666 lines
20 KiB
Python
666 lines
20 KiB
Python
#!/usr/bin/env python
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import sys
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from utils import apply_matrix_pt, get_bound, INF
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from utils import bsearch, bbox2str, matrix2str
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from pdffont import PDFUnicodeNotDefined
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def uniq(objs):
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done = set()
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for obj in objs:
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if obj in done: continue
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done.add(obj)
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yield obj
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return
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def csort(objs, key):
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idxs = dict( (obj,i) for (i,obj) in enumerate(objs) )
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return sorted(objs, key=lambda obj:(key(obj), idxs[obj]))
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## LAParams
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##
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class LAParams(object):
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def __init__(self,
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writing_mode='lr-tb',
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line_overlap=0.5,
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char_margin=2.0,
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line_margin=0.5,
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word_margin=0.1,
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all_texts=False):
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self.writing_mode = writing_mode
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self.line_overlap = line_overlap
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self.char_margin = char_margin
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self.line_margin = line_margin
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self.word_margin = word_margin
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self.all_texts = all_texts
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return
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def __repr__(self):
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return ('<LAParams: char_margin=%.1f, line_margin=%.1f, word_margin=%.1f all_texts=%r>' %
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(self.char_margin, self.line_margin, self.word_margin, self.all_texts))
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## LTItem
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##
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class LTItem(object):
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def __init__(self, bbox):
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self.set_bbox(bbox)
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return
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def __repr__(self):
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return ('<%s %s>' %
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(self.__class__.__name__, bbox2str(self.bbox)))
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def set_bbox(self, (x0,y0,x1,y1)):
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if x1 < x0: (x0,x1) = (x1,x0)
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if y1 < y0: (y0,y1) = (y1,y0)
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self.x0 = x0
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self.y0 = y0
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self.x1 = x1
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self.y1 = y1
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self.width = x1-x0
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self.height = y1-y0
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self.bbox = (x0, y0, x1, y1)
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return
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def is_hoverlap(self, obj):
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assert isinstance(obj, LTItem)
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return obj.x0 <= self.x1 and self.x0 <= obj.x1
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def hdistance(self, obj):
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assert isinstance(obj, LTItem)
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if self.is_hoverlap(obj):
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return 0
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else:
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return min(abs(self.x0-obj.x1), abs(self.x1-obj.x0))
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def hoverlap(self, obj):
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assert isinstance(obj, LTItem)
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if self.is_hoverlap(obj):
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return min(abs(self.x0-obj.x1), abs(self.x1-obj.x0))
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else:
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return 0
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def is_voverlap(self, obj):
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assert isinstance(obj, LTItem)
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return obj.y0 <= self.y1 and self.y0 <= obj.y1
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def vdistance(self, obj):
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assert isinstance(obj, LTItem)
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if self.is_voverlap(obj):
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return 0
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else:
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return min(abs(self.y0-obj.y1), abs(self.y1-obj.y0))
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def voverlap(self, obj):
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assert isinstance(obj, LTItem)
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if self.is_voverlap(obj):
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return min(abs(self.y0-obj.y1), abs(self.y1-obj.y0))
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else:
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return 0
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## LTPolygon
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##
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class LTPolygon(LTItem):
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def __init__(self, linewidth, pts):
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self.pts = pts
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self.linewidth = linewidth
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LTItem.__init__(self, get_bound(pts))
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return
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def get_pts(self):
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return ','.join( '%.3f,%.3f' % p for p in self.pts )
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## LTLine
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##
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class LTLine(LTPolygon):
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def __init__(self, linewidth, p0, p1):
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LTPolygon.__init__(self, linewidth, [p0, p1])
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return
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## LTRect
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##
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class LTRect(LTPolygon):
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def __init__(self, linewidth, (x0,y0,x1,y1)):
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LTPolygon.__init__(self, linewidth, [(x0,y0), (x1,y0), (x1,y1), (x0,y1)])
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return
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## LTImage
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##
