# Source code for fontTools.ttLib.tables.sbixGlyph

    from fontTools.misc import sstruct
    from fontTools.misc.textTools import readHex, safeEval
    import struct

    sbixGlyphHeaderFormat = """
    	>
    	originOffsetX: h	# The x-value of the point in the glyph relative to its
    						# lower-left corner which corresponds to the origin of
    						# the glyph on the screen, that is the point on the
    						# baseline at the left edge of the glyph.
    	originOffsetY: h	# The y-value of the point in the glyph relative to its
    						# lower-left corner which corresponds to the origin of
    						# the glyph on the screen, that is the point on the
    						# baseline at the left edge of the glyph.
    	graphicType:  4s	# e.g. "png "
    """

    sbixGlyphHeaderFormatSize = sstruct.calcsize(sbixGlyphHeaderFormat)

    class Glyph(object):
    	def __init__(self, glyphName=None, referenceGlyphName=None, originOffsetX=0, originOffsetY=0, graphicType=None, imageData=None, rawdata=None, gid=0):
    		self.gid = gid
    		self.glyphName = glyphName
    		self.referenceGlyphName = referenceGlyphName
    		self.originOffsetX = originOffsetX
    		self.originOffsetY = originOffsetY
    		self.rawdata = rawdata
    		self.graphicType = graphicType
    		self.imageData = imageData

    		# fix self.graphicType if it is null terminated or too short
    		if self.graphicType is not None:
    			if self.graphicType[-1] == "\0":
    				self.graphicType = self.graphicType[:-1]
    			if len(self.graphicType) > 4:
    				from fontTools import ttLib
    				raise ttLib.TTLibError("Glyph.graphicType must not be longer than 4 characters.")
    			elif len(self.graphicType) < 4:
    				# pad with spaces
    				self.graphicType += "    "[:(4 - len(self.graphicType))]

    	def decompile(self, ttFont):
    		self.glyphName = ttFont.getGlyphName(self.gid)
    		if self.rawdata is None:
    			from fontTools import ttLib
    			raise ttLib.TTLibError("No table data to decompile")
    		if len(self.rawdata) > 0:
    			if len(self.rawdata) < sbixGlyphHeaderFormatSize:
    				from fontTools import ttLib
    				#print "Glyph %i header too short: Expected %x, got %x." % (self.gid, sbixGlyphHeaderFormatSize, len(self.rawdata))
    				raise ttLib.TTLibError("Glyph header too short.")

    			sstruct.unpack(sbixGlyphHeaderFormat, self.rawdata[:sbixGlyphHeaderFormatSize], self)

    			if self.graphicType == "dupe":
    				# this glyph is a reference to another glyph's image data
    				gid, = struct.unpack(">H", self.rawdata[sbixGlyphHeaderFormatSize:])
    				self.referenceGlyphName = ttFont.getGlyphName(gid)
    			else:
    				self.imageData = self.rawdata[sbixGlyphHeaderFormatSize:]
    				self.referenceGlyphName = None
    		# clean up
    		del self.rawdata
    		del self.gid

    	def compile(self, ttFont):
    		if self.glyphName is None:
    			from fontTools import ttLib
    			raise ttLib.TTLibError("Can't compile Glyph without glyph name")
    			# TODO: if ttFont has no maxp, cmap etc., ignore glyph names and compile by index?
    			# (needed if you just want to compile the sbix table on its own)
    		self.gid = struct.pack(">H", ttFont.getGlyphID(self.glyphName))
    		if self.graphicType is None:
    			self.rawdata = b""
    		else:
    			self.rawdata = sstruct.pack(sbixGlyphHeaderFormat, self) + self.imageData

    	def toXML(self, xmlWriter, ttFont):
    		if self.graphicType == None:
    			# TODO: ignore empty glyphs?
    			# a glyph data entry is required for each glyph,
    			# but empty ones can be calculated at compile time
    			xmlWriter.simpletag("glyph", name=self.glyphName)
    			xmlWriter.newline()
    			return
    		xmlWriter.begintag("glyph",
    			graphicType=self.graphicType,
    			name=self.glyphName,
    			originOffsetX=self.originOffsetX,
    			originOffsetY=self.originOffsetY,
    		)
    		xmlWriter.newline()
    		if self.graphicType == "dupe":
    			# graphicType == "dupe" is a reference to another glyph id.
    			xmlWriter.simpletag("ref", glyphname=self.referenceGlyphName)
    		else:
    			xmlWriter.begintag("hexdata")
    			xmlWriter.newline()
    			xmlWriter.dumphex(self.imageData)
    			xmlWriter.endtag("hexdata")
    		xmlWriter.newline()
    		xmlWriter.endtag("glyph")
    		xmlWriter.newline()

    	def fromXML(self, name, attrs, content, ttFont):
    		if name == "ref":
    			# glyph is a "dupe", i.e. a reference to another glyph's image data.
    			# in this case imageData contains the glyph id of the reference glyph
    			# get glyph id from glyphname
    			self.imageData = struct.pack(">H", ttFont.getGlyphID(safeEval("'''" + attrs["glyphname"] + "'''")))
    		elif name == "hexdata":
    			self.imageData = readHex(content)
    		else:
    			from fontTools import ttLib
    			raise ttLib.TTLibError("can't handle '%s' element" % name)