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 set(self, other):
  97         self.llx_pt = other.llx_pt
  98         self.lly_pt = other.lly_pt
  99         self.urx_pt = other.urx_pt
 100         self.ury_pt = other.ury_pt
 101
 102     def lowrestuple_pt(self):
 103         if self.llx_pt is None:
 104             raise ValueError("Cannot return low-res tuple for empty bbox")
 105         return (math.floor(self.llx_pt), math.floor(self.lly_pt),
 106                 math.ceil(self.urx_pt), math.ceil(self.ury_pt))
 107
 108     def highrestuple_pt(self):
 109         if self.llx_pt is None:
 110             raise ValueError("Cannot return high-res tuple for empty bbox")
 111         return (self.llx_pt, self.lly_pt, self.urx_pt, self.ury_pt)
 112
 113     def intersects(self, other):
 114         """check, if two bboxes intersect eachother"""
 115         if self.llx_pt is None or other.llx_pt is None:
 116             return 0
 117         else:
 118             return not (self.llx_pt > other.urx_pt or
 119                         self.lly_pt > other.ury_pt or
 120                         self.urx_pt < other.llx_pt or
 121                         self.ury_pt < other.lly_pt)
 122
 123     def includepoint_pt(self, x_pt, y_pt):
 124         if self.llx_pt is None:
 125             self.llx_pt = self.urx_pt = x_pt
 126             self.ury_pt = self.ury_pt = y_pt
 127         else:
 128             self.llx_pt = min(self.llx_pt, x_pt)
 129             self.lly_pt = min(self.lly_pt, y_pt)
 130             self.urx_pt = max(self.urx_pt, x_pt)
 131             self.ury_pt = max(self.ury_pt, y_pt)
 132
 133     def transform(self, trafo):
 134         """transform bbox in place by trafo"""
 135         if self.llx_pt is None:
 136             return
 137         # we have to transform all four corner points of the bbox
 138         llx_pt, lly_pt = trafo.apply_pt(self.llx_pt, self.lly_pt)
 139         lrx_pt, lry_pt = trafo.apply_pt(self.urx_pt, self.lly_pt)
 140         urx_pt, ury_pt = trafo.apply_pt(self.urx_pt, self.ury_pt)
 141         ulx_pt, uly_pt = trafo.apply_pt(self.llx_pt, self.ury_pt)
 142
 143         # Now, by sorting, we obtain the lower left and upper right corner
 144         # of the new bounding box.
 145         self.llx_pt = min(llx_pt, lrx_pt, urx_pt, ulx_pt)
 146         self.lly_pt = min(lly_pt, lry_pt, ury_pt, uly_pt)
 147         self.urx_pt = max(llx_pt, lrx_pt, urx_pt, ulx_pt)
 148         self.ury_pt = max(lly_pt, lry_pt, ury_pt, uly_pt)
 149
 150     def transformed(self, trafo):
 151         """return bbox transformed by trafo"""
 152         if self.llx_pt is None:
 153             return empty()
 154         # we have to transform all four corner points of the bbox
 155         llx_pt, lly_pt = trafo.apply_pt(self.llx_pt, self.lly_pt)
 156         lrx_pt, lry_pt = trafo.apply_pt(self.urx_pt, self.lly_pt)
 157         urx_pt, ury_pt = trafo.apply_pt(self.urx_pt, self.ury_pt)
 158         ulx_pt, uly_pt = trafo.apply_pt(self.llx_pt, self.ury_pt)
 159
 160         # Now, by sorting, we obtain the lower left and upper right corner
 161         # of the new bounding box.
 162         return bbox_pt(min(llx_pt, lrx_pt, urx_pt, ulx_pt), min(lly_pt, lry_pt, ury_pt, uly_pt),
 163                        max(llx_pt, lrx_pt, urx_pt, ulx_pt), max(lly_pt, lry_pt, ury_pt, uly_pt))
 164
 165     def enlarge_pt(self, all_pt=0, bottom_pt=None, left_pt=None, top_pt=None, right_pt=None):
 166         """enlarge bbox in place by the given amounts in pts
 167
 168         all is used, if bottom, left, top and/or right are not given.
 169
 170         """
 171         if self.llx_pt is None:
 172             return
 173         if bottom_pt is None:
 174            bottom_pt = all_pt
 175         if left_pt is None:
 176            left_pt = all_pt
 177         if top_pt is None:
 178            top_pt = all_pt
 179         if right_pt is None:
 180            right_pt = all_pt
 181         self.llx_pt -= left_pt
 182         self.lly_pt -= bottom_pt
 183         self.urx_pt += right_pt
 184         self.ury_pt += top_pt
 185
 186     def enlarged_pt(self, all_pt=0, bottom_pt=None, left_pt=None, top_pt=None, right_pt=None):
 187         """return bbox enlarged by the given amounts in pts
 188
 189         all is used, if bottom, left, top and/or right are not given.
 190
 191         """
 192         if self.llx_pt is None:
 193             return empty()
 194         if bottom_pt is None:
 195            bottom_pt = all_pt
 196         if left_pt is None:
 197            left_pt = all_pt
 198         if top_pt is None:
 199            top_pt = all_pt
 200         if right_pt is None:
 201            right_pt = all_pt
 202         return bbox_pt(self.llx_pt-left_pt, self.lly_pt-bottom_pt, self.urx_pt+right_pt, self.ury_pt+top_pt)
 203
 204     def enlarge(self, all=0, bottom=None, left=None, top=None, right=None):
 205         """enlarge bbox in place
 206
 207         all is used, if bottom, left, top and/or right are not given.
