pyx/bbox.py

   1 #!/usr/bin/env python
   2 # -*- coding: ISO-8859-1 -*-
   3 #
   4 #
   5 # Copyright (C) 2002-2006 Jörg Lehmann <joergl@users.sourceforge.net>
   6 # Copyright (C) 2002-2004 André Wobst <wobsta@users.sourceforge.net>
   7 #
   8 # This file is part of PyX (http://pyx.sourceforge.net/).
   9 #
  10 # PyX is free software; you can redistribute it and/or modify
  11 # it under the terms of the GNU General Public License as published by
  12 # the Free Software Foundation; either version 2 of the License, or
  13 # (at your option) any later version.
  14 #
  15 # PyX is distributed in the hope that it will be useful,
  16 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 # GNU General Public License for more details.
  19 #
  20 # You should have received a copy of the GNU General Public License
  21 # along with PyX; if not, write to the Free Software
  22 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  23
  24 import math
  25 import unit
  26
  27 #
  28 # classes representing bounding boxes
  29 #
  30
  31 class bbox_pt:
  32
  33     """class for bounding boxes
  34
  35     This variant requires points in the constructor, and is used for internal
  36     purposes.
  37
  38     A bbox for which llx_pt is None represents an empty bbox, i.e., one containing
  39     no points.
  40     """
  41
  42     def __init__(self, llx_pt, lly_pt, urx_pt, ury_pt):
  43         self.llx_pt = llx_pt
  44         self.lly_pt = lly_pt
  45         self.urx_pt = urx_pt
  46         self.ury_pt = ury_pt
  47
  48     def __add__(self, other):
  49         """join two bboxes"""
  50         if self.llx_pt is not None:
  51             if other.llx_pt is not None:
  52                 return bbox_pt(min(self.llx_pt, other.llx_pt), min(self.lly_pt, other.lly_pt),
  53                                max(self.urx_pt, other.urx_pt), max(self.ury_pt, other.ury_pt))
  54             else:
  55                 return bbox_pt(self.llx_pt, self.lly_pt, self.urx_pt, self.ury_pt)
  56         else:
  57             return bbox_pt(other.llx_pt, other.lly_pt, other.urx_pt, other.ury_pt)
  58
  59     def __iadd__(self, other):
  60         """join two bboxes inplace"""
  61         if self.llx_pt is not None:
  62             if other.llx_pt is not None:
  63                 self.llx_pt = min(self.llx_pt, other.llx_pt)
  64                 self.lly_pt = min(self.lly_pt, other.lly_pt)
  65                 self.urx_pt = max(self.urx_pt, other.urx_pt)
  66                 self.ury_pt = max(self.ury_pt, other.ury_pt)
  67         else:
  68             self.llx_pt = other.llx_pt
  69             self.lly_pt = other.lly_pt
  70             self.urx_pt = other.urx_pt
  71             self.ury_pt = other.ury_pt
  72         return self
  73
  74     def __mul__(self, other):
  75         """return intersection of two bboxes"""
  76         if self.llx_pt is not None and other.llx_pt is not None:
  77             return bbox_pt(max(self.llx_pt, other.llx_pt), max(self.lly_pt, other.lly_pt),
  78                            min(self.urx_pt, other.urx_pt), min(self.ury_pt, other.ury_pt))
  79         else:
  80             return empty()
  81
  82     def __imul__(self, other):
  83         """intersect two bboxes in place"""
  84         if self.llx_pt is not None and other.llx_pt is not None:
  85             self.llx_pt = max(self.llx_pt, other.llx_pt)
  86             self.lly_pt = max(self.lly_pt, other.lly_pt)
  87             self.urx_pt = min(self.urx_pt, other.urx_pt)
  88             self.ury_pt = min(self.ury_pt, other.ury_pt)
  89         elif other.llx_pt is None:
  90             self.llx_pt = None
  91         return self
  92
  93     def copy(self):
  94         return bbox_pt(self.llx_pt, self.lly_pt, self.urx_pt, self.ury_pt)
  95
  96     def lowrestuple_pt(self):
  97         if self.llx_pt is None:
  98             raise ValueError("Cannot return low-res tuple for empty bbox")
  99         return (math.floor(self.llx_pt), math.floor(self.lly_pt),
 100                 math.ceil(self.urx_pt), math.ceil(self.ury_pt))
 101
 102     def highrestuple_pt(self):
 103         if self.llx_pt is None:
 104             raise ValueError("Cannot return high-res tuple for empty bbox")
 105         return (self.llx_pt, self.lly_pt, self.urx_pt, self.ury_pt)
 106
 107     def intersects(self, other):
 108         """check, if two bboxes intersect eachother"""
 109         if self.llx_pt is None or other.llx_pt is None:
 110             return 0
 111         else:
 112             return not (self.llx_pt > other.urx_pt or
 113                         self.lly_pt > other.ury_pt or
 114                         self.urx_pt < other.llx_pt or
 115                         self.ury_pt < other.lly_pt)
 116
 117     def includepoint_pt(self, x_pt, y_pt):
 118         if self.llx_pt is None:
 119             self.llx_pt = self.urx_pt = x_pt
 120             self.ury_pt = self.ury_pt = y_pt
 121         else:
 122             self.llx_pt = min(self.llx_pt, x_pt)
 123             self.lly_pt = min(self.lly_pt, y_pt)
 124             self.urx_pt = max(self.urx_pt, x_pt)
 125             self.ury_pt = max(self.ury_pt, y_pt)
 126
 127     def transform(self, trafo):
 128         """transform bbox in place by trafo"""
 129         if self.llx_pt is None:
 130             return
 131         # we have to transform all four corner points of the bbox
 132         llx_pt, lly_pt = trafo.apply_pt(self.llx_pt, self.lly_pt)
 133         lrx_pt, lry_pt = trafo.apply_pt(self.urx_pt, self.lly_pt)
 134         urx_pt, ury_pt = trafo.apply_pt(self.urx_pt, self.ury_pt)
 135         ulx_pt, uly_pt = trafo.apply_pt(self.llx_pt, self.ury_pt)
 136
 137         # Now, by sorting, we obtain the lower left and upper right corner
 138         # of the new bounding box.
