docstr: Calculate the bounding boxes of all glyphs in the `glyf` table.
  This is usually not called explicitly by client code.
code: def calcGlyphBounds(self):
      """Calculate the bounding boxes of all glyphs in the `glyf` table.
      This is usually not called explicitly by client code.
      """
      glyphTable = self.font["glyf"]
      for glyph in glyphTable.glyphs.values():
          glyph.recalcBounds(glyphTable)
  
imports: from .ttLib import TTFont, newTable
  from .ttLib.tables._c_m_a_p import cmap_classes
  from .ttLib.tables._g_l_y_f import flagCubic
  from .ttLib.tables.O_S_2f_2 import Panose
  from .misc.timeTools import timestampNow
  import struct
  from collections import OrderedDict
label_desc: Use image node_id 18 for calling the FontBuilder obj's underlying member method code with example usage: obj.calcGlyphBounds() without return types