Exemplo n.º 1
0
        protected override void ReadContentFrom(BinaryReader reader)
        {
            gposTableStartAt = reader.BaseStream.Position;
            //-------------------------------------------
            // GPOS Header
            //The GPOS table begins with a header that contains a version number for the table. Two versions are defined. 
            //Version 1.0 contains offsets to three tables: ScriptList, FeatureList, and LookupList. 
            //Version 1.1 also includes an offset to a FeatureVariations table.
            //For descriptions of these tables, see the chapter, OpenType Layout Common Table Formats .
            //Example 1 at the end of this chapter shows a GPOS Header table definition.
            //GPOS Header, Version 1.0
            //Value 	Type 	Description
            //USHORT 	MajorVersion 	Major version of the GPOS table, = 1
            //USHORT 	MinorVersion 	Minor version of the GPOS table, = 0
            //Offset 	ScriptList 	Offset to ScriptList table, from beginning of GPOS table
            //Offset 	FeatureList 	Offset to FeatureList table, from beginning of GPOS table
            //Offset 	LookupList 	Offset to LookupList table, from beginning of GPOS table

            //GPOS Header, Version 1.1
            //Value 	Type 	Description
            //USHORT 	MajorVersion 	Major version of the GPOS table, = 1
            //USHORT 	MinorVersion 	Minor version of the GPOS table, = 1
            //Offset 	ScriptList 	Offset to ScriptList table, from beginning of GPOS table
            //Offset 	FeatureList 	Offset to FeatureList table, from beginning of GPOS table
            //Offset 	LookupList 	Offset to LookupList table, from beginning of GPOS table
            //ULONG 	FeatureVariations 	Offset to FeatureVariations table, from beginning of GPOS table (may be NULL) 

            this.MajorVersion = reader.ReadUInt16();
            this.MinorVersion = reader.ReadUInt16();

            ushort scriptListOffset = reader.ReadUInt16();//from beginning of GSUB table
            ushort featureListOffset = reader.ReadUInt16();//from beginning of GSUB table
            ushort lookupListOffset = reader.ReadUInt16();//from beginning of GSUB table
            uint featureVariations = (MinorVersion == 1) ? reader.ReadUInt32() : 0;//from beginning of GSUB table

            //-----------------------
            //1. scriptlist             
            scriptList = ScriptList.CreateFrom(reader, gposTableStartAt + scriptListOffset);
            //-----------------------
            //2. feature list             
            featureList = FeatureList.CreateFrom(reader, gposTableStartAt + featureListOffset);
            //-----------------------
            //3. lookup list

            ReadLookupListTable(reader, gposTableStartAt + lookupListOffset);
            //-----------------------
            //4. feature variations
            if (featureVariations > 0)
            {
                reader.BaseStream.Seek(this.Header.Offset + featureVariations, SeekOrigin.Begin);
                ReadFeaureVariations(reader);
            }

        }
Exemplo n.º 2
0
        public static ScriptList CreateFrom(BinaryReader reader, long beginAt)
        {

      

            reader.BaseStream.Seek(beginAt, SeekOrigin.Begin);

            //https://www.microsoft.com/typography/otspec/chapter2.htm
            //ScriptList table
            //Type 	Name 	Description
            //USHORT 	ScriptCount 	Number of ScriptRecords
            //struct 	ScriptRecord
            //[ScriptCount] 	Array of ScriptRecords
            //-listed alphabetically by ScriptTag
            //ScriptRecord
            //Type 	Name 	Description
            //Tag 	ScriptTag 	4-byte ScriptTag identifier
            //Offset 	Script 	Offset to Script table-from beginning of ScriptList

            ScriptList scriptList = new ScriptList();
            ushort scriptCount = reader.ReadUInt16();
            ScriptRecord[] scRecords = scriptList.scriptRecords = new ScriptRecord[scriptCount];

            for (int i = 0; i < scriptCount; ++i)
            {
                //read script record
                scRecords[i] = new ScriptRecord(
                    reader.ReadUInt32(), //tag
                    reader.ReadInt16());//offset                 
            }
            //-------------
            ScriptTable[] scriptTables = scriptList.scriptTables = new ScriptTable[scriptCount];
            //then read each
            for (int i = 0; i < scriptCount; ++i)
            {
                ScriptRecord scriptRecord = scRecords[i];
                //move to
                ScriptTable scriptTable = ScriptTable.CreateFrom(reader, beginAt + scriptRecord.offset);
                scriptTable.scriptTag = scriptRecord.scriptTag;
                scriptTables[i] = scriptTable;
            }
            return scriptList;
        }