aboutsummaryrefslogtreecommitdiff
path: root/thcolor/colors.py
blob: cfc9240562950cd4c1c8219a6c400ea179ca704d (plain)
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
#!/usr/bin/env python3
# *****************************************************************************
# Copyright (C) 2019-2022 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
# This file is part of the thcolor project, which is MIT-licensed.
# *****************************************************************************
"""Color representations and conversions."""

from math import (
    atan2 as _atan2, ceil as _ceil, cos as _cos, sin as _sin, sqrt as _sqrt,
)
from typing import (
    Any as _Any, Optional as _Optional, Sequence as _Sequence, Tuple as _Tuple,
)

from .angles import (
    Angle as _Angle, DegreesAngle as _DegreesAngle,
    RadiansAngle as _RadiansAngle, TurnsAngle as _TurnsAngle,
)
from .utils import round_half_up as _round_half_up

__all__ = [
    'CMYKColor', 'Color', 'HSLColor', 'HSVColor', 'HWBColor',
    'LABColor', 'LCHColor', 'SRGBColor', 'XYZColor',
    'YIQColor', 'YUVColor',
]


class Color:
    """Class representing a color within thcolor.

    :param alpha: Value for :py:attr:`alpha`.
    """

    __slots__ = ('_alpha')
    _params: _Sequence[str] = ()

    def __init__(self, alpha: float = 1.0):
        super().__init__()

        try:
            alpha = float(alpha)
        except (TypeError, ValueError):
            raise ValueError(f'alpha should be a float, is {alpha!r}')
        else:
            if alpha < 0 or alpha > 1:
                raise ValueError('alpha should be between 0.0 and 1.0')

        self._alpha = alpha

    def __repr__(self):
        params = (
            (key, getattr(self, key))
            for key in self._params + ('alpha',)
        )
        return (
            f'{self.__class__.__name__}('
            f'{", ".join(f"{key}={val!r}" for key, val in params)})'
        )

    def __eq__(self, other: _Any) -> bool:
        if not isinstance(other, Color):
            return False

        srgb = tuple(map(lambda x: round(x, 3), self.assrgb()))
        orgb = tuple(map(lambda x: round(x, 3), other.assrgb()))

        return srgb == orgb

    @property
    def alpha(self) -> float:
        """Get the alpha component value.

        Represented as a float varying between 0.0 (invisible)
        and 1.0 (opaque).
        """

        return self._alpha

    @classmethod
    def fromtext(
        cls,
        expr: str,
        decoder: _Optional[_Any] = None,
    ) -> 'Color':
        """Create a color from a string.

        :param expr: The expression to decode.
        """

        if decoder is None:
            from .builtin import DefaultColorDecoder

            decoder = DefaultColorDecoder()

        results = decoder.decode(expr, prefer_colors=True)

        if len(results) != 1 or not isinstance(results[0], cls):
            raise ValueError(
                f'result of expression was not an instance of {cls.__name__}: '
                f'single color: {results!r}',
            )

        return results[0]

    # ---
    # Conversions.
    # ---

    def assrgb(self) -> 'SRGBColor':
        """Get an SRGBColor out of the current object."""

        raise NotImplementedError

    def ashsl(self) -> 'HSLColor':
        """Get an HSLColor out of the current object."""

        return self.assrgb().ashsl()

    def ashsv(self) -> 'HSVColor':
        """Get an HSVColor out of the current object."""

        return self.assrgb().ashsv()

    def ashwb(self) -> 'HWBColor':
        """Get an HWBColor out of the current object."""

        return self.assrgb().ashwb()

    def ascmyk(self) -> 'CMYKColor':
        """Get a CMYKColor out of the current object."""

        return self.assrgb().ascmyk()

    def aslab(self) -> 'LABColor':
        """Get a LABColor out of the current object."""

        raise NotImplementedError

    def aslch(self) -> 'LCHColor':
        """Get a LCHColor out of the current object."""

        raise NotImplementedError

    def asxyz(self) -> 'XYZColor':
        """Get an XYZColor out of the current object."""

        raise NotImplementedError

    def asyiq(self) -> 'YIQColor':
        """Get an YIQColor out of the current object."""

        return self.assrgb().asyiq()

    def asyuv(self) -> 'YUVColor':
        """Get an YUVColor out of the current object."""

        return self.assrgb().asyuv()

    # ---
    # Operations on colors.
    # ---

    def replace(self, **properties) -> 'Color':
        """Get the color with the given properties replaced.

