Source

wxPython / wx / lib / agw / floatspin.py

Full commit
   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
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
# --------------------------------------------------------------------------- #
# FLOATSPIN Control wxPython IMPLEMENTATION
# Python Code By:
#
# Andrea Gavana, @ 16 Nov 2005
# Latest Revision: 17 Aug 2011, 15.00 GMT
#
#
# TODO List/Caveats
#
# 1. Ay Idea?
#
# For All Kind Of Problems, Requests Of Enhancements And Bug Reports, Please
# Write To Me At:
#
# andrea.gavana@gmail.com
# andrea.gavana@maerskoil.com
#
# Or, Obviously, To The wxPython Mailing List!!!
#
#
# End Of Comments
# --------------------------------------------------------------------------- #


"""
L{FloatSpin} implements a floating point `wx.SpinCtrl`.


Description
===========

L{FloatSpin} implements a floating point `wx.SpinCtrl`. It is built using a custom
`wx.PyControl`, composed by a `wx.TextCtrl` and a `wx.SpinButton`. In order to
correctly handle floating points numbers without rounding errors or non-exact
floating point representations, L{FloatSpin} uses the great L{FixedPoint} class
from Tim Peters.

What you can do:

- Set the number of representative digits for your floating point numbers;
- Set the floating point format (``%f``, ``%F``, ``%e``, ``%E``, ``%g``, ``%G``);
- Set the increment of every ``EVT_FLOATSPIN`` event;
- Set minimum, maximum values for L{FloatSpin} as well as its range;
- Change font and colour for the underline `wx.TextCtrl`.


Usage
=====

Usage example::

    import wx
    import wx.lib.agw.floatspin as FS

    class MyFrame(wx.Frame):

        def __init__(self, parent):
        
            wx.Frame.__init__(self, parent, -1, "FloatSpin Demo")

            panel = wx.Panel(self)
            
            floatspin = FS.FloatSpin(panel, -1, pos=(50, 50), min_val=0, max_val=1,
                                     increment=0.01, value=0.1, agwStyle=FS.FS_LEFT)
            floatspin.SetFormat("%f")
            floatspin.SetDigits(2)

            
    # our normal wxApp-derived class, as usual

    app = wx.PySimpleApp()

    frame = MyFrame(None)
    app.SetTopWindow(frame)
    frame.Show()

    app.MainLoop()



Events
======

L{FloatSpin} catches 3 different types of events:

1) Spin events: events generated by spinning up/down the spinbutton;
2) Char events: playing with up/down arrows of the keyboard increase/decrease
   the value of L{FloatSpin};
3) Mouse wheel event: using the wheel will change the value of L{FloatSpin}.

In addition, there are some other functionalities:

- It remembers the initial value as a default value, call L{SetToDefaultValue}, or
  press ``Esc`` to return to it;
- ``Shift`` + arrow = 2 * increment        (or ``Shift`` + mouse wheel);
- ``Ctrl``  + arrow = 10 * increment       (or ``Ctrl`` + mouse wheel);
- ``Alt``   + arrow = 100 * increment      (or ``Alt`` + mouse wheel);
- Combinations of ``Shift``, ``Ctrl``, ``Alt`` increment the L{FloatSpin} value by the
  product of the factors;
- ``PgUp`` & ``PgDn`` = 10 * increment * the product of the ``Shift``, ``Ctrl``, ``Alt``
  factors;
- ``Space`` sets the control's value to it's last valid state.


Window Styles
=============

This class supports the following window styles:

=============== =========== ==================================================
Window Styles   Hex Value   Description
=============== =========== ==================================================
``FS_READONLY``         0x1 Sets L{FloatSpin} as read-only control.
``FS_LEFT``             0x2 Horizontally align the underlying `wx.TextCtrl` on the left.
``FS_CENTRE``           0x4 Horizontally align the underlying `wx.TextCtrl` on center.
``FS_RIGHT``            0x8 Horizontally align the underlying `wx.TextCtrl` on the right.
=============== =========== ==================================================


Events Processing
=================

This class processes the following events:

================= ==================================================
Event Name        Description
================= ==================================================
``EVT_FLOATSPIN`` Emitted when the user changes the value of L{FloatSpin}, either with the mouse or with the keyboard.
================= ==================================================


License And Version
===================

L{FloatSpin} control is distributed under the wxPython license.

Latest revision: Andrea Gavana @ 17 Aug 2011, 15.00 GMT

Version 0.9


Backward Incompatibilities
==========================

Modifications to allow `min_val` or `max_val` to be ``None`` done by:

James Bigler,
SCI Institute, University of Utah,
March 14, 2007

:note: Note that the changes I made will break backward compatibility,
 because I changed the contructor's parameters from `min` / `max` to
 `min_val` / `max_val` to be consistent with the other functions and to
 eliminate any potential confusion with the built in `min` and `max`
 functions.

You specify open ranges like this (you can equally do this in the
constructor)::

    SetRange(min_val=1, max_val=None)     # [1,  ]
    SetRange(min_val=None, max_val=0)     # [ , 0]

or no range::

    SetRange(min_val=None, max_val=None)  # [ , ]

"""


#----------------------------------------------------------------------
# Beginning Of FLOATSPIN wxPython Code
#----------------------------------------------------------------------

import wx
import locale
from math import ceil, floor

# Set The Styles For The Underline wx.TextCtrl
FS_READONLY = 1
""" Sets L{FloatSpin} as read-only control. """
FS_LEFT = 2
""" Horizontally align the underlying `wx.TextCtrl` on the left. """
FS_CENTRE = 4
""" Horizontally align the underlying `wx.TextCtrl` on center. """
FS_RIGHT = 8
""" Horizontally align the underlying `wx.TextCtrl` on the right. """

# Define The FloatSpin Event
wxEVT_FLOATSPIN = wx.NewEventType()

#-----------------------------------#
#        FloatSpinEvent
#-----------------------------------#

EVT_FLOATSPIN = wx.PyEventBinder(wxEVT_FLOATSPIN, 1)
""" Emitted when the user changes the value of L{FloatSpin}, either with the mouse or""" \
""" with the keyboard. """

# ---------------------------------------------------------------------------- #
# Class FloatSpinEvent
# ---------------------------------------------------------------------------- #

class FloatSpinEvent(wx.PyCommandEvent):
    """ This event will be sent when a ``EVT_FLOATSPIN`` event is mapped in the parent. """

    def __init__(self, eventType, eventId=1, nSel=-1, nOldSel=-1):
        """
        Default class constructor.

