Merge pull request #17569 from vavallee/fix/17056-no-image-upscaling

Stop image endpoints from upscaling beyond the source resolution

1 files changed, 29 insertions, 0 deletions

diff --git a/MediaBrowser.Model/Drawing/DrawingUtils.cs b/MediaBrowser.Model/Drawing/DrawingUtils.cs
index 2040d26bbb..1fdd6a4a49 100644
--- a/MediaBrowser.Model/Drawing/DrawingUtils.cs
+++ b/MediaBrowser.Model/Drawing/DrawingUtils.cs
@@ -104,6 +104,35 @@ namespace MediaBrowser.Model.Drawing
         }
 
         /// <summary>
+        /// Scales a size down uniformly until it fits inside a bounding box.
+        /// Returns the original size if it already fits, so this never upscales.
+        /// </summary>
+        /// <param name="size">The size object.</param>
+        /// <param name="boundingBox">The box the result has to fit inside.</param>
+        /// <returns>A new size object, or <paramref name="size"/> if it already fits.</returns>
+        public static ImageDimensions ScaleDownToFit(ImageDimensions size, ImageDimensions boundingBox)
+        {
+            if (size.Width <= 0 || size.Height <= 0 || boundingBox.Width <= 0 || boundingBox.Height <= 0)
+            {
+                return size;
+            }
+
+            double widthRatio = size.Width / (double)boundingBox.Width;
+            double heightRatio = size.Height / (double)boundingBox.Height;
+            double scaleRatio = Math.Max(widthRatio, heightRatio);
+
+            if (scaleRatio <= 1)
+            {
+                return size;
+            }
+
+            var newWidth = Math.Clamp(Convert.ToInt32(Math.Round(size.Width / scaleRatio)), 1, boundingBox.Width);
+            var newHeight = Math.Clamp(Convert.ToInt32(Math.Round(size.Height / scaleRatio)), 1, boundingBox.Height);
+
+            return new ImageDimensions(newWidth, newHeight);
+        }
+
+        /// <summary>
         /// Gets the new width.
         /// </summary>
         /// <param name="currentHeight">Height of the current.</param>