        For changing the alpha on an RGB color:

        .. code-block:: python

            >>> SRGBColor(.1, .2, .3).replace(alpha=.5)
            ... SRGBColor(red=0.1, green=0.2, blue=0.3, alpha=0.5)

        For changing the lightness on an HSL color:

        .. code-block:: pycon

            >>> HSLColor(DegreesAngle(270), .5, 1).replace(lightness=.2)
            ... HSLColor(hue=DegreesAngle(degrees=270.0), saturation=0.5,
            ...          lightness=0.2, alpha=1.0)

        :param properties: Properties to change from the original color.
        """

        params = {
            key: getattr(self, key)
            for key in (*self._params, 'alpha')
        }

        for key, value in properties.items():
            if key not in params:
                raise KeyError(
                    f'no such argument {key!r} in '
                    f'{self.__class__.__name__} parameters',
                )

            params[key] = value

        return type(self)(**params)

    def darker(self, by: float = 0.1) -> 'Color':
        """Get a darker version of the given color.

        :param by: Percentage by which the color should be darker.
        """

        color = self.ashsl()
        return color.replace(lightness=max(color.lightness - by, 0.0))

    def lighter(self, by: float = 0.1) -> 'Color':
        """Get a lighter version of the given color.

        :param by: Percentage by which the color should be lighter.
        """

        color = self.ashsl()
        return color.replace(lightness=min(color.lightness + by, 1.0))

    def desaturate(self, by: float = 0.1) -> 'Color':
        """Get a less saturated version of the given color.

        :param by: Percentage by which the color should be
                   desaturated.
        """

        color = self.ashsl()
        return color.replace(saturation=max(color.saturation - by, 0.0))

    def saturate(self, by: float = 0.1) -> 'Color':
        """Get a more saturated version of the given color.

        :param by: Percentage by which the color should be
                   saturated.
        """

        color = self.ashsl()
        return color.replace(saturation=min(color.saturation + by, 1.0))

    def css(self) -> _Sequence[str]:
        """Get the CSS color descriptions.

        Includes older CSS specifications compatibility,
        as a sequence of strings.

        For example:

            >>> SRGBColor.frombytes(18, 52, 86, 0.82).css()
            ... ("#123456", "rgba(18, 52, 86, 82%)")
        """

        def _percent(prop):
            per = _round_half_up(prop, 4) * 100
            if per == int(per):
                per = int(per)
            return per

        def _deg(agl):
            return int(agl.asdegrees().degrees)

        def statements():
            # Start by yelling a #RRGGBB color, compatible with most
            # web browsers around the world, followed by the rgba()
            # notation if the alpha value isn't 1.0.
            a = _round_half_up(self.alpha, 3)

            try:
                rgb = self.assrgb()
            except NotImplementedError:
                pass
            else:
                r, g, b = rgb.asbytes()

                yield f'#{r:02X}{g:02X}{b:02X}'

                if a < 1.0:
                    yield f'rgba({r}, {g}, {b}, {_percent(a)}%)'

            # Then yield more specific CSS declarations in case
            # they're supported (which would be neat!).
            if isinstance(self, HSLColor):
                hue, sat, lgt = (
                    self.hue, self.saturation, self.lightness,
                )
                args = (
                    f'{_deg(hue)}deg, {_percent(sat)}%, {_percent(lgt)}%'
                )

                if a < 1.0:
                    yield f'hsla({args}, {_percent(a)}%)'
                else:
                    yield f'hsl({args})'
            elif isinstance(self, HWBColor):
                hue, wht, blk = (
                    self.hue, self.whiteness, self.blackness)

                args = f'{_deg(hue)}deg, ' \
                    f'{_percent(wht)}%, {_percent(blk)}%'

                if a < 1.0:
                    yield f'hwba({args}, {_percent(a)}%)'
                else:
                    yield f'hwb({args})'

        return tuple(statements())

# ---
# Color implementations.
# ---


class SRGBColor(Color):
    """A color expressed using its channel intensities in the sRGB profile.

    :param red: Value for :py:attr:`red`.
    :param green: Value for :py:attr:`green`.
    :param blue: Value for :py:attr:`blue`.
    :param alpha: Value for :py:attr:`alpha`.
    """

    __slots__ = ('_red', '_green', '_blue')
    _params = ('red', 'green', 'blue')

    def __init__(
        self,
        red: float,
        green: float,
        blue: float,
        alpha: float = 1.0,
    ):
        super().__init__(alpha)

        try:
            red = float(red)
        except (TypeError, ValueError):
            raise ValueError(f'red should be a float, is {red!r}')

        try:
            green = float(green)
        except (TypeError, ValueError):
            raise ValueError(f'green should be a float, is {green!r}')

        try:
            blue = float(blue)
        except (TypeError, ValueError):
            raise ValueError(f'blue should be a float, is {blue!r}')

        self._red = red
        self._green = green
        self._blue = blue

    def __iter__(self):
        return iter((
            self.red,
            self.green,
            self.blue,
            self.alpha,
        ))

    @property
    def red(self) -> float:
        """Get the intensity of the red channel.