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class LTImage(LTItem):
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def __init__(self, name, stream, bbox):
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LTItem.__init__(self, bbox)
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self.name = name
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self.stream = stream
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self.srcsize = (stream.get_any(('W', 'Width')),
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stream.get_any(('H', 'Height')))
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self.imagemask = stream.get_any(('IM', 'ImageMask'))
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self.bits = stream.get_any(('BPC', 'BitsPerComponent'), 1)
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self.colorspace = stream.get_any(('CS', 'ColorSpace'))
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if not isinstance(self.colorspace, list):
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self.colorspace = [self.colorspace]
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return
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def __repr__(self):
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(w,h) = self.srcsize
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return ('<%s(%s) %s %dx%d>' %
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(self.__class__.__name__, self.name,
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bbox2str(self.bbox), w, h))
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## LTText
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##
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class LTText(object):
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def __init__(self, text):
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self.text = text
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return
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def __repr__(self):
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return ('<%s %r>' %
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(self.__class__.__name__, self.get_text()))
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def get_text(self):
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return self.text
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## LTAnon
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##
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class LTAnon(LTText):
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pass
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## LTChar
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##
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class LTChar(LTItem, LTText):
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debug = 0
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def __init__(self, matrix, font, fontsize, scaling, rise, cid):
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self.matrix = matrix
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self.font = font
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self.fontsize = fontsize
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self.adv = font.char_width(cid) * fontsize * scaling
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try:
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text = font.to_unichr(cid)
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assert isinstance(text, unicode), text
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except PDFUnicodeNotDefined:
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text = '?'
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LTText.__init__(self, text)
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# compute the boundary rectangle.
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if self.font.is_vertical():
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# vertical
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width = font.get_width() * fontsize
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(vx,vy) = font.char_disp(cid)
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if vx is None:
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vx = width/2
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else:
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vx = vx * fontsize * .001
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vy = (1000 - vy) * fontsize * .001
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tx = -vx
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ty = vy + rise
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bll = (tx, ty+self.adv)
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bur = (tx+width, ty)
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else:
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# horizontal
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height = font.get_height() * fontsize
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descent = font.get_descent() * fontsize
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ty = descent + rise
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bll = (0, ty)
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bur = (self.adv, ty+height)
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(a,b,c,d,e,f) = self.matrix
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self.upright = (0 < a*d*scaling and b*c <= 0)
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bbox = (apply_matrix_pt(self.matrix, bll) +
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apply_matrix_pt(self.matrix, bur))
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LTItem.__init__(self, bbox)
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return
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def __repr__(self):
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if self.debug:
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return ('<%s %s matrix=%s font=%r fontsize=%.1f adv=%s text=%r>' %
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(self.__class__.__name__, bbox2str(self.bbox),
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matrix2str(self.matrix), self.font, self.fontsize,
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self.adv, self.get_text()))
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else:
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return '<char %r>' % self.text
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def get_size(self):
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return max(self.width, self.height)
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def is_compatible(self, obj):
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return True
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## LTContainer
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##
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class LTContainer(LTItem):
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def __init__(self, objs=None, bbox=(0,0,0,0)):
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LTItem.__init__(self, bbox)
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if objs:
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self._objs = objs[:]
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else:
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self._objs = []
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return
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def __iter__(self):
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return iter(self.get_objs())
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def __len__(self):
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return len(self.get_objs())
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def add(self, obj):
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self._objs.append(obj)
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return
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def merge(self, container):
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self._objs.extend(container._objs)
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return
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def get_objs(self):
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return self._objs
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# fixate(): determines its boundery.
