LayerChannel.cs

﻿#region Licence
/*
Copyright (c) 2013, Darren Horrocks
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
    * Neither the name of the <organization> nor the
      names of its contributors may be used to endorse or promote products
      derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#endregion
using System.Diagnostics;
using System.Globalization;
using System.IO;

namespace System.Drawing.PSD
{
	public partial class Layer
	{
		public class Channel
		{
			/// <summary>
			/// The layer to which this channel belongs
			/// </summary>
			public Layer Layer { get; private set; }


			/// <summary>
			/// 0 = red, 1 = green, etc.
			/// 1 = transparency mask
			/// 2 = user supplied layer mask
			/// </summary>
            public Int16 ID { get; private set; }

			/// <summary>
			/// The length of the compressed channel data.
			/// </summary>
            public Int32 Length { get; private set; }

			/// <summary>
			/// The compressed raw channel data
			/// </summary>
			public Byte[] Data { get; set; }
			public Byte[] ImageData { get; set; }
            public ImageCompression ImageCompression { get; set; }

			internal Channel(Int16 id, Layer layer)
			{
				ID = id;
				Layer = layer;
				Layer.Channels.Add(this);
				Layer.SortedChannels.Add(ID, this);
			}

			internal Channel(BinaryReverseReader reverseReader, Layer layer)
			{
				Debug.WriteLine("Channel started at " + reverseReader.BaseStream.Position.ToString(CultureInfo.InvariantCulture));

				ID = reverseReader.ReadInt16();
				Length = reverseReader.ReadInt32();

				Layer = layer;
			}

			internal void Save(BinaryReverseWriter reverseWriter)
			{
				Debug.WriteLine("Channel Save started at " + reverseWriter.BaseStream.Position.ToString(CultureInfo.InvariantCulture));

				reverseWriter.Write(ID);

				CompressImageData();

				reverseWriter.Write(Data.Length + 2); // 2 bytes for the image compression
			}

			internal void LoadPixelData(BinaryReverseReader reverseReader)
			{
				Debug.WriteLine("Channel.LoadPixelData started at " + reverseReader.BaseStream.Position.ToString(CultureInfo.InvariantCulture));

				Data = reverseReader.ReadBytes(Length);

				using (BinaryReverseReader imageReader = DataReader)
				{
					ImageCompression = (ImageCompression)imageReader.ReadInt16();

					Int32 bytesPerRow = 0;

					switch (Layer.PsdFile.Depth)
					{
						case 1:
							bytesPerRow = Layer.Rect.Width;//NOT sure
							break;
						case 8:
							bytesPerRow = Layer.Rect.Width;
							break;
						case 16:
							bytesPerRow = Layer.Rect.Width * 2;
							break;
					}

					ImageData = new Byte[Layer.Rect.Height * bytesPerRow];

					switch (ImageCompression)
					{
						case ImageCompression.Raw:
							imageReader.Read(ImageData, 0, ImageData.Length);
							break;
						case ImageCompression.Rle:
							{
								Int32[] rowLengthList = new Int32[Layer.Rect.Height];

								for (Int32 i = 0; i < rowLengthList.Length; i++) rowLengthList[i] = imageReader.ReadInt16();

								for (Int32 i = 0; i < Layer.Rect.Height; i++)
								{
									Int32 rowIndex = i * Layer.Rect.Width;
									RleHelper.DecodedRow(imageReader.BaseStream, ImageData, rowIndex, bytesPerRow);

									//if (rowLenghtList[i] % 2 == 1)
									//  readerImg.ReadByte();
								}
							}
							break;
					}
				}
			}

			private void CompressImageData()
			{
				if (ImageCompression == ImageCompression.Rle)
				{
					MemoryStream memoryStream = new MemoryStream();
					BinaryReverseWriter reverseWriter = new BinaryReverseWriter(memoryStream);

					// we will write the correct lengths later, so remember 
					// the position
					Int64 lengthPosition = reverseWriter.BaseStream.Position;

					Int32[] rleRowLenghs = new Int32[Layer.Rect.Height];

					if (ImageCompression == ImageCompression.Rle)
					{
						for (Int32 i = 0; i < rleRowLenghs.Length; i++)
						{
							reverseWriter.Write((Int16)0x1234);
						}
					}

					Int32 bytesPerRow = 0;

					switch (Layer.PsdFile.Depth)
					{
						case 1:
							bytesPerRow = Layer.Rect.Width;//NOT Shure
							break;
						case 8:
							bytesPerRow = Layer.Rect.Width;
							break;
						case 16:
							bytesPerRow = Layer.Rect.Width * 2;
							break;
					}

					for (Int32 row = 0; row < Layer.Rect.Height; row++)
					{
						Int32 rowIndex = row * Layer.Rect.Width;
						rleRowLenghs[row] = RleHelper.EncodedRow(reverseWriter.BaseStream, ImageData, rowIndex, bytesPerRow);
					}

					Int64 endPosition = reverseWriter.BaseStream.Position;

					reverseWriter.BaseStream.Position = lengthPosition;

					foreach (Int32 length in rleRowLenghs)
					{
						reverseWriter.Write((Int16)length);
					}

					reverseWriter.BaseStream.Position = endPosition;

					memoryStream.Close();

					Data = memoryStream.ToArray();

					memoryStream.Dispose();

				}
				else
				{
					Data = (byte[])ImageData.Clone();
				}
			}

			internal void SavePixelData(BinaryReverseWriter writer)
			{
				Debug.WriteLine("Channel SavePixelData started at " + writer.BaseStream.Position.ToString(CultureInfo.InvariantCulture));

				writer.Write((short)ImageCompression);
				writer.Write(ImageData);
			}

			public BinaryReverseReader DataReader
			{
				get
				{
					return Data == null ? null : new BinaryReverseReader(new MemoryStream(Data));
				}
			}
		}

	}
}