"""
This is a python interface to Adobe Font Metrics Files. Although a
number of other python implementations exist (and may be more complete
than mine) I decided not to go with them because either they were
either
1) copyighted or used a non-BSD compatible license
2) had too many dependencies and I wanted a free standing lib
3) Did more than I needed and it was easier to write my own than
figure out how to just get what I needed from theirs
It is pretty easy to use, and requires only built-in python libs
>>> from afm import AFM
>>> fh = file('ptmr8a.afm')
>>> afm = AFM(fh)
>>> afm.string_width_height('What the heck?')
(6220.0, 683)
>>> afm.get_fontname()
'Times-Roman'
>>> afm.get_kern_dist('A', 'f')
0
>>> afm.get_kern_dist('A', 'y')
-92.0
>>> afm.get_bbox_char('!')
[130, -9, 238, 676]
>>> afm.get_bbox_font()
[-168, -218, 1000, 898]
AUTHOR:
John D. Hunter <jdhunter@ace.bsd.uchicago.edu>
"""
import sys, os
from _mathtext_data import uni2type1
#Convert string the a python type
_to_int = int
_to_float = float
_to_str = str
def _to_list_of_ints(s):
s = s.replace(',', ' ')
return [_to_int(val) for val in s.split()]
def _to_list_of_floats(s):
return [_to_float(val) for val in s.split()]
def _to_bool(s):
if s.lower().strip() in ('false', '0', 'no'): return False
else: return True
def _sanity_check(fh):
"""
Check if the file at least looks like AFM.
If not, raise RuntimeError.
"""
# Remember the file position in case the caller wants to
# do something else with the file.
pos = fh.tell()
try:
line = fh.readline()
finally:
fh.seek(pos, 0)
# AFM spec, Section 4: The StartFontMetrics keyword [followed by a
# version number] must be the first line in the file, and the
# EndFontMetrics keyword must be the last non-empty line in the
# file. We just check the first line.
if not line.startswith('StartFontMetrics'):
raise RuntimeError('Not an AFM file')
def _parse_header(fh):
"""
Reads the font metrics header (up to the char metrics) and returns
a dictionary mapping key to val. val will be converted to the
appropriate python type as necessary; eg 'False'->False, '0'->0,
'-168 -218 1000 898'-> [-168, -218, 1000, 898]
Dictionary keys are
StartFontMetrics, FontName, FullName, FamilyName, Weight,
ItalicAngle, IsFixedPitch, FontBBox, UnderlinePosition,
UnderlineThickness, Version, Notice, EncodingScheme, CapHeight,
XHeight, Ascender, Descender, StartCharMetrics
"""
headerConverters = {
'StartFontMetrics': _to_float,
'FontName': _to_str,
'FullName': _to_str,
'FamilyName': _to_str,
'Weight': _to_str,
'ItalicAngle': _to_float,
'IsFixedPitch': _to_bool,
'FontBBox': _to_list_of_ints,
'UnderlinePosition': _to_int,
'UnderlineThickness': _to_int,
'Version': _to_str,
'Notice': _to_str,
'EncodingScheme': _to_str,
'CapHeight': _to_float, # Is the second version a mistake, or
'Capheight': _to_float, # do some AFM files contain 'Capheight'? -JKS
'XHeight': _to_float,
'Ascender': _to_float,
'Descender': _to_float,
'StdHW': _to_float,
'StdVW': _to_float,
'StartCharMetrics': _to_int,
'CharacterSet': _to_str,
'Characters': _to_int,
}
d = {}
while 1:
line = fh.readline()
if not line: break
line = line.rstrip()
if line.startswith('Comment'): continue
lst = line.split( ' ', 1 )
#print '%-s\t%-d line :: %-s' % ( fh.name, len(lst), line )
key = lst[0]
if len( lst ) == 2:
val = lst[1]
else:
val = ''
#key, val = line.split(' ', 1)
try: d[key] = headerConverters[key](val)
except ValueError:
print >>sys.stderr, 'Value error parsing header in AFM:', key, val
continue
except KeyError:
print >>sys.stderr, 'Found an unknown keyword in AFM header (was %s)' % key
continue
if key=='StartCharMetrics': return d
raise RuntimeError('Bad parse')
def _parse_char_metrics(fh):
"""
Return a character metric dictionary. Keys are the ASCII num of
the character, values are a (wx, name, bbox) tuple, where
wx is the character width
name is the postscript language name
bbox (llx, lly, urx, ury)
This function is incomplete per the standard, but thus far parse
all the sample afm files I have
"""
ascii_d = {}
name_d = {}
while 1:
line = fh.readline()
if not line: break
line = line.rstrip()
if line.startswith('EndCharMetrics'): return ascii_d, name_d
vals = line.split(';')[:4]
if len(vals) !=4 : raise RuntimeError('Bad char metrics line: %s' % line)
num = _to_int(vals[0].split()[1])
wx = _to_float(vals[1].split()[1])
name = vals[2].split()[1]
bbox = _to_list_of_ints(vals[3][2:])