        :param `eventType`: the event type;
        :param `eventId`: the event identifier;
        :param `nSel`: the current selection;
        :param `nOldSel`: the old selection.
        """

        wx.PyCommandEvent.__init__(self, eventType, eventId)
        self._eventType = eventType


    def SetPosition(self, pos):
        """
        Sets event position.

        :param `pos`: an integer specyfing the event position.
        """

        self._position = pos


    def GetPosition(self):
        """ Returns event position. """

        return self._position


#----------------------------------------------------------------------------
# FloatTextCtrl
#----------------------------------------------------------------------------


class FloatTextCtrl(wx.TextCtrl):
    """
    A class which holds a `wx.TextCtrl`, one of the two building blocks
    of L{FloatSpin}.
    """
    
    def __init__(self, parent, id=wx.ID_ANY, value="", pos=wx.DefaultPosition,
                 size=wx.DefaultSize, style=wx.TE_NOHIDESEL | wx.TE_PROCESS_ENTER,
                 validator=wx.DefaultValidator,
                 name=wx.TextCtrlNameStr):
        """
        Default class constructor.
        Used internally. Do not call directly this class in your code!

        :param `parent`: the L{FloatTextCtrl} parent;
        :param `id`: an identifier for the control: a value of -1 is taken to mean a default;
        :param `value`: default text value;
        :param `pos`: the control position. A value of (-1, -1) indicates a default position,
         chosen by either the windowing system or wxPython, depending on platform;
        :param `size`: the control size. A value of (-1, -1) indicates a default size,
         chosen by either the windowing system or wxPython, depending on platform;
        :param `style`: the window style;
        :param `validator`: the window validator;
        :param `name`: the window name.
        
        """

        wx.TextCtrl.__init__(self, parent, id, value, pos, size, style, validator, name)

        self._parent = parent
        self.Bind(wx.EVT_WINDOW_DESTROY, self.OnDestroy)
        self.Bind(wx.EVT_CHAR, self.OnChar)
        self.Bind(wx.EVT_KILL_FOCUS, self.OnKillFocus)


    def OnDestroy(self, event):
        """
        Handles the ``wx.EVT_WINDOW_DESTROY`` event for L{FloatTextCtrl}.

        :param `event`: a `wx.WindowDestroyEvent` event to be processed.

        :note: This method tries to correctly handle the control destruction under MSW.
        """

        if self._parent:
            self._parent._textctrl = None
            self._parent = None


    def OnChar(self, event):
        """
        Handles the ``wx.EVT_CHAR`` event for L{FloatTextCtrl}.

        :param `event`: a `wx.KeyEvent` event to be processed.
        """

        if self._parent:
            self._parent.OnChar(event)


    def OnKillFocus(self, event):
        """
        Handles the ``wx.EVT_KILL_FOCUS`` event for L{FloatTextCtrl}.

        :param `event`: a `wx.FocusEvent` event to be processed.

        :note: This method synchronizes the `wx.SpinButton` and the `wx.TextCtrl`
         when focus is lost.
         """

        if self._parent:
            self._parent.SyncSpinToText(True)

        event.Skip()


#---------------------------------------------------------------------------- #
# FloatSpin
# This Is The Main Class Implementation
# ---------------------------------------------------------------------------- #

class FloatSpin(wx.PyControl):
    """
    L{FloatSpin} implements a floating point `wx.SpinCtrl`. It is built using a custom
    `wx.PyControl`, composed by a `wx.TextCtrl` and a `wx.SpinButton`. In order to
    correctly handle floating points numbers without rounding errors or non-exact
    floating point representations, L{FloatSpin} uses the great L{FixedPoint} class
    from Tim Peters.
    """

    def __init__(self, parent, id=wx.ID_ANY, pos=wx.DefaultPosition,
                 size=(95,-1), style=0, value=0.0, min_val=None, max_val=None,
                 increment=1.0, digits=-1, agwStyle=FS_LEFT,
                 name="FloatSpin"):
        """
        Default class constructor.

        :param `parent`: the L{FloatSpin} parent;
        :param `id`: an identifier for the control: a value of -1 is taken to mean a default;
        :param `pos`: the control position. A value of (-1, -1) indicates a default position,
         chosen by either the windowing system or wxPython, depending on platform;
        :param `size`: the control size. A value of (-1, -1) indicates a default size,
         chosen by either the windowing system or wxPython, depending on platform;
        :param `style`: the window style;
        :param `value`: is the current value for L{FloatSpin};
        :param `min_val`: the minimum value, ignored if ``None``;
        :param `max_val`: the maximum value, ignored if ``None``;
        :param `increment`: the increment for every L{FloatSpinEvent} event;
        :param `digits`: number of representative digits for your floating point numbers;
        :param `agwStyle`: one of the following bits:

         =============== =========== ==================================================
         Window Styles   Hex Value   Description
         =============== =========== ==================================================
         ``FS_READONLY``         0x1 Sets L{FloatSpin} as read-only control.
         ``FS_LEFT``             0x2 Horizontally align the underlying `wx.TextCtrl` on the left.
         ``FS_CENTRE``           0x4 Horizontally align the underlying `wx.TextCtrl` on center.
         ``FS_RIGHT``            0x8 Horizontally align the underlying `wx.TextCtrl` on the right.
         =============== =========== ==================================================

        :param `name`: the window name.

