shaka-player
Version:
DASH/EME video player library
318 lines (292 loc) • 9.74 kB
JavaScript
/*! @license
* Shaka Player
* Copyright 2016 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
goog.provide('shaka.text.Utils');
goog.require('shaka.log');
goog.require('shaka.text.Cue');
goog.require('shaka.text.CueRegion');
shaka.text.Utils = class {
/**
* Flatten nested cue payloads recursively. If a cue has nested cues,
* their contents should be combined and replace the payload of the parent.
*
* @param {!shaka.text.Cue} cue
* @param {?shaka.text.Cue=} parentCue
* @return {string}
* @private
*/
static flattenPayload_(cue, parentCue) {
if (cue.lineBreak) {
// This is a vertical lineBreak, so insert a newline.
return '\n';
}
if (cue.nestedCues.length) {
return cue.nestedCues.map((nested) => {
return shaka.text.Utils.flattenPayload_(nested, cue);
}).join('');
}
if (!cue.payload) {
return cue.payload;
}
// Handle bold, italics and underline
const openStyleTags = [];
const bold = cue.fontWeight >= shaka.text.Cue.fontWeight.BOLD;
const italics = cue.fontStyle == shaka.text.Cue.fontStyle.ITALIC;
const underline = cue.textDecoration.includes(
shaka.text.Cue.textDecoration.UNDERLINE);
if (bold) {
openStyleTags.push(['b']);
}
if (italics) {
openStyleTags.push(['i']);
}
if (underline) {
openStyleTags.push(['u']);
}
// Handle color classes, if the value consists of letters
let color = cue.color;
if (color == '' && parentCue) {
color = parentCue.color;
}
let classes = '';
const colorName = shaka.text.Utils.getColorName_(color);
if (colorName) {
classes += `.${colorName}`;
}
let bgColor = cue.backgroundColor;
if (bgColor == '' && parentCue) {
bgColor = parentCue.backgroundColor;
}
const bgColorName = shaka.text.Utils.getColorName_(bgColor);
if (bgColorName) {
classes += `.bg_${bgColorName}`;
}
if (classes) {
openStyleTags.push(['c', classes]);
}
return openStyleTags.reduceRight((acc, [tag, classes = '']) => {
return `<${tag}${classes}>${acc}</${tag}>`;
}, cue.payload);
}
/**
* Gets the color name from a color string.
*
* @param {string} string
* @return {?string}
* @private
*/
static getColorName_(string) {
let colorString = string.toLowerCase();
const rgb = colorString.replace(/\s/g, '')
.match(/^rgba?\((\d+),(\d+),(\d+),?([^,\s)]+)?/i);
if (rgb) {
colorString = '#' +
(parseInt(rgb[1], 10) | (1 << 8)).toString(16).slice(1) +
(parseInt(rgb[2], 10) | (1 << 8)).toString(16).slice(1) +
(parseInt(rgb[3], 10) | (1 << 8)).toString(16).slice(1);
} else if (colorString.startsWith('#') && colorString.length > 7) {
// With this we lose the alpha of the color, but it is better than having
// no color.
colorString = colorString.slice(0, 7);
}
switch (colorString) {
case 'white':
case '#fff':
case '#ffffff':
return 'white';
case 'lime':
case '#0f0':
case '#00ff00':
return 'lime';
case 'cyan':
case '#0ff':
case '#00ffff':
return 'cyan';
case 'red':
case '#f00':
case '#ff0000':
return 'red';
case 'yellow':
case '#ff0':
case '#ffff00':
return 'yellow';
case 'magenta':
case '#f0f':
case '#ff00ff':
return 'magenta';
case 'blue':
case '#00f':
case '#0000ff':
return 'blue';
case 'black':
case '#000':
case '#000000':
return 'black';
}
// No color name
return null;
}
/**
* We don't want to modify the array or objects passed in, since we don't
* technically own them. So we build a new array and replace certain items
* in it if they need to be flattened.
* We also don't want to flatten the text payloads starting at a container
* element; otherwise, for containers encapsulating multiple caption lines,
* the lines would merge into a single cue. This is undesirable when a
* subset of the captions are outside of the append time window. To fix
* this, we only call flattenPayload() starting at elements marked as
* isContainer = false.
