Added UnsafePixelCollection that does not boundary checking (closes #37)

Source/Magick.NET/Shared/IMagickImage.cs

@@ -1781,6 +1781,15 @@ public partial interface IMagickImage : IEquatable<IMagickImage>, IComparable<IM
         [SuppressMessage("Microsoft.Design", "CA1024:UsePropertiesWhereAppropriate", Justification = "Should be a method.")]
         IPixelCollection GetPixels();
 
+        /// <summary>
+        /// Returns a pixel collection that can be used to read or modify the pixels of this image. This instance
+        /// will not do any bounds checking and directly call ImageMagick.
+        /// </summary>
+        /// <returns>A pixel collection that can be used to read or modify the pixels of this image.</returns>
+        /// <exception cref="MagickException">Thrown when an error is raised by ImageMagick.</exception>
+        [SuppressMessage("Microsoft.Design", "CA1024:UsePropertiesWhereAppropriate", Justification = "Should be a method.")]
+        IPixelCollection GetPixelsUnsafe();
+
         /// <summary>
         /// Retrieve a named profile from the image.
         /// </summary>

Source/Magick.NET/Shared/MagickImage.cs

@@ -3265,6 +3265,20 @@ public IPixelCollection GetPixels()
             return new SafePixelCollection(this);
         }
 
+        /// <summary>
+        /// Returns a pixel collection that can be used to read or modify the pixels of this image. This instance
+        /// will not do any bounds checking and directly call ImageMagick.
+        /// </summary>
+        /// <returns>A pixel collection that can be used to read or modify the pixels of this image.</returns>
+        /// <exception cref="MagickException">Thrown when an error is raised by ImageMagick.</exception>
+        public IPixelCollection GetPixelsUnsafe()
+        {
+            if (Settings.Ping)
+                throw new InvalidOperationException("Image contains no pixel data.");
+
+            return new UnsafePixelCollection(this);
+        }
+
         /// <summary>
         /// Retrieve a named profile from the image.
         /// </summary>

Source/Magick.NET/Shared/Pixels/PixelCollection.cs

@@ -105,7 +105,8 @@ public QuantumType[] GetValues()
 
         public virtual void SetPixel(Pixel pixel)
         {
-            SetPixelUnchecked(pixel.X, pixel.Y, pixel.Value);
+            if (pixel != null)
+                SetPixelUnchecked(pixel.X, pixel.Y, pixel.Value);
         }
 
         public void SetPixel(IEnumerable<Pixel> pixels)

Source/Magick.NET/Shared/Pixels/UnsafePixelCollection.cs

@@ -0,0 +1,42 @@
+// Copyright 2013-2017 Dirk Lemstra <https://github.com/dlemstra/Magick.NET/>
+//
+// Licensed under the ImageMagick License (the "License"); you may not use this file except in
+// compliance with the License. You may obtain a copy of the License at
+//
+//   https://www.imagemagick.org/script/license.php
+//
+// Unless required by applicable law or agreed to in writing, software distributed under the
+// License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+// either express or implied. See the License for the specific language governing permissions
+// and limitations under the License.
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+#if Q8
+using QuantumType = System.Byte;
+#elif Q16
+using QuantumType = System.UInt16;
+#elif Q16HDRI
+using QuantumType = System.Single;
+#else
+#error Not implemented!
+#endif
+
+namespace ImageMagick
+{
+    internal sealed class UnsafePixelCollection : PixelCollection
+    {
+        public UnsafePixelCollection(MagickImage image)
+            : base(image)
+        {
+        }
+
+        public override void SetPixel(int x, int y, QuantumType[] value)
+        {
+            if (value != null)
+                base.SetPixel(x, y, value);
+        }
+    }
+}

Tests/Magick.NET.Tests/Shared/Pixels/SafePixelCollectionTests.cs

@@ -71,9 +71,8 @@ public void Indexer_InsideImage_ReturnsPixel()
                 using (IPixelCollection pixels = image.GetPixels())
                 {
                     Pixel pixel = pixels[300, 100];
-                    MagickColor color = pixel.ToColor();
 
-                    ColorAssert.AreEqual(MagickColors.Red, color);
+                    ColorAssert.AreEqual(MagickColors.Red, pixel.ToColor());
                 }
             }
         }
@@ -274,7 +273,7 @@ public void GetPixel_OutsideImage_ThrowsException()
                 {
                     ExceptionAssert.ThrowsArgumentException<ArgumentOutOfRangeException>("x", () =>
                     {
-                        Pixel pixel = pixels.GetPixel(image.Width + 1, 0);
+                        pixels.GetPixel(image.Width + 1, 0);
                     });
                 }
             }