This file is indexed.

/usr/share/pyshared/pyepl/mechinput.py is in python-pyepl 1.1.0+git12-g365f8e3-2.

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
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
# PyEPL: mechinput.py
#
# Copyright (C) 2003-2005 Michael J. Kahana
# Authors: Ian Schleifer, Per Sederberg, Aaron Geller, Josh Jacobs
# URL: http://memory.psych.upenn.edu/programming/pyepl
#
# Distributed under the terms of the GNU Lesser General Public License
# (LGPL). See the license.txt that came with this file.

"""
This module provides a layer of abstraction to the input data of
mechanical input devices (i.e. mouse, keyboard, joystick).
"""

from repository import WeakKeyDictionary, MethodCallback
import sys
import timing
import hardware

class Roller:
    """
    Abstraction to any continuous motion component without bounds.
    """
    def __init__(self, name = None):
        """
        Set up housekeeping.
        """
        if name == None:
            self.name = repr(self)
        else:
            self.name = name
        self.callbacks = WeakKeyDictionary() # callback -> args
        self.counter = 0.0
        self.parents = ()
    def __mul__(self, x):
        """
        Return a ScaledRoller.
        """
        return ScaledRoller(self, x)
    __rmul__ = __mul__
    def move(self, amount):
        """
        Add to cumulative change in position.

