398 lines
12 KiB
Python
398 lines
12 KiB
Python
|
|
||
|
|
"""
|
||
|
|
Miscellaneous Routines.
|
||
|
|
"""
|
||
|
|
import struct
|
||
|
|
# from sys import maxint as INF #doesn't work anymore under Python3,
|
||
|
|
# but PDF still uses 32 bits ints
|
||
|
|
INF = (1<<31) - 1
|
||
|
|
|
||
|
|
import six #Python 2+3 compatibility
|
||
|
|
|
||
|
|
if six.PY3:
|
||
|
|
import chardet # For str encoding detection in Py3
|
||
|
|
unicode = str
|
||
|
|
|
||
|
|
def make_compat_bytes(in_str):
|
||
|
|
"In Py2, does nothing. In Py3, converts to bytes, encoding to unicode."
|
||
|
|
assert isinstance(in_str, str), str(type(in_str))
|
||
|
|
if six.PY2:
|
||
|
|
return in_str
|
||
|
|
else:
|
||
|
|
return in_str.encode()
|
||
|
|
|
||
|
|
def make_compat_str(in_str):
|
||
|
|
"In Py2, does nothing. In Py3, converts to string, guessing encoding."
|
||
|
|
assert isinstance(in_str, (bytes, str, unicode)), str(type(in_str))
|
||
|
|
if six.PY3 and isinstance(in_str, bytes):
|
||
|
|
enc = chardet.detect(in_str)
|
||
|
|
in_str = in_str.decode(enc['encoding'])
|
||
|
|
return in_str
|
||
|
|
|
||
|
|
def compatible_encode_method(bytesorstring, encoding='utf-8', erraction='ignore'):
|
||
|
|
"When Py2 str.encode is called, it often means bytes.encode in Py3. This does either."
|
||
|
|
if six.PY2:
|
||
|
|
assert isinstance(bytesorstring, (str, unicode)), str(type(bytesorstring))
|
||
|
|
return bytesorstring.encode(encoding, erraction)
|
||
|
|
if six.PY3:
|
||
|
|
if isinstance(bytesorstring, str): return bytesorstring
|
||
|
|
assert isinstance(bytesorstring, bytes), str(type(bytesorstring))
|
||
|
|
return bytesorstring.decode(encoding, erraction)
|
||
|
|
|
||
|
|
## PNG Predictor
|
||
|
|
##
|
||
|
|
def apply_png_predictor(pred, colors, columns, bitspercomponent, data):
|
||
|
|
if bitspercomponent != 8:
|
||
|
|
# unsupported
|
||
|
|
raise ValueError("Unsupported `bitspercomponent': %d" %
|
||
|
|
bitspercomponent)
|
||
|
|
nbytes = colors * columns * bitspercomponent // 8
|
||
|
|
i = 0
|
||
|
|
buf = b''
|
||
|
|
line0 = b'\x00' * columns
|
||
|
|
for i in range(0, len(data), nbytes+1):
|
||
|
|
ft = data[i]
|
||
|
|
if six.PY2:
|
||
|
|
ft = six.byte2int(ft)
|
||
|
|
i += 1
|
||
|
|
line1 = data[i:i+nbytes]
|
||
|
|
line2 = b''
|
||
|
|
if ft == 0:
|
||
|
|
# PNG none
|
||
|
|
line2 += line1
|
||
|
|
elif ft == 1:
|
||
|
|
# PNG sub (UNTESTED)
|
||
|
|
c = 0
|
||
|
|
for b in line1:
|
||
|
|
if six.PY2:
|
||
|
|
b = six.byte2int(b)
|
||
|
|
c = (c+b) & 255
|
||
|
|
line2 += six.int2byte(c)
|
||
|
|
elif ft == 2:
|
||
|
|
# PNG up
|
||
|
|
for (a, b) in zip(line0, line1):
|
||
|
|
if six.PY2:
|
||
|
|
a, b = six.byte2int(a), six.byte2int(b)
|
||
|
|
c = (a+b) & 255
|
||
|
|
line2 += six.int2byte(c)
|
||
|
|
elif ft == 3:
|
||
|
|
# PNG average (UNTESTED)
|
||
|
|
c = 0
|
||
|
|
for (a, b) in zip(line0, line1):
|
||
|
|
if six.PY2:
|
||
|
|
a, b = six.byte2int(a), six.byte2int(b)
|
||
|
|
c = ((c+a+b)//2) & 255
|
||
|
|
line2 += six.int2byte(c)
|
||
|
|
else:
|
||
|
|
# unsupported
|
||
|
|
raise ValueError("Unsupported predictor value: %d" % ft)
|
||
|
|
buf += line2
|
||
|
|
line0 = line2
|
||
|
|
return buf
|
||
|
|
|
||
|
|
|
||
|
|
## Matrix operations
|
||
|
|
##
|
||
|
|
MATRIX_IDENTITY = (1, 0, 0, 1, 0, 0)
|
||
|
|
|
||
|
|
|
||
|
|
def mult_matrix(m1, m0):
|
||
|
|
(a1, b1, c1, d1, e1, f1) = m1
|
||
|
|
(a0, b0, c0, d0, e0, f0) = m0
|
||
|
|
"""Returns the multiplication of two matrices."""