        """

        wx.PyControl.__init__(self, parent, id, pos, size, style|wx.NO_BORDER|
                              wx.NO_FULL_REPAINT_ON_RESIZE | wx.CLIP_CHILDREN,
                              wx.DefaultValidator, name)

        # Don't call SetRange here, because it will try to modify
        # self._value whose value doesn't exist yet.
        self.SetRangeDontClampValue(min_val, max_val)
        self._value = self.ClampValue(FixedPoint(str(value), 20))
        self._defaultvalue = self._value
        self._increment = FixedPoint(str(increment), 20)
        self._spinmodifier = FixedPoint(str(1.0), 20)
        self._digits = digits
        self._snapticks = False
        self._spinbutton = None
        self._textctrl = None
        self._spinctrl_bestsize = wx.Size(-999, -999)

        # start Philip Semanchuk addition
        # The textbox & spin button are drawn slightly differently 
        # depending on the platform. The difference is most pronounced
        # under OS X.
        if "__WXMAC__" in wx.PlatformInfo:
            self._gap = 8
            self._spin_top = 3
            self._text_left = 4
            self._text_top = 4
        elif "__WXMSW__" in wx.PlatformInfo:
            self._gap = 1
            self._spin_top = 0
            self._text_left = 0
            self._text_top = 0
        else:
            # GTK
            self._gap = -1
            self._spin_top = 0
            self._text_left = 0
            self._text_top = 0
        # end Philip Semanchuk addition

        self.SetLabel(name)
        # start Philip Semanchuk change
        # Set the background color to match that of the parent. wxMac supports
        # transparency, and that gives the best results on that platform.
        # Other platforms ignore wx.ALPHA_TRANSPARENT.
        colour = parent.GetBackgroundColour()
        colour.Set(colour.Red(), colour.Green(), colour.Blue(), 
                   wx.ALPHA_TRANSPARENT)
        self.SetBackgroundColour(colour)
        # end Philip Semanchuk change
        self.SetForegroundColour(parent.GetForegroundColour())

        width = size[0]
        height = size[1]
        best_size = self.DoGetBestSize()

        if width == -1:
            width = best_size.GetWidth()
        if height == -1:
            height = best_size.GetHeight()

        self._validkeycode = [43, 44, 45, 46, 69, 101, 127, 314]
        self._validkeycode.extend(range(48, 58))
        self._validkeycode.extend([wx.WXK_RETURN, wx.WXK_TAB, wx.WXK_BACK,
                                   wx.WXK_LEFT, wx.WXK_RIGHT])

        self._spinbutton = wx.SpinButton(self, wx.ID_ANY, wx.DefaultPosition,
                                         size=(-1, height),
                                         style=wx.SP_ARROW_KEYS | wx.SP_VERTICAL |
                                         wx.SP_WRAP)

        txtstyle = wx.TE_NOHIDESEL | wx.TE_PROCESS_ENTER

        if agwStyle & FS_RIGHT:
            txtstyle = txtstyle | wx.TE_RIGHT
        elif agwStyle & FS_CENTRE:
            txtstyle = txtstyle | wx.TE_CENTER

        if agwStyle & FS_READONLY:
            txtstyle = txtstyle | wx.TE_READONLY

        self._textctrl = FloatTextCtrl(self, wx.ID_ANY, str(self._value),
                                       wx.DefaultPosition,
                                       (width-self._spinbutton.GetSize().GetWidth(), height),
                                       txtstyle)

        # start Philip Semanchuk addition
        # Setting the textctrl's size in the ctor also sets its min size. 
        # But the textctrl is entirely controlled by the parent floatspin 
        # control and should accept whatever size its parent dictates, so
        # here we tell it to forget its min size.
        self._textctrl.SetMinSize(wx.DefaultSize)
        # Setting the spin buttons's size in the ctor also sets its min size. 
        # Under OS X that results in a rendering artifact because spin buttons
        # are a little shorter than textboxes. 
        # Setting the min size to the default allows OS X to draw the spin
        # button correctly. However, Windows and KDE take the call to
        # SetMinSize() as a cue to size the spin button taller than the
        # textbox, so we avoid the call there.
        if "__WXMAC__" in wx.PlatformInfo:
            self._spinbutton.SetMinSize(wx.DefaultSize)
        # end Philip Semanchuk addition

        self._mainsizer = wx.BoxSizer(wx.HORIZONTAL)
        # Ensure the spin button is shown, and the text widget takes
        # all remaining free space
        self._mainsizer.Add(self._textctrl, 1)
        self._mainsizer.Add(self._spinbutton, 0)
        self.SetSizer(self._mainsizer)
        self._mainsizer.Layout()

        self.SetFormat()
        self.SetDigits(digits)

        # set the value here without generating an event

        decimal = locale.localeconv()["decimal_point"]
        strs = ("%100." + str(self._digits) + self._textformat[1])%self._value
        strs = strs.replace(".", decimal)

        strs = strs.strip()
        strs = self.ReplaceDoubleZero(strs)

        self._textctrl.SetValue(strs)

        if not (agwStyle & FS_READONLY):
            self.Bind(wx.EVT_SPIN_UP, self.OnSpinUp)
            self.Bind(wx.EVT_SPIN_DOWN, self.OnSpinDown)
            self._spinbutton.Bind(wx.EVT_LEFT_DOWN, self.OnSpinMouseDown)
            
        self._textctrl.Bind(wx.EVT_TEXT_ENTER, self.OnTextEnter)
        self._textctrl.Bind(wx.EVT_MOUSEWHEEL, self.OnMouseWheel)
        self._spinbutton.Bind(wx.EVT_MOUSEWHEEL, self.OnMouseWheel)

        self.Bind(wx.EVT_SET_FOCUS, self.OnFocus)
        self.Bind(wx.EVT_KILL_FOCUS, self.OnKillFocus)
        self.Bind(wx.EVT_SIZE, self.OnSize)

        # start Philip Semanchuk move
        self.SetBestSize((width, height))
        # end Philip Semanchuk move


    def OnDestroy(self, event):
        """
        Handles the ``wx.EVT_WINDOW_DESTROY`` event for L{FloatSpin}.

        :param `event`: a `wx.WindowDestroyEvent` event to be processed.

        :note: This method tries to correctly handle the control destruction under MSW.
        """

        # Null This Since MSW Sends KILL_FOCUS On Deletion
        if self._textctrl:
            self._textctrl._parent = None
            self._textctrl.Destroy()
            self._textctrl = None

        self._spinbutton.Destroy()
        self._spinbutton = None


    def DoGetBestSize(self):
        """
        Gets the size which best suits the window: for a control, it would be the
        minimal size which doesn't truncate the control, for a panel - the same
        size as it would have after a call to `Fit()`.
        
