bbox.py

   1 # -*- encoding: utf-8 -*-
   2 #
   3 #
   4 # Copyright (C) 2002-2006 Jörg Lehmann <joergl@users.sourceforge.net>
   5 # Copyright (C) 2002-2004 André Wobst <wobsta@users.sourceforge.net>
   6 #
   7 # This file is part of PyX (http://pyx.sourceforge.net/).
   8 #
   9 # PyX is free software; you can redistribute it and/or modify
  10 # it under the terms of the GNU General Public License as published by
  11 # the Free Software Foundation; either version 2 of the License, or
  12 # (at your option) any later version.
  13 #
  14 # PyX is distributed in the hope that it will be useful,
  15 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 # GNU General Public License for more details.
  18 #
  19 # You should have received a copy of the GNU General Public License
  20 # along with PyX; if not, write to the Free Software
  21 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  22
  23 import math
  24 import path, unit
  25
  26 #
  27 # classes representing bounding boxes
  28 #
  29
  30 class bbox_pt:
  31
  32     """class for bounding boxes
  33
  34     This variant requires points in the constructor, and is used for internal
  35     purposes.
  36
  37     A bbox for which llx_pt is None represents an empty bbox, i.e., one containing
  38     no points.
  39     """
  40
  41     def __init__(self, llx_pt, lly_pt, urx_pt, ury_pt):
  42         self.llx_pt = llx_pt
  43         self.lly_pt = lly_pt
  44         self.urx_pt = urx_pt
  45         self.ury_pt = ury_pt
  46
  47     def __nonzero__(self):
  48         return self.llx_pt is not None
  49
  50     def __add__(self, other):
  51         """join two bboxes"""
  52         if self.llx_pt is not None:
  53             if other.llx_pt is not None:
  54                 return bbox_pt(min(self.llx_pt, other.llx_pt), min(self.lly_pt, other.lly_pt),
  55                                max(self.urx_pt, other.urx_pt), max(self.ury_pt, other.ury_pt))
  56             else:
  57                 return bbox_pt(self.llx_pt, self.lly_pt, self.urx_pt, self.ury_pt)
  58         else:
  59             return bbox_pt(other.llx_pt, other.lly_pt, other.urx_pt, other.ury_pt)
  60
  61     def __iadd__(self, other):
  62         """join two bboxes inplace"""
  63         if self.llx_pt is not None:
  64             if other.llx_pt is not None:
  65                 self.llx_pt = min(self.llx_pt, other.llx_pt)
  66                 self.lly_pt = min(self.lly_pt, other.lly_pt)
  67                 self.urx_pt = max(self.urx_pt, other.urx_pt)
  68                 self.ury_pt = max(self.ury_pt, other.ury_pt)
  69         else:
  70             self.llx_pt = other.llx_pt
  71             self.lly_pt = other.lly_pt
  72             self.urx_pt = other.urx_pt
  73             self.ury_pt = other.ury_pt
  74         return self
  75
  76     def __mul__(self, other):
  77         """return intersection of two bboxes"""
  78         if self.llx_pt is not None and other.llx_pt is not None:
  79             return bbox_pt(max(self.llx_pt, other.llx_pt), max(self.lly_pt, other.lly_pt),
  80                            min(self.urx_pt, other.urx_pt), min(self.ury_pt, other.ury_pt))
  81         else:
  82             return empty()
  83
  84     def __imul__(self, other):
  85         """intersect two bboxes in place"""
  86         if self.llx_pt is not None and other.llx_pt is not None:
  87             self.llx_pt = max(self.llx_pt, other.llx_pt)
  88             self.lly_pt = max(self.lly_pt, other.lly_pt)
  89             self.urx_pt = min(self.urx_pt, other.urx_pt)
  90             self.ury_pt = min(self.ury_pt, other.ury_pt)
  91         elif other.llx_pt is None:
  92             self.llx_pt = None
  93         return self
  94
  95     def copy(self):
  96         return bbox_pt(self.llx_pt, self.lly_pt, self.urx_pt, self.ury_pt)
  97
  98     def set(self, other):
  99         self.llx_pt = other.llx_pt
 100         self.lly_pt = other.lly_pt
 101         self.urx_pt = other.urx_pt
 102         self.ury_pt = other.ury_pt
 103
 104     def lowrestuple_pt(self):
 105         if self.llx_pt is None:
 106             raise ValueError("Cannot return low-res tuple for empty bbox")
 107         return (math.floor(self.llx_pt), math.floor(self.lly_pt),
 108                 math.ceil(self.urx_pt), math.ceil(self.ury_pt))
 109
 110     def highrestuple_pt(self):
 111         if self.llx_pt is None:
 112             raise ValueError("Cannot return high-res tuple for empty bbox")
 113         return (self.llx_pt, self.lly_pt, self.urx_pt, self.ury_pt)
 114
 115     def intersects(self, other):
 116         """check, if two bboxes intersect eachother"""
 117         if self.llx_pt is None or other.llx_pt is None:
 118             return 0
 119         else:
 120             return not (self.llx_pt > other.urx_pt or
 121                         self.lly_pt > other.ury_pt or
 122                         self.urx_pt < other.llx_pt or
 123                         self.ury_pt < other.lly_pt)
 124
 125     def includepoint_pt(self, x_pt, y_pt):
 126         if self.llx_pt is None:
 127             self.llx_pt = self.urx_pt = x_pt
 128             self.lly_pt = self.ury_pt = y_pt
 129         else:
 130             self.llx_pt = min(self.llx_pt, x_pt)
 131             self.lly_pt = min(self.lly_pt, y_pt)
 132             self.urx_pt = max(self.urx_pt, x_pt)
 133             self.ury_pt = max(self.ury_pt, y_pt)
 134
 135     def transform(self, trafo):
 136         """transform bbox in place by trafo"""
 137         if self.llx_pt is None:
 138             return
 139         # we have to transform all four corner points of the bbox
 140         llx_pt, lly_pt = trafo.apply_pt(self.llx_pt, self.lly_pt)
 141         lrx_pt, lry_pt = trafo.apply_pt(self.urx_pt, self.lly_pt)
 142         urx_pt, ury_pt = trafo.apply_pt(self.urx_pt, self.ury_pt)
 143         ulx_pt, uly_pt = trafo.apply_pt(self.llx_pt, self.ury_pt)
 144
 145         # Now, by sorting, we obtain the lower left and upper right corner
 146         # of the new bounding box.
 147         self.llx_pt = min(llx_pt, lrx_pt, urx_pt, ulx_pt)
 148         self.lly_pt = min(lly_pt, lry_pt, ury_pt, uly_pt)
 149         self.urx_pt = max(llx_pt, lrx_pt, urx_pt, ulx_pt)
 150         self.ury_pt = max(lly_pt, lry_pt, ury_pt, uly_pt)
 151
 152     def transformed(self, trafo):
 153         """return bbox transformed by trafo"""
 154         if self.llx_pt is None:
 155             return empty()
 156         # we have to transform all four corner points of the bbox
 157         llx_pt, lly_pt = trafo.apply_pt(self.llx_pt, self.lly_pt)
 158         lrx_pt, lry_pt = trafo.apply_pt(self.urx_pt, self.lly_pt)
 159         urx_pt, ury_pt = trafo.apply_pt(self.urx_pt, self.ury_pt)
 160         ulx_pt, uly_pt = trafo.apply_pt(self.llx_pt, self.ury_pt)
 161
 162         # Now, by sorting, we obtain the lower left and upper right corner
 163         # of the new bounding box.
 164         return bbox_pt(min(llx_pt, lrx_pt, urx_pt, ulx_pt), min(lly_pt, lry_pt, ury_pt, uly_pt),
 165                        max(llx_pt, lrx_pt, urx_pt, ulx_pt), max(lly_pt, lry_pt, ury_pt, uly_pt))
 166
 167     def enlarge_pt(self, all_pt=0, bottom_pt=None, left_pt=None, top_pt=None, right_pt=None):
 168         """enlarge bbox in place by the given amounts in pts
 169
 170         all is used, if bottom, left, top and/or right are not given.
 171
 172         """
 173         if self.llx_pt is None:
 174             return
 175         if bottom_pt is None:
 176            bottom_pt = all_pt
 177         if left_pt is None:
 178            left_pt = all_pt
 179         if top_pt is None:
 180            top_pt = all_pt
 181         if right_pt is None:
 182            right_pt = all_pt
 183         self.llx_pt -= left_pt
 184         self.lly_pt -= bottom_pt
 185         self.urx_pt += right_pt
 186         self.ury_pt += top_pt
 187
 188     def enlarged_pt(self, all_pt=0, bottom_pt=None, left_pt=None, top_pt=None, right_pt=None):
 189         """return bbox enlarged by the given amounts in pts
 190
 191         all is used, if bottom, left, top and/or right are not given.
 192
 193         """
 194         if self.llx_pt is None:
 195             return empty()
 196         if bottom_pt is None:
 197            bottom_pt = all_pt
 198         if left_pt is None:
 199            left_pt = all_pt
 200         if top_pt is None:
 201            top_pt = all_pt
 202         if right_pt is None:
 203            right_pt = all_pt
 204         return bbox_pt(self.llx_pt-left_pt, self.lly_pt-bottom_pt, self.urx_pt+right_pt, self.ury_pt+top_pt)
 205
 206     def enlarge(self, all=0, bottom=None, left=None, top=None, right=None):
 207         """enlarge bbox in place
 208
 209         all is used, if bottom, left, top and/or right are not given.
