Skip to content
Permalink
Branch: master
Find file Copy path
Find file Copy path
Fetching contributors…
Cannot retrieve contributors at this time
735 lines (607 sloc) 21.3 KB
#!/usr/bin/env python
from .utils import INF
from .utils import Plane
from .utils import get_bound
from .utils import uniq
from .utils import csort
from .utils import fsplit
from .utils import bbox2str
from .utils import matrix2str
from .utils import apply_matrix_pt
## IndexAssigner
##
class IndexAssigner:
def __init__(self, index=0):
self.index = index
return
def run(self, obj):
if isinstance(obj, LTTextBox):
obj.index = self.index
self.index += 1
elif isinstance(obj, LTTextGroup):
for x in obj:
self.run(x)
return
## LAParams
##
class LAParams:
def __init__(self,
line_overlap=0.5,
char_margin=2.0,
line_margin=0.5,
word_margin=0.1,
boxes_flow=0.5,
detect_vertical=False,
all_texts=False):
self.line_overlap = line_overlap
self.char_margin = char_margin
self.line_margin = line_margin
self.word_margin = word_margin
self.boxes_flow = boxes_flow
self.detect_vertical = detect_vertical
self.all_texts = all_texts
return
def __repr__(self):
return ('<LAParams: char_margin=%.1f, line_margin=%.1f, word_margin=%.1f all_texts=%r>' %
(self.char_margin, self.line_margin, self.word_margin, self.all_texts))
## LTItem
##
class LTItem:
def analyze(self, laparams):
"""Perform the layout analysis."""
return
## LTText
##
class LTText:
def __repr__(self):
return ('<%s %r>' %
(self.__class__.__name__, self.get_text()))
def get_text(self):
raise NotImplementedError
## LTComponent
##
class LTComponent(LTItem):
def __init__(self, bbox):
LTItem.__init__(self)
self.set_bbox(bbox)
return
def __repr__(self):
return ('<%s %s>' %
(self.__class__.__name__, bbox2str(self.bbox)))
# Disable comparison.
def __lt__(self, _):
raise ValueError
def __le__(self, _):
raise ValueError
def __gt__(self, _):
raise ValueError
def __ge__(self, _):
raise ValueError
def set_bbox(self, bbox):
(x0, y0, x1, y1) = bbox
self.x0 = x0
self.y0 = y0
self.x1 = x1
self.y1 = y1
self.width = x1-x0
self.height = y1-y0
self.bbox = bbox
return
def is_empty(self):
return self.width <= 0 or self.height <= 0
def is_hoverlap(self, obj):
assert isinstance(obj, LTComponent)
return obj.x0 <= self.x1 and self.x0 <= obj.x1
def hdistance(self, obj):
assert isinstance(obj, LTComponent)
if self.is_hoverlap(obj):
return 0
else:
return min(abs(self.x0-obj.x1), abs(self.x1-obj.x0))
def hoverlap(self, obj):
assert isinstance(obj, LTComponent)
if self.is_hoverlap(obj):
return min(abs(self.x0-obj.x1), abs(self.x1-obj.x0))
else:
return 0
def is_voverlap(self, obj):
assert isinstance(obj, LTComponent)
return obj.y0 <= self.y1 and self.y0 <= obj.y1
def vdistance(self, obj):
assert isinstance(obj, LTComponent)
if self.is_voverlap(obj):
return 0
else:
return min(abs(self.y0-obj.y1), abs(self.y1-obj.y0))
