Source code for fontTools.ttLib.tables.sbixStrike

from fontTools.misc import sstruct
from fontTools.misc.textTools import safeEval
from .sbixGlyph import Glyph
import struct

sbixStrikeHeaderFormat = """
	>
	ppem:          H	# The PPEM for which this strike was designed (e.g., 9,
						# 12, 24)
	resolution:    H	# The screen resolution (in dpi) for which this strike
						# was designed (e.g., 72)
"""

sbixGlyphDataOffsetFormat = """
	>
	glyphDataOffset:   L	# Offset from the beginning of the strike data record
							# to data for the individual glyph
"""

sbixStrikeHeaderFormatSize = sstruct.calcsize(sbixStrikeHeaderFormat)
sbixGlyphDataOffsetFormatSize = sstruct.calcsize(sbixGlyphDataOffsetFormat)


[docs] class Strike(object): def __init__(self, rawdata=None, ppem=0, resolution=72): self.data = rawdata self.ppem = ppem self.resolution = resolution self.glyphs = {}
[docs] def decompile(self, ttFont): if self.data is None: from fontTools import ttLib raise ttLib.TTLibError if len(self.data) < sbixStrikeHeaderFormatSize: from fontTools import ttLib raise ( ttLib.TTLibError, "Strike header too short: Expected %x, got %x.", ) % (sbixStrikeHeaderFormatSize, len(self.data)) # read Strike header from raw data sstruct.unpack( sbixStrikeHeaderFormat, self.data[:sbixStrikeHeaderFormatSize], self ) # calculate number of glyphs (firstGlyphDataOffset,) = struct.unpack( ">L", self.data[ sbixStrikeHeaderFormatSize : sbixStrikeHeaderFormatSize + sbixGlyphDataOffsetFormatSize ], ) self.numGlyphs = ( firstGlyphDataOffset - sbixStrikeHeaderFormatSize ) // sbixGlyphDataOffsetFormatSize - 1 # ^ -1 because there's one more offset than glyphs # build offset list for single glyph data offsets self.glyphDataOffsets = [] for i in range( self.numGlyphs + 1 ): # + 1 because there's one more offset than glyphs start = i * sbixGlyphDataOffsetFormatSize + sbixStrikeHeaderFormatSize (current_offset,) = struct.unpack( ">L", self.data[start : start + sbixGlyphDataOffsetFormatSize] ) self.glyphDataOffsets.append(current_offset) # iterate through offset list and slice raw data into glyph data records for i in range(self.numGlyphs): current_glyph = Glyph( rawdata=self.data[ self.glyphDataOffsets[i] : self.glyphDataOffsets[i + 1] ], gid=i, ) current_glyph.decompile(ttFont) self.glyphs[current_glyph.glyphName] = current_glyph del self.glyphDataOffsets del self.numGlyphs del self.data
[docs] def compile(self, ttFont): self.glyphDataOffsets = b"" self.bitmapData = b"" glyphOrder = ttFont.getGlyphOrder() # first glyph starts right after the header currentGlyphDataOffset = ( sbixStrikeHeaderFormatSize + sbixGlyphDataOffsetFormatSize * (len(glyphOrder) + 1) ) for glyphName in glyphOrder: if glyphName in self.glyphs: # we have glyph data for this glyph current_glyph = self.glyphs[glyphName] else: # must add empty glyph data record for this glyph current_glyph = Glyph(glyphName=glyphName) current_glyph.compile(ttFont) current_glyph.glyphDataOffset = currentGlyphDataOffset self.bitmapData += current_glyph.rawdata currentGlyphDataOffset += len(current_glyph.rawdata) self.glyphDataOffsets += sstruct.pack( sbixGlyphDataOffsetFormat, current_glyph ) # add last "offset", really the end address of the last glyph data record dummy = Glyph() dummy.glyphDataOffset = currentGlyphDataOffset self.glyphDataOffsets += sstruct.pack(sbixGlyphDataOffsetFormat, dummy) # pack header self.data = sstruct.pack(sbixStrikeHeaderFormat, self) # add offsets and image data after header self.data += self.glyphDataOffsets + self.bitmapData
[docs] def toXML(self, xmlWriter, ttFont): xmlWriter.begintag("strike") xmlWriter.newline() xmlWriter.simpletag("ppem", value=self.ppem) xmlWriter.newline() xmlWriter.simpletag("resolution", value=self.resolution) xmlWriter.newline() glyphOrder = ttFont.getGlyphOrder() for i in range(len(glyphOrder)): if glyphOrder[i] in self.glyphs: self.glyphs[glyphOrder[i]].toXML(xmlWriter, ttFont) # TODO: what if there are more glyph data records than (glyf table) glyphs? xmlWriter.endtag("strike") xmlWriter.newline()
[docs] def fromXML(self, name, attrs, content, ttFont): if name in ["ppem", "resolution"]: setattr(self, name, safeEval(attrs["value"])) elif name == "glyph": if "graphicType" in attrs: myFormat = safeEval("'''" + attrs["graphicType"] + "'''") else: myFormat = None if "glyphname" in attrs: myGlyphName = safeEval("'''" + attrs["glyphname"] + "'''") elif "name" in attrs: myGlyphName = safeEval("'''" + attrs["name"] + "'''") else: from fontTools import ttLib raise ttLib.TTLibError("Glyph must have a glyph name.") if "originOffsetX" in attrs: myOffsetX = safeEval(attrs["originOffsetX"]) else: myOffsetX = 0 if "originOffsetY" in attrs: myOffsetY = safeEval(attrs["originOffsetY"]) else: myOffsetY = 0 current_glyph = Glyph( glyphName=myGlyphName, graphicType=myFormat, originOffsetX=myOffsetX, originOffsetY=myOffsetY, ) for element in content: if isinstance(element, tuple): name, attrs, content = element current_glyph.fromXML(name, attrs, content, ttFont) current_glyph.compile(ttFont) self.glyphs[current_glyph.glyphName] = current_glyph else: from fontTools import ttLib raise ttLib.TTLibError("can't handle '%s' element" % name)