|
||
|
|
return (a0*a1+c0*b1, b0*a1+d0*b1,
|
||
|
|
a0*c1+c0*d1, b0*c1+d0*d1,
|
||
|
|
a0*e1+c0*f1+e0, b0*e1+d0*f1+f0)
|
||
|
|
|
||
|
|
|
||
|
|
def translate_matrix(m, v):
|
||
|
|
"""Translates a matrix by (x, y)."""
|
||
|
|
(a, b, c, d, e, f) = m
|
||
|
|
(x, y) = v
|
||
|
|
return (a, b, c, d, x*a+y*c+e, x*b+y*d+f)
|
||
|
|
|
||
|
|
|
||
|
|
def apply_matrix_pt(m, v):
|
||
|
|
(a, b, c, d, e, f) = m
|
||
|
|
(x, y) = v
|
||
|
|
"""Applies a matrix to a point."""
|
||
|
|
return (a*x+c*y+e, b*x+d*y+f)
|
||
|
|
|
||
|
|
|
||
|
|
def apply_matrix_norm(m, v):
|
||
|
|
"""Equivalent to apply_matrix_pt(M, (p,q)) - apply_matrix_pt(M, (0,0))"""
|
||
|
|
(a, b, c, d, e, f) = m
|
||
|
|
(p, q) = v
|
||
|
|
return (a*p+c*q, b*p+d*q)
|
||
|
|
|
||
|
|
|
||
|
|
## Utility functions
|
||
|
|
##
|
||
|
|
|
||
|
|
# isnumber
|
||
|
|
def isnumber(x):
|
||
|
|
return isinstance(x, (six.integer_types, float))
|
||
|
|
|
||
|
|
# uniq
|
||
|
|
def uniq(objs):
|
||
|
|
"""Eliminates duplicated elements."""
|
||
|
|
done = set()
|
||
|
|
for obj in objs:
|
||
|
|
if obj in done:
|
||
|
|
continue
|
||
|
|
done.add(obj)
|
||
|
|
yield obj
|
||
|
|
return
|
||
|
|
|
||
|
|
|
||
|
|
# fsplit
|
||
|
|
def fsplit(pred, objs):
|
||
|
|
"""Split a list into two classes according to the predicate."""
|
||
|
|
t = []
|
||
|
|
f = []
|
||
|
|
for obj in objs:
|
||
|
|
if pred(obj):
|
||
|
|
t.append(obj)
|
||
|
|
else:
|
||
|
|
f.append(obj)
|
||
|
|
return (t, f)
|
||
|
|
|
||
|
|
|
||
|
|
# drange
|
||
|
|
def drange(v0, v1, d):
|
||
|
|
"""Returns a discrete range."""
|
||
|
|
assert v0 < v1, str((v0, v1, d))
|
||
|
|
return range(int(v0)//d, int(v1+d)//d)
|
||
|
|
|
||
|
|
|
||
|
|
# get_bound
|
||
|
|
def get_bound(pts):
|
||
|
|
"""Compute a minimal rectangle that covers all the points."""
|
||
|
|
(x0, y0, x1, y1) = (INF, INF, -INF, -INF)
|
||
|
|
for (x, y) in pts:
|
||
|
|
x0 = min(x0, x)
|
||
|
|
y0 = min(y0, y)
|
||
|
|
x1 = max(x1, x)
|
||
|
|
y1 = max(y1, y)
|
||
|
|
return (x0, y0, x1, y1)
|
||
|
|
|
||
|
|
|
||
|
|
# pick
|
||
|
|
def pick(seq, func, maxobj=None):
|
||
|
|
"""Picks the object obj where func(obj) has the highest value."""
