x-size X Size of the Glyph

The pixels per row in the bit-mapped glyph that has been declared with a <glyph-data> element as part of a <private-char> element.
OPTIONAL on element: <glyph-data>
Value Meaning
A number An integer number of pixels, for example, “45”, that is the number of pixels in each row of the bitmap of the <glyph-data> element.
Restriction @x-size is an optional attribute; there is no default.
Tagged Sample

Pixel count for each row of BentArrow glyph bitmap

...
<p>... The map symbol indicating these conditions will be a
 <private-char name="BentArrow" 
   description="Symbol - right arrow bending up over right arrow bending down">
  <glyph-data id="pc5001" format="PBM" resolution="300" x-size="15" y-size="28">
   000000000001000
   000000000011100
   000000000111110
   000000001111111
   000000000001000
   000000000001000
   000000000001000
   000000000001000
   000000000001000
   000000000001000
   000000000001000
   000000000001000
   111111111110000
   000000000000000
   000000000000000
   111111111110000
   000000000001000
   000000000001000
   000000000001000
   000000000001000
   000000000001000
   000000000001000
   000000000001000
   000000000001000
   000000001111111
   000000000111110
   000000000011100
   000000000001000</glyph-data>
 </private-char>. The NOAA 1993 standard definition of
 <private-char name="BentArrow" 
   description="Symbol - right arrow bending up over right arrow bending down">
  <glyph-ref glyph-data="pc5001"/>
 </private-char> will apply.</p>
...