        Represented as a float between 0.0 (dark) and 1.0 (light).
        """

        return self._red

    @property
    def green(self) -> float:
        """Get the intensity of the green channel.

        Represented as a float between 0.0 (dark) and 1.0 (light).
        """

        return self._green

    @property
    def blue(self) -> float:
        """Get the intensity of the blue channel.

        Represented as a float between 0.0 (dark) and 1.0 (light).
        """

        return self._blue

    @classmethod
    def frombytes(
        cls,
        red: int,
        green: int,
        blue: int,
        alpha: float = 1.0,
    ) -> 'SRGBColor':
        """Get an sRGB color from colors using values between 0 and 255."""

        return cls(
            red=red / 255,
            green=green / 255,
            blue=blue / 255,
            alpha=alpha,
        )

    @classmethod
    def fromnetscapecolorname(cls, name: str) -> 'SRGBColor':
        """Get an sRGB color from a Netscape color name."""

        name = str(name)
        if name[0] == '#':
            name = name[1:]

        # Find more about this here: https://stackoverflow.com/a/8333464
        #
        # First of all:
        # - we sanitize our input by replacing invalid characters
        #   by '0' characters (the 0xFFFF limit is due to how
        #   UTF-16 was managed at the time).
        # - we truncate our input to 128 characters.
        name = name.lower()
        name = ''.join(
            c if c in '0123456789abcdef' else '00'[:1 + (ord(c) > 0xFFFF)]
            for c in name[:128]
        )[:128]

        # Then we calculate some values we're going to need.
        # `iv` is the size of the zone for a member.
        # `sz` is the size of the digits slice to take in that zone
        # (max. 8).
        # `of` is the offset in the zone of the slice to take.
        iv = _ceil(len(name) / 3)
        of = iv - 8 if iv > 8 else 0
        sz = iv - of

        # Then we isolate the slices using the values calculated
        # above. `gr` will be an array of 3 or 4 digit strings
        # (depending on the number of members).
        gr = list(map(
            lambda i: name[i * iv + of:i * iv + iv].ljust(sz, '0'),
            range(3),
        ))

        # Check how many digits we can skip at the beginning of
        # each slice.
        pre = min(map(lambda x: len(x) - len(x.lstrip('0')), gr))
        pre = min(pre, sz - 2)

        # Then we extract the values.
        r, g, b = map(lambda x: int('0' + x[pre:pre + 2], 16), gr)

        return cls.frombytes(r, g, b)

    def assrgb(self) -> 'SRGBColor':
        """Get an SRGBColor out of the current object."""

        return SRGBColor(
            red=self.red,
            green=self.green,
            blue=self.blue,
            alpha=self.alpha,
        )

    def ashsl(self) -> 'HSLColor':
        """Get an HSLColor out of the current object."""

        r, g, b = self.red, self.green, self.blue

        min_value = min((r, g, b))
        max_value = max((r, g, b))
        chroma = max_value - min_value

        if chroma == 0:
            hue = 0.
        elif r == max_value:
            hue = (g - b) / chroma
        elif g == max_value:
            hue = (b - r) / chroma + 2
        else:
            hue = (r - g) / chroma + 4

        hue = hue * 60 + (hue < 0) * 360
        lgt = (min_value + max_value) / 2
        if min_value == max_value:
            s = 0.
        else:
            s = max_value - min_value
            if lgt < 0.5:
                s /= max_value + min_value
            else:
                s /= 2 - max_value - min_value

        return HSLColor(
            hue=_DegreesAngle(_round_half_up(hue, 2)),
            saturation=_round_half_up(s, 2),
            lightness=_round_half_up(lgt, 2),
            alpha=self.alpha,
        )

    def ashsv(self) -> 'HSVColor':
        """Get an HSVColor out of the current object."""