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def fixate(self):
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if not self.width and self._objs:
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(bx0, by0, bx1, by1) = (INF, INF, -INF, -INF)
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for obj in self._objs:
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bx0 = min(bx0, obj.x0)
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by0 = min(by0, obj.y0)
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bx1 = max(bx1, obj.x1)
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by1 = max(by1, obj.y1)
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self.set_bbox((bx0, by0, bx1, by1))
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return
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## LTTextLine
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##
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class LTTextLine(LTContainer, LTText):
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def __init__(self, laparams=None):
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self.laparams = laparams
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LTContainer.__init__(self)
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return
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def __repr__(self):
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return ('<%s %s %r>' %
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(self.__class__.__name__, bbox2str(self.bbox),
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self.get_text()))
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def get_text(self):
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return ''.join( obj.text for obj in self.get_objs() if isinstance(obj, LTText) )
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def find_neighbors(self, plane, ratio):
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raise NotImplementedError
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class LTTextLineHorizontal(LTTextLine):
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def get_objs(self):
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if self.laparams is None:
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for obj in self._objs:
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yield obj
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return
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word_margin = self.laparams.word_margin
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x1 = INF
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for obj in csort(self._objs, key=lambda obj: obj.x0):
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if isinstance(obj, LTChar) and word_margin:
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margin = word_margin * obj.width
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if x1 < obj.x0-margin:
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yield LTAnon(' ')
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yield obj
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x1 = obj.x1
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yield LTAnon('\n')
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return
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def find_neighbors(self, plane, ratio):
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h = ratio*self.height
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objs = plane.find((self.x0, self.y0-h, self.x1, self.y1+h))
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return [ obj for obj in objs if isinstance(obj, LTTextLineHorizontal) ]
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class LTTextLineVertical(LTTextLine):
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def get_objs(self):
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if self.laparams is None:
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for obj in self._objs:
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yield obj
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return
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word_margin = self.laparams.word_margin
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y0 = -INF
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for obj in csort(self._objs, key=lambda obj: -obj.y1):
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if isinstance(obj, LTChar) and word_margin:
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margin = word_margin * obj.height
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if obj.y1+margin < y0:
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yield LTAnon(' ')
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yield obj
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y0 = obj.y0
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yield LTAnon('\n')
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return
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def find_neighbors(self, plane, ratio):
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w = ratio*self.width
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objs = plane.find((self.x0-w, self.y0, self.x1+w, self.y1))
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return [ obj for obj in objs if isinstance(obj, LTTextLineVertical) ]
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## LTTextBox
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##
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## A set of text objects that are grouped within
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## a certain rectangular area.
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##
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class LTTextBox(LTContainer):
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def __init__(self, objs):
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LTContainer.__init__(self, objs=objs)
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self.index = None
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return
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def __repr__(self):
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return ('<%s(%s) %s %r...>' %
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(self.__class__.__name__, self.index,
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bbox2str(self.bbox), self.get_text()[:20]))
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def get_text(self):
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return ''.join( obj.get_text() for obj in self.get_objs() if isinstance(obj, LTTextLine) )
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class LTTextBoxHorizontal(LTTextBox):
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def get_objs(self):
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return csort(self._objs, key=lambda obj: -obj.y1)
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class LTTextBoxVertical(LTTextBox):
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def get_objs(self):
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return csort(self._objs, key=lambda obj: -obj.x1)
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## LTTextGroup
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##
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class LTTextGroup(LTContainer):
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def __init__(self, objs):
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LTContainer.__init__(self, objs=objs)
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LTContainer.fixate(self)
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return
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class LTTextGroupLRTB(LTTextGroup):
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def get_objs(self):
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# reorder the objects from top-left to bottom-right.
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return csort(self._objs, key=lambda obj: obj.x0+obj.x1-(obj.y0+obj.y1))
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class LTTextGroupTBRL(LTTextGroup):
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def get_objs(self):
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# reorder the objects from top-right to bottom-left.
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return csort(self._objs, key=lambda obj: -(obj.x0+obj.x1)-(obj.y0+obj.y1))
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## Plane
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##
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## A data structure for objects placed on a plane.
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## Can efficiently find objects in a certain rectangular area.
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## It maintains two parallel lists of objects, each of
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## which is sorted by its x or y coordinate.
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##
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class Plane(object):
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def __init__(self, objs):
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self.xobjs = []
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self.yobjs = []
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self.idxs = dict( (obj,i) for (i,obj) in enumerate(objs) )
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for obj in objs:
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self.place(obj)
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self.xobjs.sort()
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self.yobjs.sort()
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return
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# place(obj): place an object in a certain area.
