/// <summary>
/// Reads resolution information from a PSD file object.
/// </summary>
/// <param name="psd">The PSD file object from which to obtain resolution information.</param>
/// <returns>
/// The resolution information obtained from the PSD file, or <c>null</c> if the file contains no resolution
/// information.
/// </returns>
public static ResolutionInfo FromPSD(PSDFile psd)
{
var resource = psd.ImageResources.FirstOrDefault(ir => ir.ID == ResolutionInfoResourceID);
if (resource == null)
{
return(null);
}
var resInfo = new ResolutionInfo();
using (var ms = new MemoryStream(resource.Data, writable: false))
{
int horizontalResolutionDPIFixedPoint = ms.ReadBigEndianInt32();
resInfo.HorizontalResolutionDPI = horizontalResolutionDPIFixedPoint / FixedPointDivisor;
if (resInfo.HorizontalResolutionDPI <= 0.0)
{
throw new PSDFormatException($"horizontal resolution is {resInfo.HorizontalResolutionDPI}, expected more than 0.0");
}
resInfo.HorizontalResolutionDisplayUnit = (ResolutionDisplayUnit)ms.ReadBigEndianInt16();
if (!Enum.IsDefined(typeof(ResolutionDisplayUnit), resInfo.HorizontalResolutionDisplayUnit))
{
throw new PSDFormatException(
$"horizontal resolution display unit is {resInfo.HorizontalResolutionDisplayUnit}, expected one of {string.Join(", ", EnumUtils.GetUnderlyingValues<ResolutionDisplayUnit, short>())}"
);
}
resInfo.WidthDisplayUnit = (SizeDisplayUnit)ms.ReadBigEndianInt16();
if (!Enum.IsDefined(typeof(SizeDisplayUnit), resInfo.WidthDisplayUnit))
{
throw new PSDFormatException(
$"width display unit is {resInfo.WidthDisplayUnit}, expected one of {string.Join(", ", EnumUtils.GetUnderlyingValues<SizeDisplayUnit, short>())}"
);
}
int verticalResolutionDPIFixedPoint = ms.ReadBigEndianInt32();
resInfo.VerticalResolutionDPI = verticalResolutionDPIFixedPoint / FixedPointDivisor;
if (resInfo.VerticalResolutionDPI <= 0.0)
{
throw new PSDFormatException($"vertical resolution is {resInfo.VerticalResolutionDPI}, expected more than 0.0");
}
resInfo.VerticalResolutionDisplayUnit = (ResolutionDisplayUnit)ms.ReadBigEndianInt16();
if (!Enum.IsDefined(typeof(ResolutionDisplayUnit), resInfo.VerticalResolutionDisplayUnit))
{
throw new PSDFormatException(
$"vertical resolution display unit is {resInfo.VerticalResolutionDisplayUnit}, expected one of {string.Join(", ", EnumUtils.GetUnderlyingValues<ResolutionDisplayUnit, short>())}"
);
}
resInfo.HeightDisplayUnit = (SizeDisplayUnit)ms.ReadBigEndianInt16();
if (!Enum.IsDefined(typeof(SizeDisplayUnit), resInfo.HeightDisplayUnit))
{
throw new PSDFormatException(
$"height display unit is {resInfo.HeightDisplayUnit}, expected one of {string.Join(", ", EnumUtils.GetUnderlyingValues<SizeDisplayUnit, short>())}"
);
}
}
return(resInfo);
}
/// <summary>
/// Reads the PSD header from a stream and populates a <see cref="PSDFile"/> with the information.