def voverlap(self, obj):
assert isinstance(obj, LTComponent)
if self.is_voverlap(obj):
return min(abs(self.y0-obj.y1), abs(self.y1-obj.y0))
else:
return 0
## LTCurve
##
class LTCurve(LTComponent):
def __init__(self, linewidth, pts):
LTComponent.__init__(self, get_bound(pts))
self.pts = pts
self.linewidth = linewidth
return
def get_pts(self):
return ','.join('%.3f,%.3f' % p for p in self.pts)
## LTLine
##
class LTLine(LTCurve):
def __init__(self, linewidth, p0, p1):
LTCurve.__init__(self, linewidth, [p0, p1])
return
## LTRect
##
class LTRect(LTCurve):
def __init__(self, linewidth, bbox):
(x0, y0, x1, y1) = bbox
LTCurve.__init__(self, linewidth, [(x0, y0), (x1, y0), (x1, y1), (x0, y1)])
return
## LTImage
##
class LTImage(LTComponent):
def __init__(self, name, stream, bbox):
LTComponent.__init__(self, bbox)
self.name = name
self.stream = stream
self.srcsize = (stream.get_any(('W', 'Width')),
stream.get_any(('H', 'Height')))
self.imagemask = stream.get_any(('IM', 'ImageMask'))
self.bits = stream.get_any(('BPC', 'BitsPerComponent'), 1)
self.colorspace = stream.get_any(('CS', 'ColorSpace'))
if not isinstance(self.colorspace, list):
self.colorspace = [self.colorspace]
return
def __repr__(self):
return ('<%s(%s) %s %r>' %
(self.__class__.__name__, self.name,
bbox2str(self.bbox), self.srcsize))
## LTAnno
##
class LTAnno(LTItem, LTText):
def __init__(self, text):
self._text = text
return
def get_text(self):
return self._text
## LTChar
##
class LTChar(LTComponent, LTText):
def __init__(self, matrix, font, fontsize, scaling, rise,
text, textwidth, textdisp):
LTText.__init__(self)
self._text = text
self.matrix = matrix
self.fontname = font.fontname
self.adv = textwidth * fontsize * scaling
# compute the boundary rectangle.
if font.is_vertical():
# vertical
width = font.get_width() * fontsize
(vx, vy) = textdisp
if vx is None:
vx = width * 0.5
else:
vx = vx * fontsize * .001
vy = (1000 - vy) * fontsize * .001
tx = -vx
ty = vy + rise
bll = (tx, ty+self.adv)
bur = (tx+width, ty)
else:
# horizontal
height = font.get_height() * fontsize
descent = font.get_descent() * fontsize
ty = descent + rise
bll = (0, ty)
bur = (self.adv, ty+height)
(a, b, c, d, e, f) = self.matrix
self.upright = (0 < a*d*scaling and b*c <= 0)
(x0, y0) = apply_matrix_pt(self.matrix, bll)
(x1, y1) = apply_matrix_pt(self.matrix, bur)
if x1 < x0:
(x0, x1) = (x1, x0)
if y1 < y0:
(y0, y1) = (y1, y0)
LTComponent.__init__(self, (x0, y0, x1, y1))
if font.is_vertical():
self.size = self.width
else:
self.size = self.height
return
def __repr__(self):
return ('<%s %s matrix=%s font=%r adv=%s text=%r>' %
(self.__class__.__name__, bbox2str(self.bbox),
matrix2str(self.matrix), self.fontname, self.adv,
self.get_text()))
def get_text(self):
return self._text
def is_compatible(self, obj):
"""Returns True if two characters can coexist in the same line."""
