/
ttml_text_parser.js
1326 lines (1173 loc) · 42.2 KB
/
ttml_text_parser.js
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
/*! @license
* Shaka Player
* Copyright 2016 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
goog.provide('shaka.text.TtmlTextParser');
goog.require('goog.asserts');
goog.require('shaka.log');
goog.require('shaka.text.Cue');
goog.require('shaka.text.CueRegion');
goog.require('shaka.text.TextEngine');
goog.require('shaka.util.ArrayUtils');
goog.require('shaka.util.Error');
goog.require('shaka.util.StringUtils');
goog.require('shaka.util.XmlUtils');
/**
* @implements {shaka.extern.TextParser}
* @export
*/
shaka.text.TtmlTextParser = class {
/**
* @override
* @export
*/
parseInit(data) {
goog.asserts.assert(false, 'TTML does not have init segments');
}
/**
* @override
* @export
*/
parseMedia(data, time) {
const TtmlTextParser = shaka.text.TtmlTextParser;
const XmlUtils = shaka.util.XmlUtils;
const ttpNs = TtmlTextParser.parameterNs_;
const ttsNs = TtmlTextParser.styleNs_;
const str = shaka.util.StringUtils.fromUTF8(data);
const cues = [];
const parser = new DOMParser();
let xml = null;
// dont try to parse empty string as
// DOMParser will not throw error but return an errored xml
if (str == '') {
return cues;
}
try {
xml = parser.parseFromString(str, 'text/xml');
} catch (exception) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.TEXT,
shaka.util.Error.Code.INVALID_XML,
'Failed to parse TTML.');
}
if (xml) {
const parserError = xml.getElementsByTagName('parsererror')[0];
if (parserError) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.TEXT,
shaka.util.Error.Code.INVALID_XML,
parserError.textContent);
}
const tt = xml.getElementsByTagName('tt')[0];
// TTML should always have tt element.
if (!tt) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.TEXT,
shaka.util.Error.Code.INVALID_XML,
'TTML does not contain <tt> tag.');
}
const body = tt.getElementsByTagName('body')[0];
if (!body) {
return [];
}
// Get the framerate, subFrameRate and frameRateMultiplier if applicable.
const frameRate = XmlUtils.getAttributeNS(tt, ttpNs, 'frameRate');
const subFrameRate = XmlUtils.getAttributeNS(tt, ttpNs, 'subFrameRate');
const frameRateMultiplier =
XmlUtils.getAttributeNS(tt, ttpNs, 'frameRateMultiplier');
const tickRate = XmlUtils.getAttributeNS(tt, ttpNs, 'tickRate');
const cellResolution = XmlUtils.getAttributeNS(
tt, ttpNs, 'cellResolution');
const spaceStyle = tt.getAttribute('xml:space') || 'default';
const extent = XmlUtils.getAttributeNS(tt, ttsNs, 'extent');
if (spaceStyle != 'default' && spaceStyle != 'preserve') {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.TEXT,
shaka.util.Error.Code.INVALID_XML,
'Invalid xml:space value: ' + spaceStyle);
}
const whitespaceTrim = spaceStyle == 'default';
const rateInfo = new TtmlTextParser.RateInfo_(
frameRate, subFrameRate, frameRateMultiplier, tickRate);
const cellResolutionInfo =
TtmlTextParser.getCellResolution_(cellResolution);
const metadata = tt.getElementsByTagName('metadata')[0];
const metadataElements = metadata ? XmlUtils.getChildren(metadata) : [];
const styles = Array.from(tt.getElementsByTagName('style'));
const regionElements = Array.from(tt.getElementsByTagName('region'));
const cueRegions = [];
for (const region of regionElements) {
const cueRegion =
TtmlTextParser.parseCueRegion_(region, styles, extent);
if (cueRegion) {
cueRegions.push(cueRegion);
}
}
// A <body> element should only contain <div> elements, not <p> or <span>
// elements. We used to allow this, but it is non-compliant, and the
// loose nature of our previous parser made it difficult to implement TTML
// nesting more fully.
if (XmlUtils.findChildren(body, 'p').length) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.TEXT,
shaka.util.Error.Code.INVALID_TEXT_CUE,
'<p> can only be inside <div> in TTML');
}
for (const div of XmlUtils.findChildren(body, 'div')) {
// A <div> element should only contain <p>, not <span>.
