public void Save(PsdBinaryWriter writer, bool globalLayerInfo,
bool isLargeDocument)
{
Util.DebugMessage(writer.BaseStream,
$"Save, Begin, LayerInfo, {Signature}, {Key}");
writer.WriteAsciiChars(Signature);
writer.WriteAsciiChars(Key);
var startPosition = writer.BaseStream.Position;
using (var lengthWriter = new PsdBlockLengthWriter(writer,
LayerInfoUtil.HasLongLength(Key, isLargeDocument)))
{
// Depending on the key, the length may be unpadded, 2-padded, or
// 4-padded. Thus, it is up to each implementation of WriteData to
// pad the length correctly.
WriteData(writer);
}
// Data for global layer info is always padded to a multiple of 4,
// even if this causes the stated length to be incorrect.
if (globalLayerInfo)
{
writer.WritePadding(startPosition, 4);
}
Util.DebugMessage(writer.BaseStream,
$"Save, End, LayerInfo, {Signature}, {Key}");
}
/// <summary>
/// Loads the next LayerInfo record.
/// </summary>
/// <param name="reader">The file reader</param>
/// <param name="psdFile">The PSD file.</param>
/// <param name="globalLayerInfo">True if the LayerInfo record is being
/// loaded from the end of the Layer and Mask Information section;
/// false if it is being loaded from the end of a Layer record.</param>
public static LayerInfo Load(PsdBinaryReader reader, PsdFile psdFile,
bool globalLayerInfo)
{
Util.DebugMessage(reader.BaseStream, "Load, Begin, LayerInfo");
// Some keys use a signature of 8B64, but the identity of these keys
// is undocumented. We will therefore accept either signature.
var signature = reader.ReadAsciiChars(4);
if ((signature != "8BIM") && (signature != "8B64"))
{
throw new PsdInvalidException(
$"{nameof(LayerInfo)} signature invalid, must be 8BIM or 8B64.");
}
var key = reader.ReadAsciiChars(4);
var hasLongLength = LayerInfoUtil.HasLongLength(key, psdFile.IsLargeDocument);
var length = hasLongLength
? reader.ReadInt64()
: reader.ReadInt32();
var startPosition = reader.BaseStream.Position;
LayerInfo result;
switch (key)
{
case "Layr":
case "Lr16":
case "Lr32":
result = new InfoLayers(reader, psdFile, key, length);
break;
case "lsct":
case "lsdk":
result = new LayerSectionInfo(reader, key, (int)length);
break;
case "luni":
result = new LayerUnicodeName(reader);
break;
default:
result = new RawLayerInfo(reader, signature, key, length);
break;
}
// May have additional padding applied.
var endPosition = startPosition + length;
if (reader.BaseStream.Position < endPosition)
{
reader.BaseStream.Position = endPosition;
}
// Documentation states that the length is even-padded. Actually:
// 1. Most keys have 4-padded lengths.
// 2. However, some keys (LMsk) have even-padded lengths.
// 3. Other keys (Txt2, Lr16, Lr32) have unpadded lengths.
//
// Photoshop writes data that is always 4-padded, even when the stated
// length is not a multiple of 4. The length mismatch seems to occur
// only on global layer info. We do not read extra padding in other
// cases because third-party programs are likely to follow the spec.
if (globalLayerInfo)
{
reader.ReadPadding(startPosition, 4);
}
Util.DebugMessage(reader.BaseStream,
$"Load, End, LayerInfo, {result.Signature}, {result.Key}");
return(result);
}