        :note: Overridden from `wx.PyControl`.
        """

        if self._spinctrl_bestsize.x == -999:

            spin = wx.SpinCtrl(self, -1)
            self._spinctrl_bestsize = spin.GetBestSize()

            # oops something went wrong, set to reasonable value
            if self._spinctrl_bestsize.GetWidth() < 20:
                self._spinctrl_bestsize.SetWidth(95)
            if self._spinctrl_bestsize.GetHeight() < 10:
                self._spinctrl_bestsize.SetHeight(22)

            spin.Destroy()

        return self._spinctrl_bestsize


    def DoSendEvent(self):
        """ Send the event to the parent. """

        event = wx.CommandEvent(wx.wxEVT_COMMAND_SPINCTRL_UPDATED, self.GetId())
        event.SetEventObject(self)
        event.SetInt(int(self._value + 0.5))

        if self._textctrl:
            event.SetString(self._textctrl.GetValue())

        self.GetEventHandler().ProcessEvent(event)

        eventOut = FloatSpinEvent(wxEVT_FLOATSPIN, self.GetId())
        eventOut.SetPosition(int(self._value + 0.5))
        eventOut.SetEventObject(self)
        self.GetEventHandler().ProcessEvent(eventOut)


    def OnSpinMouseDown(self, event):
        """
        Handles the ``wx.EVT_LEFT_DOWN`` event for L{FloatSpin}.

        :param `event`: a `wx.MouseEvent` event to be processed.

        :note: This method works on the underlying `wx.SpinButton`.
        """

        modifier = FixedPoint(str(1.0), 20)
        if event.ShiftDown():
            modifier = modifier*2.0
        if event.ControlDown():
            modifier = modifier*10.0
        if event.AltDown():
            modifier = modifier*100.0

        self._spinmodifier = modifier

        event.Skip()


    def OnSpinUp(self, event):
        """
        Handles the ``wx.EVT_SPIN_UP`` event for L{FloatSpin}.

        :param `event`: a `wx.SpinEvent` event to be processed.
        """

        if self._textctrl and self._textctrl.IsModified():
            self.SyncSpinToText(False)

        if self.InRange(self._value + self._increment*self._spinmodifier):

            self._value = self._value + self._increment*self._spinmodifier
            self.SetValue(self._value)
            self.DoSendEvent()


    def OnSpinDown(self, event):
        """
        Handles the ``wx.EVT_SPIN_DOWN`` event for L{FloatSpin}.

        :param `event`: a `wx.SpinEvent` event to be processed.
        """

        if self._textctrl and self._textctrl.IsModified():
            self.SyncSpinToText(False)

        if self.InRange(self._value - self._increment*self._spinmodifier):

            self._value = self._value - self._increment*self._spinmodifier
            self.SetValue(self._value)
            self.DoSendEvent()


    def OnTextEnter(self, event):
        """
        Handles the ``wx.EVT_TEXT_ENTER`` event for L{FloatSpin}.

        :param `event`: a `wx.KeyEvent` event to be processed.

        :note: This method works on the underlying `wx.TextCtrl`.
        """

        self.SyncSpinToText(True)
        event.Skip()


    def OnChar(self, event):
        """
        Handles the ``wx.EVT_CHAR`` event for L{FloatSpin}.

        :param `event`: a `wx.KeyEvent` event to be processed.

        :note: This method works on the underlying `wx.TextCtrl`.
        """

        modifier = FixedPoint(str(1.0), 20)
        if event.ShiftDown():
            modifier = modifier*2.0
        if event.ControlDown():
            modifier = modifier*10.0
        if event.AltDown():
            modifier = modifier*100.0

        keycode = event.GetKeyCode()

        if keycode == wx.WXK_UP:

            if self._textctrl and self._textctrl.IsModified():
                self.SyncSpinToText(False)

            self.SetValue(self._value + self._increment*modifier)
            self.DoSendEvent()

        elif keycode == wx.WXK_DOWN:

            if self._textctrl and self._textctrl.IsModified():
                self.SyncSpinToText(False)

            self.SetValue(self._value - self._increment*modifier)
            self.DoSendEvent()

        elif keycode == wx.WXK_PRIOR:

            if self._textctrl and self._textctrl.IsModified():
                self.SyncSpinToText(False)

            self.SetValue(self._value + 10.0*self._increment*modifier)
            self.DoSendEvent()

        elif keycode == wx.WXK_NEXT:

            if self._textctrl and self._textctrl.IsModified():
                self.SyncSpinToText(False)

            self.SetValue(self._value - 10.0*self._increment*modifier)
            self.DoSendEvent()

        elif keycode == wx.WXK_SPACE:

            self.SetValue(self._value)
            event.Skip(False)

        elif keycode == wx.WXK_ESCAPE:

            self.SetToDefaultValue()
            self.DoSendEvent()

        elif keycode == wx.WXK_TAB:

            new_event = wx.NavigationKeyEvent()
            new_event.SetEventObject(self.GetParent())
            new_event.SetDirection(not event.ShiftDown())
            # CTRL-TAB changes the (parent) window, i.e. switch notebook page
            new_event.SetWindowChange(event.ControlDown())
            new_event.SetCurrentFocus(self)
            self.GetParent().GetEventHandler().ProcessEvent(new_event)

        else:
            if keycode not in self._validkeycode:
                return

            event.Skip()


    def OnMouseWheel(self, event):
        """
        Handles the ``wx.EVT_MOUSEWHEEL`` event for L{FloatSpin}.

        :param `event`: a `wx.MouseEvent` event to be processed.
        """

        modifier = FixedPoint(str(1.0), 20)
        if event.ShiftDown():
            modifier = modifier*2.0
        if event.ControlDown():
            modifier = modifier*10.0
        if event.AltDown():
            modifier = modifier*100.0

        if self._textctrl and self._textctrl.IsModified():
            self.SyncSpinToText(False)

        if event.GetWheelRotation() > 0:
            self.SetValue(self._value + self._increment*modifier)
            self.DoSendEvent()

        else:

            self.SetValue(self._value - self._increment*modifier)
            self.DoSendEvent()


    def OnSize(self, event):
        """
        Handles the ``wx.EVT_SIZE`` event for L{FloatSpin}.

        :param `event`: a `wx.SizeEvent` event to be processed.

        :note: This method resizes the text control and reposition the spin button when
         resized.
        """
        # start Philip Semanchuk addition
        event_width = event.GetSize().width
        
        self._textctrl.SetPosition((self._text_left, self._text_top))
        
        text_width, text_height = self._textctrl.GetSizeTuple()
        
        spin_width, _ = self._spinbutton.GetSizeTuple()
        
        text_width = event_width - (spin_width + self._gap + self._text_left)

        self._textctrl.SetSize(wx.Size(text_width, text_height))
        
        # The spin button is always snug against the right edge of the 
        # control.
        self._spinbutton.SetPosition((event_width - spin_width, self._spin_top))
        
        event.Skip()
        # end Philip Semanchuk addition


    def ReplaceDoubleZero(self, strs):
        """
        Replaces the (somewhat) python ugly `+e000` with `+e00`.

