如何從Android的TTF文件中檢索字體名稱

Question

有一些Java（但使用java.awt）和C＃的示例;似乎從TTF文件獲取名稱應該不會有任何痛苦。但不幸的是，它不是。請幫忙。

Answer 1

請使用類：從http://www.ulduzsoft.com/2012/01/enumerating-the-fonts-on-android-platform/

注

class TTFAnalyzer 
{ 
    // This function parses the TTF file and returns the font name specified in the file 
    public String getTtfFontName(String fontFilename) 
    { 
     try 
     { 
      // Parses the TTF file format. 
      // See http://developer.apple.com/fonts/ttrefman/rm06/Chap6.html 
      m_file = new RandomAccessFile(fontFilename, "r"); 

      // Read the version first 
      int version = readDword(); 

      // The version must be either 'true' (0x74727565) or 0x00010000 
      if (version != 0x74727565 && version != 0x00010000) 
       return null; 

      // The TTF file consist of several sections called "tables", and we need to know how many of them are there. 
      int numTables = readWord(); 

      // Skip the rest in the header 
      readWord(); // skip searchRange 
      readWord(); // skip entrySelector 
      readWord(); // skip rangeShift 

      // Now we can read the tables 
      for (int i = 0; i < numTables; i++) 
      { 
       // Read the table entry 
       int tag = readDword(); 
       readDword(); // skip checksum 
       int offset = readDword(); 
       int length = readDword(); 

       // Now here' the trick. 'name' field actually contains the textual string name. 
       // So the 'name' string in characters equals to 0x6E616D65 
       if (tag == 0x6E616D65) 
       { 
        // Here's the name section. Read it completely into the allocated buffer 
        byte[] table = new byte[ length ]; 

        m_file.seek(offset); 
        read(table); 

        // This is also a table. See http://developer.apple.com/fonts/ttrefman/rm06/Chap6name.html 
        // According to Table 36, the total number of table records is stored in the second word, at the offset 2. 
        // Getting the count and string offset - remembering it's big endian. 
        int count = getWord(table, 2); 
        int string_offset = getWord(table, 4); 

        // Record starts from offset 6 
        for (int record = 0; record < count; record++) 
        { 
         // Table 37 tells us that each record is 6 words -> 12 bytes, and that the nameID is 4th word so its offset is 6. 
         // We also need to account for the first 6 bytes of the header above (Table 36), so... 
         int nameid_offset = record * 12 + 6; 
         int platformID = getWord(table, nameid_offset); 
         int nameid_value = getWord(table, nameid_offset + 6); 

         // Table 42 lists the valid name Identifiers. We're interested in 4 but not in Unicode encoding (for simplicity). 
         // The encoding is stored as PlatformID and we're interested in Mac encoding 
         if (nameid_value == 4 && platformID == 1) 
         { 
          // We need the string offset and length, which are the word 6 and 5 respectively 
          int name_length = getWord(table, nameid_offset + 8); 
          int name_offset = getWord(table, nameid_offset + 10); 

          // The real name string offset is calculated by adding the string_offset 
          name_offset = name_offset + string_offset; 

          // Make sure it is inside the array 
          if (name_offset >= 0 && name_offset + name_length < table.length) 
           return new String(table, name_offset, name_length); 
         } 
        } 
       } 
      } 

      return null; 
     } 
     catch (FileNotFoundException e) 
     { 
      // Permissions? 
      return null; 
     } 
     catch (IOException e) 
     { 
      // Most likely a corrupted font file 
      return null; 
     } 
    } 

    // Font file; must be seekable 
    private RandomAccessFile m_file = null; 

    // Helper I/O functions 
    private int readByte() throws IOException 
    { 
     return m_file.read() & 0xFF; 
    } 

    private int readWord() throws IOException 
    { 
     int b1 = readByte(); 
     int b2 = readByte(); 

     return b1 << 8 | b2; 
    } 

    private int readDword() throws IOException 
    { 
     int b1 = readByte(); 
     int b2 = readByte(); 
     int b3 = readByte(); 
     int b4 = readByte(); 

     return b1 << 24 | b2 << 16 | b3 << 8 | b4; 
    } 

    private void read(byte [] array) throws IOException 
    { 
     if (m_file.read(array) != array.length) 
      throw new IOException(); 
    } 

    // Helper 
    private int getWord(byte [] array, int offset) 
    { 
     int b1 = array[ offset ] & 0xFF; 
     int b2 = array[ offset + 1 ] & 0xFF; 

     return b1 << 8 | b2; 
    } 
} 

代碼，它並不適用於所有的ttf文件。