/// </summary>
/// <param name="psd">The PSD file object to populate.</param>
/// <param name="stream">The stream from which to read the PSD header.</param>
public static void ReadHeader(PSDFile psd, Stream stream)
{
string magic = stream.ReadUsAsciiString(4);
if (!string.Equals(magic, Magic, StringComparison.Ordinal))
{
throw new PSDFormatException($"unexpected magic value (is \"{magic}\", expected \"{Magic}\")");
}
short version = stream.ReadBigEndianInt16();
if (version < 1 || version > 2)
{
throw new PSDFormatException($"version is {version}, expected 1 or 2");
}
psd.Version = version;
byte[] reserved = stream.ReadBytes(6);
if (reserved.Any(b => b != 0x00))
{
throw new PSDFormatException("nonzero byte in reserved 6-byte value");
}
short numberOfChannels = stream.ReadBigEndianInt16();
if (numberOfChannels < MinChannels || numberOfChannels > MaxChannels)
{
throw new PSDFormatException(
$"number of channels is is {numberOfChannels}, expected at least {MinChannels} and at most {MaxChannels}");
}
psd.NumberOfChannels = numberOfChannels;
int height = stream.ReadBigEndianInt32();
if (height < 1)
{
throw new PSDFormatException($"height is {height}, expected at least 1");
}
if (version == 1 && height > Version1MaxDimension)
{
throw new PSDFormatException(
$"height is {height} and this is a version 1 document, expected at most {Version1MaxDimension}");
}
if (version == 2 && height > Version2MaxDimension)
{
throw new PSDFormatException(
$"height is {height} and this is a version 2 document, expected at most {Version2MaxDimension}");
}
psd.Height = height;
int width = stream.ReadBigEndianInt32();
if (width < 1)
{
throw new PSDFormatException($"width is {width}, expected at least 1");
}
if (version == 1 && width > Version1MaxDimension)
{
throw new PSDFormatException(
$"width is {width} and this is a version 1 document, expected at most {Version1MaxDimension}");
}
if (version == 2 && width > Version2MaxDimension)
{
throw new PSDFormatException(
$"width is {width} and this is a version 2 document, expected at most {Version2MaxDimension}");
}
psd.Width = width;
short depth = stream.ReadBigEndianInt16();
if (depth != 1 && depth != 8 && depth != 16 && depth != 32)
{
throw new PSDFormatException($"depth is {depth}, expected 1 or 8 or 16 or 32");
}
psd.Depth = depth;
short colorMode = stream.ReadBigEndianInt16();
if (!Enum.IsDefined(typeof(ColorMode), colorMode))
{
throw new PSDFormatException(
$"color mode is {colorMode}, expected one of {string.Join(", ", EnumUtils.GetUnderlyingValues<ColorMode, short>())}");
}
psd.ColorMode = (ColorMode)colorMode;
}
/// <summary>
/// Reads metadata about a PSD file's precomposed image data and populates a <see cref="PSDFile"/> with it.
/// </summary>
/// <param name="psd">The PSD file object to populate.</param>
/// <param name="stream">The stream from which to read the precomposed image data metadata.</param>
public static void CreateImageDataPlaceholder(PSDFile psd, Stream stream)
{
var placeholder = new PSDImageDataPlaceholder();
// read compression method
short compressionValue = stream.ReadBigEndianInt16();
if (!Enum.IsDefined(typeof(CompressionType), compressionValue))
{
throw new PSDFormatException($"unexpected compression type {compressionValue}, expected one of {string.Join(", ", EnumUtils.GetUnderlyingValues<CompressionType, short>())}");
}
placeholder.Compression = (CompressionType)compressionValue;
placeholder.Offset = stream.Position;
psd.PrecomposedImageData = placeholder;
}
/// <summary>
/// Reads the global mask information subsection of a PSD layer and mask information section from a stream
/// and populates a <see cref="PSDFile"/> with the information.
/// </summary>
/// <param name="psd">The PSD file object to populate.</param>
/// <param name="stream">The stream from which to read the layer information subsection.</param>
public static void ReadGlobalMaskInformation(PSDFile psd, Stream stream)
{
int length = stream.ReadBigEndianInt32();
if (length == 0)
{
// no global mask info
psd.GlobalLayerMask = null;
return;
}
var mask = new PSDGlobalLayerMask();
mask.OverlayColorSpace = stream.ReadBigEndianInt16();
mask.ColorComponent1 = stream.ReadBigEndianInt16();
mask.ColorComponent2 = stream.ReadBigEndianInt16();
mask.ColorComponent3 = stream.ReadBigEndianInt16();
mask.ColorComponent4 = stream.ReadBigEndianInt16();
short opacity = stream.ReadBigEndianInt16();
if (opacity < 0 || opacity > 100)
{
throw new PSDFormatException($"global mask opacity must be at least 0 and at most 100, got {opacity}");
}
mask.Opacity = opacity;
byte kind = stream.ReadByteOrThrow();
if (!Enum.IsDefined(typeof(LayerMaskKind), kind))
{
throw new PSDFormatException($"unknown layer mask kind {kind}, expected one of {string.Join(", ", EnumUtils.GetUnderlyingValues<LayerMaskKind, byte>())}");
}
mask.Kind = (LayerMaskKind)kind;
int paddingByteCount = length - 13;
stream.ReadBytes(paddingByteCount);
psd.GlobalLayerMask = mask;
}