        r, g, b = self.red, self.green, self.blue
        maxc = max(r, g, b)
        minc = min(r, g, b)

        value = maxc
        if minc == maxc:
            turns, saturation = 0., 0.
        else:
            saturation = (maxc - minc) / maxc
            rc, gc, bc = map(lambda x: (maxc - x) / (maxc - minc), (r, g, b))

            if r == maxc:
                turns = bc - gc
            elif g == maxc:
                turns = 2 + rc - bc
            else:
                turns = 4 + gc - rc

            turns = (turns / 6) % 1

        return HSVColor(
            hue=_TurnsAngle(turns),
            saturation=saturation,
            value=value,
            alpha=self.alpha,
        )

    def ashwb(self) -> 'HWBColor':
        """Get an HWBColor out of the current object."""

        r, g, b = self.red, self.green, self.blue

        max_ = max((r, g, b))
        min_ = min((r, g, b))
        chroma = max_ - min_

        if chroma == 0:
            hue = 0.
        elif r == max_:
            hue = (g - b) / chroma
        elif g == max_:
            hue = (b - r) / chroma + 2
        elif b == max_:
            hue = (r - g) / chroma + 4

        hue /= 6
        w = min_
        b = 1 - max_

        return HWBColor(
            hue=_TurnsAngle(hue),
            whiteness=w,
            blackness=b,
            alpha=self.alpha,
        )

    def ascmyk(self) -> 'CMYKColor':
        """Get a CMYKColor out of the current object."""

        r, g, b, _ = self

        k = 1 - max((r, g, b))
        if k == 1:
            c, m, y = 0, 0, 0
        else:
            c = (1 - r - k) / (1 - k)
            m = (1 - g - k) / (1 - k)
            y = (1 - b - k) / (1 - k)

        return CMYKColor(
            cyan=c,
            magenta=m,
            yellow=y,
            black=k,
            alpha=self.alpha,
        )

    def asyiq(self) -> 'YIQColor':
        """Get an YIQColor out of the current object."""

        r, g, b = self.red, self.green, self.blue

        return YIQColor(
            y=.587 * g + .114 * b + .299 * r,
            i=-.275 * g - .321 * b + .596 * r,
            q=-.523 * g + .311 * b + .212 * r,
            alpha=self.alpha,
        )

    def asbytes(self) -> _Tuple[int, int, int]:
        """Get the red, blue and green bytes."""

        return (
            int(_round_half_up(self.red * 255)),
            int(_round_half_up(self.green * 255)),
            int(_round_half_up(self.blue * 255)),
        )


class HSLColor(Color):
    """A color expressed using its hue, saturation and lightness components.

    :param hue: Value for :py:attr:`hue`.
    :param saturation: Value for :py:attr:`saturation`.
    :param lightness: Value for :py:attr:`lightness`.
    :param alpha: Value for :py:attr:`alpha`.
    """

    __slots__ = ('_hue', '_saturation', '_lightness')
    _params = ('hue', 'saturation', 'lightness')

    def __init__(
        self,
        hue: _Angle,
        saturation: float,
        lightness: float,
        alpha: float = 1.0,
    ):
        super().__init__(alpha)

        if not isinstance(hue, _Angle):
            raise ValueError('hue should be an angle')

        try:
            saturation = float(saturation)
        except (TypeError, ValueError):
            raise ValueError(
                f'saturation should be a float, is {saturation!r}',
            )
        else:
            if saturation < 0 or saturation > 1:
                raise ValueError('saturation should be between 0.0 and 1.0')

        try:
            lightness = float(lightness)
        except (TypeError, ValueError):
            raise ValueError(f'lightness should be a float, is {lightness!r}')
        else:
            if lightness < 0 or lightness > 1:
                raise ValueError('lightness should be between 0.0 and 1.0')

        self._hue = hue
        self._saturation = saturation
        self._lightness = lightness

    def __iter__(self):
        return iter((self.hue, self.saturation, self.lightness, self.alpha))

    @property
    def hue(self) -> _Angle:
        """Get the hue, as an angle."""

        return self._hue

    @property
    def saturation(self) -> float:
        """Get the saturation, between 0.0 and 1.0."""

        return self._saturation

    @property
    def lightness(self) -> float:
        """Get the lightness, between 0.0 and 1.0."""

        return self._lightness

    def assrgb(self) -> 'SRGBColor':
        """Get an SRGBColor out of the current object."""

        hue_obj, s, lgt = self.hue.asdegrees(), self.saturation, self.lightness

        if s == 0:
            # Achromatic color.