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def place(self, obj):
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assert isinstance(obj, LTItem)
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self.xobjs.append((obj.x0, obj))
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self.xobjs.append((obj.x1, obj))
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self.yobjs.append((obj.y0, obj))
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self.yobjs.append((obj.y1, obj))
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return
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# find(): finds objects that are in a certain area.
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def find(self, (x0,y0,x1,y1)):
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i0 = bsearch(self.xobjs, x0)[0]
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i1 = bsearch(self.xobjs, x1)[1]
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xobjs = set( obj for (_,obj) in self.xobjs[i0:i1] )
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i0 = bsearch(self.yobjs, y0)[0]
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i1 = bsearch(self.yobjs, y1)[1]
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yobjs = set( obj for (_,obj) in self.yobjs[i0:i1] )
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xobjs.intersection_update(yobjs)
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return sorted(xobjs, key=lambda obj: self.idxs[obj])
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## LTAnalyzer
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##
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class LTAnalyzer(LTContainer):
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def analyze(self, laparams=None):
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"""Perform the layout analysis."""
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if laparams is None: return
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# textobjs is a list of LTChar objects, i.e.
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# it has all the individual characters in the page.
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(textobjs, otherobjs) = self.get_textobjs(self._objs, laparams)
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if not textobjs: return
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textlines = list(self.get_textlines(textobjs, laparams))
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assert sum( len(line._objs) for line in textlines ) == len(textobjs)
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textboxes = list(self.get_textboxes(textlines, laparams))
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assert sum( len(box._objs) for box in textboxes ) == len(textlines)
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top = self.group_textboxes(textboxes, laparams)
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def assign_index(obj, i):
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if isinstance(obj, LTTextBox):
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obj.index = i
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i += 1
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elif isinstance(obj, LTTextGroup):
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for x in obj:
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i = assign_index(x, i)
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return i
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assign_index(top, 0)
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textboxes.sort(key=lambda box:box.index)
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self._objs = textboxes + otherobjs
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self.layout = top
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return
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def get_textobjs(self, objs, laparams):
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"""Split all the objects in the page into text-related objects and others."""
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textobjs = []
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otherobjs = []
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for obj in objs:
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if isinstance(obj, LTChar):
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textobjs.append(obj)
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else:
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otherobjs.append(obj)
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return (textobjs, otherobjs)
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def get_textlines(self, objs, laparams):
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obj0 = None
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line = None
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for obj1 in objs:
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if obj0 is not None:
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k = 0
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if (obj0.is_compatible(obj1) and obj0.is_voverlap(obj1) and
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min(obj0.height, obj1.height) * laparams.line_overlap < obj0.voverlap(obj1) and