if (XmlUtils.findChildren(div, 'span').length) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.TEXT,
shaka.util.Error.Code.INVALID_TEXT_CUE,
'<span> can only be inside <p> in TTML');
}
const pChildren = XmlUtils.findChildren(div, 'p');
if (pChildren && pChildren.length) {
for (const p of pChildren) {
const cue = TtmlTextParser.parseCue_(
p, time.periodStart, rateInfo, metadataElements, styles,
regionElements, cueRegions, whitespaceTrim,
cellResolutionInfo, /* parentCueElement= */ null);
if (cue) {
cues.push(cue);
}
}
} else {
// Only used for parsing the background image
const cue = TtmlTextParser.parseCue_(
div, time.periodStart, rateInfo, metadataElements, styles,
regionElements, cueRegions, whitespaceTrim,
cellResolutionInfo, /* parentCueElement= */ null);
if (cue) {
cues.push(cue);
}
}
}
}
return cues;
}
/**
* Parses a TTML node into a Cue.
*
* @param {!Node} cueNode
* @param {number} offset
* @param {!shaka.text.TtmlTextParser.RateInfo_} rateInfo
* @param {!Array.<!Element>} metadataElements
* @param {!Array.<!Element>} styles
* @param {!Array.<!Element>} regionElements
* @param {!Array.<!shaka.text.CueRegion>} cueRegions
* @param {boolean} whitespaceTrim
* @param {?{columns: number, rows: number}} cellResolution
* @param {?Element} parentCueElement
* @return {shaka.text.Cue}
* @private
*/
static parseCue_(
cueNode, offset, rateInfo, metadataElements, styles, regionElements,
cueRegions, whitespaceTrim, cellResolution, parentCueElement) {
/** @type {Element} */
let cueElement;
/** @type {Element} */
let parentElement = /** @type {Element} */(cueNode.parentNode);
if (cueNode.nodeType == Node.COMMENT_NODE) {
// The comments do not contain information that interests us here.
return null;
}
if (cueNode.nodeType == Node.TEXT_NODE) {
// This should generate an "anonymous span" according to the TTML spec.
// So pretend the element was a <span>. parentElement was set above, so
// we should still be able to correctly traverse up for timing
// information later.
const span = document.createElement('span');
span.textContent = cueNode.textContent;
cueElement = span;
} else {
goog.asserts.assert(cueNode.nodeType == Node.ELEMENT_NODE,
'nodeType should be ELEMENT_NODE!');
cueElement = /** @type {!Element} */(cueNode);
}
goog.asserts.assert(cueElement, 'cueElement should be non-null!');
const spaceStyle = cueElement.getAttribute('xml:space') ||
(whitespaceTrim ? 'default' : 'preserve');
const localWhitespaceTrim = spaceStyle == 'default';
// Parse any nested cues first.
const isTextNode = (node) => {
return node.nodeType == Node.TEXT_NODE;
};
const isLeafNode = Array.from(cueElement.childNodes).every(isTextNode);
const nestedCues = [];
if (!isLeafNode) {
// Otherwise, recurse into the children. Text nodes will convert into
// anonymous spans, which will then be leaf nodes.
for (const childNode of cueElement.childNodes) {
const nestedCue = shaka.text.TtmlTextParser.parseCue_(
childNode,
offset,
rateInfo,
metadataElements,
styles,
regionElements,
cueRegions,
localWhitespaceTrim,
cellResolution,
cueElement,
);
// This node may or may not generate a nested cue.
if (nestedCue) {
nestedCues.push(nestedCue);
}
}
}
const isNested = /** @type {boolean} */(parentCueElement != null);
// In this regex, "\S" means "non-whitespace character".
const hasTextContent = /\S/.test(cueElement.textContent);
const hasTimeAttributes =
cueElement.hasAttribute('begin') ||
cueElement.hasAttribute('end') ||
cueElement.hasAttribute('dur');
if (!hasTimeAttributes && !hasTextContent && cueElement.tagName != 'br' &&
nestedCues.length == 0) {
if (!isNested) {
// Disregards empty <p> elements without time attributes nor content.
// <p begin="..." smpte:backgroundImage="..." /> will go through,
// as some information could be held by its attributes.