return True
## LTContainer
##
class LTContainer(LTComponent):
def __init__(self, bbox):
LTComponent.__init__(self, bbox)
self._objs = []
return
def __iter__(self):
return iter(self._objs)
def __len__(self):
return len(self._objs)
def add(self, obj):
self._objs.append(obj)
return
def extend(self, objs):
for obj in objs:
self.add(obj)
return
def analyze(self, laparams):
for obj in self._objs:
obj.analyze(laparams)
return
## LTExpandableContainer
##
class LTExpandableContainer(LTContainer):
def __init__(self):
LTContainer.__init__(self, (+INF, +INF, -INF, -INF))
return
def add(self, obj):
LTContainer.add(self, obj)
self.set_bbox((min(self.x0, obj.x0), min(self.y0, obj.y0),
max(self.x1, obj.x1), max(self.y1, obj.y1)))
return
## LTTextContainer
##
class LTTextContainer(LTExpandableContainer, LTText):
def __init__(self):
LTText.__init__(self)
LTExpandableContainer.__init__(self)
return
def get_text(self):
return ''.join(obj.get_text() for obj in self if isinstance(obj, LTText))
## LTTextLine
##
class LTTextLine(LTTextContainer):
def __init__(self, word_margin):
LTTextContainer.__init__(self)
self.word_margin = word_margin
return
def __repr__(self):
return ('<%s %s %r>' %
(self.__class__.__name__, bbox2str(self.bbox),
self.get_text()))
def analyze(self, laparams):
LTTextContainer.analyze(self, laparams)
LTContainer.add(self, LTAnno('\n'))
return
def find_neighbors(self, plane, ratio):
raise NotImplementedError
class LTTextLineHorizontal(LTTextLine):
def __init__(self, word_margin):
LTTextLine.__init__(self, word_margin)
self._x1 = +INF
return
def add(self, obj):
if isinstance(obj, LTChar) and self.word_margin:
margin = self.word_margin * max(obj.width, obj.height)
if self._x1 < obj.x0-margin:
LTContainer.add(self, LTAnno(' '))
self._x1 = obj.x1
LTTextLine.add(self, obj)
return
def find_neighbors(self, plane, ratio):
d = ratio*self.height
objs = plane.find((self.x0, self.y0-d, self.x1, self.y1+d))
return [obj for obj in objs
if (isinstance(obj, LTTextLineHorizontal) and
abs(obj.height-self.height) < d and
(abs(obj.x0-self.x0) < d or
abs(obj.x1-self.x1) < d))]
class LTTextLineVertical(LTTextLine):
def __init__(self, word_margin):
LTTextLine.__init__(self, word_margin)
self._y0 = -INF
return
def add(self, obj):
if isinstance(obj, LTChar) and self.word_margin:
margin = self.word_margin * max(obj.width, obj.height)
if obj.y1+margin < self._y0:
LTContainer.add(self, LTAnno(' '))
self._y0 = obj.y0
LTTextLine.add(self, obj)
return
def find_neighbors(self, plane, ratio):
d = ratio*self.width
objs = plane.find((self.x0-d, self.y0, self.x1+d, self.y1))
return [obj for obj in objs
if (isinstance(obj, LTTextLineVertical) and
abs(obj.width-self.width) < d and
(abs(obj.y0-self.y0) < d or
abs(obj.y1-self.y1) < d))]
## LTTextBox
##
## A set of text objects that are grouped within
## a certain rectangular area.
##
class LTTextBox(LTTextContainer):
def __init__(self):
LTTextContainer.__init__(self)
self.index = -1
return
def __repr__(self):
return ('<%s(%s) %s %r>' %
(self.__class__.__name__,
self.index, bbox2str(self.bbox), self.get_text()))
class LTTextBoxHorizontal(LTTextBox):
def analyze(self, laparams):
LTTextBox.analyze(self, laparams)
self._objs = csort(self._objs, key=lambda obj: -obj.y1)
return
def get_writing_mode(self):
return 'lr-tb'
class LTTextBoxVertical(LTTextBox):
def analyze(self, laparams):
LTTextBox.analyze(self, laparams)
self._objs = csort(self._objs, key=lambda obj: -obj.x1)
return
def get_writing_mode(self):
return 'tb-rl'
## LTTextGroup
##
class LTTextGroup(LTTextContainer):
def __init__(self, objs):
LTTextContainer.__init__(self)
self.extend(objs)
return
class LTTextGroupLRTB(LTTextGroup):
def analyze(self, laparams):
LTTextGroup.analyze(self, laparams)
# reorder the objects from top-left to bottom-right.
self._objs = csort(self._objs, key=lambda obj:
(1-laparams.boxes_flow)*(obj.x0) -
(1+laparams.boxes_flow)*(obj.y0+obj.y1))
return
class LTTextGroupTBRL(LTTextGroup):
def analyze(self, laparams):
LTTextGroup.analyze(self, laparams)
# reorder the objects from top-right to bottom-left.
self._objs = csort(self._objs, key=lambda obj:
-(1+laparams.boxes_flow)*(obj.x0+obj.x1)
- (1-laparams.boxes_flow)*(obj.y1))
return
## LTLayoutContainer
##
class LTLayoutContainer(LTContainer):
def __init__(self, bbox):
LTContainer.__init__(self, bbox)
self.groups = None
return
# group_objects: group text object to textlines.
def group_objects(self, laparams, objs):
obj0 = None
line = None
for obj1 in objs:
if obj0 is not None:
