public void CanDecompressPngEncodedFlateStream()
{
// The Xref stream is encoded with parameters.
// For flate as per http://www.adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/pdf_reference_1-7.pdf
var bytes = File.ReadAllBytes(GetNthFilename());
var streamPosition = GetOffset(bytes, "stream");
var endStreamPosition = GetOffset(bytes, "endstream", streamPosition.end);
var streamBytes = BytesBetween(streamPosition.end + 1, endStreamPosition.start - 1, bytes);
var paramsDict = new DictionaryToken(new Dictionary <NameToken, IToken>
{
{ NameToken.Predictor, new NumericToken(12) },
{ NameToken.Columns, new NumericToken(4) }
});
var dictionary = new DictionaryToken(new Dictionary <NameToken, IToken>
{
{ NameToken.Filter, NameToken.FlateDecode },
{ NameToken.DecodeParms, paramsDict }
});
var filter = new FlateFilter(new DecodeParameterResolver(null), new PngPredictor(), null);
var filtered = filter.Decode(streamBytes, dictionary, 0);
var expected =
"1 0 15 0 1 0 216 0 1 2 160 0 1 2 210 0 1 3 84 0 1 4 46 0 1 7 165 0 1 70 229 0 1 72 84 0 1 96 235 0 1 98 18 0 2 0 12 0 2 0 12 1 2 0 12 2 2 0 12 3 2 0 12 4 2 0 12 5 2 0 12 6 2 0 12 7 2 0 12 8"
.Split(' ')
.Select(byte.Parse).ToArray();
Assert.Equal(filtered, expected);
}
public void CanDecompressPngEncodedFlateStream()
{
// The Xref stream is encoded with parameters.
// For flate as per http://www.adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/pdf_reference_1-7.pdf
var bytes = File.ReadAllBytes(GetNthFilename());
var streamPosition = GetOffset(bytes, "stream");
var endStreamPosition = GetOffset(bytes, "endstream", streamPosition.end);
var streamBytes = BytesBetween(streamPosition.end + 1, endStreamPosition.start - 1, bytes);
var paramsDict = new PdfDictionary();
paramsDict.Set(CosName.PREDICTOR, new CosFloat("12"));
paramsDict.Set(CosName.COLUMNS, new CosFloat("4"));
var dict = new PdfDictionary();
dict.Set(CosName.FILTER, CosName.FLATE_DECODE);
dict.Set(CosName.DECODE_PARMS, paramsDict);
var filter = new FlateFilter(new DecodeParameterResolver(null), new PngPredictor(), null);
var filtered = filter.Decode(streamBytes, dict, 0);
var expected =
"1 0 15 0 1 0 216 0 1 2 160 0 1 2 210 0 1 3 84 0 1 4 46 0 1 7 165 0 1 70 229 0 1 72 84 0 1 96 235 0 1 98 18 0 2 0 12 0 2 0 12 1 2 0 12 2 2 0 12 3 2 0 12 4 2 0 12 5 2 0 12 6 2 0 12 7 2 0 12 8"
.Split(' ')
.Select(byte.Parse).ToArray();
Assert.Equal(filtered, expected);
}
private byte[] CompressBytes()
{
using (var memoryStream = new MemoryStream(fontFileBytes.ToArray()))
{
var parameters = new DictionaryToken(new Dictionary <NameToken, IToken>());
var flater = new FlateFilter(new DecodeParameterResolver(new NoOpLog()), new PngPredictor(), new NoOpLog());
var bytes = flater.Encode(memoryStream, parameters, 0);
return(bytes);
}
}
public static byte[] CompressBytes(byte[] bytes)
{
using (var memoryStream = new MemoryStream(bytes))
{
var parameters = new DictionaryToken(new Dictionary <NameToken, IToken>());
var flater = new FlateFilter();
var result = flater.Encode(memoryStream, parameters, 0);
return(result);
}
}