// <p /> won't, as it would not be displayed.
return null;
} else if (localWhitespaceTrim) {
// Disregards empty anonymous spans when (local) trim is true.
return null;
}
}
// Get local time attributes.
let {start, end} = shaka.text.TtmlTextParser.parseTime_(
cueElement, rateInfo);
// Resolve local time relative to parent elements. Time elements can appear
// all the way up to 'body', but not 'tt'.
while (parentElement && parentElement.nodeType == Node.ELEMENT_NODE &&
parentElement.tagName != 'tt') {
({start, end} = shaka.text.TtmlTextParser.resolveTime_(
parentElement, rateInfo, start, end));
parentElement = /** @type {Element} */(parentElement.parentNode);
}
if (start == null) {
start = 0;
}
start += offset;
// If end is null, that means the duration is effectively infinite.
if (end == null) {
end = Infinity;
} else {
end += offset;
}
if (!hasTimeAttributes && nestedCues.length > 0) {
// If no time is defined for this cue, base the timing information on
// the time of the nested cues. In the case of multiple nested cues with
// different start times, it is the text displayer's responsibility to
// make sure that only the appropriate nested cue is drawn at any given
// time.
start = Infinity;
end = 0;
for (const cue of nestedCues) {
start = Math.min(start, cue.startTime);
end = Math.max(end, cue.endTime);
}
}
if (cueElement.tagName == 'br') {
const cue = new shaka.text.Cue(start, end, '');
cue.lineBreak = true;
return cue;
}
let payload = '';
if (isLeafNode) {
// If the childNodes are all text, this is a leaf node. Get the payload.
payload = cueElement.textContent;
if (localWhitespaceTrim) {
// Trim leading and trailing whitespace.
payload = payload.trim();
// Collapse multiple spaces into one.
payload = payload.replace(/\s+/g, ' ');
}
}
const cue = new shaka.text.Cue(start, end, payload);
cue.nestedCues = nestedCues;
if (cellResolution) {
cue.cellResolution = cellResolution;
}
// Get other properties if available.
const regionElement = shaka.text.TtmlTextParser.getElementsFromCollection_(
cueElement, 'region', regionElements, /* prefix= */ '')[0];
if (regionElement && regionElement.getAttribute('xml:id')) {
const regionId = regionElement.getAttribute('xml:id');
cue.region = cueRegions.filter((region) => region.id == regionId)[0];
}
let imageElement = null;
for (const nameSpace of shaka.text.TtmlTextParser.smpteNsList_) {
imageElement = shaka.text.TtmlTextParser.getElementsFromCollection_(
cueElement, 'backgroundImage', metadataElements, '#',
nameSpace)[0];
if (imageElement) {
break;
}
}
const isLeaf = nestedCues.length == 0;
let regionElementForStyle = regionElement;
if (parentCueElement && isNested && !cueElement.getAttribute('region') &&
!cueElement.getAttribute('style')) {
regionElementForStyle =
shaka.text.TtmlTextParser.getElementsFromCollection_(
parentCueElement, 'region', regionElements, /* prefix= */ '')[0];
}
shaka.text.TtmlTextParser.addStyle_(
cue,
cueElement,
regionElementForStyle,
imageElement,
styles,
isNested,
isLeaf);
return cue;
}
/**
* Parses an Element into a TextTrackCue or VTTCue.
*
* @param {!Element} regionElement
* @param {!Array.<!Element>} styles Defined in the top of tt element and
* used principally for images.
* @param {?string} globalExtent
* @return {shaka.text.CueRegion}
* @private
*/
static parseCueRegion_(regionElement, styles, globalExtent) {
const TtmlTextParser = shaka.text.TtmlTextParser;
const region = new shaka.text.CueRegion();
const id = regionElement.getAttribute('xml:id');
if (!id) {
shaka.log.warning('TtmlTextParser parser encountered a region with ' +
'no id. Region will be ignored.');
return null;
}
region.id = id;
let globalResults = null;
if (globalExtent) {
globalResults = TtmlTextParser.percentValues_.exec(globalExtent) ||
TtmlTextParser.pixelValues_.exec(globalExtent);
}
const globalWidth = globalResults ? Number(globalResults[1]) : null;
const globalHeight = globalResults ? Number(globalResults[2]) : null;
let results = null;
let percentage = null;
const extent = TtmlTextParser.getStyleAttributeFromRegion_(
regionElement, styles, 'extent');
if (extent) {
percentage = TtmlTextParser.percentValues_.exec(extent);
results = percentage || TtmlTextParser.pixelValues_.exec(extent);
if (results != null) {
region.width = Number(results[1]);
region.height = Number(results[2]);
if (!percentage) {
if (globalWidth != null) {
region.width = region.width * 100 / globalWidth;
}
if (globalHeight != null) {
region.height = region.height * 100 / globalHeight;
}
}
region.widthUnits = percentage || globalWidth != null ?