        :param `strs`: a string (possibly) containing a `+e00` substring.
        """

        if self._textformat not in ["%g", "%e", "%E", "%G"]:
            return strs

        if strs.find("e+00") >= 0:
            strs = strs.replace("e+00", "e+0")
        elif strs.find("e-00") >= 0:
            strs = strs.replace("e-00", "e-0")
        elif strs.find("E+00") >= 0:
            strs = strs.replace("E+00", "E+0")
        elif strs.find("E-00") >= 0:
            strs = strs.replace("E-00", "E-0")

        return strs


    def SetValue(self, value):
        """
        Sets the L{FloatSpin} value.

        :param `value`: the new value.
        """        
        if not self._textctrl or not self.InRange(value):
            return

        if self._snapticks and self._increment != 0.0:

            finite, snap_value = self.IsFinite(value)

            if not finite: # FIXME What To Do About A Failure?

                if (snap_value - floor(snap_value) < ceil(snap_value) - snap_value):
                    value = self._defaultvalue + floor(snap_value)*self._increment
                else:
                    value = self._defaultvalue + ceil(snap_value)*self._increment

        decimal = locale.localeconv()["decimal_point"]
        strs = ("%100." + str(self._digits) + self._textformat[1])%value
        strs = strs.replace(".", decimal)
        strs = strs.strip()
        strs = self.ReplaceDoubleZero(strs)

        if value != self._value or strs != self._textctrl.GetValue():

            self._textctrl.SetValue(strs)
            self._textctrl.DiscardEdits()
            self._value = value


    def GetValue(self):
        """ Returns the L{FloatSpin} value. """

        return float(self._value)


    def SetRangeDontClampValue(self, min_val, max_val):
        """
        Sets the allowed range.

        :param `min_val`: the minimum value for L{FloatSpin}. If it is ``None`` it is
         ignored;
        :param `max_val`: the maximum value for L{FloatSpin}. If it is ``None`` it is
         ignored.

        :note: This method doesn't modify the current value.
        """

        if (min_val != None):
            self._min = FixedPoint(str(min_val), 20)
        else:
            self._min = None
        if (max_val != None):
            self._max = FixedPoint(str(max_val), 20)
        else:
            self._max = None


    def SetRange(self, min_val, max_val):
        """
        Sets the allowed range.

        :param `min_val`: the minimum value for L{FloatSpin}. If it is ``None`` it is
         ignored;
        :param `max_val`: the maximum value for L{FloatSpin}. If it is ``None`` it is
         ignored.

        :note: This method doesn't modify the current value.

        :note: You specify open ranges like this (you can equally do this in the
         constructor)::

             SetRange(min_val=1, max_val=None)
             SetRange(min_val=None, max_val=0)


         or no range::

             SetRange(min_val=None, max_val=None)
        
        """

        self.SetRangeDontClampValue(min_val, max_val)

        value = self.ClampValue(self._value)
        if (value != self._value):
            self.SetValue(value)


    def ClampValue(self, var):
        """
        Clamps `var` between `_min` and `_max` depending if the range has
        been specified.

        :param `var`: the value to be clamped.
        
        :return: A clamped copy of `var`.
        """

        if (self._min != None):
            if (var < self._min):
                var = self._min
                return var

        if (self._max != None):
            if (var > self._max):
                var = self._max
                
        return var


    def SetIncrement(self, increment):
        """
        Sets the increment for every ``EVT_FLOATSPIN`` event.

        :param `increment`: a floating point number specifying the L{FloatSpin} increment.
        """

        if increment < 1./10.0**self._digits:
            raise Exception("\nERROR: Increment Should Be Greater Or Equal To 1/(10**digits).")

        self._increment = FixedPoint(str(increment), 20)
        self.SetValue(self._value)


    def GetIncrement(self):
        """ Returns the increment for every ``EVT_FLOATSPIN`` event. """

        return self._increment


    def SetDigits(self, digits=-1):
        """
        Sets the number of digits to show.

        :param `digits`: the number of digits to show. If `digits` < 0, L{FloatSpin}
         tries to calculate the best number of digits based on input values passed
         in the constructor.
        """

        if digits < 0:
            incr = str(self._increment)
            if incr.find(".") < 0:
                digits = 0
            else:
                digits = len(incr[incr.find(".")+1:])

        self._digits = digits

        self.SetValue(self._value)


    def GetDigits(self):
        """ Returns the number of digits shown. """

        return self._digits


    def SetFormat(self, fmt="%f"):
        """
        Set the string format to use.

        :param `fmt`: the new string format to use. One of the following strings:

         ====== =================================
         Format Description
         ====== =================================         
         'e'    Floating point exponential format (lowercase)
         'E'    Floating point exponential format (uppercase)
         'f'    Floating point decimal format
         'F'    Floating point decimal format
         'g'    Floating point format. Uses lowercase exponential format if exponent is less than -4 or not less than precision, decimal format otherwise
         'G'    Floating point format. Uses uppercase exponential format if exponent is less than -4 or not less than precision, decimal format otherwise
         ====== =================================         

        """

        if fmt not in ["%f", "%g", "%e", "%E", "%F", "%G"]:
            raise Exception('\nERROR: Bad Float Number Format: ' + repr(fmt) + '. It Should Be ' \
                            'One Of "%f", "%g", "%e", "%E", "%F", "%G"')

        self._textformat = fmt

        if self._digits < 0:
            self.SetDigits()

        self.SetValue(self._value)


    def GetFormat(self):
        """
        Returns the string format in use.

        :see: L{SetFormat} for a list of valid string formats.
        """

        return self._textformat


    def SetDefaultValue(self, defaultvalue):
        """
        Sets the L{FloatSpin} default value.