        INPUT ARGS:
          amount- The amount to move (arbitrary units).
        """
        if amount:
            self.counter = self.counter + amount
            for c, args in self.callbacks.items():
                c(amount, *args)
    def update(self):  # to be overridden
        """
        Keep the value up to date.
        """
        for parent in self.parents:
            parent.update()
    def getChange(self):
        """
        Get cumulative change since last getChange (or since
        initialization).
        """
        self.update()
        c = self.counter
        self.counter = 0.0
        return c
    def addCallback(self, c, *args):
        """
        Call c(change, *args) whenever the position changes.  This
        Roller's reference to c will be weak.
        """
        self.callbacks[c] = args
    def echo(self):
        """
        Return an EchoRoller of this Roller.
        """
        return EchoRoller(self)
Roller.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class EchoRoller(Roller):
    """
    """
    def __init__(self, roller):
        """
        """
        Roller.__init__(self, "EchoRoller for %s" % roller.name)
        self.roller = roller
        self.parents = (roller,)
        self.cb = MethodCallback(self.move)
        roller.addCallback(self.cb)
    def echo(self):
        """
        Return an EchoRoller of this Roller.
        """
        return EchoRoller(self.roller)
EchoRoller.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class ThrottledRoller(Roller):
    """
    Roller based on another Roller, but throttled by a maximum
    velocity and/or a maximum acceleration.
    """
    def __init__(self, roller, maxAccel = None, maxVel = None, name = None):
        """
        Create a ThrottledRoller with maxAccel roller units per
        millisecond per millisecond maximum acceleration and maxVel
        roller units per millisecond maximum velocity.  None for
        either of those values means that the constraint will not be
        applied.
        """
        if name == None:
            name = "ThrottledRoller from %s" % roller.name
        else:
            name = name
        Roller.__init__(self, name)
        self.roller = roller
        self.parents = [roller]
        self.maxAccel = maxAccel
        self.maxVel = maxVel
        self.accum = 0.0
        self.lastvelocity = 0.0
        self.lasttime = timing.now()
        self.cb = MethodCallback(self.callback)
        roller.addCallback(self.cb)
    def update(self):
        """
        Keep the value up to date.
        """
        Roller.update(self)
        self.callback(0.0)
    def callback(self, change):
        """
        Callback used to communicate with parent Roller.  The parent
        roller passes the amount that it is changeing to the callback.
        """
        thistime = timing.now()
        elapsed = thistime - self.lasttime
        if not elapsed:
            self.accum = self.accum + change
            return
        change = change + self.accum
        self.accum = 0.0
        thisvelocity = change / elapsed
        if self.maxAccel:
            if abs(thisvelocity - self.lastvelocity) / elapsed > self.maxAccel:
                if thisvelocity < self.lastvelocity:
                    thisvelocity = self.lastvelocity - self.maxAccel * elapsed
                else:
                    thisvelocity = self.lastvelocity + self.maxAccel * elapsed
        if self.maxVel:
                if thisvelocity > self.maxVel:
                    thisvelocity = self.maxVel
                elif thisvelocity < -self.maxVel:
                    thisvelocity = -self.maxVel
        self.lasttime = thistime
        self.lastvelocity = thisvelocity
        self.move(thisvelocity * elapsed)
ThrottledRoller.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class ScaledRoller(Roller):
    """
    Roller based on another roller such that all positive motion is
    proportional to all positive motion in the parent and all negative
    motion is proportional to all motion of the parent.
    """
    def __init__(self, roller, scale, reverse_scale = None, name = None):
        """
        Create ScaledRoller with 'scale' and optionally different
        'reverse_scale'.
        """
        if name == None:
            name = "ScaledRoller from %s" % roller.name
        else:
            name = name
        Roller.__init__(self, name)
        if reverse_scale == None:
            self.reverse_scale = scale
        else:
            self.reverse_scale = reverse_scale
        self.forward_scale = scale
        self.roller = roller
        self.parents = [roller]
        self.cb = MethodCallback(self.callback)
        roller.addCallback(self.cb)
    def callback(self, change):
        """
        Callback used to communicate with parent Roller.
        """
        if change < 0:
            self.move(change * self.reverse_scale)
        else:
            self.move(change * self.forward_scale)
ScaledRoller.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class JointRoller(Roller):
    """
    Roller whose motion equals the sum of the motions of certain other
    Rollers.
    """
    def __init__(self, *rollers):
        """
        Create JointRoller based on rollers.
        """
        Roller.__init__(self, "JointRoller")
        self.rollers = rollers
        self.parents = rollers
        self.cb = MethodCallback(self.move)
        for roller in rollers:
            roller.addCallback(self.cb)
JointRoller.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class Axis:
    """
    Abstraction to any continuous motion component with bounds.
    """
    def __init__(self, name = None, posmin = -1.0, posmax = 1.0):
        """
        Set up housekeeping.
        """
        if name == None:
            self.name = repr(self)
        else:
            self.name = name
        self.callbacks = WeakKeyDictionary() # callback -> args
        self.position = 0.0
        self.posmin = posmin
        self.posmax = posmax
        self.parents = ()
    def halt(self):  # To be overridden
        pass
    def setPosition(self, p, timestamp = None):
        """
        Set the position of this axis between 1.0 and -1.0.
        """
        if p != self.position:
            if timestamp == None:
                timestamp = (timing.now(), long(0))
            self.position = p
            for c, args in self.callbacks.items():
                c(p, timestamp, *args)
    def update(self):  # to be overridden
        """
        Keep the value up to date.
        """
        for parent in self.parents:
            parent.update()
    def getPosition(self):
        """
        Return position.
        """
        self.update()
        return self.position
    def normalize(self, pos):
        """
        Return pos normalized between -1.0 and 1.0.
        """
        return 2 * (pos - self.posmin) / (self.posmax - self.posmin) - 1
    def getNormalized(self):
        """
        Return position normalized between -1.0 and 1.0.
        """
        self.update()
        return self.normalize(self.position)
    def addCallback(self, c, *args):
        """
        Call c(position, timestamp, *args) whenever the position
        changes.  This axis' reference to c will be weak.
        """
        self.callbacks[c] = args
    def __mul__(self, other):
        """
        """
        return ScaledAxis(self, other)
Axis.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class ScaledAxis(Axis):
    """
    A virtual Axis whose position is always equal to the position of a
    source Axis times a constant.
    """
    def __init__(self, axis, scale, rscale = None, name = None):
        """
        Create ScaledAxis based on axis with specified scale.
        """
        if name == None:
            name = "ScaledAxis (%s * %f)" % (axis.name, scale)
        else:
            name = name
        if rscale is None:
            rscale = scale
        Axis.__init__(self, name, axis.posmin * scale, axis.posmax * scale)
        self.axis = axis
        self.scale = scale
        self.rscale = rscale
        self.cb = MethodCallback(self.callback)
        axis.addCallback(self.cb)
        self.parents = (axis,)
    def callback(self, position, timestamp):
        """
        This method accepts information from the source axis.
        """
        if position > 0:
            self.setPosition(position * self.scale, timestamp)
        else:
            self.setPosition(position * self.rscale, timestamp)
ScaledAxis.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class AxisScaledAxis(Axis):
    """
    """
    def __init__(self, axis1, axis2, name = None):
        """
        """
        if name == None:
            name = "AxisScaledAxis (%s * %s)" % (axis1, axis2)
        else:
            name = name
        Axis.__init__(self, name, axis1.posmin * axis2.posmin, axis1.posmax * axis2.posmax)
        self.axis1 = axis1
        self.axis2 = axis2
        self.cb = MethodCallback(self.callback)
        axis1.addCallback(self.cb)
        axis2.addCallback(self.cb)
        self.parents = (axis1, axis2)
    def callback(self, position, timestamp):
        """
        """
        self.setPosition(self.axis1.getPosition() * self.axis2.getPosition())
AxisScaledAxis.__module__ = "pyepl.mechinput"  # cope with pyrex bug

