public void DecompressImageData()
{
if (dataDecompressed)
{
return;
}
var rect = Rect;
var bytesPerRow = Util.BytesPerRow(rect, Layer.PsdFile.BitDepth);
var bytesTotal = rect.Height * bytesPerRow;
if (this.ImageCompression != PhotoshopFile.ImageCompression.Raw)
{
imageData = new byte[bytesTotal];
var stream = new MemoryStream(Data);
switch (this.ImageCompression)
{
case ImageCompression.Rle:
var rleReader = new RleReader(stream);
for (int i = 0; i < rect.Height; i++)
{
int rowIndex = i * bytesPerRow;
rleReader.Read(imageData, rowIndex, bytesPerRow);
}
break;
case ImageCompression.Zip:
case ImageCompression.ZipPrediction:
// .NET implements Deflate (RFC 1951) but not zlib (RFC 1950),
// so we have to skip the first two bytes.
stream.ReadByte();
stream.ReadByte();
var deflateStream = new DeflateStream(stream, CompressionMode.Decompress);
var bytesDecompressed = deflateStream.Read(imageData, 0, bytesTotal);
Debug.Assert(bytesDecompressed == bytesTotal, "ZIP deflation output is different length than expected.");
break;
}
}
// Reverse multi-byte pixels to little-endian. This cannot be done
// on 32-bit depth images with ZipPrediction because the bytes have
// been packed together.
bool fReverseEndianness = (Layer.PsdFile.BitDepth == 16) ||
(Layer.PsdFile.BitDepth == 32) && (ImageCompression != PhotoshopFile.ImageCompression.ZipPrediction);
if (fReverseEndianness)
{
ReverseEndianness(imageData, rect);
}
if (this.ImageCompression == PhotoshopFile.ImageCompression.ZipPrediction)
{
UnpredictImageData(rect);
}
dataDecompressed = true;
}
private void DecompressImageData()
{
using (var stream = new MemoryStream(ImageDataRaw))
{
var bytesPerRow = Util.BytesPerRow(Rect, Layer.PsdFile.BitDepth);
var bytesTotal = (int)Rect.height * bytesPerRow;
ImageData = new byte[bytesTotal];
switch (this.ImageCompression)
{
case ImageCompression.Rle:
var rleReader = new RleReader(stream);
for (int i = 0; i < Rect.height; i++)
{
int rowIndex = i * bytesPerRow;
rleReader.Read(ImageData, rowIndex, bytesPerRow);
}
break;
case ImageCompression.Zip:
case ImageCompression.ZipPrediction:
// .NET implements Deflate (RFC 1951) but not zlib (RFC 1950),
// so we have to skip the first two bytes.
stream.ReadByte();
stream.ReadByte();
var deflateStream = new DeflateStream(stream, CompressionMode.Decompress);
// bytesDecompressed
deflateStream.Read(ImageData, 0, bytesTotal);
break;
default:
throw new PsdInvalidException("Unknown image compression method.");
}
}
}