# Workaround: If the character name is 'Euro', give it the corresponding
# character code, according to WinAnsiEncoding (see PDF Reference).
if name == 'Euro':
num = 128
if num != -1:
ascii_d[num] = (wx, name, bbox)
name_d[name] = (wx, bbox)
raise RuntimeError('Bad parse')
def _parse_kern_pairs(fh):
"""
Return a kern pairs dictionary; keys are (char1, char2) tuples and
values are the kern pair value. For example, a kern pairs line like
KPX A y -50
will be represented as
d[ ('A', 'y') ] = -50
"""
line = fh.readline()
if not line.startswith('StartKernPairs'):
raise RuntimeError('Bad start of kern pairs data: %s'%line)
d = {}
while 1:
line = fh.readline()
if not line: break
line = line.rstrip()
if len(line)==0: continue
if line.startswith('EndKernPairs'):
fh.readline() # EndKernData
return d
vals = line.split()
if len(vals)!=4 or vals[0]!='KPX':
raise RuntimeError('Bad kern pairs line: %s'%line)
c1, c2, val = vals[1], vals[2], _to_float(vals[3])
d[(c1,c2)] = val
raise RuntimeError('Bad kern pairs parse')
def _parse_composites(fh):
"""
Return a composites dictionary. Keys are the names of the
composites. vals are a num parts list of composite information,
with each element being a (name, dx, dy) tuple. Thus if a
composites line reading:
CC Aacute 2 ; PCC A 0 0 ; PCC acute 160 170 ;
will be represented as
d['Aacute'] = [ ('A', 0, 0), ('acute', 160, 170) ]
"""
d = {}
while 1:
line = fh.readline()
if not line: break
line = line.rstrip()
if len(line)==0: continue
if line.startswith('EndComposites'):
return d
vals = line.split(';')
cc = vals[0].split()
name, numParts = cc[1], _to_int(cc[2])
pccParts = []
for s in vals[1:-1]:
pcc = s.split()
name, dx, dy = pcc[1], _to_float(pcc[2]), _to_float(pcc[3])
pccParts.append( (name, dx, dy) )
d[name] = pccParts
raise RuntimeError('Bad composites parse')
def _parse_optional(fh):
"""
Parse the optional fields for kern pair data and composites
return value is a kernDict, compositeDict which are the return
values from parse_kern_pairs, and parse_composites if the data
exists, or empty dicts otherwise
"""
optional = {
'StartKernData' : _parse_kern_pairs,
'StartComposites' : _parse_composites,
}
d = {'StartKernData':{}, 'StartComposites':{}}
while 1:
line = fh.readline()
if not line: break
line = line.rstrip()
if len(line)==0: continue
key = line.split()[0]
if optional.has_key(key): d[key] = optional[key](fh)
l = ( d['StartKernData'], d['StartComposites'] )
return l
def parse_afm(fh):
"""
Parse the Adobe Font Metics file in file handle fh
Return value is a (dhead, dcmetrics, dkernpairs, dcomposite) tuple where
dhead : a parse_header dict
dcmetrics : a parse_composites dict
dkernpairs : a parse_kern_pairs dict, possibly {}
dcomposite : a parse_composites dict , possibly {}
"""
_sanity_check(fh)
dhead = _parse_header(fh)
dcmetrics_ascii, dcmetrics_name = _parse_char_metrics(fh)
doptional = _parse_optional(fh)
return dhead, dcmetrics_ascii, dcmetrics_name, doptional[0], doptional[1]
class AFM:
def __init__(self, fh):
"""
Parse the AFM file in file object fh
"""
(dhead, dcmetrics_ascii, dcmetrics_name, dkernpairs, dcomposite) = \
parse_afm(fh)
self._header = dhead
self._kern = dkernpairs
self._metrics = dcmetrics_ascii
self._metrics_by_name = dcmetrics_name
self._composite = dcomposite
def get_bbox_char(self, c, isord=False):
if not isord: c=ord(c)
wx, name, bbox = self._metrics[c]
return bbox
def string_width_height(self, s):
"""
Return the string width (including kerning) and string height
as a w,h tuple
"""
if not len(s): return 0,0
totalw = 0
namelast = None
miny = 1e9
maxy = 0
for c in s:
if c == '\n': continue
wx, name, bbox = self._metrics[ord(c)]