def getPosMin(x):
    return x.posmin

def getPosMax(x):
    return x.posmax

class JointAxis(Axis):
    """
    A virtual Axis whose position is always equal to the sum of its
    source axes.  Its normalized position is always equal to the mean
    of the normalized positions of it source axes.
    """
    def __init__(self, *axes):
        """
        Arguments are taken as source axes.
        """
        Axis.__init__(self, "JointAxis", min(map(getPosMin, axes)), max(map(getPosMax, axes)))
        self.axes = axes
        self.cb = MethodCallback(self.callback)
        self.positions = []
        for n, axis in enumerate(axes):
            axis.addCallback(self.cb, n)
            self.positions.append(0.0)
        self.parents = axes
        self.sum = 0.0
    def callback(self, position, timestamp, n):
        """
        Callback used for communication with source axes.
        """
        self.sum = self.sum + (position - self.positions[n])
        self.positions[n] = position
        self.setPosition(self.sum, timestamp)
JointAxis.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class ThrottledAxis(Axis):
    """
    """
    def __init__(self, axis, maxVel = None, maxAccel = None, name = None):
        """
        """
        if name == None:
            name = "ThrottledAxis from %s" % axis.name
        else:
            name = name
        Axis.__init__(self, name, axis.posmin, axis.posmax)
        self.axis = axis
        self.lasttime = timing.now()
        self.lastpos = axis.getPosition()
        self.lastspeed = 0.0
        self.maxVel = maxVel
        self.maxAccel = maxAccel
        self.cb = MethodCallback(self.callback)
        axis.addCallback(self.cb)
        self.parents = (axis,)
    def halt(self):
        """
        """
        self.lastspeed = 0.0
        self.lastpos = 0.0
    def update(self):
        """
        """
        self.callback(self.axis.getPosition(), (timing.now(), long(0)))
    def callback(self, position, timestamp):
        """
        """
        thistime = timestamp[0]
        interval = thistime - self.lasttime
        if not interval:
            return
        speed = (position - self.lastpos) / interval
        accel = (speed - self.lastspeed) / interval
        if not self.maxAccel is None:
            if accel > self.maxAccel:
                speed = self.lastspeed + (self.maxAccel * interval)
            elif accel < -self.maxAccel:
                speed = self.lastspeed - (self.maxAccel * interval)
        if not self.maxVel is None:
            if speed > self.maxVel:
                speed = self.maxVel
            elif speed < -self.maxVel:
                speed = -self.maxVel
        position = self.lastpos + (speed * interval)
        self.setPosition(position, timestamp)
        self.lasttime = thistime
        self.lastpos = position
        self.lastspeed = speed
ThrottledAxis.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class RollerAxis(Axis):
    """
    A virtual Axis whose position is controlled by the movement of a
    Roller.
    """
    def __init__(self, roller, min = -1.0, max = 1.0, start = 0.0, name = None):
        """
        Create RollerAxis from roller.  min, max, and start may be
        used to specify minimum position, maximum position, and
        starting position, respectively.
        """
        if name == None:
            name = "RollerAxis from %s" % roller.name
        else:
            name = name
        Axis.__init__(self, name, min, max)
        self.roller = roller
        self.min = min
        self.max = max
        self.setPosition(start)
        self.cb = MethodCallback(self.callback)
        roller.addCallback(self.cb)
    def callback(self, delta):
        """
        Callback for communicating with the attached roller.
        """
        newpos = self.getPosition() + delta
        if newpos > max:
            newpos = max
        elif newpos < min:
            newpos = min
        self.setPosition(newpos)
    def getPosition(self):
        """
        Update roller first!
        """
        self.roller.update()
        return Axis.getPosition(self)
RollerAxis.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class AxisRoller(Roller):
    """
    Roller whose rate of change is controlled by the position of an
    axis.
    """
    def __init__(self, axis, speedfactor = 1.0, backwardspeedfactor = None, name = None):
        """
        Create AxisRoller from axis with specified speedfactor
        (defaults to 1.0).  Speedfactor units are roller units per
        millisecond per axis unit.
        """
        if name == None:
            name = "AxisRoller from %s" % axis.name
        else:
            name = name
        if backwardspeedfactor is None:
            backwardspeedfactor = speedfactor
        Roller.__init__(self, name)
        self.axis = axis
        self.speedfactor = speedfactor
        self.backwardspeedfactor = backwardspeedfactor
        self.lasttime = timing.now()
    def update(self):
        """
        Update the change for this roller in a time-consistent manner.
        """
        Roller.update(self)
        thistime = timing.now()
        elapsed = thistime - self.lasttime
        if elapsed:
            norm = self.axis.getNormalized()
            if norm > 0:
                self.move(elapsed * self.speedfactor * norm)
            else:
                self.move(elapsed * self.backwardspeedfactor * norm)
            self.lasttime = thistime
AxisRoller.__module__ = "pyepl.mechinput"  # cope with pyrex bug