            return SRGBColor(
                red=lgt,
                green=lgt,
                blue=lgt,
                alpha=self.alpha,
            )

        def _hue_to_rgb(t1, t2, hue):
            hue %= 6

            if hue < 1:
                return t1 + (t2 - t1) * hue
            elif hue < 3:
                return t2
            elif hue < 4:
                return t1 + (t2 - t1) * (4 - hue)
            return t1

        hue = (hue_obj.degrees % 360) / 60
        if lgt <= 0.5:
            t2 = lgt * (s + 1)
        else:
            t2 = lgt + s - (lgt * s)

        t1 = lgt * 2 - t2

        return SRGBColor(
            red=_hue_to_rgb(t1, t2, hue + 2),
            green=_hue_to_rgb(t1, t2, hue),
            blue=_hue_to_rgb(t1, t2, hue - 2),
            alpha=self.alpha,
        )

    def ashsl(self) -> 'HSLColor':
        """Get an HSLColor out of the current object."""

        return HSLColor(
            hue=self.hue,
            saturation=self.saturation,
            lightness=self.lightness,
            alpha=self.alpha,
        )


class HSVColor(Color):
    """A color expressed using its hue, saturation and value components.

    :param hue: Value for :py:attr:`hue`.
    :param saturation: Value for :py:attr:`saturation`.
    :param value: Value for :py:attr:`value`.
    :param alpha: Value for :py:attr:`alpha`.
    """

    __slots__ = ('_hue', '_saturation', '_value')
    _params = ('hue', 'saturation', 'value')

    def __init__(
        self,
        hue: _Angle,
        saturation: float,
        value: float,
        alpha: float = 1.0,
    ):
        super().__init__(alpha)

        self._hue = hue
        self._saturation = saturation
        self._value = value

    def __iter__(self):
        return iter((self.hue, self.saturation, self.value, self.alpha))

    @property
    def hue(self) -> _Angle:
        """Get the hue, as an angle."""

        return self._hue

    @property
    def saturation(self) -> float:
        """Get the saturation, between 0.0 and 1.0."""

        return self._saturation

    @property
    def value(self) -> float:
        """Get the value, between 0.0 and 1.0."""

        return self._value

    def assrgb(self) -> 'SRGBColor':
        """Get an SRGBColor out of the current object."""

        hue, saturation, value = (
            self.hue.asturns(),
            self.saturation,
            self.value,
        )

        if saturation == 0:
            r, g, b = value, value, value
        else:
            f = hue.turns * 6.0
            f, i = f - int(f), int(f) % 6

            p = value * (1.0 - saturation)
            q = value * (1.0 - saturation * f)
            t = value * (1.0 - saturation * (1.0 - f))

            if i == 0:
                r, g, b = value, t, p
            elif i == 1:
                r, g, b = q, value, p
            elif i == 2:
                r, g, b = p, value, t
            elif i == 3:
                r, g, b = p, q, value
            elif i == 4:
                r, g, b = t, p, value
            elif i == 5:
                r, g, b = value, p, q

        return SRGBColor(
            red=r,
            green=g,
            blue=b,
            alpha=self.alpha,
        )

    def ashsv(self) -> 'HSVColor':
        """Get an HSVColor out of the current object."""

        return HSVColor(
            hue=self.hue,
            saturation=self.saturation,
            value=self.value,
            alpha=self.alpha,
        )


class HWBColor(Color):
    """A color expressed using its hue, whiteness and blackness components.

    :param hue: Value for :py:attr:`hue`.
    :param whiteness: Value for :py:attr:`whiteness`.
    :param blackness: Value for :py:attr:`blackness`.
    :param alpha: Value for :py:attr:`alpha`.
    """

    __slots__ = ('_hue', '_whiteness', '_blackness')
    _params = ('hue', 'whiteness', 'blackness')

    def __init__(
        self,
        hue: _Angle,
        whiteness: float = 0.0,
        blackness: float = 0.0,
        alpha: float = 1.0,
    ):
        super().__init__(alpha)

        self._hue = hue
        self._whiteness = whiteness
        self._blackness = blackness

    def __iter__(self):
        return iter((self.hue, self.whiteness, self.blackness, self.alpha))

    @property
    def hue(self) -> _Angle:
        """Get the hue, as an angle."""

        return self._hue

    @property
    def whiteness(self) -> float:
        """Get the whiteness, as a value between 0.0 and 1.0."""

        return self._whiteness

    @property
    def blackness(self) -> float:
        """Get the blackness, as a value between 0.0 and 1.0."""

        return self._blackness

    def assrgb(self) -> 'SRGBColor':
        """Get an SRGBColor out of the current object."""

        hue, w, bl = self.hue, self.whiteness, self.blackness

        color = HSLColor(hue, 1.0, .5).assrgb()
        r, g, b = color.red, color.green, color.blue

        if w + bl > 1:
            w, bl = map(lambda x: x / (w + bl), (w, bl))

        r, g, b = map(lambda x: x * (1 - w - bl) + w, (r, g, b))

        return SRGBColor(
            red=r,
            green=g,
            blue=b,
            alpha=self.alpha,
        )

    def ashwb(self) -> 'HWBColor':
        """Get an HWBColor out of the current object."""

        return HWBColor(
            hue=self.hue,
            whiteness=self.whiteness,
            blackness=self.blackness,
            alpha=self.alpha,
        )


class CMYKColor(Color):
    """A color expressed using its CMYK channels' intensities.