 208
 209         """
 210         if self.llx_pt is None:
 211             return
 212         bottom_pt = left_pt = top_pt = right_pt = unit.topt(all)
 213         if bottom is not None:
 214            bottom_pt = unit.topt(bottom)
 215         if left is not None:
 216            left_pt = unit.topt(left)
 217         if top is not None:
 218            top_pt = unit.topt(top)
 219         if right is not None:
 220            right_pt = unit.topt(right)
 221         self.llx_pt -= left_pt
 222         self.lly_pt -= bottom_pt
 223         self.urx_pt += right_pt
 224         self.ury_pt += top_pt
 225
 226     def enlarged(self, all=0, bottom=None, left=None, top=None, right=None):
 227         """return bbox enlarged
 228
 229         all is used, if bottom, left, top and/or right are not given.
 230
 231         """
 232         if self.llx_pt is None:
 233             return empty()
 234         bottom_pt = left_pt = top_pt = right_pt = unit.topt(all)
 235         if bottom is not None:
 236            bottom_pt = unit.topt(bottom)
 237         if left is not None:
 238            left_pt = unit.topt(left)
 239         if top is not None:
 240            top_pt = unit.topt(top)
 241         if right is not None:
 242            right_pt = unit.topt(right)
 243         return bbox_pt(self.llx_pt-left_pt, self.lly_pt-bottom_pt, self.urx_pt+right_pt, self.ury_pt+top_pt)
 244
 245     def rect(self):
 246         """return rectangle corresponding to bbox"""
 247         if self.llx_pt is None:
 248             raise ValueError("Cannot return path for empty bbox")
 249         import path
 250         return path.rect_pt(self.llx_pt, self.lly_pt, self.urx_pt-self.llx_pt, self.ury_pt-self.lly_pt)
 251
 252     path = rect
 253
 254     def height_pt(self):
 255         """return height of bbox in pts"""
 256         if self.llx_pt is None:
 257             raise ValueError("Cannot return heigth of empty bbox")
 258         return self.ury_pt-self.lly_pt
 259
 260     def width_pt(self):
 261         """return width of bbox in pts"""
 262         if self.llx_pt is None:
 263             raise ValueError("Cannot return width of empty bbox")
 264         return self.urx_pt-self.llx_pt
 265
 266     def top_pt(self):
 267         """return top coordinate of bbox in pts"""
 268         if self.llx_pt is None:
 269             raise ValueError("Cannot return top coordinate of empty bbox")
 270         return self.ury_pt
 271
 272     def bottom_pt(self):
 273         """return bottom coordinate of bbox in pts"""
 274         if self.llx_pt is None:
 275             raise ValueError("Cannot return bottom coordinate of empty bbox")
 276         return self.lly_pt
 277
 278     def left_pt(self):
 279         """return left coordinate of bbox in pts"""
 280         if self.llx_pt is None:
 281             raise ValueError("Cannot return left coordinate of empty bbox")
 282         return self.llx_pt
 283
 284     def right_pt(self):
 285         """return right coordinate of bbox in pts"""
 286         if self.llx_pt is None:
 287             raise ValueError("Cannot return right coordinate of empty bbox")
 288         return self.urx_pt
 289
 290     def center_pt(self):
 291         """return coordinates of the center of the bbox in pts"""
 292         if self.llx_pt is None:
 293             raise ValueError("Cannot return center coordinates of empty bbox")
 294         return 0.5 * (self.llx_pt+self.urx_pt), 0.5 * (self.lly_pt+self.ury_pt)
 295
 296     def height(self):
 297         """return height of bbox"""
 298         return self.height_pt() * unit.t_pt
 299
 300     def width(self):
 301         """return width of bbox"""
 302         return self.width_pt() * unit.t_pt
 303
 304     def top(self):
 305         """return top coordinate of bbox"""
 306         return self.ury_pt * unit.t_pt
 307
 308     def bottom(self):
 309         """return bottom coordinate of bbox"""
 310         return self.lly_pt * unit.t_pt
 311
 312     def left(self):
 313         """return left coordinate of bbox"""
 314         return self.llx_pt * unit.t_pt
 315
 316     def right(self):
 317         """return right coordinate of bbox"""
 318         return self.urx_pt * unit.t_pt
 319
 320     def center(self):
 321         """return coordinates of the center of the bbox"""
 322         centerx_pt, centery_pt = self.center_pt()
 323         return centerx_pt * unit.t_pt, centery_pt * unit.t_pt
 324
 325
 326 class bbox(bbox_pt):
 327
 328     """class for bounding boxes"""
 329
 330     def __init__(self, llx_pt, lly_pt, urx_pt, ury_pt):
 331         llx_pt = unit.topt(llx_pt)
 332         lly_pt = unit.topt(lly_pt)
 333         urx_pt = unit.topt(urx_pt)
 334         ury_pt = unit.topt(ury_pt)
 335         bbox_pt.__init__(self, llx_pt, lly_pt, urx_pt, ury_pt)
 336
 337
 338 class empty(bbox_pt):
 339
 340     """empty bounding box, i.e., one containing no point"""
 341     def __init__(self):
 342         bbox_pt.__init__(self, None, None, None, None)