        :param `defaultvalue`: a floating point value representing the new default
         value for L{FloatSpin}.
        """

        if self.InRange(defaultvalue):
            self._defaultvalue = FixedPoint(str(defaultvalue), 20)


    def GetDefaultValue(self):
        """ Returns the L{FloatSpin} default value. """

        return self._defaultvalue


    def IsDefaultValue(self):
        """ Returns whether the current value is the default value or not. """

        return self._value == self._defaultvalue


    def SetToDefaultValue(self):
        """ Sets L{FloatSpin} value to its default value. """

        self.SetValue(self._defaultvalue)


    def SetSnapToTicks(self, forceticks=True):
        """
        Force the value to always be divisible by the increment. Initially ``False``.

        :param `forceticks`: ``True`` to force the snap to ticks option, ``False`` otherwise.
        
        :note: This uses the default value as the basis, you will get strange results
         for very large differences between the current value and default value
         when the increment is very small.
        """

        if self._snapticks != forceticks:

            self._snapticks = forceticks
            self.SetValue(self._value)


    def GetSnapToTicks(self):
        """ Returns whether the snap to ticks option is active or not. """

        return self._snapticks


    def OnFocus(self, event):
        """
        Handles the ``wx.EVT_SET_FOCUS`` event for L{FloatSpin}.

        :param `event`: a `wx.FocusEvent` event to be processed.
        """

        if self._textctrl:
            self._textctrl.SetFocus()

        event.Skip()


    def OnKillFocus(self, event):
        """
        Handles the ``wx.EVT_KILL_FOCUS`` event for L{FloatSpin}.

        :param `event`: a `wx.FocusEvent` event to be processed.
        """

        self.SyncSpinToText(True)
        event.Skip()


    def SyncSpinToText(self, send_event=True, force_valid=True):
        """
        Synchronize the underlying `wx.TextCtrl` with `wx.SpinButton`.

        :param `send_event`: ``True`` to send a ``EVT_FLOATSPIN`` event, ``False``
         otherwise;
        :param `force_valid`: ``True`` to force a valid value (i.e. inside the
         provided range), ``False`` otherwise.
        """

        if not self._textctrl:
            return

        curr = self._textctrl.GetValue()
        curr = curr.strip()
        decimal = locale.localeconv()["decimal_point"]
        curr = curr.replace(decimal, ".")

        if curr:
            try:
                curro = float(curr)
                curr = FixedPoint(curr, 20)
            except:
                self.SetValue(self._value)
                return

            if force_valid or not self.HasRange() or self.InRange(curr):

                if force_valid and self.HasRange():

                    curr = self.ClampValue(curr)

                if self._value != curr:
                    self.SetValue(curr)

                    if send_event:
                        self.DoSendEvent()

        elif force_valid:

            # textctrl is out of sync, discard and reset
            self.SetValue(self.GetValue())


    def SetFont(self, font=None):
        """
        Sets the underlying `wx.TextCtrl` font.

        :param `font`: a valid instance of `wx.Font`.
        """

        if font is None:
            font = wx.SystemSettings_GetFont(wx.SYS_DEFAULT_GUI_FONT)

        if not self._textctrl:
            return False

        return self._textctrl.SetFont(font)


    def GetFont(self):
        """ Returns the underlying `wx.TextCtrl` font. """

        if not self._textctrl:
            return self.GetFont()

        return self._textctrl.GetFont()


    def GetMin(self):
        """
        Returns the minimum value for L{FloatSpin}. It can be a
        number or ``None`` if no minimum is present.
        """

        return self._min


    def GetMax(self):
        """
        Returns the maximum value for L{FloatSpin}. It can be a
        number or ``None`` if no minimum is present.
        """

        return self._max


    def HasRange(self):
        """ Returns whether L{FloatSpin} range has been set or not. """

        return (self._min != None) or (self._max != None)


    def InRange(self, value):
        """
        Returns whether a value is inside L{FloatSpin} range.

        :param `value`: the value to test.
        """

        if (not self.HasRange()):
            return True
        if (self._min != None):
            if (value < self._min):
                return False
        if (self._max != None):
            if (value > self._max):
                return False
        return True


    def GetTextCtrl(self):
        """ Returns the underlying `wx.TextCtrl`. """

        return self._textctrl


    def IsFinite(self, value):
        """
        Tries to determine if a value is finite or infinite/NaN.

        :param `value`: the value to test.
        """

        try:
            snap_value = (value - self._defaultvalue)/self._increment
            finite = True
        except:
            finite = False
            snap_value = None

        return finite, snap_value



# Class FixedPoint, version 0.0.4.
# Released to the public domain 28-Mar-2001,
# by Tim Peters (tim.one@home.com).

# Provided as-is; use at your own risk; no warranty; no promises; enjoy!


# 28-Mar-01 ver 0.0,4
#     Use repr() instead of str() inside __str__, because str(long) changed
#     since this was first written (used to produce trailing "L", doesn't
#     now).
#
# 09-May-99 ver 0,0,3
#     Repaired __sub__(FixedPoint, string); was blowing up.
#     Much more careful conversion of float (now best possible).
#     Implemented exact % and divmod.
#
# 14-Oct-98 ver 0,0,2
#     Added int, long, frac.  Beefed up docs.  Removed DECIMAL_POINT
#     and MINUS_SIGN globals to discourage bloating this class instead
#     of writing formatting wrapper classes (or subclasses)
#
# 11-Oct-98 ver 0,0,1
#     posted to c.l.py

__version__ = 0, 0, 4

# The default value for the number of decimal digits carried after the
# decimal point.  This only has effect at compile-time.
DEFAULT_PRECISION = 2

class FixedPoint(object):
    """
    FixedPoint objects support decimal arithmetic with a fixed number of
    digits (called the object's precision) after the decimal point.  The
    number of digits before the decimal point is variable & unbounded.

    The precision is user-settable on a per-object basis when a FixedPoint
    is constructed, and may vary across FixedPoint objects.  The precision
    may also be changed after construction via `FixedPoint.set_precision(p)`.
    Note that if the precision of a FixedPoint is reduced via L{FixedPoint.set_precision},
    information may be lost to rounding.