    :param cyan: Value for :py:attr:`cyan`.
    :param magenta: Value for :py:attr:`magenta`.
    :param yellow: Value for :py:attr:`yellow`.
    :param black: Value for :py:attr:`black`.
    :param alpha: Value for :py:attr:`alpha`.
    """

    __slots__ = ('_cyan', '_magenta', '_yellow', '_black')
    _params = ('cyan', 'magenta', 'yellow', 'black')

    def __init__(
        self,
        cyan: float,
        magenta: float,
        yellow: float,
        black: float,
        alpha: float = 1.0,
    ):
        super().__init__(alpha)

        self._cyan = cyan
        self._magenta = magenta
        self._yellow = yellow
        self._black = black

    def __iter__(self):
        return iter((
            self.cyan,
            self.magenta,
            self.yellow,
            self.black,
            self.alpha,
        ))

    @property
    def cyan(self):
        """Get the cyan channel intensity between 0.0 and 1.0."""

        return self._cyan

    @property
    def magenta(self):
        """Get the magenta channel intensity between 0.0 and 1.0."""

        return self._magenta

    @property
    def yellow(self):
        """Get the yellow channel intensity between 0.0 and 1.0."""

        return self._yellow

    @property
    def black(self):
        """Get the black channel intensity between 0.0 and 1.0."""

        return self._black

    def assrgb(self) -> 'SRGBColor':
        """Get an SRGBColor out of the current object."""

        c, m, y, k = self.cyan, self.magenta, self.yellow, self.black

        r = 1 - min(1, c * (1 - k) + k)
        g = 1 - min(1, m * (1 - k) + k)
        b = 1 - min(1, y * (1 - k) + k)

        return SRGBColor(
            red=r,
            green=g,
            blue=b,
            alpha=self.alpha,
        )

    def ascmyk(self) -> 'CMYKColor':
        """Get a CMYKColor out of the current object."""

        return CMYKColor(
            cyan=self.cyan,
            magenta=self.magenta,
            yellow=self.yellow,
            black=self.black,
            alpha=self.alpha,
        )


class LABColor(Color):
    """A color expressed using its CIELAB color space cartesian coordinates.

    :param lightness: Value for :py:attr:`lightness`.
    :param a: Value for :py:attr:`a`.
    :param b: Value for :py:attr:`b`.
    :param alpha: Value for :py:attr:`alpha`.
    """

    __slots__ = ('_lightness', '_a', '_b')
    _params = ('lightness', 'a', 'b')

    def __init__(
        self,
        lightness: float,
        a: float,
        b: float,
        alpha: float = 1.0,
    ):
        super().__init__(alpha)

        self._lightness = lightness
        self._a = a
        self._b = b

    def __iter__(self):
        return iter((self.lightness, self.a, self.b, self.alpha))

    @property
    def lightness(self) -> float:
        """Get the CIE lightness.

        Similar to the lightness in the HSL representation.
        Represented as a float between 0.0 and 1.0.
        """

        return self._lightness

    @property
    def a(self) -> float:
        """Get the A axis value in the Lab colorspace."""

        return self._a

    @property
    def b(self) -> float:
        """Get the B axis value in the Lab colorspace."""

        return self._b

    def assrgb(self) -> 'SRGBColor':
        """Get an SRGBColor out of the current object."""

        return self.asxyz().assrgb()

    def aslab(self) -> 'LABColor':
        """Get a LABColor out of the current object."""

        return LABColor(
            lightness=self.lightness,
            a=self.a,
            b=self.b,
            alpha=self.alpha,
        )

    def aslch(self) -> 'LCHColor':
        """Get a LCHColor out of the current object."""

        l, a, b = self.lightness, self.a, self.b

        return LCHColor(
            lightness=l,
            chroma=_sqrt(a ** 2 + b ** 2),
            hue=_RadiansAngle(_atan2(b, a)).asprincipal(),
            alpha=self.alpha,
        )


class LCHColor(Color):
    """A color expressed using its CIELAB color space polar coordinates.