shaka.text.CueRegion.units.PERCENTAGE :
shaka.text.CueRegion.units.PX;
region.heightUnits = percentage || globalHeight != null ?
shaka.text.CueRegion.units.PERCENTAGE :
shaka.text.CueRegion.units.PX;
}
}
const origin = TtmlTextParser.getStyleAttributeFromRegion_(
regionElement, styles, 'origin');
if (origin) {
percentage = TtmlTextParser.percentValues_.exec(origin);
results = percentage || TtmlTextParser.pixelValues_.exec(origin);
if (results != null) {
region.viewportAnchorX = Number(results[1]);
region.viewportAnchorY = Number(results[2]);
if (!percentage) {
if (globalHeight != null) {
region.viewportAnchorY = region.viewportAnchorY * 100 /
globalHeight;
}
if (globalWidth != null) {
region.viewportAnchorX = region.viewportAnchorX * 100 /
globalWidth;
}
}
region.viewportAnchorUnits = percentage || globalWidth != null ?
shaka.text.CueRegion.units.PERCENTAGE :
shaka.text.CueRegion.units.PX;
}
}
return region;
}
/**
* Adds applicable style properties to a cue.
*
* @param {!shaka.text.Cue} cue
* @param {!Element} cueElement
* @param {Element} region
* @param {Element} imageElement
* @param {!Array.<!Element>} styles
* @param {boolean} isNested
* @param {boolean} isLeaf
* @private
*/
static addStyle_(
cue, cueElement, region, imageElement, styles, isNested, isLeaf) {
const TtmlTextParser = shaka.text.TtmlTextParser;
const Cue = shaka.text.Cue;
// Styles should be inherited from regions, if a style property is not
// associated with a Content element (or an anonymous span).
const shouldInheritRegionStyles = isNested || isLeaf;
const direction = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'direction', shouldInheritRegionStyles);
if (direction == 'rtl') {
cue.direction = Cue.direction.HORIZONTAL_RIGHT_TO_LEFT;
}
// Direction attribute specifies one-dimentional writing direction
// (left to right or right to left). Writing mode specifies that
// plus whether text is vertical or horizontal.
// They should not contradict each other. If they do, we give
// preference to writing mode.
const writingMode = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'writingMode', shouldInheritRegionStyles);
// Set cue's direction if the text is horizontal, and cue's writingMode if
// it's vertical.
if (writingMode == 'tb' || writingMode == 'tblr') {
cue.writingMode = Cue.writingMode.VERTICAL_LEFT_TO_RIGHT;
} else if (writingMode == 'tbrl') {
cue.writingMode = Cue.writingMode.VERTICAL_RIGHT_TO_LEFT;
} else if (writingMode == 'rltb' || writingMode == 'rl') {
cue.direction = Cue.direction.HORIZONTAL_RIGHT_TO_LEFT;
} else if (writingMode) {
cue.direction = Cue.direction.HORIZONTAL_LEFT_TO_RIGHT;
}
const align = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'textAlign', shouldInheritRegionStyles);
if (align) {
cue.positionAlign = TtmlTextParser.textAlignToPositionAlign_[align];
cue.lineAlign = TtmlTextParser.textAlignToLineAlign_[align];
goog.asserts.assert(align.toUpperCase() in Cue.textAlign,
align.toUpperCase() +
' Should be in Cue.textAlign values!');
cue.textAlign = Cue.textAlign[align.toUpperCase()];
} else {
// Default value is START: https://bit.ly/32OGmvo
cue.textAlign = Cue.textAlign.START;
}
const displayAlign = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'displayAlign', shouldInheritRegionStyles);
if (displayAlign) {
goog.asserts.assert(displayAlign.toUpperCase() in Cue.displayAlign,
displayAlign.toUpperCase() +
' Should be in Cue.displayAlign values!');
cue.displayAlign = Cue.displayAlign[displayAlign.toUpperCase()];
}
const color = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'color', shouldInheritRegionStyles);
if (color) {
cue.color = color;
}
// Background color should not be set on a container. If this is a nested
// cue, you can set the background. If it's a top-level that happens to
// also be a leaf, you can set the background.
