private IEnumerable <IEnumerable <TPixelFormat> > ReadPBMData <TPixelFormat>(Stream stream,
NetpbmHeader <TPixelFormat> header, IImageFactory <TPixelFormat> imageFactory)
{
// read the bits!
if (header.ImageType == ImageType.PBM)
{
for (int r = 0; r < header.Height; ++r)
{
yield return(ReadBinaryPBMRow(stream, header.Width, imageFactory));
}
}
else if (header.ImageType == ImageType.PlainPBM)
{
for (int r = 0; r < header.Height; ++r)
{
yield return(ReadPlainRow(stream, header.Width, r == header.Height - 1, imageFactory));
}
}
else
{
throw new ArgumentOutOfRangeException("header.ImageType", header.ImageType, "image type unsupported by this method");
}
/*return imageFactory.MakeImage(width, height, imageFactory.BitmapOnPixelComponentValue,
* new[] {Component.Black}, rows);*/
}
public NetpbmImage <byte> MakeImage(NetpbmHeader <byte> header, IEnumerable <IEnumerable <byte> > pixelData)
{
Exception exception;
try
{
return(new NetpbmImage8(header, pixelData));
}
catch (ArgumentOutOfRangeException exc)
{
exception = exc;
}
catch (OverflowException exc)
{
exception = exc;
}
throw new InvalidDataException("invalid image format", exception);
}
/// <summary>
/// Returns the set of Netpbm image types into which the image with the given header can be encoded.
/// </summary>
/// <returns>The Netpbm image types an image with the given header can be encoded into.</returns>
/// <param name="header">The header of the image to be encoded.</param>
/// <typeparam name="TPixelComponent">The pixel component type of the image.</typeparam>
public ISet <ImageType> SupportedTypesForHeader <TPixelComponent>(NetpbmHeader <TPixelComponent> header)
{
// big PAM is always supported
var types = new HashSet <ImageType> {
ImageType.BigPAM
};
if (header.BytesPerPixelComponent > 2)
{
// all other formats limit pixel values to two bytes per component
return(types);
}
// PAM supports any component types
types.Add(ImageType.PAM);
// PPM requires RGB
if (
header.Components.Count == 3 &&
header.Components[0] == Component.Red &&
header.Components[1] == Component.Green &&
header.Components[2] == Component.Blue
)
{
types.Add(ImageType.PPM);
types.Add(ImageType.PlainPPM);
}
// PGM requires grayscale (black-to-white)
if (
header.Components.Count == 1 &&
header.Components[0] == Component.White
)
{
types.Add(ImageType.PGM);
types.Add(ImageType.PlainPGM);
}
return(types);
}
/// <summary>
/// Returns a new image which is the given image with the components of the given type inverted and changed to
/// another type.
/// </summary>
/// <typeparam name="TPixelComponent">The pixel component type being used.</typeparam>
/// <param name="image">The image whose component to invert.</param>
/// <param name="from">The component whose values to invert.</param>
/// <param name="to">The new component type of the component being inverted.</param>
/// <returns>A copy of <paramref name="image"/> where all components of type <paramref name="from"/> are
/// inverted and changed to type <paramref name="to"/>.</returns>
private NetpbmImage <TPixelComponent> InvertComponent <TPixelComponent>(NetpbmImage <TPixelComponent> image,
Component from, Component to)
{
Contract.Requires(image.Header.Components.Contains(from));
var componentIndices =
new HashSet <int>(Enumerable.Range(0, image.Header.Components.Count).Where(i => image.Header.Components[i] == from));
var newRows = image.NativeRows.Select(oldRow => InvertRowComponent(oldRow, image, componentIndices, from, to));
var newComponents = image.Header.Components.Select(c => c == from ? to : c);
var header = new NetpbmHeader <TPixelComponent>(
image.Header.ImageType,
image.Header.Width,
image.Header.Height,
image.Header.BytesPerPixelComponent,
newComponents,
image.Header.HighestComponentValue
);
return(image.NewImageOfSameType(header, newRows));
}
private NetpbmImage <TPixelComponent> CorrectOrder <TPixelComponent>(IList <Component> requestedOrder,
NetpbmImage <TPixelComponent> image)
{
Contract.Requires(requestedOrder.Count == image.Header.Components.Count);
Contract.Requires(ListsContainTheSameElements(requestedOrder, image.Header.Components));
if (requestedOrder.SequenceEqual(image.Header.Components))
{
// short-circuit
return(image.NewImageOfSameType(image.Header, image.NativeRows));
}
var newToOldOrder = new int[requestedOrder.Count];
var currentOrder = new List <int>(image.Header.Components.Select(c => (int)c));
for (int i = 0; i < requestedOrder.Count; ++i)
{
var index = currentOrder.IndexOf((int)requestedOrder[i]);
Debug.Assert(index != -1);
newToOldOrder[i] = index;
currentOrder[index] = -1;
}
Debug.Assert(currentOrder.All(o => o == -1));
var newRows = image.NativeRows.Select(originalRow => TransposeComponentOrder(originalRow, image.Header.Width, newToOldOrder));
var newHeader = new NetpbmHeader <TPixelComponent>(
image.Header.ImageType,
image.Header.Width,
image.Header.Height,
image.Header.BytesPerPixelComponent,
requestedOrder,
image.Header.HighestComponentValue
);
return(image.NewImageOfSameType(newHeader, newRows));
}
public NetpbmImage32(NetpbmHeader <uint> header, IEnumerable <IEnumerable <uint> > pixelData)
: base(header, pixelData)
{
}
public override NetpbmImage <BigInteger> NewImageOfSameType(NetpbmHeader <BigInteger> header,
IEnumerable <IEnumerable <BigInteger> > pixelData)
{
return(new NetpbmImageBigInteger(header, pixelData));
}
public NetpbmImageBigInteger(NetpbmHeader <BigInteger> header, IEnumerable <IEnumerable <BigInteger> > pixelData)
: base(header, pixelData)
{
}
/// <summary>
/// Returns the PAM tuple name and necessary component permutation for images with the given header.