# halign: obj0 and obj1 is horizontally aligned.
#
# +------+ - - -
# | obj0 | - - +------+ -
# | | | obj1 | | (line_overlap)
# +------+ - - | | -
# - - - +------+
#
# |<--->|
# (char_margin)
halign = (obj0.is_compatible(obj1) and
obj0.is_voverlap(obj1) and
(min(obj0.height, obj1.height) * laparams.line_overlap <
obj0.voverlap(obj1)) and
(obj0.hdistance(obj1) <
max(obj0.width, obj1.width) * laparams.char_margin))
# valign: obj0 and obj1 is vertically aligned.
#
# +------+
# | obj0 |
# | |
# +------+ - - -
# | | | (char_margin)
# +------+ - -
# | obj1 |
# | |
# +------+
#
# |<-->|
# (line_overlap)
valign = (laparams.detect_vertical and
obj0.is_compatible(obj1) and
obj0.is_hoverlap(obj1) and
(min(obj0.width, obj1.width) * laparams.line_overlap <
obj0.hoverlap(obj1)) and
(obj0.vdistance(obj1) <
max(obj0.height, obj1.height) * laparams.char_margin))
if ((halign and isinstance(line, LTTextLineHorizontal)) or
(valign and isinstance(line, LTTextLineVertical))):
line.add(obj1)
elif line is not None:
yield line
line = None
else:
if valign and not halign:
line = LTTextLineVertical(laparams.word_margin)
line.add(obj0)
line.add(obj1)
elif halign and not valign:
line = LTTextLineHorizontal(laparams.word_margin)
line.add(obj0)
line.add(obj1)
else:
line = LTTextLineHorizontal(laparams.word_margin)
line.add(obj0)
yield line
line = None
obj0 = obj1
if line is None:
line = LTTextLineHorizontal(laparams.word_margin)
line.add(obj0)
yield line
return
# group_textlines: group neighboring lines to textboxes.
def group_textlines(self, laparams, lines):
plane = Plane(self.bbox)
plane.extend(lines)
boxes = {}
for line in lines:
neighbors = line.find_neighbors(plane, laparams.line_margin)
if line not in neighbors: continue
members = []
for obj1 in neighbors:
members.append(obj1)
if obj1 in boxes:
members.extend(boxes.pop(obj1))
if isinstance(line, LTTextLineHorizontal):
box = LTTextBoxHorizontal()
else:
box = LTTextBoxVertical()
for obj in uniq(members):
box.add(obj)
boxes[obj] = box
done = set()
for line in lines:
if line not in boxes: continue
box = boxes[line]
if box in done:
continue
done.add(box)
if not box.is_empty():
yield box
return
# group_textboxes: group textboxes hierarchically.
def group_textboxes(self, laparams, boxes):
assert boxes
def dist(obj1, obj2):
"""A distance function between two TextBoxes.
Consider the bounding rectangle for obj1 and obj2.
Return its area less the areas of obj1 and obj2,
shown as 'www' below. This value may be negative.
+------+..........+ (x1, y1)
| obj1 |wwwwwwwwww:
+------+www+------+
:wwwwwwwwww| obj2 |
(x0, y0) +..........+------+
"""
x0 = min(obj1.x0, obj2.x0)
y0 = min(obj1.y0, obj2.y0)
x1 = max(obj1.x1, obj2.x1)
y1 = max(obj1.y1, obj2.y1)
return ((x1-x0)*(y1-y0) - obj1.width*obj1.height - obj2.width*obj2.height)
def isany(obj1, obj2):
"""Check if there's any other object between obj1 and obj2.
