Fix bug in DecodeCommands - spatial scaling was always forced

Author: lilith

src/Imageflow/Fluent/DecodeCommands.cs

@@ -5,7 +5,6 @@
 
 namespace Imageflow.Fluent
 {
-    [Flags]
     public enum DecderDownscalingMode
     {
         /// <summary>
@@ -35,15 +34,15 @@ public class DecodeCommands
 
         public DecderDownscalingMode DownscalingMode { get; set; } = DecderDownscalingMode.Unspecified;
 
-        public bool DiscardColorProfile { get; set; } = false;
+        public bool DiscardColorProfile { get; set; }
 
         public object[] ToImageflowDynamic()
         {
             object downscale = DownscaleHint.HasValue ? new { 
                 jpeg_downscale_hints = new {
                     width = DownscaleHint.Value.Width,
                     height  = DownscaleHint.Value.Height,
-                    scale_luma_spatially = (DownscalingMode | DecderDownscalingMode.SpatialLumaScaling) > 0,
+                    scale_luma_spatially = DownscalingMode == DecderDownscalingMode.SpatialLumaScaling || DownscalingMode == DecderDownscalingMode.GammaCorrectSpatialLumaScaling,
                     gamma_correct_for_srgb_during_spatial_luma_scaling = DownscalingMode == DecderDownscalingMode.GammaCorrectSpatialLumaScaling
                 } 
              }: null;