def derivativeAxis(axis, speedfactor = 1.0, min = -1.0, max = 1.0, start = 0.0, name = None):
    """
    Get an axis whose position's rate of change is proportional to the
    position of the input axis within min and max absolute position
    boundaries.
    """
    if name == None:
        name = "Axis derived from %s" % axis.name
    else:
        name = name
    return RollerAxis(AxisRoller(axis, speedfactor), min, max, start, name)

class AxisScaledRoller(Roller):
    """
    Movement of parent roller scaled by the normalized position of the
    parent axis and a constant (factor).
    """
    def __init__(self, roller, axis, factor = 1.0, name = None):
        """
        Create AxisScaledRoller.
        """
        if name == None:
            name = "AxisScaledRoller (%s * %s * %f)" % (roller.name, axis.name, factor)
        else:
            name = name
        Roller.__init__(self, name)
        self.roller = roller
        self.parents = [roller]
        self.axis = axis
        self.factor = factor
        self.cb = MethodCallback(self.callback)
        roller.addCallback(self.cb)
    def callback(self, delta):
        """
        Callback for communicating with the attached roller.
        """
        self.move(delta * self.axis.getNormalized() * self.factor)
AxisScaledRoller.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class Button:
    """
    Abstraction to any on/off input component.
    """
    def __init__(self, name = None):
        """
        Set up housekeeping.
        """
        if name == None:
            self.name = repr(self)
        else:
            self.name = name
        self.callbacks = WeakKeyDictionary() # callback -> args
        self.pressed = False
        self.presstime = None
    def __getstate__(self):
        """
        Don't give pickle hardware states.
        """
        return self.name, self.callbacks
#        return self.name
    def __setstate__(self, state):
        """
        Reset hardware states when unpickled.
        """
        self.name, self.callbacks = state
#        self.name = state
        self.pressed = False
        self.presstime = None
    def __and__(self, x):
        """
        And operator creates a ButtonCombo.
        """
        return ButtonCombo(self, x)
    def __or__(self, x):
        """
        Or operator creates an EitherCombo.
        """
        return EitherButton(self, x)
    def setPressed(self, p, timestamp = None):
        """
        Set the pressed state of this button (True or False).
        """
        if p != self.pressed:
            if timestamp == None:
                timestamp = (timing.now(), long(0))
            self.presstime = timestamp
            self.pressed = p
            for c, args in self.callbacks.items():
                c(p, timestamp, *args)
    def isPressed(self):
        """
        Return True if pressed.  Otherwise return False.
        """
        return self.pressed
    def wait(self, clk = None, pressed = True):
        """
        Wait until this button's pressed state matches the argument
        pressed.  Returns the time at which the state matched.  If clk
        is supplied (a PresentationClock), it will be updated to the
        time at which the state became matching.
        """
        while pressed != self.pressed:
            hardware.pollEvents()
        if clk:
            clk.tare(self.presstime)
        return self.presstime
    def addCallback(self, c, *args):
        """
        Call c(pressed, timestamp, *args) whenever the state changes.
        This button's reference to c will be weak.
        """
        self.callbacks[c] = args
Button.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class ButtonCombo(Button):
    """
    Vitrual button that is considered pressed when a combination of
    other buttons is pressed.
    """
    def __init__(self, *combo):
        """
        Create ButtonCombo.  Arguments of buttons to be included in
        the combination.
        """
        Button.__init__(self, "Button combination (AND)")
        self.state = []
        self.combo = combo
        self.cb = MethodCallback(self.callback)
        for n, button in enumerate(combo):
            button.addCallback(self.cb, n)
            self.state.append(button.isPressed())
    def callback(self, pressed, timestamp, n):
        """
        Callback used for communication with the buttons which are a
        part if this combination.
        """
        self.state[n] = pressed
        if False in self.state:
            self.setPressed(False, timestamp)
        else:
            self.setPressed(True, timestamp)
ButtonCombo.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class EitherButton(Button):
    """
    Virtual button this is considered pressed when any one of a set of
    other buttons is pressed.
    """
    def __init__(self, *set):
        """
        Create EitherButton.  Arguments of buttons to be included in
        the set.
        """
        Button.__init__(self, "Button set (OR)")
        self.state = []
        self.set = set
        self.cb = MethodCallback(self.callback)
        for n, button in enumerate(set):
            button.addCallback(self.cb, n)
            self.state.append(button.isPressed())
    def callback(self, pressed, timestamp, n):
        """
        Callback used for communication with the buttons which are a
        part if this set.
        """
        self.state[n] = pressed
        if True in self.state:
            self.setPressed(True, timestamp)
        else:
            self.setPressed(False, timestamp)
EitherButton.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class NotchRoller(Roller):
    """
    Roller whose position is changed in discreet amounts upon the
    depression of certain buttons.
    """
    def __init__(self, *buttonamounts):
        """
        Constructor takes any number of 2-tuples: (Button, amount).
        """
        Roller.__init__(self, "NotchRoller")