|
||
|
|
maxscore = None
|
||
|
|
for obj in seq:
|
||
|
|
score = func(obj)
|
||
|
|
if maxscore is None or maxscore < score:
|
||
|
|
(maxscore, maxobj) = (score, obj)
|
||
|
|
return maxobj
|
||
|
|
|
||
|
|
|
||
|
|
# choplist
|
||
|
|
def choplist(n, seq):
|
||
|
|
"""Groups every n elements of the list."""
|
||
|
|
r = []
|
||
|
|
for x in seq:
|
||
|
|
r.append(x)
|
||
|
|
if len(r) == n:
|
||
|
|
yield tuple(r)
|
||
|
|
r = []
|
||
|
|
return
|
||
|
|
|
||
|
|
|
||
|
|
# nunpack
|
||
|
|
def nunpack(s, default=0):
|
||
|
|
"""Unpacks 1 to 4 or 8 byte integers (big endian)."""
|
||
|
|
l = len(s)
|
||
|
|
if not l:
|
||
|
|
return default
|
||
|
|
elif l == 1:
|
||
|
|
return ord(s)
|
||
|
|
elif l == 2:
|
||
|
|
return struct.unpack('>H', s)[0]
|
||
|
|
elif l == 3:
|
||
|
|
return struct.unpack('>L', b'\x00'+s)[0]
|
||
|
|
elif l == 4:
|
||
|
|
return struct.unpack('>L', s)[0]
|
||
|
|
elif l == 8:
|
||
|
|
return struct.unpack('>Q', s)[0]
|
||
|
|
else:
|
||
|
|
raise TypeError('invalid length: %d' % l)
|
||
|
|
|
||
|
|
|
||
|
|
# decode_text
|
||
|
|
PDFDocEncoding = ''.join(six.unichr(x) for x in (
|
||
|
|
0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007,
|
||
|
|
0x0008, 0x0009, 0x000a, 0x000b, 0x000c, 0x000d, 0x000e, 0x000f,
|
||
|
|
0x0010, 0x0011, 0x0012, 0x0013, 0x0014, 0x0015, 0x0017, 0x0017,
|
||
|
|
0x02d8, 0x02c7, 0x02c6, 0x02d9, 0x02dd, 0x02db, 0x02da, 0x02dc,
|
||
|
|
0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0025, 0x0026, 0x0027,
|
||
|
|
0x0028, 0x0029, 0x002a, 0x002b, 0x002c, 0x002d, 0x002e, 0x002f,
|
||
|
|
0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037,
|
||
|
|
0x0038, 0x0039, 0x003a, 0x003b, 0x003c, 0x003d, 0x003e, 0x003f,
|
||
|
|
0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047,
|
||
|
|
0x0048, 0x0049, 0x004a, 0x004b, 0x004c, 0x004d, 0x004e, 0x004f,
|
||
|
|
0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057,
|
||
|
|
0x0058, 0x0059, 0x005a, 0x005b, 0x005c, 0x005d, 0x005e, 0x005f,
|
||
|
|
0x0060, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x0067,
|
||
|
|
0x0068, 0x0069, 0x006a, 0x006b, 0x006c, 0x006d, 0x006e, 0x006f,
|
||
|
|
0x0070, 0x0071, 0x0072, 0x0073, 0x0074, 0x0075, 0x0076, 0x0077,
|
||
|
|
0x0078, 0x0079, 0x007a, 0x007b, 0x007c, 0x007d, 0x007e, 0x0000,
|
||
|
|
0x2022, 0x2020, 0x2021, 0x2026, 0x2014, 0x2013, 0x0192, 0x2044,
|
||
|
|
0x2039, 0x203a, 0x2212, 0x2030, 0x201e, 0x201c, 0x201d, 0x2018,
|
||
|
|
0x2019, 0x201a, 0x2122, 0xfb01, 0xfb02, 0x0141, 0x0152, 0x0160,
|
||
|
|
0x0178, 0x017d, 0x0131, 0x0142, 0x0153, 0x0161, 0x017e, 0x0000,
|
||
|
|
0x20ac, 0x00a1, 0x00a2, 0x00a3, 0x00a4, 0x00a5, 0x00a6, 0x00a7,
|
||
|
|
0x00a8, 0x00a9, 0x00aa, 0x00ab, 0x00ac, 0x0000, 0x00ae, 0x00af,
