The StringFormat module allows for character-by-character formatting of
strings. It imitates the PIDDLE string drawing and string metrics
interface. The string formatting is done with specialized XML syntax
within the string. Therefore, the interface for the StringFormat module
consists of wrapper functions for the PIDDLE string interface and
various XML tags and characters.

StringFormat functions 

       drawString(canvas, s, x, y, [font], [color], [angle]) 
       stringWidth(canvas, s, [font]) 
       fontHeight(canvas, [font]) 
       fontAscent(canvas, [font]) 
       fontDescent(canvas, [font]) 

StringFormat XML tags 

       <b> </b> - bold 
       <i> </i> - italics 
       <u> </u> - underline 
       <super> </super> - superscript 
       <sub> </sub> - subscript 

StringFormat XML characters 

       Greek Letter Symbols as specified in MathML 

