This file is indexed.

/usr/lib/python3/dist-packages/Onboard/Layout.py is in onboard 1.3.0-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
# -*- coding: utf-8 -*-

# Copyright © 2012 Gerd Kohlberger <lowfi@chello.at>
# Copyright © 2011-2014, 2016 marmuta <marmvta@gmail.com>
#
# This file is part of Onboard.
#
# Onboard is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# Onboard is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.

""" Classes for recursive layout definition """

from __future__ import division, print_function, unicode_literals

from Onboard.utils import Rect, TreeItem

### Config Singleton ###
from Onboard.Config import Config
config = Config()
########################


class KeyContext(object):
    """
    Transforms logical coordinates to canvas coordinates and vice versa.
    """
    def __init__(self):
        # logical rectangle as defined by the keyboard layout,
        # never changed after loading.
        self.initial_log_rect = Rect(0.0, 0.0, 1.0, 1.0)  # includes border

        # logical rectangle as defined by the keyboard layout
        self.log_rect = Rect(0.0, 0.0, 1.0, 1.0)  # includes border

        # canvas rectangle in drawing units
        self.canvas_rect = Rect(0.0, 0.0, 1.0, 1.0)

    def __repr__(self):
        return "log={} canvas={}".format(list(self.log_rect),
                                          list(self.canvas_rect))

    def log_to_canvas(self, coord):
        return (self.log_to_canvas_x(coord[0]), \
                self.log_to_canvas_y(coord[1]))

    def log_to_canvas_rect(self, rect):
        if rect.is_empty():
            return Rect()
        return Rect(self.log_to_canvas_x(rect.x),
                    self.log_to_canvas_y(rect.y),
                    self.scale_log_to_canvas_x(rect.w),
                    self.scale_log_to_canvas_y(rect.h))

    def log_to_canvas_x(self, x):
        canvas_rect = self.canvas_rect
        log_rect = self.log_rect
        return canvas_rect.x + (x - log_rect.x) * canvas_rect.w / log_rect.w

    def log_to_canvas_y(self, y):
        canvas_rect = self.canvas_rect
        log_rect = self.log_rect
        return canvas_rect.y + (y - log_rect.y) * canvas_rect.h / log_rect.h

    def scale_log_to_canvas(self, coord):
        return (self.scale_log_to_canvas_x(coord[0]), \
                self.scale_log_to_canvas_y(coord[1]))

    def scale_log_to_canvas_x(self, x):
        return x * self.canvas_rect.w / self.log_rect.w

    def scale_log_to_canvas_y(self, y):
        return y * self.canvas_rect.h / self.log_rect.h


    def canvas_to_log(self, coord):
        return (self.canvas_to_log_x(coord[0]), \
                self.canvas_to_log_y(coord[1]))

    def canvas_to_log_rect(self, rect):
        return Rect(self.canvas_to_log_x(rect.x),
                    self.canvas_to_log_y(rect.y),
                    self.scale_canvas_to_log_x(rect.w),
                    self.scale_canvas_to_log_y(rect.h))

    def canvas_to_log_x(self, x):
        canvas_rect = self.canvas_rect
        log_rect = self.log_rect
        return (x - canvas_rect.x) * log_rect.w / canvas_rect.w + log_rect.x

    def canvas_to_log_y(self, y):
        canvas_rect = self.canvas_rect
        log_rect = self.log_rect
        return (y - canvas_rect.y) * log_rect.h / canvas_rect.h + log_rect.y


    def scale_canvas_to_log_x(self, x):
        return x * self.log_rect.w / self.canvas_rect.w

    def scale_canvas_to_log_y(self, y):
        return y * self.log_rect.h / self.canvas_rect.h

    def log_to_canvas_path(self, path):
        result = path.copy()
        log_to_canvas_x = self.log_to_canvas_x
        log_to_canvas_y = self.log_to_canvas_y
        for op, coords in result.segments:
            for i in range(0, len(coords), 2):
                coords[i]   = log_to_canvas_x(coords[i])
                coords[i+1] = log_to_canvas_y(coords[i+1])
        return result