|
||
|
|
0x00b0, 0x00b1, 0x00b2, 0x00b3, 0x00b4, 0x00b5, 0x00b6, 0x00b7,
|
||
|
|
0x00b8, 0x00b9, 0x00ba, 0x00bb, 0x00bc, 0x00bd, 0x00be, 0x00bf,
|
||
|
|
0x00c0, 0x00c1, 0x00c2, 0x00c3, 0x00c4, 0x00c5, 0x00c6, 0x00c7,
|
||
|
|
0x00c8, 0x00c9, 0x00ca, 0x00cb, 0x00cc, 0x00cd, 0x00ce, 0x00cf,
|
||
|
|
0x00d0, 0x00d1, 0x00d2, 0x00d3, 0x00d4, 0x00d5, 0x00d6, 0x00d7,
|
||
|
|
0x00d8, 0x00d9, 0x00da, 0x00db, 0x00dc, 0x00dd, 0x00de, 0x00df,
|
||
|
|
0x00e0, 0x00e1, 0x00e2, 0x00e3, 0x00e4, 0x00e5, 0x00e6, 0x00e7,
|
||
|
|
0x00e8, 0x00e9, 0x00ea, 0x00eb, 0x00ec, 0x00ed, 0x00ee, 0x00ef,
|
||
|
|
0x00f0, 0x00f1, 0x00f2, 0x00f3, 0x00f4, 0x00f5, 0x00f6, 0x00f7,
|
||
|
|
0x00f8, 0x00f9, 0x00fa, 0x00fb, 0x00fc, 0x00fd, 0x00fe, 0x00ff,
|
||
|
|
))
|
||
|
|
|
||
|
|
|
||
|
|
def decode_text(s):
|
||
|
|
"""Decodes a PDFDocEncoding string to Unicode."""
|
||
|
|
if s.startswith(b'\xfe\xff'):
|
||
|
|
return six.text_type(s[2:], 'utf-16be', 'ignore')
|
||
|
|
else:
|
||
|
|
return ''.join(PDFDocEncoding[c] for c in s)
|
||
|
|
|
||
|
|
|
||
|
|
# enc
|
||
|
|
def enc(x, codec='ascii'):
|
||
|
|
"""Encodes a string for SGML/XML/HTML"""
|
||
|
|
if six.PY3 and isinstance(x, bytes):
|
||
|
|
return ''
|
||
|
|
x = x.replace('&', '&').replace('>', '>').replace('<', '<').replace('"', '"')
|
||
|
|
if codec:
|
||
|
|
x = x.encode(codec, 'xmlcharrefreplace')
|
||
|
|
return x
|
||
|
|
|
||
|
|
|
||
|
|
def bbox2str(bbox):
|
||
|
|
(x0, y0, x1, y1) = bbox
|
||
|
|
return '%.3f,%.3f,%.3f,%.3f' % (x0, y0, x1, y1)
|
||
|
|
|
||
|
|
|
||
|
|
def matrix2str(m):
|
||
|
|
(a, b, c, d, e, f) = m
|
||
|
|
return '[%.2f,%.2f,%.2f,%.2f, (%.2f,%.2f)]' % (a, b, c, d, e, f)
|
||
|
|
|
||
|
|
def vecBetweenBoxes(obj1, obj2):
|
||
|
|
"""A distance function between two TextBoxes.
|
||
|
|
|
||
|
|
Consider the bounding rectangle for obj1 and obj2.
|
||
|
|
Return vector between 2 boxes boundaries if they don't overlap, otherwise returns vector betweeen boxes centers
|
||
|
|
+------+..........+ (x1, y1)
|
||
|
|
| obj1 | :
|
||
|
|
+------+www+------+
|
||
|
|
: | obj2 |
|
||
|
|
(x0, y0) +..........+------+
|
||
|
|
"""
|
||
|
|
(x0, y0) = (min(obj1.x0, obj2.x0), min(obj1.y0, obj2.y0))
|
||
|
|
(x1, y1) = (max(obj1.x1, obj2.x1), max(obj1.y1, obj2.y1))
|
||
|
|
(ow, oh) = (x1-x0, y1-y0)
|
||
|
|
(iw, ih) = (ow-obj1.width-obj2.width, oh-obj1.height-obj2.height)
|
||
|
|
if iw<0 and ih<0:
|
||
|
|
# if one is inside another we compute euclidean distance
|
||
|
|
(xc1, yc1) = ( (obj1.x0+obj1.x1)/2, (obj1.y0+obj1.y1)/2 )
|
||
|
|
(xc2, yc2) = ( (obj2.x0+obj2.x1)/2, (obj2.y0+obj2.y1)/2 )
|
||
|
|
return (xc1-xc2, yc1-yc2)
|
||
|
|
else:
|
||
|
|
return (max(0, iw), max(0, ih))
