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# Copyright 2013 Google, Inc. All Rights Reserved.
#
# Google Author(s): Matt Fontaine
from fontTools.misc.textTools import bytesjoin
from fontTools.misc import sstruct
from . import E_B_D_T_
from .BitmapGlyphMetrics import (
BigGlyphMetrics,
bigGlyphMetricsFormat,
SmallGlyphMetrics,
smallGlyphMetricsFormat,
)
from .E_B_D_T_ import (
BitmapGlyph,
BitmapPlusSmallMetricsMixin,
BitmapPlusBigMetricsMixin,
)
import struct
class table_C_B_D_T_(E_B_D_T_.table_E_B_D_T_):
"""Color Bitmap Data table
The ``CBDT`` table contains color bitmap data for glyphs. It must
be used in concert with the ``CBLC`` table.
It is backwards-compatible with the monochrome/grayscale ``EBDT`` table.
See also https://learn.microsoft.com/en-us/typography/opentype/spec/cbdt
"""
# Change the data locator table being referenced.
locatorName = "CBLC"
# Modify the format class accessor for color bitmap use.
def getImageFormatClass(self, imageFormat):
try:
return E_B_D_T_.table_E_B_D_T_.getImageFormatClass(self, imageFormat)
except KeyError:
return cbdt_bitmap_classes[imageFormat]
# Helper method for removing export features not supported by color bitmaps.
# Write data in the parent class will default to raw if an option is unsupported.
def _removeUnsupportedForColor(dataFunctions):
dataFunctions = dict(dataFunctions)
del dataFunctions["row"]
return dataFunctions
class ColorBitmapGlyph(BitmapGlyph):
fileExtension = ".png"
xmlDataFunctions = _removeUnsupportedForColor(BitmapGlyph.xmlDataFunctions)
class cbdt_bitmap_format_17(BitmapPlusSmallMetricsMixin, ColorBitmapGlyph):
def decompile(self):
self.metrics = SmallGlyphMetrics()
dummy, data = sstruct.unpack2(smallGlyphMetricsFormat, self.data, self.metrics)
(dataLen,) = struct.unpack(">L", data[:4])
data = data[4:]
# For the image data cut it to the size specified by dataLen.
assert dataLen <= len(data), "Data overun in format 17"
self.imageData = data[:dataLen]
def compile(self, ttFont):
dataList = []
dataList.append(sstruct.pack(smallGlyphMetricsFormat, self.metrics))
dataList.append(struct.pack(">L", len(self.imageData)))
dataList.append(self.imageData)
return bytesjoin(dataList)
class cbdt_bitmap_format_18(BitmapPlusBigMetricsMixin, ColorBitmapGlyph):
def decompile(self):
self.metrics = BigGlyphMetrics()
dummy, data = sstruct.unpack2(bigGlyphMetricsFormat, self.data, self.metrics)
(dataLen,) = struct.unpack(">L", data[:4])
data = data[4:]
# For the image data cut it to the size specified by dataLen.
assert dataLen <= len(data), "Data overun in format 18"
self.imageData = data[:dataLen]
def compile(self, ttFont):
dataList = []
dataList.append(sstruct.pack(bigGlyphMetricsFormat, self.metrics))
dataList.append(struct.pack(">L", len(self.imageData)))
dataList.append(self.imageData)
return bytesjoin(dataList)
class cbdt_bitmap_format_19(ColorBitmapGlyph):
def decompile(self):
(dataLen,) = struct.unpack(">L", self.data[:4])
data = self.data[4:]
assert dataLen <= len(data), "Data overun in format 19"
self.imageData = data[:dataLen]
def compile(self, ttFont):
return struct.pack(">L", len(self.imageData)) + self.imageData
# Dict for CBDT extended formats.
cbdt_bitmap_classes = {
17: cbdt_bitmap_format_17,
18: cbdt_bitmap_format_18,
19: cbdt_bitmap_format_19,
}
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