    :param lightness: Value for :py:attr:`lightness`.
    :param chroma: Value for :py:attr:`chroma`.
    :param hue: Value for :py:attr:`hue`.
    :param alpha: Value for :py:attr:`alpha`.
    """

    __slots__ = ('_lightness', '_chroma', '_hue', '_alpha')
    _params = ('lightness', 'chroma', 'hue')

    def __init__(
        self,
        lightness: float,
        chroma: float,
        hue: _Angle,
        alpha: float = 1.0,
    ):
        super().__init__(alpha)

        try:
            lightness = float(lightness)
        except (TypeError, ValueError):
            raise ValueError(f'lightness should be a float, is {lightness!r}')
        else:
            if lightness < 0 or lightness > 1:
                raise ValueError('lightness should be between 0.0 and 1.0')

        try:
            chroma = float(chroma)
        except (TypeError, ValueError):
            raise ValueError(f'chroma should be a float, is {chroma!r}')
        else:
            if chroma < 0:
                chroma = 0.0

        if not isinstance(hue, _Angle):
            raise TypeError(f'hue should be an Angle, is {hue!r}')

        self._lightness = lightness
        self._chroma = chroma
        self._hue = hue

    def __iter__(self):
        return iter((self.lightness, self.chroma, self.hue, self.alpha))

    @property
    def lightness(self) -> float:
        """Get the CIE lightness.

        Similar to the lightness in the HSL representation.
        Represented as a float between 0.0 and 1.0.
        """

        return self._lightness

    @property
    def chroma(self) -> float:
        """Get the chroma.

        Represented as a positive number theoretically  unbounded.
        """

        return self._chroma

    @property
    def hue(self) -> _Angle:
        """Get the hue, as an angle."""

        return self._hue

    def assrgb(self) -> 'SRGBColor':
        """Get an SRGBColor out of the current object."""

        return self.aslab().asxyz().assrgb()

    def aslab(self) -> 'LABColor':
        """Get a LABColor out of the current object."""

        l, c, h = self.lightness, self.chroma, self.hue.asradians()

        return LABColor(
            lightness=l,
            a=c * _cos(h.radians),
            b=c * _sin(h.radians),
            alpha=self.alpha,
        )

    def aslch(self) -> 'LCHColor':
        """Get a LCHColor out of the current object."""

        return LCHColor(
            lightness=self.lightness,
            chroma=self.chroma,
            hue=self.hue,
            alpha=self.alpha,
        )


class XYZColor(Color):
    """A color expressed using its CIEXYZ color space coordinates.

    :param x: Value for :py:attr:`x`.
    :param y: Value for :py:attr:`y`.
    :param z: Value for :py:attr:`z`.
    :param alpha: Value for :py:attr:`alpha`.
    """

    __slots__ = ('_x', '_y', '_z')
    _params = ('x', 'y', 'z')

    def __init__(self, x: float, y: float, z: float, alpha: float = 1.0):
        super().__init__(alpha)

        try:
            x = float(x)
        except (TypeError, ValueError):
            raise ValueError(f'x should be a float, is {x!r}')
        else:
            if x < 0 or x > 1:
                raise ValueError('x should be between 0.0 and 1.0')

        try:
            y = float(y)
        except (TypeError, ValueError):
            raise ValueError(f'y should be a float, is {y!r}')
        else:
            if y < 0 or y > 1:
                raise ValueError('y should be between 0.0 and 1.0')

        try:
            z = float(z)
        except (TypeError, ValueError):
            raise ValueError(f'z should be a float, is {z!r}')
        else:
            if z < 0 or z > 1:
                raise ValueError('z should be between 0.0 and 1.0')

        self._x = x
        self._y = y
        self._z = z

    def __iter__(self):
        return iter((self.x, self.y, self.z, self.alpha))

    @property
    def x(self) -> float:
        """Get the CIE X component, between 0.0 and 1.0."""

        return self._x

    @property
    def y(self) -> float:
        """Get the CIE Y component, between 0.0 and 1.0."""

        return self._y

    @property
    def z(self) -> float:
        """Get the CIE Z component, between 0.0 and 1.0."""

        return self._z

    def assrgb(self) -> 'SRGBColor':
        """Get an SRGBColor out of the current object."""

