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from fontTools.misc import sstruct
from fontTools.misc.textTools import safeEval
from fontTools.misc.fixedTools import (
ensureVersionIsLong as fi2ve,
versionToFixed as ve2fi,
)
from . import DefaultTable
import math
hheaFormat = """
> # big endian
tableVersion: L
ascent: h
descent: h
lineGap: h
advanceWidthMax: H
minLeftSideBearing: h
minRightSideBearing: h
xMaxExtent: h
caretSlopeRise: h
caretSlopeRun: h
caretOffset: h
reserved0: h
reserved1: h
reserved2: h
reserved3: h
metricDataFormat: h
numberOfHMetrics: H
"""
class table__h_h_e_a(DefaultTable.DefaultTable):
"""Horizontal Header table
The ``hhea`` table contains information needed during horizontal
text layout.
.. note::
This converter class is kept in sync with the :class:`._v_h_e_a.table__v_h_e_a`
table constructor.
See also https://learn.microsoft.com/en-us/typography/opentype/spec/hhea
"""
# Note: Keep in sync with table__v_h_e_a
dependencies = ["hmtx", "glyf", "CFF ", "CFF2"]
# OpenType spec renamed these, add aliases for compatibility
@property
def ascender(self):
return self.ascent
@ascender.setter
def ascender(self, value):
self.ascent = value
@property
def descender(self):
return self.descent
@descender.setter
def descender(self, value):
self.descent = value
def decompile(self, data, ttFont):
sstruct.unpack(hheaFormat, data, self)
def compile(self, ttFont):
if ttFont.recalcBBoxes and (
ttFont.isLoaded("glyf")
or ttFont.isLoaded("CFF ")
or ttFont.isLoaded("CFF2")
):
self.recalc(ttFont)
self.tableVersion = fi2ve(self.tableVersion)
return sstruct.pack(hheaFormat, self)
def recalc(self, ttFont):
if "hmtx" not in ttFont:
return
hmtxTable = ttFont["hmtx"]
self.advanceWidthMax = max(adv for adv, _ in hmtxTable.metrics.values())
boundsWidthDict = {}
if "glyf" in ttFont:
glyfTable = ttFont["glyf"]
for name in ttFont.getGlyphOrder():
g = glyfTable[name]
if g.numberOfContours == 0:
continue
if g.numberOfContours < 0 and not hasattr(g, "xMax"):
# Composite glyph without extents set.
# Calculate those.
g.recalcBounds(glyfTable)
boundsWidthDict[name] = g.xMax - g.xMin
elif "CFF " in ttFont or "CFF2" in ttFont:
if "CFF " in ttFont:
topDict = ttFont["CFF "].cff.topDictIndex[0]
else:
topDict = ttFont["CFF2"].cff.topDictIndex[0]
charStrings = topDict.CharStrings
for name in ttFont.getGlyphOrder():
cs = charStrings[name]
bounds = cs.calcBounds(charStrings)
if bounds is not None:
boundsWidthDict[name] = int(
math.ceil(bounds[2]) - math.floor(bounds[0])
)
if boundsWidthDict:
minLeftSideBearing = float("inf")
minRightSideBearing = float("inf")
xMaxExtent = -float("inf")
for name, boundsWidth in boundsWidthDict.items():
advanceWidth, lsb = hmtxTable[name]
rsb = advanceWidth - lsb - boundsWidth
extent = lsb + boundsWidth
minLeftSideBearing = min(minLeftSideBearing, lsb)
minRightSideBearing = min(minRightSideBearing, rsb)
xMaxExtent = max(xMaxExtent, extent)
self.minLeftSideBearing = minLeftSideBearing
self.minRightSideBearing = minRightSideBearing
self.xMaxExtent = xMaxExtent
else: # No glyph has outlines.
self.minLeftSideBearing = 0
self.minRightSideBearing = 0
self.xMaxExtent = 0
def toXML(self, writer, ttFont):
formatstring, names, fixes = sstruct.getformat(hheaFormat)
for name in names:
value = getattr(self, name)
if name == "tableVersion":
value = fi2ve(value)
value = "0x%08x" % value
writer.simpletag(name, value=value)
writer.newline()
def fromXML(self, name, attrs, content, ttFont):
if name == "tableVersion":
setattr(self, name, ve2fi(attrs["value"]))
return
setattr(self, name, safeEval(attrs["value"]))
|