    ##### Speed-optimized overloads #####

    def log_to_canvas(self, coord):
        canvas_rect = self.canvas_rect
        log_rect = self.log_rect
        return canvas_rect.x + (coord[0] - log_rect.x) * \
                             canvas_rect.w / log_rect.w, \
               canvas_rect.y + (coord[1] - log_rect.y) * \
                             canvas_rect.h / log_rect.h

    def log_to_canvas_rect(self, rect):
        """ ~50% faster than the above. """
        w = rect.w
        h = rect.h
        if w <= 0 or h <= 0:
            return Rect()

        canvas_rect = self.canvas_rect
        log_rect = self.log_rect
        scale_w = canvas_rect.w / log_rect.w
        scale_h = canvas_rect.h / log_rect.h

        return Rect(canvas_rect.x + (rect.x - log_rect.x) * scale_w,
                    canvas_rect.y + (rect.y - log_rect.y) * scale_h,
                    w * scale_w,
                    h * scale_h)

    def scale_log_to_canvas(self, coord):
        canvas_rect = self.canvas_rect
        log_rect = self.log_rect
        return coord[0] * canvas_rect.w / log_rect.w, \
               coord[1] * canvas_rect.h / log_rect.h


class LayoutRoot:
    """
    Decorator class wrapping the root item.
    Implements extensive caching to avoid most of the expensive
    (for python) traversal of the layout tree.
    """
    def __init__(self, item):
        self.__dict__['_item'] = item    # item to decorate
        self.invalidate_caches()
        self.init_chamfer_sizes()

    def __getattr__(self, name):
        return getattr(self._item, name)

    def __setattr__(self, name, value):
        self._item.__setattr__(name, value)

    def invalidate_caches(self):
        self.invalidate_traversal_caches()
        self.invalidate_geometry_caches()

    def invalidate_traversal_caches(self):
        # speed up iterating the tree
        self._cached_items = {}
        self._cached_keys = {}
        self._cached_visible_items = {}
        self._cached_layer_items = {}
        self._cached_layer_keys = {}
        self._cached_key_groups = {}

        # cache available layers
        self._cached_layer_ids = None

    def invalidate_geometry_caches(self):
        # speed up hit testing
        self._cached_hit_rects = {}
        self._last_hit_args = None
        self._last_hit_key = None

    def fit_inside_canvas(self, canvas_border_rect):
        self._item.fit_inside_canvas(canvas_border_rect)

        # rects likely changed
        # -> invalidate geometry related caches
        self.invalidate_geometry_caches()

    def do_fit_inside_canvas(self, canvas_border_rect):
        self._item.do_fit_inside_canvas(canvas_border_rect)

        # rects likely changed
        # -> invalidate geometry related caches
        self.invalidate_geometry_caches()

    def set_visible_layers(self, layer_ids):
        """
        Show all items of layer "layer", hide all items of the other layers.
        """
        self.invalidate_caches()
        self._item.set_visible_layers(layer_ids)

    def set_item_visible(self, item, visible):
        if item.visible != visible:
            item.set_visible(visible)
            self.invalidate_caches()

    def iter_items(self):
        items = self._cached_items
        if not items:
            items = tuple(self._item.iter_items())
            self._cached_items = items
        return items

    def iter_keys(self, group_name = None):
        items = self._cached_keys.get(group_name)
        if not items:
            items = tuple(self._item.iter_keys(group_name))
            self._cached_keys[group_name] = items
        return items

    def iter_visible_items(self):
        items = self._cached_visible_items
        if not items:
            items = tuple(self._item.iter_visible_items())
            self._cached_visible_items = items
        return items

    def iter_layer_keys(self, layer_id):
        """
        Returns cached visible keys per layer, re-creates cache if necessary.
        Use iter_layer_keys if performance doesn't matter.
        """
        items = self._cached_layer_keys.get(layer_id)
        if not items:
            items = tuple(self._item.iter_layer_keys(layer_id))
            self._cached_layer_keys[layer_id] = items
        return items