"""
x0 = min(obj1.x0, obj2.x0)
y0 = min(obj1.y0, obj2.y0)
x1 = max(obj1.x1, obj2.x1)
y1 = max(obj1.y1, obj2.y1)
objs = set(plane.find((x0, y0, x1, y1)))
return objs.difference((obj1, obj2))
def key_obj(t):
(c,d,_,_) = t
return (c,d)
# XXX this still takes O(n^2) :(
dists = []
for i in range(len(boxes)):
obj1 = boxes[i]
for j in range(i+1, len(boxes)):
obj2 = boxes[j]
dists.append((0, dist(obj1, obj2), obj1, obj2))
# We could use dists.sort(), but it would randomize the test result.
dists = csort(dists, key=key_obj)
plane = Plane(self.bbox)
plane.extend(boxes)
while dists:
(c, d, obj1, obj2) = dists.pop(0)
if c == 0 and isany(obj1, obj2):
dists.append((1, d, obj1, obj2))
continue
if (isinstance(obj1, (LTTextBoxVertical, LTTextGroupTBRL)) or
isinstance(obj2, (LTTextBoxVertical, LTTextGroupTBRL))):
group = LTTextGroupTBRL([obj1, obj2])
else:
group = LTTextGroupLRTB([obj1, obj2])
plane.remove(obj1)
plane.remove(obj2)
dists = [ (c,d,obj1,obj2) for (c,d,obj1,obj2) in dists
if (obj1 in plane and obj2 in plane) ]
for other in plane:
dists.append((0, dist(group, other), group, other))
dists = csort(dists, key=key_obj)
plane.add(group)
assert len(plane) == 1
return list(plane)
def analyze(self, laparams):
# textobjs is a list of LTChar objects, i.e.
# it has all the individual characters in the page.
(textobjs, otherobjs) = fsplit(lambda obj: isinstance(obj, LTChar), self)
for obj in otherobjs:
obj.analyze(laparams)
if not textobjs:
return
textlines = list(self.group_objects(laparams, textobjs))
(empties, textlines) = fsplit(lambda obj: obj.is_empty(), textlines)
for obj in empties:
obj.analyze(laparams)
textboxes = list(self.group_textlines(laparams, textlines))
if -1 <= laparams.boxes_flow and laparams.boxes_flow <= +1 and textboxes:
self.groups = self.group_textboxes(laparams, textboxes)
assigner = IndexAssigner()
for group in self.groups:
group.analyze(laparams)
assigner.run(group)
textboxes.sort(key=lambda box: box.index)
else:
def getkey(box):
if isinstance(box, LTTextBoxVertical):
return (0, -box.x1, box.y0)
else:
return (1, box.y0, box.x0)
textboxes.sort(key=getkey)
self._objs = textboxes + otherobjs + empties
return
## LTFigure
##
class LTFigure(LTLayoutContainer):
def __init__(self, name, bbox, matrix):
self.name = name
self.matrix = matrix
(x, y, w, h) = bbox
bbox = get_bound(apply_matrix_pt(matrix, (p, q))
for (p, q) in ((x, y), (x+w, y), (x, y+h), (x+w, y+h)))
LTLayoutContainer.__init__(self, bbox)
return
def __repr__(self):
return ('<%s(%s) %s matrix=%s>' %
(self.__class__.__name__, self.name,
bbox2str(self.bbox), matrix2str(self.matrix)))
def analyze(self, laparams):
if not laparams.all_texts:
return
LTLayoutContainer.analyze(self, laparams)
return
## LTPage
##
class LTPage(LTLayoutContainer):
def __init__(self, pageid, bbox, rotate=0):
LTLayoutContainer.__init__(self, bbox)
self.pageid = pageid
self.rotate = rotate
return
def __repr__(self):
return ('<%s(%r) %s rotate=%r>' %
(self.__class__.__name__, self.pageid,
bbox2str(self.bbox), self.rotate))
You can’t perform that action at this time.