 139         self.llx_pt = min(llx_pt, lrx_pt, urx_pt, ulx_pt)
 140         self.lly_pt = min(lly_pt, lry_pt, ury_pt, uly_pt)
 141         self.urx_pt = max(llx_pt, lrx_pt, urx_pt, ulx_pt)
 142         self.ury_pt = max(lly_pt, lry_pt, ury_pt, uly_pt)
 143
 144     def transformed(self, trafo):
 145         """return bbox transformed by trafo"""
 146         if self.llx_pt is None:
 147             return empty()
 148         # we have to transform all four corner points of the bbox
 149         llx_pt, lly_pt = trafo.apply_pt(self.llx_pt, self.lly_pt)
 150         lrx_pt, lry_pt = trafo.apply_pt(self.urx_pt, self.lly_pt)
 151         urx_pt, ury_pt = trafo.apply_pt(self.urx_pt, self.ury_pt)
 152         ulx_pt, uly_pt = trafo.apply_pt(self.llx_pt, self.ury_pt)
 153
 154         # Now, by sorting, we obtain the lower left and upper right corner
 155         # of the new bounding box.
 156         return bbox_pt(min(llx_pt, lrx_pt, urx_pt, ulx_pt), min(lly_pt, lry_pt, ury_pt, uly_pt),
 157                        max(llx_pt, lrx_pt, urx_pt, ulx_pt), max(lly_pt, lry_pt, ury_pt, uly_pt))
 158
 159     def enlarge_pt(self, all_pt=0, bottom_pt=None, left_pt=None, top_pt=None, right_pt=None):
 160         """enlarge bbox in place by the given amounts in pts
 161
 162         all is used, if bottom, left, top and/or right are not given.
 163
 164         """
 165         if self.llx_pt is None:
 166             return
 167         if bottom_pt is None:
 168            bottom_pt = all_pt
 169         if left_pt is None:
 170            left_pt = all_pt
 171         if top_pt is None:
 172            top_pt = all_pt
 173         if right_pt is None:
 174            right_pt = all_pt
 175         self.llx_pt -= left_pt
 176         self.lly_pt -= bottom_pt
 177         self.urx_pt += right_pt
 178         self.ury_pt += top_pt
 179
 180     def enlarged_pt(self, all_pt=0, bottom_pt=None, left_pt=None, top_pt=None, right_pt=None):
 181         """return bbox enlarged by the given amounts in pts
 182
 183         all is used, if bottom, left, top and/or right are not given.
 184
 185         """
 186         if self.llx_pt is None:
 187             return empty()
 188         if bottom_pt is None:
 189            bottom_pt = all_pt
 190         if left_pt is None:
 191            left_pt = all_pt
 192         if top_pt is None:
 193            top_pt = all_pt
 194         if right_pt is None:
 195            right_pt = all_pt
 196         return bbox_pt(self.llx_pt-left_pt, self.lly_pt-bottom_pt, self.urx_pt+right_pt, self.ury_pt+top_pt)
 197
 198     def enlarge(self, all=0, bottom=None, left=None, top=None, right=None):
 199         """enlarge bbox in place
 200
 201         all is used, if bottom, left, top and/or right are not given.