    def iter_layer_items(self, layer_id = None, only_visible = True):
        args = (layer_id, only_visible)
        items = self._cached_layer_items.get(args)
        if not items:
            items = tuple(self._item.iter_layer_items(*args))
            self._cached_layer_items[args] = items
        return items

    def get_layer_ids(self):
        layer_ids = self._cached_layer_ids
        if not layer_ids:
            layer_ids = self._item.get_layer_ids()
            self._cached_layer_ids = layer_ids
        return layer_ids

    def get_key_groups(self):
        """
        Return all keys sorted by group.
        """
        key_groups = self._cached_key_groups
        if not key_groups:
            key_groups = self._item.get_key_groups()
            self._cached_key_groups = key_groups
        return key_groups

    def get_key_at(self, point, active_layer):
        """
        Find the topmost key at point.
        """
        # After motion-notify-event the query-tooltit event calls this
        # a second time with the same point. Avoid re-searching in that case.
        args = (point, active_layer)
        if self._last_hit_args == args:
            return self._last_hit_key

        key = None
        x, y = point
        hit_rects = self._get_hit_rects(active_layer)
        for x0, y0, x1, y1, k in hit_rects:
            # Inlined test, not using Rect.is_point_within for speed.
            if x >= x0 and x < x1 and \
               y >= y0 and y < y1:
                if k.geometry is None or \
                   k.get_hit_path().is_point_within(point):
                    key = k
                    break

        self._last_hit_args = args
        self._last_hit_key = key

        return key

    def _get_hit_rects(self, active_layer):
        try:
            hit_rects = self._cached_hit_rects[active_layer]
        except KeyError:
            # All visible and sensitive key items sorted in z-order.
            # Keys of the active layer have priority over non-layer keys
            # (layer switcher, hide, etc.).
            iter_layer_keys = self.iter_layer_keys
            items = list(reversed(list(iter_layer_keys(active_layer)))) + \
                    list(reversed(list(iter_layer_keys(None))))

            hit_rects = [item.get_hit_rect().to_extents() + (item,) \
                     for item in items]
            self._cached_hit_rects[active_layer] = hit_rects

        return hit_rects

    def init_chamfer_sizes(self):
        chamfer_sizes = self._calc_chamfer_sizes()
        for key in self.iter_global_keys():
            if key.chamfer_size is None:
                layer_id = key.get_layer()
                chamfer_size = chamfer_sizes.get(layer_id)
                if not chamfer_size is None:
                    key.chamfer_size = chamfer_size

    def _calc_chamfer_sizes(self):
        chamfer_sizes = {}
        for layer_id in [None] + self.get_layer_ids():
            # find the most frequent key width or height of the layer
            hist = {}
            for key in self.iter_layer_keys(layer_id):
                r = key.get_border_rect()
                s = min(r.w, r.h)
                hist[s] = hist.get(s, 0) + 1
            most_frequent_size = \
                max(list(zip(list(hist.values()), list(hist.keys()))))[1] \
                if hist else None
            chamfer_size = most_frequent_size * 0.5 \
                if not most_frequent_size is None else None
            chamfer_sizes[layer_id] = chamfer_size
        return chamfer_sizes


class LayoutItem(TreeItem):
    """ Abstract base class for layoutable items """

    # group string of the item, label size group for keys
    group = None

    # take this item out of the size group when updating the layout.
    # Instead chose the best label size for this item alone.
    ignore_group = None

    # name of the layer the item is to be shown on, None for all layers
    layer_id = None

    # filename of the svg file where the key geometry is defined
    filename = None

    # key context for transformation between logical and canvas coordinates
    context = None

    # State of visibility. Also determines if drawing space will be
    # assigned to this item and its children.
    visible = True

    # sensitivity, aka. greying; False to stop interaction with the item
    sensitive = True

    # Border around the item. The border "shrinks" the item and
    # is invisible but still sensitive to clicks.
    border = 0.0

    # Expand item in LayoutBoxes
    # "True"  expands the item into the space of invisible siblings.
    # "False" keeps it at the size of the even distribution of all siblings.
    #         Usually this will lock the key to the aspect ratio of its
    #         svg geometry.
    expand = True