 210
 211         """
 212         if self.llx_pt is None:
 213             return
 214         bottom_pt = left_pt = top_pt = right_pt = unit.topt(all)
 215         if bottom is not None:
 216            bottom_pt = unit.topt(bottom)
 217         if left is not None:
 218            left_pt = unit.topt(left)
 219         if top is not None:
 220            top_pt = unit.topt(top)
 221         if right is not None:
 222            right_pt = unit.topt(right)
 223         self.llx_pt -= left_pt
 224         self.lly_pt -= bottom_pt
 225         self.urx_pt += right_pt
 226         self.ury_pt += top_pt
 227
 228     def enlarged(self, all=0, bottom=None, left=None, top=None, right=None):
 229         """return bbox enlarged
 230
 231         all is used, if bottom, left, top and/or right are not given.
 232
 233         """
 234         if self.llx_pt is None:
 235             return empty()
 236         bottom_pt = left_pt = top_pt = right_pt = unit.topt(all)
 237         if bottom is not None:
 238            bottom_pt = unit.topt(bottom)
 239         if left is not None:
 240            left_pt = unit.topt(left)
 241         if top is not None:
 242            top_pt = unit.topt(top)
 243         if right is not None:
 244            right_pt = unit.topt(right)
 245         return bbox_pt(self.llx_pt-left_pt, self.lly_pt-bottom_pt, self.urx_pt+right_pt, self.ury_pt+top_pt)
 246
 247     def rect(self):
 248         """return rectangle corresponding to bbox"""
 249         if self.llx_pt is None:
 250             raise ValueError("Cannot return path for empty bbox")
 251         return path.rect_pt(self.llx_pt, self.lly_pt, self.urx_pt-self.llx_pt, self.ury_pt-self.lly_pt)
 252
 253     path = rect
 254
 255     def height_pt(self):
 256         """return height of bbox in pts"""
 257         if self.llx_pt is None:
 258             raise ValueError("Cannot return heigth of empty bbox")
 259         return self.ury_pt-self.lly_pt
 260
 261     def width_pt(self):
 262         """return width of bbox in pts"""
 263         if self.llx_pt is None:
 264             raise ValueError("Cannot return width of empty bbox")
 265         return self.urx_pt-self.llx_pt
 266
 267     def top_pt(self):
 268         """return top coordinate of bbox in pts"""
 269         if self.llx_pt is None:
 270             raise ValueError("Cannot return top coordinate of empty bbox")
 271         return self.ury_pt
 272
 273     def bottom_pt(self):
 274         """return bottom coordinate of bbox in pts"""
 275         if self.llx_pt is None:
 276             raise ValueError("Cannot return bottom coordinate of empty bbox")
 277         return self.lly_pt
 278
 279     def left_pt(self):
 280         """return left coordinate of bbox in pts"""
 281         if self.llx_pt is None:
 282             raise ValueError("Cannot return left coordinate of empty bbox")
 283         return self.llx_pt
 284
 285     def right_pt(self):
 286         """return right coordinate of bbox in pts"""
 287         if self.llx_pt is None:
 288             raise ValueError("Cannot return right coordinate of empty bbox")
 289         return self.urx_pt
 290
 291     def center_pt(self):
 292         """return coordinates of the center of the bbox in pts"""
 293         if self.llx_pt is None:
 294             raise ValueError("Cannot return center coordinates of empty bbox")
 295         return 0.5 * (self.llx_pt+self.urx_pt), 0.5 * (self.lly_pt+self.ury_pt)
 296
 297     def height(self):
 298         """return height of bbox"""
 299         return self.height_pt() * unit.t_pt
 300
 301     def width(self):
 302         """return width of bbox"""
 303         return self.width_pt() * unit.t_pt
 304
 305     def top(self):
 306         """return top coordinate of bbox"""
 307         return self.ury_pt * unit.t_pt
 308
 309     def bottom(self):
 310         """return bottom coordinate of bbox"""
 311         return self.lly_pt * unit.t_pt
 312
 313     def left(self):
 314         """return left coordinate of bbox"""
 315         return self.llx_pt * unit.t_pt
 316
 317     def right(self):
 318         """return right coordinate of bbox"""
 319         return self.urx_pt * unit.t_pt
 320
 321     def center(self):
 322         """return coordinates of the center of the bbox"""
 323         centerx_pt, centery_pt = self.center_pt()
 324         return centerx_pt * unit.t_pt, centery_pt * unit.t_pt
 325
 326
 327 class bbox(bbox_pt):
 328
 329     """class for bounding boxes"""
 330
 331     def __init__(self, llx_pt, lly_pt, urx_pt, ury_pt):
 332         llx_pt = unit.topt(llx_pt)
 333         lly_pt = unit.topt(lly_pt)
 334         urx_pt = unit.topt(urx_pt)
 335         ury_pt = unit.topt(ury_pt)
 336         bbox_pt.__init__(self, llx_pt, lly_pt, urx_pt, ury_pt)
 337
 338
 339 class empty(bbox_pt):
 340
 341     """empty bounding box, i.e., one containing no point"""
 342     def __init__(self):
 343         bbox_pt.__init__(self, None, None, None, None)