Add missing exception handling. Fix #293

Former-commit-id: 3592ce3d67c70c1bd34ded26c48a0a3472ffd0d9
Former-commit-id: acb1420d8740919a329bba50d93c4f996e66f97d
Former-commit-id: 56dca60cbada6d0929f029b7a6a43570272bc5eb

src/ImageProcessorCore/ParallelImageProcessor.cs

@@ -34,6 +34,8 @@ namespace ImageProcessorCore
 
         /// <inheritdoc/>
         public void Apply(ImageBase target, ImageBase source, Rectangle sourceRectangle)
+        {
+            try
             {
                 // We don't want to affect the original source pixels so we make clone here.
                 ImageFrame frame = source as ImageFrame;
@@ -71,6 +73,12 @@ namespace ImageProcessorCore
 
                 this.AfterApply(temp, target, target.Bounds, sourceRectangle);
             }
+            catch (Exception ex)
+            {
+
+                throw new ImageProcessingException($"An error occured when processing the image using {this.GetType().Name}. See the inner exception for more detail.", ex);
+            }
+        }
 
         /// <inheritdoc/>
         public void Apply(ImageBase target, ImageBase source, int width, int height, Rectangle targetRectangle = default(Rectangle), Rectangle sourceRectangle = default(Rectangle))

src/ImageProcessorCore/Samplers/Crop.cs

@@ -31,6 +31,7 @@ namespace ImageProcessorCore.Samplers
                     {
                         target[x, y] = source[x, y];
                     }
+
                     this.OnRowProcessed();
                 }
             });