l,b,w,h = bbox
# find the width with kerning
try: kp = self._kern[ (namelast, name) ]
except KeyError: kp = 0
totalw += wx + kp
# find the max y
thismax = b+h
if thismax>maxy: maxy = thismax
# find the min y
thismin = b
if thismin<miny: miny = thismin
return totalw, maxy-miny
def get_str_bbox_and_descent(self, s):
"""
Return the string bounding box
"""
if not len(s): return 0,0,0,0
totalw = 0
namelast = None
miny = 1e9
maxy = 0
left = 0
if not isinstance(s, unicode):
s = s.decode()
for c in s:
if c == '\n': continue
name = uni2type1.get(ord(c), 'question')
try:
wx, bbox = self._metrics_by_name[name]
except KeyError:
name = 'question'
wx, bbox = self._metrics_by_name[name]
l,b,w,h = bbox
if l<left: left = l
# find the width with kerning
try: kp = self._kern[ (namelast, name) ]
except KeyError: kp = 0
totalw += wx + kp
# find the max y
thismax = b+h
if thismax>maxy: maxy = thismax
# find the min y
thismin = b
if thismin<miny: miny = thismin
return left, miny, totalw, maxy-miny, -miny
def get_str_bbox(self, s):
"""
Return the string bounding box
"""
return self.get_str_bbox_and_descent(s)[:4]
def get_name_char(self, c, isord=False):
"""
Get the name of the character, ie, ';' is 'semicolon'
"""
if not isord: c=ord(c)
wx, name, bbox = self._metrics[c]
return name
def get_width_char(self, c, isord=False):
"""
Get the width of the character from the character metric WX
field
"""
if not isord: c=ord(c)
wx, name, bbox = self._metrics[c]
return wx
def get_width_from_char_name(self, name):
"""
Get the width of the character from a type1 character name
"""
wx, bbox = self._metrics_by_name[name]
return wx
def get_height_char(self, c, isord=False):
"""
Get the height of character c from the bounding box. This is
the ink height (space is 0)
"""
if not isord: c=ord(c)
wx, name, bbox = self._metrics[c]
return bbox[-1]
def get_kern_dist(self, c1, c2):
"""
Return the kerning pair distance (possibly 0) for chars c1 and
c2
"""
name1, name2 = self.get_name_char(c1), self.get_name_char(c2)
return self.get_kern_dist_from_name(name1, name2)
def get_kern_dist_from_name(self, name1, name2):
"""
Return the kerning pair distance (possibly 0) for chars c1 and
c2
"""
try: return self._kern[ (name1, name2) ]
except: return 0
def get_fontname(self):
"Return the font name, eg, Times-Roman"
return self._header['FontName']
def get_fullname(self):
"Return the font full name, eg, Times-Roman"
return self._header['FullName']
def get_familyname(self):
"Return the font family name, eg, Times"
return self._header['FamilyName']
def get_weight(self):
"Return the font weight, eg, 'Bold' or 'Roman'"
return self._header['Weight']
def get_angle(self):
"Return the fontangle as float"
return self._header['ItalicAngle']
def get_capheight(self):
"Return the cap height as float"
return self._header['CapHeight']
def get_xheight(self):
"Return the xheight as float"
return self._header['XHeight']
def get_underline_thickness(self):
"Return the underline thickness as float"
return self._header['UnderlineThickness']
def get_horizontal_stem_width(self):
"""
Return the standard horizontal stem width as float, or None if
not specified in AFM file.
"""
return self._header.get('StdHW', None)
def get_vertical_stem_width(self):
"""
Return the standard vertical stem width as float, or None if
not specified in AFM file.
"""
return self._header.get('StdVW', None)
if __name__=='__main__':
#pathname = '/usr/local/lib/R/afm/'
pathname = '/usr/local/share/fonts/afms/adobe'
for fname in os.listdir(pathname):
fh = file(os.path.join(pathname,fname))
afm = AFM(fh)
w,h = afm.string_width_height('John Hunter is the Man!')
