// Parses the format 12 cmap table
// Refer to https://www.microsoft.com/typography/otspec/cmap.htm to learn about how this format is organized
private void ParseFormat12(byte[] source, ref uint offset, List <GlyphModel> allChars)
{
CmapFormat12Header header = ParseCmapFormat12Header(source, ref offset);
for (int i = 0; i < header.nGroups; i++)
{
uint startCharCode = ReadDataAndIncreaseIndex <uint>(source, ref offset, sizeof(uint));
uint endCharCode = ReadDataAndIncreaseIndex <uint>(source, ref offset, sizeof(uint));
uint startGlyphID = ReadDataAndIncreaseIndex <uint>(source, ref offset, sizeof(uint));
for (uint j = startCharCode; j <= endCharCode; j++)
{
GlyphModel newChar = new GlyphModel();
newChar.CodePoint = j;
newChar.GlyphID = (ushort)startGlyphID;
startGlyphID++;
byte[] byteJ = BitConverter.GetBytes(j);
newChar.Definition = Encoding.UTF32.GetString(byteJ);
if (!allChars.Contains(newChar))
{
allChars.Add(newChar);
}
}
}
}
// Reads through the header information of the cmap format 12 table
private CmapFormat12Header ParseCmapFormat12Header(byte[] source, ref uint offset)
{
CmapFormat12Header header = new CmapFormat12Header();
header.format = ReadDataAndIncreaseIndex <ushort>(source, ref offset, sizeof(ushort));
Debug.Assert(header.format == 12);
header.reserved = ReadDataAndIncreaseIndex <ushort>(source, ref offset, sizeof(ushort));
header.length = ReadDataAndIncreaseIndex <uint>(source, ref offset, sizeof(uint));
header.language = ReadDataAndIncreaseIndex <uint>(source, ref offset, sizeof(uint));
header.nGroups = ReadDataAndIncreaseIndex <uint>(source, ref offset, sizeof(uint));
return(header);
}