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obj0.hdistance(obj1) < min(obj0.width, obj1.width) * laparams.char_margin):
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# obj0 and obj1 is horizontally aligned:
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#
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# +------+ - - -
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# | obj0 | - - +------+ -
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# | | | obj1 | | (line_overlap)
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# +------+ - - | | -
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# - - - +------+
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#
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# |<--->|
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# (char_margin)
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k |= 1
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if (obj0.is_compatible(obj1) and obj0.is_hoverlap(obj1) and
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min(obj0.width, obj1.width) * laparams.line_overlap < obj0.hoverlap(obj1) and
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obj0.vdistance(obj1) < min(obj0.height, obj1.height) * laparams.char_margin):
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# obj0 and obj1 is vertically aligned:
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#
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# +------+
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# | obj0 |
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# | |
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# +------+ - - -
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# | | | (char_margin)
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# +------+ - -
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# | obj1 |
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# | |
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# +------+
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#
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# |<-->|
|
|
# (line_overlap)
|
|
k |= 2
|
|
if ( (k & 1 and isinstance(line, LTTextLineHorizontal)) or
|
|
(k & 2 and isinstance(line, LTTextLineVertical)) ):
|
|
line.add(obj1)
|
|
elif line is not None:
|
|
line.fixate()
|
|
yield line
|
|
line = None
|
|
else:
|
|
if k == 2:
|
|
line = LTTextLineVertical(laparams)
|
|
line.add(obj0)
|
|
line.add(obj1)
|
|
elif k == 1:
|
|
line = LTTextLineHorizontal(laparams)
|
|
line.add(obj0)
|
|
line.add(obj1)
|
|
else:
|
|
line = LTTextLineHorizontal(laparams)
|
|
line.add(obj0)
|
|
line.fixate()
|
|
yield line
|
|
line = None
|
|
obj0 = obj1
|
|
if line is None:
|
|
line = LTTextLineHorizontal(laparams)
|
|
line.add(obj0)
|
|
line.fixate()
|
|
yield line
|
|
return
|
|
|
|
def get_textboxes(self, lines, laparams):
|
|
plane = Plane(lines)
|
|
groups = {}
|
|
for line in lines:
|
|
neighbors = line.find_neighbors(plane, laparams.line_margin)
|
|
assert line in neighbors, line
|
|
members = neighbors[:]
|
|
for obj1 in neighbors:
|
|
if obj1 in groups:
|
|
members.extend(groups.pop(obj1))
|
|
members = list(uniq(members))
|
|
if isinstance(line, LTTextLineHorizontal):
|
|
group = LTTextBoxHorizontal(members)
|
|
else:
|
|
group = LTTextBoxVertical(members)
|
|
for obj in members:
|
|
groups[obj] = group
|
|
done = set()
|
|
for line in lines:
|
|
group = groups[line]
|
|
if group in done: continue
|
|
done.add(group)
|
|
group.fixate()
|
|
yield group
|
|
return
|
|
|
|
def group_textboxes(self, textboxes, laparams):
|
|
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.
|
|
+------+..........+
|
|
| obj1 |wwwwwwwwww:
|
|
+------+www+------+
|
|
:wwwwwwwwww| obj2 |
|
|
+..........+------+
|
|
"""
|
|
return ((max(obj1.x1,obj2.x1) - min(obj1.x0,obj2.x0)) *
|
|
(max(obj1.y1,obj2.y1) - min(obj1.y0,obj2.y0)) -
|
|
(obj1.width*obj1.height + obj2.width*obj2.height))
|
|
textboxes = textboxes[:]
|
|
# XXX this is slow when there're many textboxes.
|
|
while 2 <= len(textboxes):
|
|
mindist = INF
|
|
minpair = None
|
|
textboxes = csort(textboxes, key=lambda obj: obj.width*obj.height)
|
|
for i in xrange(len(textboxes)):
|
|
for j in xrange(i+1, len(textboxes)):
|
|
(obj1, obj2) = (textboxes[i], textboxes[j])
|
|
d = dist(obj1, obj2)
|
|
if d < mindist:
|
|
mindist = d
|
|
minpair = (obj1, obj2)
|
|
assert minpair
|
|
(obj1, obj2) = minpair
|
|
textboxes.remove(obj1)
|
|
textboxes.remove(obj2)
|
|
if isinstance(obj1, LTTextBoxHorizontal):
|
|
group = LTTextGroupLRTB([obj1, obj2])
|
|
else:
|
|
group = LTTextGroupTBRL([obj1, obj2])
|
|
textboxes.append(group)
|
|
assert len(textboxes) == 1
|
|
return textboxes.pop()
|
|
|
|
|
|
## LTFigure
|
|
##
|
|
class LTFigure(LTAnalyzer):
|
|
|
|
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)) )
|
|
LTAnalyzer.__init__(self, bbox=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=None):
|
|
if laparams is not None and laparams.all_texts:
|
|
LTAnalyzer.analyze(self, laparams=laparams)
|
|
return
|
|
|
|
|
|
## LTPage
|
|
##
|
|
class LTPage(LTAnalyzer):
|
|
|
|
def __init__(self, pageid, bbox, rotate=0):
|
|
LTAnalyzer.__init__(self, bbox=bbox)
|
|
self.pageid = pageid
|
|
self.rotate = rotate
|
|
self.layout = None
|
|
return
|
|
|
|
def __repr__(self):
|
|
return ('<%s(%r) %s rotate=%r>' %
|
|
(self.__class__.__name__, self.pageid,
|
|
bbox2str(self.bbox), self.rotate))
|