|
||
|
|
|
||
|
|
## Plane
|
||
|
|
##
|
||
|
|
## A set-like data structure for objects placed on a plane.
|
||
|
|
## Can efficiently find objects in a certain rectangular area.
|
||
|
|
## It maintains two parallel lists of objects, each of
|
||
|
|
## which is sorted by its x or y coordinate.
|
||
|
|
##
|
||
|
|
class Plane(object):
|
||
|
|
|
||
|
|
def __init__(self, bbox, gridsize=50):
|
||
|
|
self._seq = [] # preserve the object order.
|
||
|
|
self._objs = set()
|
||
|
|
self._grid = {}
|
||
|
|
self.gridsize = gridsize
|
||
|
|
(self.x0, self.y0, self.x1, self.y1) = bbox
|
||
|
|
return
|
||
|
|
|
||
|
|
def __repr__(self):
|
||
|
|
return ('<Plane objs=%r>' % list(self))
|
||
|
|
|
||
|
|
def __iter__(self):
|
||
|
|
return ( obj for obj in self._seq if obj in self._objs )
|
||
|
|
|
||
|
|
def __len__(self):
|
||
|
|
return len(self._objs)
|
||
|
|
|
||
|
|
def __contains__(self, obj):
|
||
|
|
return obj in self._objs
|
||
|
|
|
||
|
|
def _getrange(self, bbox):
|
||
|
|
(x0, y0, x1, y1) = bbox
|
||
|
|
if (x1 <= self.x0 or self.x1 <= x0 or
|
||
|
|
y1 <= self.y0 or self.y1 <= y0): return
|
||
|
|
x0 = max(self.x0, x0)
|
||
|
|
y0 = max(self.y0, y0)
|
||
|
|
x1 = min(self.x1, x1)
|
||
|
|
y1 = min(self.y1, y1)
|
||
|
|
for y in drange(y0, y1, self.gridsize):
|
||
|
|
for x in drange(x0, x1, self.gridsize):
|
||
|
|
yield (x, y)
|
||
|
|
return
|
||
|
|
|
||
|
|
# extend(objs)
|
||
|
|
def extend(self, objs):
|
||
|
|
for obj in objs:
|
||
|
|
self.add(obj)
|
||
|
|
return
|
||
|
|
|
||
|
|
# add(obj): place an object.
|
||
|
|
def add(self, obj):
|
||
|
|
for k in self._getrange((obj.x0, obj.y0, obj.x1, obj.y1)):
|
||
|
|
if k not in self._grid:
|
||
|
|
r = []
|
||
|
|
self._grid[k] = r
|
||
|
|
else:
|
||
|
|
r = self._grid[k]
|
||
|
|
r.append(obj)
|
||
|
|
self._seq.append(obj)
|
||
|
|
self._objs.add(obj)
|
||
|
|
return
|
||
|
|
|
||
|
|
# remove(obj): displace an object.
|
||
|
|
def remove(self, obj):
|
||
|
|
for k in self._getrange((obj.x0, obj.y0, obj.x1, obj.y1)):
|
||
|
|
try:
|
||
|
|
self._grid[k].remove(obj)
|
||
|
|
except (KeyError, ValueError):
|
||
|
|
pass
|
||
|
|
self._objs.remove(obj)
|
||
|
|
return
|
||
|
|
|
||
|
|
# find(): finds objects that are in a certain area.
|
||
|
|
def find(self, bbox):
|
||
|
|
(x0, y0, x1, y1) = bbox
|
||
|
|
done = set()
|
||
|
|
for k in self._getrange(bbox):
|
||
|
|
if k not in self._grid:
|
||
|
|
continue
|
||
|
|
for obj in self._grid[k]:
|
||
|
|
if obj in done:
|
||
|
|
continue
|
||
|
|
done.add(obj)
|
||
|
|
if (obj.x1 <= x0 or x1 <= obj.x0 or
|
||
|
|
obj.y1 <= y0 or y1 <= obj.y0):
|
||
|
|
continue
|
||
|
|
yield obj
|
||
|
|
return
|