private NetpbmImage <TPixelComponent> CorrectOrderBA <TPixelComponent>(NetpbmImage <TPixelComponent> image)
{
Contract.Requires(image.Header.Components.Count == 2);
Contract.Requires(image.Header.Components.Contains(Component.Black));
Contract.Requires(image.Header.Components.Contains(Component.Alpha));
return(CorrectOrder(new[] { Component.Black, Component.Alpha }, image));
}
private NetpbmImage <TPixelComponent> CorrectOrderRGB <TPixelComponent>(NetpbmImage <TPixelComponent> image)
{
Contract.Requires(image.Header.Components.Count == 3);
Contract.Requires(image.Header.Components.Contains(Component.Red));
Contract.Requires(image.Header.Components.Contains(Component.Green));
Contract.Requires(image.Header.Components.Contains(Component.Blue));
return(CorrectOrder(new[] { Component.Red, Component.Green, Component.Blue }, image));
}
private NetpbmImage <TPixelComponent> CorrectOrderCMYK <TPixelComponent>(NetpbmImage <TPixelComponent> image)
{
Contract.Requires(image.Header.Components.Count == 4);
Contract.Requires(image.Header.Components.Contains(Component.Cyan));
Contract.Requires(image.Header.Components.Contains(Component.Magenta));
Contract.Requires(image.Header.Components.Contains(Component.Yellow));
Contract.Requires(image.Header.Components.Contains(Component.Black));
return(CorrectOrder(new[] { Component.Cyan, Component.Magenta, Component.Yellow, Component.Black }, image));
}
/// <summary>
/// Encodes up to eight bitmap values into a byte. The values are stored from the most significant bit downward,
/// i.e. the leftmost value is stored in the most significant bit.
/// </summary>
/// <returns>The bitmap pixels encoded into a byte.</returns>
/// <param name="image">The image being encoded.</param>
/// <param name="pixels">The bitmap pixels to encode into a byte.</param>
/// <typeparam name="TPixelComponent">The type of the pixel component.</typeparam>
private byte EncodeBitmapValuesIntoByte <TPixelComponent>(NetpbmImage <TPixelComponent> image, IList <TPixelComponent> pixels)
{
Contract.Assert(pixels.Count > 0 && pixels.Count < 9);
byte theByte = 0;
// earliest value = most significant bit
for (int i = 0; i < 8; ++i)
{
if (!image.IsComponentValueZero(pixels[i]))
{
theByte |= (byte)(1 << (7 - i));
}
}
return(theByte);
}
/// <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 IEnumerable <TPixelComponent> InvertRowComponent <TPixelComponent>(IEnumerable <TPixelComponent> row,
NetpbmImage <TPixelComponent> image, HashSet <int> componentIndices, Component from, Component to)
{
var componentCount = image.Header.Components.Count;
var oldRowPixels = row.Batch(componentCount);
foreach (var oldPixel in oldRowPixels)
{
var oldPixelArray = oldPixel.ToArray();
for (int c = 0; c < componentCount; ++c)
{
if (componentIndices.Contains(c))
{
yield return(image.InvertPixelValue(oldPixelArray[c]));
}
else
{
yield return(oldPixelArray[c]);
}
}
}
}
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));
}
/// <summary>
/// Writes a row of image data into the stream in the given format.
/// </summary>
/// <param name="image">The image whose row is being encoded (for formatting purposes).</param>
/// <param name="row">The row to write.</param>
/// <param name="stream">The stream to write into.</param>
/// <param name="type">The format according to which to write.</param>
public void WriteImageRow <TPixelComponent>(NetpbmImage <TPixelComponent> image, IEnumerable <TPixelComponent> row, Stream stream, ImageType type)
{
using (var writer = new NetpbmBinaryWriter(stream, new UTF8Encoding(false, true), leaveOpen: true))
{
bool isPlain;
switch (type)
{
case ImageType.PBM:
case ImageType.PGM:
case ImageType.PPM:
case ImageType.PAM:
case ImageType.BigPAM:
isPlain = false;
break;
case ImageType.PlainPBM:
case ImageType.PlainPGM:
case ImageType.PlainPPM:
isPlain = true;
break;
default:
throw new ArgumentOutOfRangeException("type", type, "unknown image type");
}
if (isPlain)
{
// output row as decimal numbers
// add a newline after the row to make things nicer
foreach (var value in row)
{
writer.WriteUnprefixed(value.ToString());
writer.Write(' ');
}
writer.Write('\n');
}
else if (type == ImageType.PBM)
{
// special case: bit-packed format!
var values = new List <TPixelComponent>(8);
foreach (var value in row)
{
values.Add(value);
if (values.Count == 8)
{
byte theByte = EncodeBitmapValuesIntoByte(image, values);
writer.Write(theByte);
values.Clear();
}
}
if (values.Count != 0)
{
byte theByte = EncodeBitmapValuesIntoByte(image, values);
writer.Write(theByte);
}
}
else
{
// just the big endian bytes
foreach (var value in row)
{
writer.Write(image.ComponentToBigEndianBytes(value).ToArray());
}
}
}
}
/// <summary>
/// Writes the image data into the stream in the given format.