        # For more information about this algorithm, see these links:
        #
        # * http://www.easyrgb.com/en/math.php#text9
        #   (insufficient precision but you get the gist of the algorithm).
        # * https://stackoverflow.com/a/45238704

        x, y, z = self.x, self.y, self.z

        r = x * 3.2404542 + y * -1.5371385 + z * -.4985314
        g = x * -.9692660 + y * 1.8760108 + z * .0415560
        b = x * .0556434 + y * -.2040259 + z * 1.0572252

        r, g, b = map(
            lambda x: (
                1.055 * (x ** (1 / 2.4)) - .055
                if x > .0031308
                else 12.92 * x
            ),
            (r, g, b),
        )

        return SRGBColor(
            red=r,
            green=g,
            blue=b,
            alpha=self.alpha,
        )

    def aslab(self) -> 'LABColor':
        """Get a LABColor out of the current object."""

        x, y, z = self.x, self.y, self.z

        # Uses the current industry standard formula, delta E 2000,
        # on D65/2°.
        # For more information, see the following links:
        #
        # * http://www.easyrgb.com/en/math.php#text9
        # * https://github.com/cangoektas/xyz-to-lab/blob/master/src/index.js

        D65 = (95.047, 100, 108.883)

        def calculate(data):
            value, ref = data
            value = value * 100 / ref
            if value > .008856:
                return value ** (1 / 3)
            return value * 7.878 + 16 / 116

        x, y, z = map(calculate, zip((x, y, z), D65))

        return LABColor(
            lightness=(116 * y - 16) / 100,
            a=500 * (x - y),
            b=200 * (y - z),
            alpha=self.alpha,
        )

    def asxyz(self) -> 'XYZColor':
        """Get an XYZColor out of the current object."""

        return XYZColor(
            x=self.x,
            y=self.y,
            z=self.z,
            alpha=self.alpha,
        )


class YIQColor(Color):
    """A color expressed using its YIQ components.

    :param y: Value for :py:attr:`y`.
    :param i: Value for :py:attr:`i`.
    :param q: Value for :py:attr:`q`.
    :param alpha: Value for :py:attr:`alpha`.
    """

    __slots__ = ('_y', '_i', '_q')
    _params = ('y', 'i', 'q')

    def __init__(
        self,
        y: float,
        i: float,
        q: float,
        alpha: float = 1.0,
    ):
        super().__init__(alpha)

        self._y = y
        self._i = i
        self._q = q

    def __iter__(self):
        return iter((self.y, self.i, self.q, self.alpha))

    @property
    def y(self) -> float:
        """Get the luma."""

        return self._y

    @property
    def i(self) -> float:
        """Get the orange-blue range value."""

        return self._i

    @property
    def q(self) -> float:
        """Get the purple-green range value."""

        return self._q

    def assrgb(self) -> 'SRGBColor':
        """Get an SRGBColor out of the current object."""

        y, i, q = self.y, self.i, self.q

        return SRGBColor(
            red=max(0.0, min(1.0, (
                y + .9468822170900693 * i + .6235565819861433 * q
            ))),
            green=max(0.0, min(1.0, (
                y - .27478764629897834 * i - .6356910791873801 * q
            ))),
            blue=max(0.0, min(1.0, (
                y - 1.1085450346420322 * i + 1.7090069284064666 * q
            ))),
            alpha=self.alpha,
        )

    def asyiq(self) -> 'YIQColor':
        """Get an YIQColor out of the current object."""

        return YIQColor(
            y=self.y,
            i=self.i,
            q=self.q,
            alpha=self.alpha,
        )


class YUVColor(Color):
    """A color expressed using its YUV components.

    :param y: Value for :py:attr:`y`.
    :param u: Value for :py:attr:`u`.
    :param v: Value for :py:attr:`v`.
    :param alpha: Value for :py:attr:`alpha`.
    """

    __slots__ = ('_y', '_u', '_v')
    _params = ('y', 'u', 'v')

    def __init__(
        self,
        y: float,
        u: float,
        v: float,
        alpha: float = 1.0,
    ):
        super().__init__(alpha)

        self._y = y
        self._u = u
        self._v = v

    def __iter__(self):
        return iter((self.y, self.u, self.v, self.alpha))

    @property
    def y(self) -> float:
        """Get the luma."""

        return self._y

    @property
    def u(self) -> float:
        """Get the U chrominance."""

        return self._u

    @property
    def v(self) -> float:
        """Get the V chrominance."""

        return self._v

    def asyuv(self) -> 'YUVColor':
        """Get an YUVColor out of the current object."""

        return YUVColor(
            y=self.y,
            u=self.u,
            v=self.v,
            alpha=self.alpha,
        )

# End of file.