code: def write_ImageMapLine(tlx, tly, brx, bry, w, h, dpi, chr, segment_start, segment_end):
      
      tlx, brx = [canvas2px(x, w, dpi) for x in (tlx, brx)]
      tly, bry = [canvas2px(y, h, dpi) for y in (tly, bry)]
      chr, bac_list = chr.split(':')
      return '<area shape="rect" coords="' + \
             ",".join(str(x) for x in (tlx, tly, brx, bry)) \
             + '" href="#' + chr + '"' \
             + ' title="' + chr + ':' + str(segment_start) + '..' + str(segment_end) + '"' \
             + ' />'
docs: Write out an image map area line with the coordinates passed to this
      function
      <area shape="rect" coords="tlx,tly,brx,bry" href="#chr7" title="chr7:100001..500001">