        self.buttonamounts = buttonamounts
        self.cb = MethodCallback(self.callback)
        for buttonamount in buttonamounts:
            buttonamount[0].addCallback(self.cb, buttonamount[1])
    def callback(self, pressed, timestamp, amount):
        """
        Callback used for communication with the Buttons.
        """
        if pressed:
            self.move(amount)
NotchRoller.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class ButtonRoller(Roller):
    """
    Roller whose rate of change is controlled by two buttons.
    """
    def __init__(self, inc_button, dec_button, speed = 1.0, backspeed = None, name = None):
        """
        Create ButtonRoller where inc_button being pressed causes
        positive movement at speed roller units per millisecond and
        dec_button being pressed causes negative movement at speed
        roller units per millisecond.
        """
        if name is None:
            name = "ButtonRoller from %s and %s" % (inc_button.name, dec_button.name)
        else:
            name = name
        if backspeed is None:
            backspeed = speed
        Roller.__init__(self, name)
        self.inc_button = inc_button
        self.dec_button = dec_button
        self.speed = speed
        self.backspeed = backspeed
        self.lasttime = timing.now()
    def update(self):
        """
        Update the Roller's movement in a time-consistent manner.
        """
        Roller.update(self)
        thistime = timing.now()
        elapsed = thistime - self.lasttime
        if elapsed:
            if(self.inc_button.isPressed()):
                self.move(elapsed * self.speed)
            if(self.dec_button.isPressed()):
                self.move(elapsed * -self.backspeed)
            self.lasttime = thistime
ButtonRoller.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class ButtonAxis(Axis):
    """
    Axis whose position is controlled by two buttons.
    """
    def __init__(self, high_button, low_button, magnitude = 1.0, lmagnitude = None, name = None, minpos = -1.0, maxpos = 1.0):
        """
        Create ButtonAxis where pressing high_button sets the axis
        position to magnitude.  Pressing low_button sets the position
        to negative magnitude.  Both or neither button sets the
        position to 0.0.
        """
        if name == None:
            name = "ButtonAxis from %s and %s" % (high_button.name, low_button.name)
        else:
            name = name
        if lmagnitude is None:
            lmagnitude = magnitude
        Axis.__init__(self, name, minpos, maxpos)
        self.high_button = high_button
        self.low_button = low_button
        self.magnitude = magnitude
        self.lmagnitude = lmagnitude
        self.cb = MethodCallback(self.callback)
        high_button.addCallback(self.cb)
        low_button.addCallback(self.cb)
    def callback(self, pressed, timestamp):
        """
        Callback to communicate with buttons.
        """
        if self.high_button.isPressed():
            value = self.magnitude
        else:
            value = 0
        if self.low_button.isPressed():
            value = value - self.lmagnitude
        self.setPosition(value, timestamp)
ButtonAxis.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class AxisButton(Button):
    """
    Button which is considered pressed when a certain axis' position
    falls within a certain range and not otherwise.
    """
    def __init__(self, axis, low = 0.9, high = 1.0, name = None):
        """
        Create AxisButton from axis such that this Button is
        considered pressed when the position of axis falls between low
        and high.
        """
        if name == None:
            name = "AxisButton from %s" % (axis.name)
        else:
            name = name
        Button.__init__(self, name)
        self.axis = axis
        self.low = low
        self.high = high
        self.cb = MethodCallback(self.callback)
        axis.addCallback(self.cb)
    def callback(self, position, timestamp):
        """
        Callback used to communicate with the axis.
        """
        if self.low <= self.axis.normalize(position) <= self.high:
            self.setPressed(True, timestamp)
        else:
            self.setPressed(False, timestamp)
AxisButton.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class ChooserIter:
    def __init__(self, chooser):
        self.chooser = chooser
        self.iterators = [iter(self.chooser.items)]
    def next(self):
        while True:
            try:
                r = self.iterators[-1].next()
            except StopIteration:
                self.iterators.pop()
                continue
            except IndexError:
                raise StopIteration
            if isinstance(r, self.chooser.__class__):
                self.iterators.append(iter(r))
                continue
            break
        return r
ChooserIter.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class Chooser:
    """
    Super-class for input component choosers.
    """
    def __init__(self, *items):
        """
        Initialize.
        """
        self.items = items
        self.chosen = None
        self.timestamp = None
    def __and__(self, x):
        """
        And operator produces a Chooser including the mechanical input
        abstraction objects from both operands.
        """
        return self.__class__(self, x)
    def __iter__(self):
        """
        Get all items in this Chooser, including items within child
        Choosers.
        """
        return ChooserIter(self)
    def choose(self, chosen, timestamp):
        """
        Indicate that an item has been chosen.
        """
        self.chosen = chosen
        self.timestamp = timestamp
    def waitChoice(self, minDuration=None, maxDuration=None, clock=None):
        """
        Wait for an item to be chosen.
        """
        if clock:
            startTime = clock.get()
        else:
            startTime = hardware.universal_time()

