_h_m_t_x.py revision 32c10eecffb4923e0721c395e4b80fb732543f18 
1from __future__ import print_function, division
2from fontTools.misc.py23 import *
3from fontTools.misc.textTools import safeEval
4from . import DefaultTable
5import sys
6import array
7import warnings
8
9
10class table__h_m_t_x(DefaultTable.DefaultTable):
11
12	headerTag = 'hhea'
13	advanceName = 'width'
14	sideBearingName = 'lsb'
15	numberOfMetricsName = 'numberOfHMetrics'
16
17	def decompile(self, data, ttFont):
18		numGlyphs = ttFont['maxp'].numGlyphs
19		numberOfMetrics = int(getattr(ttFont[self.headerTag], self.numberOfMetricsName))
20		if numberOfMetrics > numGlyphs:
21			numberOfMetrics = numGlyphs # We warn later.
22		# Note: advanceWidth is unsigned, but we read/write as signed.
23		metrics = array.array("h", data[:4 * numberOfMetrics])
24		if sys.byteorder != "big":
25			metrics.byteswap()
26		data = data[4 * numberOfMetrics:]
27		numberOfSideBearings = numGlyphs - numberOfMetrics
28		sideBearings = array.array("h", data[:2 * numberOfSideBearings])
29		data = data[2 * numberOfSideBearings:]
30
31		if sys.byteorder != "big":
32			sideBearings.byteswap()
33		if data:
34			sys.stderr.write("too much data for hmtx/vmtx table\n")
35		self.metrics = {}
36		for i in range(numberOfMetrics):
37			glyphName = ttFont.getGlyphName(i)
38			self.metrics[glyphName] = list(metrics[i*2:i*2+2])
39		lastAdvance = metrics[-2]
40		for i in range(numberOfSideBearings):
41			glyphName = ttFont.getGlyphName(i + numberOfMetrics)
42			self.metrics[glyphName] = [lastAdvance, sideBearings[i]]
43
44	def compile(self, ttFont):
45		metrics = []
46		for glyphName in ttFont.getGlyphOrder():
47			metrics.append(self.metrics[glyphName])
48		lastAdvance = metrics[-1][0]
49		lastIndex = len(metrics)
50		while metrics[lastIndex-2][0] == lastAdvance:
51			lastIndex -= 1
52			if lastIndex <= 1:
53				# all advances are equal
54				lastIndex = 1
55				break
56		additionalMetrics = metrics[lastIndex:]
57		additionalMetrics = [sb for advance, sb in additionalMetrics]
58		metrics = metrics[:lastIndex]
59		setattr(ttFont[self.headerTag], self.numberOfMetricsName, len(metrics))
60
61		allMetrics = []
62		for item in metrics:
63			allMetrics.extend(item)
64		allMetrics = array.array("h", allMetrics)
65		if sys.byteorder != "big":
66			allMetrics.byteswap()
67		data = allMetrics.tostring()
68
69		additionalMetrics = array.array("h", additionalMetrics)
70		if sys.byteorder != "big":
71			additionalMetrics.byteswap()
72		data = data + additionalMetrics.tostring()
73		return data
74
75	def toXML(self, writer, ttFont):
76		names = sorted(self.metrics.keys())
77		for glyphName in names:
78			advance, sb = self.metrics[glyphName]
79			writer.simpletag("mtx", [
80					("name", glyphName),
81					(self.advanceName, advance),
82					(self.sideBearingName, sb),
83					])
84			writer.newline()
85
86	def fromXML(self, name, attrs, content, ttFont):
87		if not hasattr(self, "metrics"):
88			self.metrics = {}
89		if name == "mtx":
90			self.metrics[attrs["name"]] = [safeEval(attrs[self.advanceName]),
91					safeEval(attrs[self.sideBearingName])]
92
93	def __getitem__(self, glyphName):
94		return self.metrics[glyphName]
95
96	def __setitem__(self, glyphName, advance_sb_pair):
97		self.metrics[glyphName] = tuple(advance_sb_pair)
98
99