    # sublayout sub-trees
    sublayouts = None

    # parent item of sublayout roots
    sublayout_parent = None

    # override switching back to layer 0 on key press
    # True:  do switch to layer 0 on press
    # False: dont't
    # None:  maybe, hard-coded default-behavior for compatibility with <0.99
    unlatch_layer = None

    # False if the key should be ignored by the scanner
    scannable = True

    # Determines scanning order
    scan_priority = None

    # parsing helpers, only valid while loading a layout
    templates = None
    keysym_rules = None

    def __init__(self):
        self.context = KeyContext()

    def __repr__(self):
        return "{}({})".format(type(self).__name__, repr(self.id))

    def dumps(self):
        """
        Recursively dumps the layout (sub-) tree starting from self.
        Returns a multi-line string.
        """
        global _level
        if not "_level" in globals():
            _level = -1
        _level += 1
        s = "   "*_level + "{} id={} layer_id={} fn={} vis={}\n".format(
                                  object.__repr__(self),
                                  repr(self.id),
                                  repr(self.layer_id),
                                  repr(self.filename),
                                  repr(self.visible),
                                  ) + \
               "".join(item.dumps() for item in self.items)
        _level -= 1
        return s

    def set_id(self, id):
        self.id = id

    def get_rect(self):
        """ Get bounding box in logical coordinates """
        return self.get_border_rect().deflate(self.border)

    def get_border_rect(self):
        """ Get bounding rect including border in logical coordinates """
        return self.context.log_rect

    def set_border_rect(self, border_rect):
        """ Set bounding rect including border in logical coordinates """
        self.context.log_rect = border_rect

    def get_initial_border_rect(self):
        """
        Get initial bounding rect including border in logical coordinates
        """
        return self.context.initial_log_rect

    def set_initial_border_rect(self, border_rect):
        """
        Set initial bounding rect including border in logical coordinates.
        """
        self.context.initial_log_rect = border_rect

    def get_canvas_rect(self):
        """ Get bounding box in canvas coordinates """
        return self.context.log_to_canvas_rect(self.get_rect())

    def get_canvas_border_rect(self):
        """ Get bounding rect including border in canvas coordinates """
        return self.context.canvas_rect

    def get_log_aspect_ratio(self):
        """
        Return the aspect ratio of the visible logical extents
        of the layout tree.
        """
        size = self.get_log_extents()
        return size[0] / float(size[1])

    def get_log_extents(self):
        """
        Get the logical extents of the layout tree.
        Extents ignore invisible, "collapsed" items,
        ie. an invisible click column is not included.
        """
        return self.get_border_rect().get_size()

    def get_canvas_extents(self):
        """
        Get the canvas extents of the layout tree.
        """
        size = self.get_log_extents()
        return self.context.scale_log_to_canvas(size)

    def get_extra_render_size(self):
        """ Account for stroke width and antialiasing of keys and bars"""
        root = self.get_layout_root()
        return root.context.scale_log_to_canvas((2.0, 2.0))

    def fit_inside_canvas(self, canvas_border_rect):
        """
        Scale item and its children to fit inside the given canvas_rect.
        """
        # recursively update item's bounding boxes
        self.update_log_rect()

        # recursively fit inside canvas
        self.do_fit_inside_canvas(canvas_border_rect)

    def do_fit_inside_canvas(self, canvas_border_rect):
        """
        Scale item and its children to fit inside the given canvas_rect.
        """
        self.context.canvas_rect = canvas_border_rect

    def update_log_rect(self):
        for item in self.iter_depth_first():
            item._update_log_rect()

    def _update_log_rect(self):
        """
        Override this for layout items that have to calculate their
        logical rectangle.
        """
        pass

    def get_hit_rect(self):
        """ Returns true if the point lies within the items borders. """
        return self.get_canvas_border_rect().inflate(1)

    def is_point_within(self, canvas_point):
        """ Returns true if the point lies within the items borders. """
        rect = self.get_hit_rect()
        return rect.is_point_within(canvas_point)