        # set up minDuration            
        if minDuration:
            # will wait for minDuration before accepting key presses
            minStart = minDuration + startTime
        else:
            minStart = startTime

        # see if set up maxTime
        if maxDuration:
            stopTime = startTime + maxDuration
        else:
            stopTime = 0
            
        # wait for a keypress that occured after start of wait
        while (self.chosen is None) or (self.timestamp[0] < minStart):
            if maxDuration and stopTime <= hardware.universal_time():
                # we had a max duration, so break
                break
            hardware.pollEvents()

        chosen = self.chosen
        timestamp = self.timestamp

        # if nothing chosen or we are not in the correct range 
        if timestamp is None or timestamp[0]<minStart:
            # set chosen to None
            chosen = None
            #set timestamp to stoptime
            timestamp = (stopTime,0)
        
            
	# if there is a clock, tare the time
	if clock:
	    clock.tare(timestamp)

        # reset the internal chosen button and time
        self.chosen = None
        self.timestamp = None

        # return chosen button and time
        return chosen, timestamp
Chooser.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class ButtonChooser(Chooser):
    """
    This class represents a set of buttons.  It can be used to
    determine which button, out of the set, has been pressed.
    """
    def __init__(self, *buttons):
        """
        Constructs ButtonChooser from a list of possible Buttons and
        other ButtonChoosers.
        """
        Chooser.__init__(self, *buttons)
        self.cb = MethodCallback(self.callback)
        for n, b in enumerate(self):
            b.addCallback(self.cb, n, b)
    def waitWithTime(self, minDuration=None, maxDuration=None, clock=None):
        """
        Wait until a button is _newly_ pressed.  Return a 2-tuple of
        the Button and the time at which it was pressed.
        """
        return self.waitChoice(minDuration,maxDuration,clock)
    def wait(self, minDuration=None, maxDuration=None, clock=None):
        """
        Like wait_with_time, but returns only the Button object.
        """
        return self.waitWithTime(minDuration,maxDuration,clock)[0]
    def callback(self, pressed, timestamp, n, b):
        """
        Callback used to get information from buttons.
        """
        if pressed:
            self.choose(b, timestamp)
ButtonChooser.__module__ = "pyepl.mechinput"  # cope with pyrex bug


class FirstButtonChooser(Chooser):
    """
    This class represents a set of buttons.  It can be used to
    determine which button, out of the set, has been pressed first,
    but only after you have set the minimum start time (and optional
    end time) via the setTimeRange method.

