            var rotate = ShouldRotate(orientation);
 
             return new Task<BitmapSource>(() =>
             {
@@ -49,14 +51,19 @@ public override Task<BitmapSource> GetThumbnail(Size size, Size fullSize)
                     img.BeginInit();
                     img.UriSource = new Uri(Path);
                     img.CacheOption = BitmapCacheOption.OnLoad;
-                    img.DecodePixelWidth = decodeWidth;
-                    img.DecodePixelHeight = decodeHeight; // specific size to avoid .net's double to int conversion
+                    img.DecodePixelWidth = rotate ? decodeHeight : decodeWidth;
+                    img.DecodePixelHeight = rotate ? decodeWidth : decodeHeight; // specific size to avoid .net's double to int conversion
                     img.EndInit();
 
-                    var scaled = new TransformedBitmap(img,
-                        new ScaleTransform(fullSize.Width / img.PixelWidth, fullSize.Height / img.PixelHeight));
-                    scaled.Freeze();
-                    return scaled;
+                    var scaled = rotate ?
+                        new TransformedBitmap(img,
+                            new ScaleTransform(fullSize.Height / img.PixelWidth, fullSize.Width / img.PixelHeight))
+                        : new TransformedBitmap(img,
+                            new ScaleTransform(fullSize.Width / img.PixelWidth, fullSize.Height / img.PixelHeight));
+
+                    var rotated = ApplyTransformFromExif(scaled, orientation);
+                    rotated.Freeze();
+                    return rotated;
                 }
                 catch (Exception e)
                 {
@@ -78,8 +85,10 @@ public override Task<BitmapSource> GetRenderedFrame(int index)
                     img.CacheOption = BitmapCacheOption.OnLoad;
                     img.EndInit();
 
-                    img.Freeze();
-                    return img;
+                    var img2 = ApplyTransformFromExif(img, Meta.GetOrientation());
+                    img2.Freeze();
+
+                    return img2;
                 }
                 catch (Exception e)
                 {
@@ -89,6 +98,52 @@ public override Task<BitmapSource> GetRenderedFrame(int index)
             });
         }
 
+        private static bool ShouldRotate(Orientation orientation)
+        {
+            bool rotate = false;
+            switch (orientation)
+            {
+                case Orientation.LeftTop:
+                case Orientation.RightTop:
+                case Orientation.RightBottom:
+                case Orientation.Leftbottom:
+                    rotate = true;
+                    break;
+            }
+
+            return rotate;
+        }
+
+        private static BitmapSource ApplyTransformFromExif(BitmapSource image, Orientation orientation)
+        {
+            switch (orientation)
+            {
+                case Orientation.Undefined:
+                case Orientation.TopLeft:
+                    return image;
+                case Orientation.TopRight:
+                    return new TransformedBitmap(image, new ScaleTransform(-1, 1, 0, 0));
+                case Orientation.BottomRight:
+                    return new TransformedBitmap(image, new RotateTransform(180));
+                case Orientation.BottomLeft:
+                    return new TransformedBitmap(image, new ScaleTransform(1, 1, 0, 0));
+                case Orientation.LeftTop:
+                    return new TransformedBitmap(
+                        new TransformedBitmap(image, new RotateTransform(90)),
+                        new ScaleTransform(-1, 1, 0, 0));
+                case Orientation.RightTop:
+                    return new TransformedBitmap(image, new RotateTransform(90));
+                case Orientation.RightBottom:
+                    return new TransformedBitmap(
+                        new TransformedBitmap(image, new RotateTransform(270)),
+                        new ScaleTransform(-1, 1, 0, 0));
+                case Orientation.Leftbottom:
+                    return new TransformedBitmap(image, new RotateTransform(270));
+            }
+
+            return image;
+        }
+
         public override void Dispose()
         {
         }