// See https://github.com/google/shaka-player/issues/2623
// This used to be handled in the displayer, but that is confusing. The Cue
// structure should reflect what you want to happen in the displayer, and
// the displayer shouldn't have to know about TTML.
const backgroundColor = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'backgroundColor',
shouldInheritRegionStyles);
if (backgroundColor) {
cue.backgroundColor = backgroundColor;
}
const border = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'border', shouldInheritRegionStyles);
if (border) {
cue.border = border;
}
const fontFamily = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'fontFamily', shouldInheritRegionStyles);
if (fontFamily) {
cue.fontFamily = fontFamily;
}
const fontWeight = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'fontWeight', shouldInheritRegionStyles);
if (fontWeight && fontWeight == 'bold') {
cue.fontWeight = Cue.fontWeight.BOLD;
}
const wrapOption = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'wrapOption', shouldInheritRegionStyles);
if (wrapOption && wrapOption == 'noWrap') {
cue.wrapLine = false;
} else {
cue.wrapLine = true;
}
const lineHeight = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'lineHeight', shouldInheritRegionStyles);
if (lineHeight && lineHeight.match(TtmlTextParser.unitValues_)) {
cue.lineHeight = lineHeight;
}
const fontSize = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'fontSize', shouldInheritRegionStyles);
if (fontSize) {
const isValidFontSizeUnit =
fontSize.match(TtmlTextParser.unitValues_) ||
fontSize.match(TtmlTextParser.percentValue_);
if (isValidFontSizeUnit) {
cue.fontSize = fontSize;
}
}
const fontStyle = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'fontStyle', shouldInheritRegionStyles);
if (fontStyle) {
goog.asserts.assert(fontStyle.toUpperCase() in Cue.fontStyle,
fontStyle.toUpperCase() +
' Should be in Cue.fontStyle values!');
cue.fontStyle = Cue.fontStyle[fontStyle.toUpperCase()];
}
if (imageElement) {
// According to the spec, we should use imageType (camelCase), but
// historically we have checked for imagetype (lowercase).
// This was the case since background image support was first introduced
// in PR #1859, in April 2019, and first released in v2.5.0.
// Now we check for both, although only imageType (camelCase) is to spec.
const backgroundImageType =
imageElement.getAttribute('imageType') ||
imageElement.getAttribute('imagetype');
const backgroundImageEncoding = imageElement.getAttribute('encoding');
const backgroundImageData = imageElement.textContent.trim();
if (backgroundImageType == 'PNG' &&
backgroundImageEncoding == 'Base64' &&
backgroundImageData) {
cue.backgroundImage = 'data:image/png;base64,' + backgroundImageData;
}
}
const letterSpacing = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'letterSpacing', shouldInheritRegionStyles);
if (letterSpacing && letterSpacing.match(TtmlTextParser.unitValues_)) {
cue.letterSpacing = letterSpacing;
}
const linePadding = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'linePadding', shouldInheritRegionStyles);
if (linePadding && linePadding.match(TtmlTextParser.unitValues_)) {
cue.linePadding = linePadding;
}
const opacity = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'opacity', shouldInheritRegionStyles);
if (opacity) {
cue.opacity = parseFloat(opacity);
}
// Text decoration is an array of values which can come both from the
// element's style or be inherited from elements' parent nodes. All of those
// values should be applied as long as they don't contradict each other. If
// they do, elements' own style gets preference.
const textDecorationRegion = TtmlTextParser.getStyleAttributeFromRegion_(
region, styles, 'textDecoration');
if (textDecorationRegion) {
TtmlTextParser.addTextDecoration_(cue, textDecorationRegion);
}
const textDecorationElement = TtmlTextParser.getStyleAttributeFromElement_(
cueElement, styles, 'textDecoration');
if (textDecorationElement) {
TtmlTextParser.addTextDecoration_(cue, textDecorationElement);
}
}
/**
* Parses text decoration values and adds/removes them to/from the cue.