    def set_visible(self, visible):
        self.visible = visible

    def is_visible(self):
        """ Returns visibility status """
        return self.visible

    def is_path_visible(self):
        """ Are all items in the path to the root visible? """
        item = self
        while item:
            if not item.visible:
                return False
            item = item.parent
        return True

    def has_visible_key(self):
        """
        Checks if there is any visible key in the
        subtree starting at self.
        """
        for item in self.iter_visible_items():
            if item.is_key():
                return True
        return False

    def is_path_scannable(self):
        """ Are all items in the path to the root scannable? """
        item = self
        while item:
            if not item.scannable:
                return False
            item = item.parent
        return True

    def get_path_scan_priority(self):
        """ Return the closeset scan_priority in the path to the root. """
        item = self
        while item:
            if not item.scan_priority is None:
                return item.scan_priority
            item = item.parent
        return 0

    def get_layout_root(self):
        """ Return the root layout item """
        item = self
        while item:
            if item.parent is None:
                return item
            item = item.parent

    def get_global_layout_root(self):
        """ Return the root layout item """
        item = self
        while item:
            if item.parent is None:
                return item
            item = item.parent

    def get_layer(self):
        """ Return the first layer_id on the path from the tree root to self """
        layer_id = None
        item = self
        while item:
            if not item.layer_id is None:
                layer_id = item.layer_id
            item = item.parent
        return layer_id

    def set_visible_layers(self, layer_ids):
        """
        Show all items of layers <layer_ids>, hide all items of the other layers.
        """
        if not self.layer_id is None:
            if not self.is_key():
                self.visible = self.layer_id in layer_ids

        for item in self.items:
            item.set_visible_layers(layer_ids)

    def get_layer_ids(self, _layer_ids=None):
        """
        Search the tree for layer ids and return them in order of appearance
        """
        if _layer_ids is None:
            _layer_ids = []

        if not self.layer_id is None and \
           not self.layer_id in _layer_ids:
            _layer_ids.append(self.layer_id)

        for item in self.items:
            item.get_layer_ids(_layer_ids)

        return _layer_ids

    def get_key_groups(self):
        """
        Traverse the tree and return all keys sorted by group.
        """
        key_groups = {}
        for key in self.iter_keys():
            keys = key_groups.get(key.group, [])
            keys.append(key)
            key_groups[key.group] = keys
        return key_groups

    def raise_to_top(self):
        """ raise self to the top of its siblings """
        if self.parent:
            self.parent.items.remove(self)
            self.parent.items.append(self)

    def lower_to_bottom(self):
        """ lower self to the bottom of its siblings """
        if self.parent:
            self.parent.items.remove(self)
            self.parent.items.insert(0, self)

    def raise_to_top(self):
        if self.parent:
            self.parent.items.remove(self)
            #self.parent.items.insert(0, self)
            self.parent.items.append(self)

    def get_filename(self):
        """
        Recursively finds the closeset definition of the svg filename.
        """
        if self.filename:
            return self.filename
        if self.parent:
            return self.parent.get_filename()
        return None

    def can_unlatch_layer(self):
        """
        Recursively finds the closeset definition of the
        unlatch_layer attribute.
        """
        if not self.unlatch_layer is None:
            return self.unlatch_layer
        if self.parent:
            return self.parent.can_unlatch_layer()
        return None

    def is_key(self):
        """ Returns true if self is a key. """
        return False

    def iter_visible_items(self):
        """
        Traverses top to bottom all visible layout items of the
        layout tree. Invisible paths are cut short.
        """
        if self.visible:

            yield self

            for item in self.items:
                for visible_item in item.iter_visible_items():
                    yield visible_item

    def iter_keys(self, group_name = None):
        """
        Iterates through all keys of the layout tree.
        """
        if self.is_key():
            if group_name is None or key.group == group_name:
                yield self

        for item in self.items:
            for key in item.iter_keys(group_name):
                yield key

    def iter_global_items(self):
        """
        Iterates through all items of the tree including sublayouts.
        """
        yield self

        for item in self.items:
            for child in item.iter_global_items():
                yield child

