/// <summary>
/// Retrieves the specifed dictionary object as an object encoded with CCITTFaxDecode filter (TIFF).
/// </summary>
/// <param name="dictionary">The dictionary to extract the object from.</param>
/// <returns>The image retrieve from the dictionary. If not found or an invalid image, then null is returned.</returns>
private static Image ImageFromCCITTFaxDecode(PdfDictionary dictionary)
{
Image image = null;
PdfDictionaryImageMetaData imageData = new PdfDictionaryImageMetaData(dictionary);
PixelFormat format = GetPixelFormat(imageData.ColorSpace, imageData.BitsPerPixel, true);
Bitmap bitmap = new Bitmap(imageData.Width, imageData.Height, format);
// Determine if BLACK=1, create proper indexed color palette.
CCITTFaxDecodeParameters ccittFaxDecodeParameters = new CCITTFaxDecodeParameters(dictionary.Elements["/DecodeParms"].Get() as PdfDictionary);
if (ccittFaxDecodeParameters.BlackIs1) bitmap.Palette = PdfIndexedColorSpace.CreateColorPalette(Color.Black, Color.White);
else bitmap.Palette = PdfIndexedColorSpace.CreateColorPalette(Color.White, Color.Black);
using (MemoryStream stream = new MemoryStream(GetTiffImageBufferFromCCITTFaxDecode(imageData, dictionary.Stream.Value))) {
using (Tiff tiff = Tiff.ClientOpen("<INLINE>", "r", stream, new TiffStream())) {
if (tiff == null) return (null);
int stride = tiff.ScanlineSize();
byte[] buffer = new byte[stride];
for (int i = 0; i < imageData.Height; i++) {
tiff.ReadScanline(buffer, i);
Rectangle imgRect = new Rectangle(0, i, imageData.Width, 1);
BitmapData imgData = bitmap.LockBits(imgRect, ImageLockMode.WriteOnly, PixelFormat.Format1bppIndexed);
Marshal.Copy(buffer, 0, imgData.Scan0, buffer.Length);
bitmap.UnlockBits(imgData);
}
}
}
return (bitmap);
}
/// <summary>
/// Retrieves the specifed dictionary object as an object encoded with CCITTFaxDecode filter (TIFF).
/// </summary>
/// <param name="dictionary">The dictionary to extract the object from.</param>
/// <returns>The image retrieve from the dictionary. If not found or an invalid image, then null is returned.</returns>
private static Image ImageFromCCITTFaxDecode(PdfDictionary dictionary)
{
PdfDictionaryImageMetaData imageData = new PdfDictionaryImageMetaData(dictionary);
PixelFormat format = GetPixelFormat(imageData.ColorSpace, imageData.BitsPerPixel, true);
Bitmap bitmap = new Bitmap(imageData.Width, imageData.Height, format);
// Determine if BLACK=1, create proper indexed color palette.
PdfDictionary decodeParams;
var decodeParamsObject = dictionary.Elements["/DecodeParms"].Get();
if (decodeParamsObject is PdfArray)
{
decodeParams = (decodeParamsObject as PdfArray).First() as PdfDictionary;
}
else if (decodeParamsObject is PdfDictionary)
{
decodeParams = decodeParamsObject as PdfDictionary;
}
else
{
throw new NotSupportedException("Unknown format of CCITTFaxDecode params.");
}
CCITTFaxDecodeParameters ccittFaxDecodeParameters = new CCITTFaxDecodeParameters(decodeParams);
if (ccittFaxDecodeParameters.BlackIs1)
{
bitmap.Palette = PdfIndexedColorSpace.CreateColorPalette(Color.Black, Color.White);
}
else
{
bitmap.Palette = PdfIndexedColorSpace.CreateColorPalette(Color.White, Color.Black);
}
if (ccittFaxDecodeParameters.K == 0 || ccittFaxDecodeParameters.K > 0)
{
imageData.Compression = Compression.CCITTFAX3;
}
else if (ccittFaxDecodeParameters.K < 0)
{
imageData.Compression = Compression.CCITTFAX4;
}
using (MemoryStream stream = new MemoryStream(GetTiffImageBufferFromCCITTFaxDecode(imageData, dictionary.Stream.Value))) {
using (Tiff tiff = Tiff.ClientOpen("<INLINE>", "r", stream, new TiffStream())) {
if (tiff == null)
{
return(null);
}
int stride = tiff.ScanlineSize();
byte[] buffer = new byte[stride];
for (int i = 0; i < imageData.Height; i++)
{
tiff.ReadScanline(buffer, i);
Rectangle imgRect = new Rectangle(0, i, imageData.Width, 1);
BitmapData imgData = bitmap.LockBits(imgRect, ImageLockMode.WriteOnly, PixelFormat.Format1bppIndexed);
Marshal.Copy(buffer, 0, imgData.Scan0, buffer.Length);
bitmap.UnlockBits(imgData);
}
}
}
return(bitmap);
}