/// </summary>
/// <param name="image">The image whose data to write.</param>
/// <param name="stream">The stream into which to write the data.</param>
/// <param name="type">The type of Netpbm image according to which to encode the data.</param>
/// <typeparam name="TPixelComponent">The type of pixel component values.</typeparam>
public void WriteImageData <TPixelComponent>(NetpbmImage <TPixelComponent> image, Stream stream, ImageType type)
{
// check if the format is supported
var supportedTypes = SupportedTypesForImage(image);
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))
{
bool isPlain;
switch (type)
{
case ImageType.PBM:
case ImageType.PGM:
case ImageType.PPM:
case ImageType.PAM:
case ImageType.BigPAM:
isPlain = false;
break;
case ImageType.PlainPBM:
case ImageType.PlainPGM:
case ImageType.PlainPPM:
isPlain = true;
break;
default:
throw new ArgumentOutOfRangeException("type", type, "unknown image type");
}
if (isPlain)
{
// output in row-major order as decimal numbers
// add newlines after each row to make things nicer
foreach (var row in image.NativeRows)
{
foreach (var value in row)
{
writer.WriteUnprefixed(value.ToString());
writer.Write(' ');
}
writer.Write('\n');
}
}
else if (type == ImageType.PBM)
{
// special case: bit-packed format!
var values = new List <TPixelComponent>(8);
foreach (var row in image.NativeRows)
{
foreach (var value in row)
{
values.Add(value);
if (values.Count == 8)
{
byte theByte = EncodeBitmapValuesIntoByte(image, values);
writer.Write(theByte);
values.Clear();
}
}
if (values.Count != 0)
{
byte theByte = EncodeBitmapValuesIntoByte(image, values);
writer.Write(theByte);
}
}
}
else
{
// just the big endian bytes
foreach (var row in image.NativeRows)
{
foreach (var value in row)
{
writer.Write(image.ComponentToBigEndianBytes(value).ToArray());
}
}
}
}
}
/// <summary>
/// Returns the set of Netpbm image types into which the given image can be encoded.
/// </summary>
/// <returns>The Netpbm image types the given image can be encoded into.</returns>
/// <param name="img">The image to be encoded.</param>
/// <typeparam name="TPixelComponent">The pixel component type of the image.</typeparam>
public ISet <ImageType> SupportedTypesForImage <TPixelComponent>(NetpbmImage <TPixelComponent> img)
{
return(SupportedTypesForHeader(img.Header));
}
/// <summary>
/// Writes the image into the stream in the given format.
/// </summary>
/// <param name="image">The image to write.</param>
/// <param name="stream">The stream into which to write the image.</param>
/// <param name="type">The type of Netpbm image into which to encode the image.</param>
/// <typeparam name="TPixelComponent">The type of pixel component values.</typeparam>
public void WriteImage <TPixelComponent>(NetpbmImage <TPixelComponent> image, Stream stream, ImageType type)
{
WriteImageHeader(image.Header, stream, type);
WriteImageData(image, stream, type);
}
/// <summary>
/// Returns a new image which is the given image converted to a canonical form.
/// </summary>
/// <typeparam name="TPixelComponent">The pixel component type being used.</typeparam>
/// <param name="image">The image whose canonical form to return.</param>
/// <param name="grayscaleConversion">Whether to perform grayscale conversion and what kind.</param>
/// <returns>The new image, in canonical form.</returns>
public NetpbmImage <TPixelComponent> Canonicalize <TPixelComponent>(NetpbmImage <TPixelComponent> image,
GrayscaleConversion grayscaleConversion = GrayscaleConversion.None)
{
var ret = image.NewImageOfSameType(image.Header, image.NativeRows);
// perform grayscale conversion if necessary
if (grayscaleConversion == GrayscaleConversion.BlackToWhite && image.Header.Components.Contains(Component.Black))
{
ret = InvertComponent(ret, Component.Black, Component.White);
}
else if (grayscaleConversion == GrayscaleConversion.WhiteToBlack && image.Header.Components.Contains(Component.White))
{
ret = InvertComponent(ret, Component.White, Component.Black);
}
// canonicalize order
if (
ret.Header.Components.Count == 3 &&
ret.Header.Components.Contains(Component.Red) &&
ret.Header.Components.Contains(Component.Green) &&
ret.Header.Components.Contains(Component.Blue)
)
{
ret = CorrectOrderRGB(ret);
}
else if (
ret.Header.Components.Count == 4 &&
ret.Header.Components.Contains(Component.Red) &&
ret.Header.Components.Contains(Component.Green) &&
ret.Header.Components.Contains(Component.Blue) &&
ret.Header.Components.Contains(Component.Alpha)
)
{
ret = CorrectOrderRGBA(ret);
}
else if (
ret.Header.Components.Count == 2 &&
ret.Header.Components.Contains(Component.White) &&
ret.Header.Components.Contains(Component.Alpha)
)
{
ret = CorrectOrderWA(ret);
}
else if (
ret.Header.Components.Count == 2 &&
ret.Header.Components.Contains(Component.Black) &&
ret.Header.Components.Contains(Component.Alpha)
)
{
ret = CorrectOrderBA(ret);
}
else if (
ret.Header.Components.Count == 4 &&
ret.Header.Components.Contains(Component.Cyan) &&
ret.Header.Components.Contains(Component.Magenta) &&
ret.Header.Components.Contains(Component.Yellow) &&
ret.Header.Components.Contains(Component.Black)
)
{
ret = CorrectOrderCMYK(ret);
}
else if (
ret.Header.Components.Count == 5 &&
ret.Header.Components.Contains(Component.Cyan) &&
ret.Header.Components.Contains(Component.Magenta) &&
ret.Header.Components.Contains(Component.Yellow) &&
ret.Header.Components.Contains(Component.Black) &&
ret.Header.Components.Contains(Component.Alpha)
)
{
ret = CorrectOrderCMYKA(ret);
}
return(ret);
}