        if self.sublayouts:
            for item in self.sublayouts:
                for child in item.iter_global_items():
                    yield child

    def iter_global_keys(self, group_name = None):
        """
        Iterates through all keys of the layout tree including sublayouts.
        """
        if self.is_key():
            if group_name is None or key.group == group_name:
                yield self

        for item in self.items:
            for key in item.iter_global_keys(group_name):
                yield key

        if self.sublayouts:
            for item in self.sublayouts:
                for key in item.iter_global_keys(group_name):
                    yield key

    def iter_layer_keys(self, layer_id = None):
        """
        Iterates through all keys of the given layer.
        """
        for item in self.iter_layer_items(layer_id):
            if item.is_key():
                yield item

    def iter_layer_items(self, layer_id = None, only_visible = True,
                              _found_layer_id = None):
        """
        Iterate through all items of the given layer.
        The first layer definition found in the path to each key wins.
        layer=None iterates through all keys that don't have a layer
        specified anywhere in their path.
        """
        if only_visible and not self.visible:
            return

        if self.layer_id == layer_id:
            _found_layer_id = layer_id

        if self.layer_id and self.layer_id != _found_layer_id:
            return

        if _found_layer_id == layer_id:
            yield self

        for item in self.items:
            for item in item.iter_layer_items(layer_id, only_visible,
                                              _found_layer_id):
                yield item

    def find_instance_in_path(self, classinfo):
        """ Find an item of a certain type in the path from self to the root. """
        item = self
        while item:
            if isinstance(item, classinfo):
                return item
            item = item.parent
        return None

    def update_templates(self, templates):
        if templates:
            if self.templates is None:
                self.templates = templates
            else:
                self.templates.update(templates)

    def update_keysym_rules(self, keysym_rules):
        if keysym_rules:
            if self.keysym_rules is None:
                self.keysym_rules = keysym_rules
            else:
                self.keysym_rules.update(keysym_rules)

    def append_sublayout(self, sublayout):
        if sublayout:
            if self.sublayouts is None:
                self.sublayouts = []
            self.sublayouts.append(sublayout)

    def find_sublayout(self, id):
        """
        Look for a sublayout item upwards from self to the root.
        """
        for item in self.iter_to_root():
            sublayouts = item.sublayouts
            if sublayouts:
                for sublayout in sublayouts:
                    if sublayout.id == id:
                        return sublayout
        return None

    def iter_to_global_root(self):
        """
        Iterate through sublayouts all the way to the global layout root.
        LayoutLoader needs this to access key templates from inside of
        sublayouts.
        """
        item = self
        while item:
            yield item
            item = item.parent or item.sublayout_parent


class LayoutBox(LayoutItem):
    """
    Container for distributing items along a single horizontal or
    vertical axis. Items touch, but don't overlap.
    """

    # Spread out child items horizontally or vertically.
    horizontal = True

    # distance between items
    spacing = 1

    # Don't extend bounding box into invisibles
    compact = False

    def __init__(self, horizontal = True):
        super(LayoutBox, self).__init__()
        if self.horizontal != horizontal:
            self.horizontal = horizontal

    def _update_log_rect(self):
        self.context.log_rect = self._calc_bounds()

    def _calc_bounds(self):
        """
        Calculate the bounding rectangle over all items of this panel.
        Include invisible items to stretch the visible ones into their
        space too.
        """
        compact = self.compact
        bounds = None
        for item in self.items:
            if not compact or item.visible:
                rect = item.get_border_rect()
                if not rect.is_empty():
                    if bounds is None:
                        bounds = rect
                    else:
                        bounds = bounds.union(rect)

        if bounds is None:
            return Rect()
        return bounds

    def do_fit_inside_canvas(self, canvas_border_rect):
        """ Scale items to fit inside the given canvas_rect """

        LayoutItem.do_fit_inside_canvas(self, canvas_border_rect)

        axis = 0 if self.horizontal else 1
        items = self.items

        # get canvas rectangle without borders
        canvas_rect = self.get_canvas_rect()

        # Find the combined length of all items, including
        # invisible ones (logical coordinates).
        length = 0.0
        for i, item in enumerate(items):
            rect = item.get_border_rect()
            if not rect.is_empty():
                if i:
                    length += self.spacing
                length += rect[axis+2]