    Example::    

        >>> x = FixedPoint("5.55")  # precision defaults to 2
        >>> print x
        5.55
        >>> x.set_precision(1)      # round to one fraction digit
        >>> print x
        5.6
        >>> print FixedPoint("5.55", 1)  # same thing setting to 1 in constructor
        5.6
        >>> repr(x) #  returns constructor string that reproduces object exactly
        "FixedPoint('5.6', 1)"
        >>>


    When L{FixedPoint} objects of different precision are combined via + - * /,
    the result is computed to the larger of the inputs' precisions, which also
    becomes the precision of the resulting L{FixedPoint} object. Example::

        >>> print FixedPoint("3.42") + FixedPoint("100.005", 3)
        103.425
        >>>


    When a L{FixedPoint} is combined with other numeric types (ints, floats,
    strings representing a number) via + - * /, then similarly the computation
    is carried out using -- and the result inherits -- the L{FixedPoint}'s
    precision. Example::

        >>> print FixedPoint(1) / 7
        0.14
        >>> print FixedPoint(1, 30) / 7
        0.142857142857142857142857142857
        >>>


    The string produced by `str(x)` (implictly invoked by `print`) always
    contains at least one digit before the decimal point, followed by a
    decimal point, followed by exactly `x.get_precision()` digits.  If `x` is
    negative, `str(x)[0] == "-"`.

    The L{FixedPoint} constructor can be passed an int, long, string, float,
    L{FixedPoint}, or any object convertible to a float via `float()` or to a
    long via `long()`. Passing a precision is optional; if specified, the
    precision must be a non-negative int. There is no inherent limit on
    the size of the precision, but if very very large you'll probably run
    out of memory.

    Note that conversion of floats to L{FixedPoint} can be surprising, and
    should be avoided whenever possible. Conversion from string is exact
    (up to final rounding to the requested precision), so is greatly
    preferred. Example::

        >>> print FixedPoint(1.1e30)
        1099999999999999993725589651456.00
        >>> print FixedPoint("1.1e30")
        1100000000000000000000000000000.00
        >>>


    """

    # the exact value is self.n / 10**self.p;
    # self.n is a long; self.p is an int

    def __init__(self, value=0, precision=DEFAULT_PRECISION):
        """
        Default class constructor.

        :param `value`: the initial value;
        :param `precision`: must be an int >= 0, and defaults to ``DEFAULT_PRECISION``.
        """
        
        self.n = self.p = 0
        self.set_precision(precision)
        p = self.p

        if isinstance(value, type("42.3e5")):
            n, exp = _string2exact(value)
            # exact value is n*10**exp = n*10**(exp+p)/10**p
            effective_exp = exp + p
            if effective_exp > 0:
                n = n * _tento(effective_exp)
            elif effective_exp < 0:
                n = _roundquotient(n, _tento(-effective_exp))
            self.n = n
            return

        if isinstance(value, type(42)) or isinstance(value, type(42L)):
            self.n = long(value) * _tento(p)
            return

        if isinstance(value, FixedPoint):
            temp = value.copy()
            temp.set_precision(p)
            self.n, self.p = temp.n, temp.p
            return

        if isinstance(value, type(42.0)):
            # XXX ignoring infinities and NaNs and overflows for now
            import math
            f, e = math.frexp(abs(value))
            assert f == 0 or 0.5 <= f < 1.0
            # |value| = f * 2**e exactly

            # Suck up CHUNK bits at a time; 28 is enough so that we suck
            # up all bits in 2 iterations for all known binary double-
            # precision formats, and small enough to fit in an int.
            CHUNK = 28
            top = 0L
            # invariant: |value| = (top + f) * 2**e exactly
            while f:
                f = math.ldexp(f, CHUNK)
                digit = int(f)
                assert digit >> CHUNK == 0
                top = (top << CHUNK) | digit
                f = f - digit
                assert 0.0 <= f < 1.0
                e = e - CHUNK

            # now |value| = top * 2**e exactly
            # want n such that n / 10**p = top * 2**e, or
            # n = top * 10**p * 2**e
            top = top * _tento(p)
            if e >= 0:
                n = top << e
            else:
                n = _roundquotient(top, 1L << -e)
            if value < 0:
                n = -n
            self.n = n
            return

        if isinstance(value, type(42-42j)):
            raise TypeError("can't convert complex to FixedPoint: " +
                            `value`)

        # can we coerce to a float?
        yes = 1
        try:
            asfloat = float(value)
        except:
            yes = 0
        if yes:
            self.__init__(asfloat, p)
            return

        # similarly for long
        yes = 1
        try:
            aslong = long(value)
        except:
            yes = 0
        if yes:
            self.__init__(aslong, p)
            return

        raise TypeError("can't convert to FixedPoint: " + `value`)


    def get_precision(self):
        """
        Return the precision of this L{FixedPoint}.

        :note: The precision is the number of decimal digits carried after
         the decimal point, and is an int >= 0.
        """

        return self.p


    def set_precision(self, precision=DEFAULT_PRECISION):
        """
        Change the precision carried by this L{FixedPoint} to `precision`.

        :param `precision`: must be an int >= 0, and defaults to
         ``DEFAULT_PRECISION``.

        :note: If `precision` is less than this FixedPoint's current precision,
         information may be lost to rounding.
        """

        try:
            p = int(precision)
        except:
            raise TypeError("precision not convertable to int: " +
                            `precision`)
        if p < 0:
            raise ValueError("precision must be >= 0: " + `precision`)

        if p > self.p:
            self.n = self.n * _tento(p - self.p)
        elif p < self.p:
            self.n = _roundquotient(self.n, _tento(self.p - p))
        self.p = p


    def __str__(self):
        
        n, p = self.n, self.p
        i, f = divmod(abs(n), _tento(p))
        if p:
            frac = repr(f)[:-1]
            frac = "0" * (p - len(frac)) + frac
        else:
            frac = ""
        return "-"[:n<0] + \
               repr(i)[:-1] + \
               "." + frac


    def __repr__(self):

        return "FixedPoint" + `(str(self), self.p)`


    def copy(self):
        """ Create a copy of the current L{FixedPoint}. """
        
        return _mkFP(self.n, self.p)

    __copy__ = __deepcopy__ = copy


    def __cmp__(self, other):
        
        if (other == None):
            return 1
        xn, yn, p = _norm(self, other)
        return cmp(xn, yn)


    def __hash__(self):
        # caution!  == values must have equal hashes, and a FixedPoint
        # is essentially a rational in unnormalized form.  There's
        # really no choice here but to normalize it, so hash is
        # potentially expensive.
        n, p = self.__reduce()

