xref: /external/fonttools/Lib/fontTools/ttLib/tables/_h_h_e_a.py

import DefaultTable
import sstruct
from fontTools.misc.textTools import safeEval

hheaFormat = """
		>	# big endian
		tableVersion:			16.16F
		ascent:					h
		descent:				h
		lineGap:				h
		advanceWidthMax:		H
		minLeftSideBearing:		h
		minRightSideBearing:	h
		xMaxExtent:				h
		caretSlopeRise:			h
		caretSlopeRun:			h
		reserved0:				h
		reserved1:				h
		reserved2:				h
		reserved3:				h
		reserved4:				h
		metricDataFormat:		h
		numberOfHMetrics:		H
"""

class table__h_h_e_a(DefaultTable.DefaultTable):

	dependencies = ['hmtx', 'glyf']

	def decompile(self, data, ttFont):
		sstruct.unpack(hheaFormat, data, self)

	def compile(self, ttFont):
		if ttFont.isLoaded('glyf') and ttFont.recalcBBoxes:
			self.recalc(ttFont)
		return sstruct.pack(hheaFormat, self)

	def recalc(self, ttFont):
		hmtxTable = ttFont['hmtx']
		if ttFont.has_key('glyf'):
			glyfTable = ttFont['glyf']
			advanceWidthMax = -100000    # arbitrary big negative number
			minLeftSideBearing = 100000  # arbitrary big number
			minRightSideBearing = 100000 # arbitrary big number
			xMaxExtent = -100000         # arbitrary big negative number

			for name in ttFont.getGlyphOrder():
				width, lsb = hmtxTable[name]
				g = glyfTable[name]
				if g.numberOfContours <= 0:
					continue
				advanceWidthMax = max(advanceWidthMax, width)
				minLeftSideBearing = min(minLeftSideBearing, lsb)
				rsb = width - lsb - (g.xMax - g.xMin)
				minRightSideBearing = min(minRightSideBearing, rsb)
				extent = lsb + (g.xMax - g.xMin)
				xMaxExtent = max(xMaxExtent, extent)
			self.advanceWidthMax = advanceWidthMax
			self.minLeftSideBearing = minLeftSideBearing
			self.minRightSideBearing = minRightSideBearing
			self.xMaxExtent = xMaxExtent
		else:
			# XXX CFF recalc...
			pass

	def toXML(self, writer, ttFont):
		formatstring, names, fixes = sstruct.getformat(hheaFormat)
		for name in names:
			value = getattr(self, name)
			if type(value) == type(0L):
				value = int(value)
			writer.simpletag(name, value=value)
			writer.newline()

	def fromXML(self, (name, attrs, content), ttFont):
		setattr(self, name, safeEval(attrs["value"]))