/// </summary>
/// <param name="header">The header.</param>
/// <typeparam name="TPixelComponent">The pixel component type.</typeparam>
protected virtual string GetPamTupleType <TPixelComponent>(NetpbmHeader <TPixelComponent> header)
{
if (
header.Components.Count == 1 &&
header.Components[0] == Component.White
)
{
return("GRAYSCALE");
}
else if (
header.Components.Count == 2 &&
header.Components[0] == Component.White &&
header.Components[1] == Component.Alpha
)
{
return("GRAYSCALE_ALPHA");
}
else if (
header.Components.Count == 3 &&
header.Components[0] == Component.Red &&
header.Components[1] == Component.Green &&
header.Components[2] == Component.Blue
)
{
return("RGB");
}
else if (
header.Components.Count == 4 &&
header.Components[0] == Component.Red &&
header.Components[1] == Component.Green &&
header.Components[2] == Component.Blue &&
header.Components[3] == Component.Alpha
)
{
return("RGB_ALPHA");
}
else if (
header.Components.Count == 4 &&
header.Components[0] == Component.Cyan &&
header.Components[1] == Component.Magenta &&
header.Components[2] == Component.Yellow &&
header.Components[3] == Component.Black
)
{
// "CMYK" is an extension (compatible with GhostScript)
return("CMYK");
}
else if (
header.Components.Count == 5 &&
header.Components[0] == Component.Cyan &&
header.Components[1] == Component.Magenta &&
header.Components[2] == Component.Yellow &&
header.Components[3] == Component.Black &&
header.Components[4] == Component.Alpha
)
{
// "CMYK_ALPHA" is an extension
return("CMYK_ALPHA");
}
else
{
// extension: assemble a custom tuple type
return(string.Join("_", header.Components.Select(c => c.ToString().ToUpperInvariant())));
}
}
public NetpbmImage8(NetpbmHeader <byte> header, IEnumerable <IEnumerable <byte> > pixelData)
: base(header, pixelData)
{
}
/// <summary>
/// Initializes a new Netpbm image.
/// </summary>
/// <param name="header">The header of the image, containing all necessary information.</param>
/// <param name="pixelData">The actual pixel data of the image. Drill down rows to pixels, with the pixels
/// represented as a contiguous sequence of component values for each pixel (in pixel-major order, e.g.
/// <c>RGBRGBRGB</c>. The data passed to this constructor must not be modified after the constructor
/// completes, unless <see cref="LoadData"/> is called.</param>
protected NetpbmImage(NetpbmHeader <TPixelComponent> header, IEnumerable <IEnumerable <TPixelComponent> > pixelData)
{
Header = header;
Rows = pixelData;
_loaded = false;
}
/// <summary>
/// Creates and returns a new image of the same type as this image.
/// </summary>
/// <param name="header">The header of the new image.</param>
/// <param name="pixelData">The actual pixel data of the image. Drill down rows to pixels, with the pixels
/// represented as a contiguous sequence of component values for each pixel (in pixel-major order, e.g.