        # Find the stretch factor, that fills the available canvas space with
        # evenly distributed, all visible items.
        fully_visible_scale = canvas_rect[axis+2] / length \
                              if length else 1.0
        canvas_spacing = fully_visible_scale * self.spacing

        # Transform items into preliminary canvas space, drop invisibles
        # and find the total lengths of expandable and non-expandable
        # items (preliminary canvas coordinates).
        length_expandables = 0.0
        num_expandables = 0
        length_nonexpandables = 0.0
        num_nonexpandables = 0
        for i, item in enumerate(items):
            length = item.get_border_rect()[axis+2]
            if length and item.has_visible_key():
                length *= fully_visible_scale
                if item.expand:
                    length_expandables += length
                    num_expandables += 1
                else:
                    length_nonexpandables += length
                    num_nonexpandables += 1

        # Calculate a second stretch factor for expandable and actually
        # visible items. This takes care of the part of the canvas_rect,
        # that isn't covered by the first factor yet.
        # All calculation is done in preliminary canvas coordinates.
        length_target = canvas_rect[axis+2] - length_nonexpandables - \
                   canvas_spacing * (num_nonexpandables + num_expandables - 1)
        expandable_scale = length_target / length_expandables \
                           if length_expandables else 1.0

        # Calculate the final canvas rectangles and traverse
        # the tree recursively.
        position = 0.0
        for i, item in enumerate(items):
            rect = item.get_border_rect()
            if item.has_visible_key():
                length  = rect[axis+2]
                spacing = canvas_spacing
            else:
                length  = 0.0
                spacing = 0.0

            scale = fully_visible_scale
            if item.expand:
                scale *= expandable_scale
            canvas_length = length * scale

            # set the final canvas rect
            r = Rect(*canvas_rect)
            r[axis]   = canvas_rect[axis] + position
            r[axis+2] = canvas_length
            item.do_fit_inside_canvas(r)

            position += canvas_length + spacing

    def get_log_extents(self):
        """
        Get the logical extents of the layout tree.
        Extents ignore invisible, "collapsed" items,
        ie. an invisible click column is not included.
        """
        rect = None
        for item in self.items:
            r = item.get_border_rect()
            if rect is None:
                rect = r.copy()
            else:
                if self.horizontal:
                    rect.w += r.w
                else:
                    rect.h += r.h

        return rect.get_size()


class LayoutPanel(LayoutItem):
    """
    Group of keys layed out at fixed positions relative to each other.
    """

    # Don't extend bounding box into invisibles
    compact = False

    def do_fit_inside_canvas(self, canvas_border_rect):
        """
        Scale panel to fit inside the given canvas_rect.
        """
        LayoutItem.do_fit_inside_canvas(self, canvas_border_rect)

        # Setup children's transformations, take care of the border.
        if self.get_border_rect().is_empty():
            # Clear all item's transformations if there are no visible items.
            for item in self.items:
                item.context.canvas_rect = Rect()
        else:
            context = KeyContext()
            context.log_rect = self.get_border_rect()
            context.canvas_rect = self.get_canvas_rect() # exclude border

            for item in self.items:
                rect = context.log_to_canvas_rect(item.context.log_rect)
                item.do_fit_inside_canvas(rect)

    def _update_log_rect(self):
        self.context.log_rect = self._calc_bounds()

    def _calc_bounds(self):
        """ Calculate the bounding rectangle over all items of this panel """
        # If there is no visible item return an empty rect
        if all(not item.is_visible() for item in self.items):
            return Rect()

        compact = self.compact
        bounds = None
        for item in self.items:
            if not compact or item.visible:
                rect = item.get_border_rect()
                if not rect.is_empty():
                    if bounds is None:
                        bounds = rect
                    else:
                        bounds = bounds.union(rect)

        if bounds is None:
            return Rect()
        return bounds