public PreviewFontInfo ReadPreview(BinaryReader reader)
{
//read preview only
//WOFF File
//WOFFHeader File header with basic font type and version, along with offsets to metadata and private data blocks.
//TableDirectory Directory of font tables, indicating the original size, compressed size and location of each table within the WOFF file.
//FontTables The font data tables from the input sfnt font, compressed to reduce bandwidth requirements.
//ExtendedMetadata An optional block of extended metadata, represented in XML format and compressed for storage in the WOFF file.
//PrivateData An optional block of private data for the font designer, foundry, or vendor to use.
PreviewFontInfo fontPreviewInfo = null;
_header = ReadWOFFHeader(reader);
if (_header == null)
{
#if DEBUG
System.Diagnostics.Debug.WriteLine("can't read ");
#endif
return(null); //notify user too
}
//
WoffTableDirectory[] woffTableDirs = ReadTableDirectories(reader);
if (woffTableDirs == null)
{
return(null);
}
//try read each compressed table
if (DecompressHandler == null)
{
if (WoffDefaultZlibDecompressFunc.DecompressHandler != null)
{
DecompressHandler = WoffDefaultZlibDecompressFunc.DecompressHandler;
}
else
{
#if DEBUG
System.Diagnostics.Debug.WriteLine("no Zlib DecompressHandler ");
#endif
return(null); //notify user too
}
}
TableEntryCollection tableEntryCollection = CreateTableEntryCollection(woffTableDirs);
//for font preview, we may not need to extract
using (MemoryStream decompressStream = new MemoryStream())
{
if (Extract(reader, woffTableDirs, decompressStream))
{
using (ByteOrderSwappingBinaryReader reader2 = new ByteOrderSwappingBinaryReader(decompressStream))
{
decompressStream.Position = 0;
OpenFontReader openFontReader = new OpenFontReader();
PreviewFontInfo previewFontInfo = openFontReader.ReadPreviewFontInfo(tableEntryCollection, reader2);
if (previewFontInfo != null)
{
//add webfont info to this preview font
previewFontInfo.IsWebFont = true;
}
return(previewFontInfo);
}
}
}
return(fontPreviewInfo);
}