public PsdFile Load(String filename)
{
using (FileStream stream = new FileStream(filename, FileMode.Open))
{
//binary reverse reader reads data types in big-endian format.
BinaryReverseReader reader = new BinaryReverseReader(stream);
#region "Headers"
//The headers area is used to check for a valid PSD file
Debug.WriteLine("LoadHeader started at " + reader.BaseStream.Position.ToString(CultureInfo.InvariantCulture));
String signature = new String(reader.ReadChars(4));
if (signature != "8BPS") throw new IOException("Bad or invalid file stream supplied");
//get the version number, should be 1 always
if ((Version = reader.ReadInt16()) != 1) throw new IOException("Invalid version number supplied");
//get rid of the 6 bytes reserverd in PSD format
reader.BaseStream.Position += 6;
//get the rest of the information from the PSD file.
//Everytime ReadInt16() is called, it reads 2 bytes.
//Everytime ReadInt32() is called, it reads 4 bytes.
_channels = reader.ReadInt16();
_rows = reader.ReadInt32();
_columns = reader.ReadInt32();
_depth = reader.ReadInt16();
ColorMode = (ColorModes)reader.ReadInt16();
//by end of headers, the reader has read 26 bytes into the file.
#endregion //End Headers
#region "ColorModeData"
Debug.WriteLine("LoadColorModeData started at " + reader.BaseStream.Position.ToString(CultureInfo.InvariantCulture));
UInt32 paletteLength = reader.ReadUInt32(); //readUint32() advances the reader 4 bytes.
if (paletteLength > 0)
{
ColorModeData = reader.ReadBytes((Int32)paletteLength);
}
#endregion //End ColorModeData
#region "Loading Image Resources"
//This part takes extensive use of classes that I didn't write therefore
//I can't document much on what they do.
Debug.WriteLine("LoadingImageResources started at " + reader.BaseStream.Position.ToString(CultureInfo.InvariantCulture));
_imageResources.Clear();
UInt32 imgResLength = reader.ReadUInt32();
if (imgResLength <= 0) return null;
Int64 startPosition = reader.BaseStream.Position;
while ((reader.BaseStream.Position - startPosition) < imgResLength)
{
ImageResource imgRes = new ImageResource(reader);
ResourceIDs resID = (ResourceIDs)imgRes.ID;
switch (resID)
{
case ResourceIDs.ResolutionInfo:
imgRes = new ResolutionInfo(imgRes);
break;
case ResourceIDs.Thumbnail1:
case ResourceIDs.Thumbnail2:
imgRes = new Thumbnail(imgRes);
break;
case ResourceIDs.AlphaChannelNames:
imgRes = new AlphaChannels(imgRes);
break;
}
_imageResources.Add(imgRes);
}
// make sure we are not on a wrong offset, so set the stream position
// manually
reader.BaseStream.Position = startPosition + imgResLength;
#endregion //End LoadingImageResources
#region "Layer and Mask Info"
//We are gonna load up all the layers and masking of the PSD now.
Debug.WriteLine("LoadLayerAndMaskInfo - Part1 started at " + reader.BaseStream.Position.ToString(CultureInfo.InvariantCulture));
UInt32 layersAndMaskLength = reader.ReadUInt32();
if (layersAndMaskLength <= 0) return null;
//new start position
startPosition = reader.BaseStream.Position;
//Lets start by loading up all the layers
LoadLayers(reader);
//we are done the layers, load up the masks
LoadGlobalLayerMask(reader);
// make sure we are not on a wrong offset, so set the stream position
// manually
reader.BaseStream.Position = startPosition + layersAndMaskLength;
#endregion //End Layer and Mask info
#region "Loading Final Image"
//we have loaded up all the information from the PSD file
//into variables we can use later on.
//lets finish loading the raw data that defines the image
//in the picture.
Debug.WriteLine("LoadImage started at " + reader.BaseStream.Position.ToString(CultureInfo.InvariantCulture));
ImageCompression = (ImageCompression)reader.ReadInt16();
ImageData = new Byte[_channels][];
//---------------------------------------------------------------
if (ImageCompression == ImageCompression.Rle)
{
// The RLE-compressed data is proceeded by a 2-byte data count for each row in the data,
// which we're going to just skip.
reader.BaseStream.Position += _rows * _channels * 2;
}
//---------------------------------------------------------------
Int32 bytesPerRow = 0;
switch (_depth)
{
case 1:
bytesPerRow = _columns;//NOT Shure
break;
case 8:
bytesPerRow = _columns;
break;
case 16:
bytesPerRow = _columns * 2;
break;
}
//---------------------------------------------------------------
for (Int32 ch = 0; ch < _channels; ch++)
{
ImageData[ch] = new Byte[_rows * bytesPerRow];
switch (ImageCompression)
{
case ImageCompression.Raw:
reader.Read(ImageData[ch], 0, ImageData[ch].Length);
break;
case ImageCompression.Rle:
{
for (Int32 i = 0; i < _rows; i++)
{
Int32 rowIndex = i * _columns;
RleHelper.DecodedRow(reader.BaseStream, ImageData[ch], rowIndex, bytesPerRow);
}
}
break;
}
}
#endregion //End LoadingFinalImage
}
return this;
} //end Load()