*
* @param {!shaka.text.Cue} cue
* @param {string} decoration
* @private
*/
static addTextDecoration_(cue, decoration) {
const Cue = shaka.text.Cue;
for (const value of decoration.split(' ')) {
switch (value) {
case 'underline':
if (!cue.textDecoration.includes(Cue.textDecoration.UNDERLINE)) {
cue.textDecoration.push(Cue.textDecoration.UNDERLINE);
}
break;
case 'noUnderline':
if (cue.textDecoration.includes(Cue.textDecoration.UNDERLINE)) {
shaka.util.ArrayUtils.remove(cue.textDecoration,
Cue.textDecoration.UNDERLINE);
}
break;
case 'lineThrough':
if (!cue.textDecoration.includes(Cue.textDecoration.LINE_THROUGH)) {
cue.textDecoration.push(Cue.textDecoration.LINE_THROUGH);
}
break;
case 'noLineThrough':
if (cue.textDecoration.includes(Cue.textDecoration.LINE_THROUGH)) {
shaka.util.ArrayUtils.remove(cue.textDecoration,
Cue.textDecoration.LINE_THROUGH);
}
break;
case 'overline':
if (!cue.textDecoration.includes(Cue.textDecoration.OVERLINE)) {
cue.textDecoration.push(Cue.textDecoration.OVERLINE);
}
break;
case 'noOverline':
if (cue.textDecoration.includes(Cue.textDecoration.OVERLINE)) {
shaka.util.ArrayUtils.remove(cue.textDecoration,
Cue.textDecoration.OVERLINE);
}
break;
}
}
}
/**
* Finds a specified attribute on either the original cue element or its
* associated region and returns the value if the attribute was found.
*
* @param {!Element} cueElement
* @param {Element} region
* @param {!Array.<!Element>} styles
* @param {string} attribute
* @param {boolean=} shouldInheritRegionStyles
* @return {?string}
* @private
*/
static getStyleAttribute_(cueElement, region, styles, attribute,
shouldInheritRegionStyles=true) {
// An attribute can be specified on region level or in a styling block
// associated with the region or original element.
const TtmlTextParser = shaka.text.TtmlTextParser;
const attr = TtmlTextParser.getStyleAttributeFromElement_(
cueElement, styles, attribute);
if (attr) {
return attr;
}
if (shouldInheritRegionStyles) {
return TtmlTextParser.getStyleAttributeFromRegion_(
region, styles, attribute);
}
return null;
}
/**
* Finds a specified attribute on the element's associated region
* and returns the value if the attribute was found.
*
* @param {Element} region
* @param {!Array.<!Element>} styles
* @param {string} attribute
* @return {?string}
* @private
*/
static getStyleAttributeFromRegion_(region, styles, attribute) {
const XmlUtils = shaka.util.XmlUtils;
const ttsNs = shaka.text.TtmlTextParser.styleNs_;
if (!region) {
return null;
}
const attr = XmlUtils.getAttributeNS(region, ttsNs, attribute);
if (attr) {
return attr;
}
return shaka.text.TtmlTextParser.getInheritedStyleAttribute_(
region, styles, attribute);
}
/**
* Finds a specified attribute on the cue element and returns the value
* if the attribute was found.
*
* @param {!Element} cueElement
* @param {!Array.<!Element>} styles
* @param {string} attribute
* @return {?string}
* @private
*/
static getStyleAttributeFromElement_(cueElement, styles, attribute) {
const XmlUtils = shaka.util.XmlUtils;
const ttsNs = shaka.text.TtmlTextParser.styleNs_;
// Styling on elements should take precedence
// over the main styling attributes
const elementAttribute = XmlUtils.getAttributeNS(
cueElement,
ttsNs,
attribute);
if (elementAttribute) {
return elementAttribute;
}
return shaka.text.TtmlTextParser.getInheritedStyleAttribute_(
cueElement, styles, attribute);
}
/**
* Finds a specified attribute on an element's styles and the styles those
* styles inherit from.
*
* @param {!Element} element
* @param {!Array.<!Element>} styles
* @param {string} attribute
* @return {?string}
* @private
*/
static getInheritedStyleAttribute_(element, styles, attribute) {
const XmlUtils = shaka.util.XmlUtils;
const ttsNs = shaka.text.TtmlTextParser.styleNs_;
const ebuttsNs = shaka.text.TtmlTextParser.styleEbuttsNs_;
const inheritedStyles =
shaka.text.TtmlTextParser.getElementsFromCollection_(
element, 'style', styles, /* prefix= */ '');
let styleValue = null;
// The last value in our styles stack takes the precedence over the others
for (let i = 0; i < inheritedStyles.length; i++) {
// Check ebu namespace first.
let styleAttributeValue = XmlUtils.getAttributeNS(
inheritedStyles[i],
ebuttsNs,
attribute);
if (!styleAttributeValue) {
// Fall back to tts namespace.
styleAttributeValue = XmlUtils.getAttributeNS(
inheritedStyles[i],
ttsNs,
attribute);
}
if (!styleAttributeValue) {
// Next, check inheritance.