    The primary use of this class is to set some buttons to watch
    during the presentation of some stimuli.  Then you can easily
    determine which button, if any was pressed first during the
    specified time range.
    """

    def __init__(self, *buttons):
        """
        Constructs FirstButtonChooser from a list of possible Buttons and
        other ButtonChoosers.
        """
        Chooser.__init__(self, *buttons)
	self.minTime = None
	self.maxTime = None
        self.cb = MethodCallback(self.callback)
        for n, b in enumerate(self):
            b.addCallback(self.cb, n, b)
    def setTimeRange(self,minTime,maxTime=None):
	"""
	Set the time range within which a button can be chosen.  

	If maxTime is None, then a button can be chosen anytime
	after the minTime.
	"""
	self.chosen = None
	self.timestamp = None
	self.minTime = minTime
	self.maxTime = maxTime
    def callback(self, pressed, timestamp, n, b):
        """
        Callback used to get information from buttons.
        """
	# only press if nothing pressed yet and beyond 
	# earliest start time.
        if pressed and \
		self.chosen is None and \
		not self.minTime is None and \
		timestamp[0] >= self.minTime and \
		(self.maxTime is None or timestamp[0] < self.maxTime):
            self.choose(b, timestamp)
FirstButtonChooser.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class AxisChooser(Chooser):
    """
    This class represents a set of axes.  It can be used to determine
    which axis, out of the set, has been moved to indicate deliberate
    selection.
    """
    def __init__(self, *axes):
        """
        Constructs AxisChooser from a list of possible Axes and other
        AxisChoosers.
        """
        Chooser.__init__(self, *axes)
        self.extrema = []
        self.cb = MethodCallback(self.callback)
        for n, a in enumerate(self):
            a.addCallback(self.cb, n, a)
            self.extrema.append([0, 0])
    def wait(self):
        """
        Wait until an axis has been moved to within ten percent of
        both unit extremes.  Return the axis that first meets this
        criterion.
        """
        self.reset()
        return self.waitChange()[0]
    def reset(self):
        """
        Forget any movement accumulated so far.
        """
        for n in xrange(len(self.extrema)):
            self.extrema[n] = [0, 0]
    def callback(self, position, timestamp, n, a):
        """
        Callback used to get information from axes.
        """
        nposition = a.normalize(position)
        if nposition < self.extrema[n][0]:
            self.extrema[n][0] = nposition
        elif nposition > self.extrema[n][1]:
            self.extrema[n][1] = nposition
        if self.extrema[n][0] < -0.9 and self.extrema[n][1] > 0.9:
            self.choose(a, timestamp)
AxisChooser.__module__ = "pyepl.mechinput"  # cope with pyrex bug

class RollerChooser(Chooser):
    """
    This class represents a set of rollers.  It can be used to
    determine which roller, out of the set, has been moved to indicate
    deliberate selection.
    """
    def __init__(self, *rollers):
        """
        Constructs RollerChooser from a list of possible Rollers and other
        RollerChoosers.
        """
        Chooser.__init__(self, *rollers)
        self.totals = []
        self.cb = MethodCallback(self.callback)
        for n, r in enumerate(self):
            r.addCallback(self.cb, n, r)
            self.totals.append(0.0)
    def wait(self):
        """
        Wait until a roller has been moved five times as much as any
        other roller in the set and at least ten units.  Return that
        roller.
        """
        self.reset()
        return self.waitChoice()[0]
    def reset(self):
        """
        Forget any movement accumulated so far.
        """
        for n in xrange(len(self.totals)):
            self.totals[n] = 0.0
    def callback(self, amount, n, r):
        """
        Callback used to get information from rollers.
        """
        self.totals[n] = self.totals[n] + amount
        for x in self.totals:
            if self.totals[n] > 10 and (self.totals[n] < (x * 5)):
                return
        self.choose(r, None)
RollerChooser.__module__ = "pyepl.mechinput"  # cope with pyrex bug