def read_data(self, vmtx):
if hasattr(self, 'ascender'):
return
field_types = (
'_version_number',
'l',
'ascender',
'h',
'descender',
'h',
'line_gap',
'h',
'advance_height_max',
'H',
'min_top_side_bearing',
'h',
'min_bottom_side_bearing',
'h',
'y_max_extent',
'h',
'caret_slope_rise',
'h',
'caret_slop_run',
'h',
'caret_offset',
'h',
'r1',
'h',
'r2',
'h',
'r3',
'h',
'r4',
'h',
'metric_data_format',
'h',
'number_of_v_metrics',
'H',
)
self._fmt = ('>%s' % (''.join(field_types[1::2]))).encode('ascii')
self._fields = field_types[0::2]
for f, val in zip(self._fields, unpack_from(self._fmt, self.raw)):
setattr(self, f, val)
raw = vmtx.raw
num = self.number_of_h_metrics
if len(raw) < 4 * num:
raise UnsupportedFont('The vmtx table has insufficient data')
long_hor_metric = raw[:4 * num]
long_hor_metric = raw[:4 * num]
a = read_array(long_hor_metric)
self.advance_heights = a[0::2]
a = read_array(long_hor_metric, 'h')
self.top_side_bearings = a[1::2]
def read_metrics(raw, num_of_metrics, num_of_glyphs, table_name):
rawsz = 4 * num_of_metrics
if len(raw) < rawsz:
raise UnsupportedFont(f'The {table_name} table has insufficient data')
long_hor_metric = raw[:rawsz]
a = read_array(long_hor_metric)
advances = a[0::2]
a = read_array(long_hor_metric, 'h')
bearings = a[1::2]
if num_of_glyphs > num_of_metrics:
extra = num_of_glyphs - num_of_metrics
raw = raw[rawsz:]
rawsz = 2 * extra
if len(raw) < rawsz:
raise UnsupportedFont(f'The {table_name} table has insufficient data for trailing bearings')
bearings += read_array(raw, 'h')
return advances, bearings