        # Obscurity: if the value is an exact integer, p will be 0 now,
        # so the hash expression reduces to hash(n).  So FixedPoints
        # that happen to be exact integers hash to the same things as
        # their int or long equivalents.  This is Good.  But if a
        # FixedPoint happens to have a value exactly representable as
        # a float, their hashes may differ.  This is a teensy bit Bad.
        return hash(n) ^ hash(p)

    def __nonzero__(self):
        return self.n != 0

    def __neg__(self):
        return _mkFP(-self.n, self.p)

    def __abs__(self):
        if self.n >= 0:
            return self.copy()
        else:
            return -self

    def __add__(self, other):
        n1, n2, p = _norm(self, other)
        # n1/10**p + n2/10**p = (n1+n2)/10**p
        return _mkFP(n1 + n2, p)

    __radd__ = __add__

    def __sub__(self, other):
        if not isinstance(other, FixedPoint):
            other = FixedPoint(other, self.p)
        return self.__add__(-other)

    def __rsub__(self, other):
        return (-self) + other

    def __mul__(self, other):
        n1, n2, p = _norm(self, other)
        # n1/10**p * n2/10**p = (n1*n2/10**p)/10**p
        return _mkFP(_roundquotient(n1 * n2, _tento(p)), p)

    __rmul__ = __mul__

    def __div__(self, other):
        n1, n2, p = _norm(self, other)
        if n2 == 0:
            raise ZeroDivisionError("FixedPoint division")
        if n2 < 0:
            n1, n2 = -n1, -n2
        # n1/10**p / (n2/10**p) = n1/n2 = (n1*10**p/n2)/10**p
        return _mkFP(_roundquotient(n1 * _tento(p), n2), p)

    def __rdiv__(self, other):
        n1, n2, p = _norm(self, other)
        return _mkFP(n2, p) / self

    def __divmod__(self, other):
        n1, n2, p = _norm(self, other)
        if n2 == 0:
            raise ZeroDivisionError("FixedPoint modulo")
        # floor((n1/10**p)/(n2*10**p)) = floor(n1/n2)
        q = n1 / n2
        # n1/10**p - q * n2/10**p = (n1 - q * n2)/10**p
        return q, _mkFP(n1 - q * n2, p)

    def __rdivmod__(self, other):
        n1, n2, p = _norm(self, other)
        return divmod(_mkFP(n2, p), self)

    def __mod__(self, other):
        return self.__divmod__(other)[1]

    def __rmod__(self, other):
        n1, n2, p = _norm(self, other)
        return _mkFP(n2, p).__mod__(self)

    # caution! float can lose precision
    def __float__(self):
        n, p = self.__reduce()
        return float(n) / float(_tento(p))

    # XXX should this round instead?
    # XXX note e.g. long(-1.9) == -1L and long(1.9) == 1L in Python
    # XXX note that __int__ inherits whatever __long__ does,
    # XXX and .frac() is affected too
    def __long__(self):
        answer = abs(self.n) / _tento(self.p)
        if self.n < 0:
            answer = -answer
        return answer

    def __int__(self):
        return int(self.__long__())

    def frac(self):
        """
        Returns fractional portion as a L{FixedPoint}.

        :note: In L{FixedPoint},
        
         this equality holds true::
        
                x = x.frac() + long(x)

            
        """
        return self - long(self)

    # return n, p s.t. self == n/10**p and n % 10 != 0
    def __reduce(self):
        n, p = self.n, self.p
        if n == 0:
            p = 0
        while p and n % 10 == 0:
            p = p - 1
            n = n / 10
        return n, p

# return 10L**n

def _tento(n, cache={}):
    try:
        return cache[n]
    except KeyError:
        answer = cache[n] = 10L ** n
        return answer

# return xn, yn, p s.t.
# p = max(x.p, y.p)
# x = xn / 10**p
# y = yn / 10**p
#
# x must be FixedPoint to begin with; if y is not FixedPoint,
# it inherits its precision from x.
#
# Note that this is called a lot, so default-arg tricks are helpful.

def _norm(x, y, isinstance=isinstance, FixedPoint=FixedPoint,
                _tento=_tento):
    assert isinstance(x, FixedPoint)
    if not isinstance(y, FixedPoint):
        y = FixedPoint(y, x.p)
    xn, yn = x.n, y.n
    xp, yp = x.p, y.p
    if xp > yp:
        yn = yn * _tento(xp - yp)
        p = xp
    elif xp < yp:
        xn = xn * _tento(yp - xp)
        p = yp
    else:
        p = xp  # same as yp
    return xn, yn, p

def _mkFP(n, p, FixedPoint=FixedPoint):
    f = FixedPoint()
    f.n = n
    f.p = p
    return f

# divide x by y, rounding to int via nearest-even
# y must be > 0
# XXX which rounding modes are useful?

def _roundquotient(x, y):
    assert y > 0
    n, leftover = divmod(x, y)
    c = cmp(leftover << 1, y)
    # c < 0 <-> leftover < y/2, etc
    if c > 0 or (c == 0 and (n & 1) == 1):
        n = n + 1
    return n

# crud for parsing strings
import re

# There's an optional sign at the start, and an optional exponent
# at the end.  The exponent has an optional sign and at least one
# digit.  In between, must have either at least one digit followed
# by an optional fraction, or a decimal point followed by at least
# one digit.  Yuck.

_parser = re.compile(r"""
    \s*
    (?P<sign>[-+])?
    (
        (?P<int>\d+) (\. (?P<frac>\d*))?
    |
        \. (?P<onlyfrac>\d+)
    )
    ([eE](?P<exp>[-+]? \d+))?
    \s* $
""", re.VERBOSE).match

del re

# return n, p s.t. float string value == n * 10**p exactly

def _string2exact(s):
    m = _parser(s)
    if m is None:
        raise ValueError("can't parse as number: " + `s`)

    exp = m.group('exp')
    if exp is None:
        exp = 0
    else:
        exp = int(exp)

    intpart = m.group('int')
    if intpart is None:
        intpart = "0"
        fracpart = m.group('onlyfrac')
    else:
        fracpart = m.group('frac')
        if fracpart is None or fracpart == "":
            fracpart = "0"
    assert intpart
    assert fracpart

    i, f = long(intpart), long(fracpart)
    nfrac = len(fracpart)
    i = i * _tento(nfrac) + f
    exp = exp - nfrac

    if m.group('sign') == "-":
        i = -i

    return i, exp