 202
 203         """
 204         if self.llx_pt is None:
 205             return
 206         bottom_pt = left_pt = top_pt = right_pt = unit.topt(all)
 207         if bottom is not None:
 208            bottom_pt = unit.topt(bottom)
 209         if left is not None:
 210            left_pt = unit.topt(left)
 211         if top is not None:
 212            top_pt = unit.topt(top)
 213         if right is not None:
 214            right_pt = unit.topt(right)
 215         self.llx_pt -= left_pt
 216         self.lly_pt -= bottom_pt
 217         self.urx_pt += right_pt
 218         self.ury_pt += top_pt
 219
 220     def enlarged(self, all=0, bottom=None, left=None, top=None, right=None):
 221         """return bbox enlarged
 222
 223         all is used, if bottom, left, top and/or right are not given.
 224
 225         """
 226         if self.llx_pt is None:
 227             return empty()
 228         bottom_pt = left_pt = top_pt = right_pt = unit.topt(all)
 229         if bottom is not None:
 230            bottom_pt = unit.topt(bottom)
 231         if left is not None:
 232            left_pt = unit.topt(left)
 233         if top is not None:
 234            top_pt = unit.topt(top)
 235         if right is not None:
 236            right_pt = unit.topt(right)
 237         return bbox_pt(self.llx_pt-left_pt, self.lly_pt-bottom_pt, self.urx_pt+right_pt, self.ury_pt+top_pt)
 238
 239     def rect(self):
 240         """return rectangle corresponding to bbox"""
 241         if self.llx_pt is None:
 242             raise ValueError("Cannot return path for empty bbox")
 243         import path
 244         return path.rect_pt(self.llx_pt, self.lly_pt, self.urx_pt-self.llx_pt, self.ury_pt-self.lly_pt)
 245
 246     path = rect
 247
 248     def height_pt(self):
 249         """return height of bbox in pts"""
 250         if self.llx_pt is None:
 251             raise ValueError("Cannot return heigth of empty bbox")
 252         return self.ury_pt-self.lly_pt
 253
 254     def width_pt(self):
 255         """return width of bbox in pts"""
 256         if self.llx_pt is None:
 257             raise ValueError("Cannot return width of empty bbox")
 258         return self.urx_pt-self.llx_pt
 259
 260     def top_pt(self):
 261         """return top coordinate of bbox in pts"""
 262         if self.llx_pt is None:
 263             raise ValueError("Cannot return top coordinate of empty bbox")
 264         return self.ury_pt
 265
 266     def bottom_pt(self):
 267         """return bottom coordinate of bbox in pts"""
 268         if self.llx_pt is None:
 269             raise ValueError("Cannot return bottom coordinate of empty bbox")
 270         return self.lly_pt
 271
 272     def left_pt(self):
 273         """return left coordinate of bbox in pts"""
 274         if self.llx_pt is None:
 275             raise ValueError("Cannot return left coordinate of empty bbox")
 276         return self.llx_pt
 277
 278     def right_pt(self):
 279         """return right coordinate of bbox in pts"""
 280         if self.llx_pt is None:
 281             raise ValueError("Cannot return right coordinate of empty bbox")
 282         return self.urx_pt
 283
 284     def center_pt(self):
 285         """return coordinates of the center of the bbox in pts"""
 286         if self.llx_pt is None:
 287             raise ValueError("Cannot return center coordinates of empty bbox")
 288         return 0.5 * (self.llx_pt+self.urx_pt), 0.5 * (self.lly_pt+self.ury_pt)
 289
 290     def height(self):
 291         """return height of bbox"""
 292         return self.height_pt() * unit.t_pt
 293
 294     def width(self):
 295         """return width of bbox"""
 296         return self.width_pt() * unit.t_pt
 297
 298     def top(self):
 299         """return top coordinate of bbox"""
 300         return self.ury_pt * unit.t_pt
 301
 302     def bottom(self):
 303         """return bottom coordinate of bbox"""
 304         return self.lly_pt * unit.t_pt
 305
 306     def left(self):
 307         """return left coordinate of bbox"""
 308         return self.llx_pt * unit.t_pt
 309
 310     def right(self):
 311         """return right coordinate of bbox"""
 312         return self.urx_pt * unit.t_pt
 313
 314     def center(self):
 315         """return coordinates of the center of the bbox"""
 316         centerx_pt, centery_pt = self.center_pt()
 317         return centerx_pt * unit.t_pt, centery_pt * unit.t_pt
 318
 319
 320 class bbox(bbox_pt):
 321
 322     """class for bounding boxes"""
 323
 324     def __init__(self, llx_pt, lly_pt, urx_pt, ury_pt):
 325         llx_pt = unit.topt(llx_pt)
 326         lly_pt = unit.topt(lly_pt)
 327         urx_pt = unit.topt(urx_pt)
 328         ury_pt = unit.topt(ury_pt)
 329         bbox_pt.__init__(self, llx_pt, lly_pt, urx_pt, ury_pt)
 330
 331
 332 class empty(bbox_pt):
 333
 334     """empty bounding box, i.e., one containing no point"""
 335     def __init__(self):
 336         bbox_pt.__init__(self, None, None, None, None)