// Styles can inherit from other styles, so traverse up that chain.
styleAttributeValue =
shaka.text.TtmlTextParser.getStyleAttributeFromElement_(
inheritedStyles[i], styles, attribute);
}
if (styleAttributeValue) {
styleValue = styleAttributeValue;
}
}
return styleValue;
}
/**
* Selects items from |collection| whose id matches |attributeName|
* from |element|.
*
* @param {Element} element
* @param {string} attributeName
* @param {!Array.<Element>} collection
* @param {string} prefixName
* @param {string=} nsName
* @return {!Array.<!Element>}
* @private
*/
static getElementsFromCollection_(
element, attributeName, collection, prefixName, nsName) {
const items = [];
if (!element || collection.length < 1) {
return items;
}
const attributeValue = shaka.text.TtmlTextParser.getInheritedAttribute_(
element, attributeName, nsName);
if (attributeValue) {
// There could be multiple items in one attribute
// <span style="style1 style2">A cue</span>
const itemNames = attributeValue.split(' ');
for (const name of itemNames) {
for (const item of collection) {
if ((prefixName + item.getAttribute('xml:id')) == name) {
items.push(item);
break;
}
}
}
}
return items;
}
/**
* Traverses upwards from a given node until a given attribute is found.
*
* @param {!Element} element
* @param {string} attributeName
* @param {string=} nsName
* @return {?string}
* @private
*/
static getInheritedAttribute_(element, attributeName, nsName) {
let ret = null;
const XmlUtils = shaka.util.XmlUtils;
while (element) {
ret = nsName ? XmlUtils.getAttributeNS(element, nsName, attributeName)
: element.getAttribute(attributeName);
if (ret) {
break;
}
// Element.parentNode can lead to XMLDocument, which is not an Element and
// has no getAttribute().
const parentNode = element.parentNode;
if (parentNode instanceof Element) {
element = parentNode;
} else {
break;
}
}
return ret;
}
/**
* Factor parent/ancestor time attributes into the parsed time of a
* child/descendent.
*
* @param {!Element} parentElement
* @param {!shaka.text.TtmlTextParser.RateInfo_} rateInfo
* @param {?number} start The child's start time
* @param {?number} end The child's end time
* @return {{start: ?number, end: ?number}}
* @private
*/
static resolveTime_(parentElement, rateInfo, start, end) {
const parentTime = shaka.text.TtmlTextParser.parseTime_(
parentElement, rateInfo);
if (start == null) {
// No start time of your own? Inherit from the parent.
start = parentTime.start;
} else {
// Otherwise, the start time is relative to the parent's start time.
if (parentTime.start != null) {
start += parentTime.start;
}
}
if (end == null) {
// No end time of your own? Inherit from the parent.
end = parentTime.end;
} else {
// Otherwise, the end time is relative to the parent's _start_ time.
// This is not a typo. Both times are relative to the parent's _start_.
if (parentTime.start != null) {
end += parentTime.start;
}
}
return {start, end};
}
/**
* Parse TTML time attributes from the given element.
*
* @param {!Element} element
* @param {!shaka.text.TtmlTextParser.RateInfo_} rateInfo
* @return {{start: ?number, end: ?number}}
* @private
*/
static parseTime_(element, rateInfo) {
const start = shaka.text.TtmlTextParser.parseTimeAttribute_(
element.getAttribute('begin'), rateInfo);
let end = shaka.text.TtmlTextParser.parseTimeAttribute_(
element.getAttribute('end'), rateInfo);
const duration = shaka.text.TtmlTextParser.parseTimeAttribute_(
element.getAttribute('dur'), rateInfo);
if (end == null && duration != null) {
end = start + duration;
}
return {start, end};
}
/**
* Parses a TTML time from the given attribute text.
*
* @param {string} text
* @param {!shaka.text.TtmlTextParser.RateInfo_} rateInfo
* @return {?number}
* @private
*/
static parseTimeAttribute_(text, rateInfo) {
let ret = null;