/// <c>RGBRGBRGB</c>.</param>
/// <returns>The new image.</returns>
public abstract NetpbmImage <TPixelComponent> NewImageOfSameType(NetpbmHeader <TPixelComponent> header,
IEnumerable <IEnumerable <TPixelComponent> > pixelData);
public NetpbmImage <TPixelFormat> ReadImageData <TPixelFormat>(Stream stream, NetpbmHeader <TPixelFormat> header,
IImageFactory <TPixelFormat> imageFactory)
{
IEnumerable <IEnumerable <TPixelFormat> > data;
switch (header.ImageType)
{
case ImageType.PlainPBM:
case ImageType.PBM:
data = ReadPBMData(stream, header, imageFactory);
break;
case ImageType.PlainPGM:
case ImageType.PGM:
case ImageType.PlainPPM:
case ImageType.PPM:
data = ReadPGMOrPPMData(stream, header, imageFactory);
break;
case ImageType.PAM:
case ImageType.BigPAM:
data = ReadPAMData(stream, header, imageFactory);
break;
default:
throw new ArgumentOutOfRangeException("header.ImageType", header.ImageType, "unknown image type");
}
return(imageFactory.MakeImage(header, data));
}
private IEnumerable <IEnumerable <TPixelFormat> > ReadPGMOrPPMData <TPixelFormat>(Stream stream,
NetpbmHeader <TPixelFormat> header, IImageFactory <TPixelFormat> imageFactory)
{
// read the bits!
if (header.ImageType == ImageType.PGM || header.ImageType == ImageType.PPM)
{
for (int r = 0; r < header.Height; ++r)
{
yield return(imageFactory.ReadRow(stream, header.Width, header.Components.Count, header.HighestComponentValue));
}
}
else if (header.ImageType == ImageType.PlainPGM || header.ImageType == ImageType.PlainPPM)
{
for (int r = 0; r < header.Height; ++r)
{
yield return(ReadPlainRow(stream, header.Width * header.Components.Count, r == header.Height - 1, imageFactory));
}
}
else
{
throw new ArgumentOutOfRangeException("header.ImageType", header.ImageType, "image type unsupported by this method");
}
}
public override NetpbmImage <ushort> NewImageOfSameType(NetpbmHeader <ushort> header,
IEnumerable <IEnumerable <ushort> > pixelData)
{
return(new NetpbmImage16(header, pixelData));
}
public NetpbmImage16(NetpbmHeader <ushort> header, IEnumerable <IEnumerable <ushort> > pixelData)
: base(header, pixelData)
{
}
/// <summary>
/// Writes the image header into the stream in the given format.
/// </summary>
/// <param name="header">The image header to write.</param>
/// <param name="stream">The stream into which to write the header.</param>
/// <param name="type">The type of Netpbm image according to which to encode the header.</param>
/// <typeparam name="TPixelComponent">The type of pixel component values.</typeparam>
public void WriteImageHeader <TPixelComponent>(NetpbmHeader <TPixelComponent> header, Stream stream, ImageType type)
{
// check if the format is supported
var supportedTypes = SupportedTypesForHeader(header);
if (!supportedTypes.Contains(type))
{
throw new ArgumentOutOfRangeException("type", type, "the image cannot be encoded into this type");
}
using (var writer = new NetpbmBinaryWriter(stream, new UTF8Encoding(false, true), leaveOpen: true))
{
int magicNumber = (int)type;
switch (type)
{
case ImageType.PBM:
case ImageType.PGM:
case ImageType.PPM:
case ImageType.PAM:
case ImageType.PlainPBM:
case ImageType.PlainPGM:
case ImageType.PlainPPM:
break;
case ImageType.BigPAM:
magicNumber = (int)ImageType.PAM;
break;
default:
throw new ArgumentOutOfRangeException("type", type, "unknown image type");
}
// output the magic
writer.WriteUnprefixed("P{0}\n", magicNumber);
if (type == ImageType.PAM || type == ImageType.BigPAM)
{
// output width line
writer.WriteUnprefixed("WIDTH {0}\n", header.Width);
// output height line
writer.WriteUnprefixed("HEIGHT {0}\n", header.Height);
// output number of components
writer.WriteUnprefixed("DEPTH {0}\n", header.Components.Count);
// maximum value
writer.WriteUnprefixed("MAXVAL {0}\n", header.HighestComponentValue);
// find the components we are working with
writer.WriteUnprefixed("TUPLTYPE {0}\n", GetPamTupleType(header));
writer.WriteUnprefixed("ENDHDR\n");
}
else
{
// output width and height
writer.WriteUnprefixed("{0} {1}\n", header.Width, header.Height);
// unless PBM (where the max value is always 1)
if (type != ImageType.PBM && type != ImageType.PlainPBM)
{
// output the max value
writer.WriteUnprefixed("{0}\n", header.HighestComponentValue);
}
// the header's final newline
writer.Write('\n');
}
}
}
public override NetpbmImage <byte> NewImageOfSameType(NetpbmHeader <byte> header,
IEnumerable <IEnumerable <byte> > pixelData)
{
return(new NetpbmImage8(header, pixelData));
}
private IEnumerable <IEnumerable <TPixelFormat> > ReadPAMData <TPixelFormat>(Stream stream, NetpbmHeader <TPixelFormat> header, IImageFactory <TPixelFormat> imageFactory)
{
// read the data!
for (int r = 0; r < header.Height; ++r)
{
yield return(imageFactory.ReadRow(stream, header.Width, header.Components.Count, header.HighestComponentValue));
}
}