*
* @param {!Array<!shaka.text.Cue>} cues
* @param {?shaka.text.Cue=} parentCue
* @return {!Array<!shaka.text.Cue>}
*/
static getCuesToFlatten(cues, parentCue) {
const result = [];
for (const cue of shaka.text.Utils.removeDuplicates(cues)) {
if (cue.isContainer) {
// Recurse to find the actual text payload cues.
result.push(...shaka.text.Utils.getCuesToFlatten(cue.nestedCues, cue));
} else {
// Flatten the payload.
const flatCue = cue.clone();
flatCue.nestedCues = [];
flatCue.payload = shaka.text.Utils.flattenPayload_(cue, parentCue);
result.push(flatCue);
}
}
return result;
}
/**
* @param {!Array<!shaka.text.Cue>} cues
* @return {!Array<!shaka.text.Cue>}
*/
static removeDuplicates(cues) {
const uniqueCues = [];
for (const cue of cues) {
const isValid = !uniqueCues.some(
(existingCue) => shaka.text.Cue.equal(cue, existingCue));
if (isValid) {
uniqueCues.push(cue);
}
}
return uniqueCues;
}
/**
* @param {!shaka.text.Cue} shakaCue
* @return {TextTrackCue}
*/
static mapShakaCueToNativeCue(shakaCue) {
if (shakaCue.startTime >= shakaCue.endTime) {
// Edge will throw in this case.
// See issue #501
shaka.log.warning('Invalid cue times: ' + shakaCue.startTime +
' - ' + shakaCue.endTime);
return null;
}
const Cue = shaka.text.Cue;
/** @type {VTTCue} */
const vttCue = new VTTCue(
shakaCue.startTime,
shakaCue.endTime,
shakaCue.payload);
const hash = (text) => {
let hash = 5381;
let i = text.length;
while (i) {
hash = (hash * 33) ^ text.charCodeAt(--i);
}
return (hash >>> 0).toString();
};
vttCue.id = hash(shakaCue.startTime.toString()) +
hash(shakaCue.endTime.toString()) +
hash(shakaCue.payload);
// NOTE: positionAlign and lineAlign settings are not supported by Chrome
// at the moment, so setting them will have no effect.
// The bug on chromium to implement them:
// https://bugs.chromium.org/p/chromium/issues/detail?id=633690
vttCue.lineAlign = shakaCue.lineAlign;
vttCue.positionAlign = shakaCue.positionAlign;
if (shakaCue.size) {
vttCue.size = shakaCue.size;
}
try {
// Safari 10 seems to throw on align='center'.
vttCue.align = shakaCue.textAlign;
} catch (exception) {}
if (shakaCue.textAlign == 'center' && vttCue.align != 'center') {
// We want vttCue.position = 'auto'. By default, |position| is set to
// "auto". If we set it to "auto" safari will throw an exception, so we
// must rely on the default value.
vttCue.align = 'middle';
}
if (shakaCue.writingMode ==
Cue.writingMode.VERTICAL_LEFT_TO_RIGHT) {
vttCue.vertical = 'lr';
} else if (shakaCue.writingMode ==
Cue.writingMode.VERTICAL_RIGHT_TO_LEFT) {
vttCue.vertical = 'rl';
}
// snapToLines flag is true by default
if (shakaCue.lineInterpretation == Cue.lineInterpretation.PERCENTAGE) {
vttCue.snapToLines = false;
}
if (shakaCue.line != null) {
vttCue.line = shakaCue.line;
}
if (shakaCue.position != null) {
vttCue.position = shakaCue.position;
}
return vttCue;
}
/**
* @param {!VTTCue} vttCue
* @return {?shaka.text.Cue}
*/
static mapNativeCueToShakaCue(vttCue) {
if (vttCue.endTime === Infinity || vttCue.endTime < vttCue.startTime) {
return null;
}
const cue = new shaka.text.Cue(vttCue.startTime, vttCue.endTime,
vttCue.text);
cue.line = typeof vttCue.line === 'number' ? vttCue.line : null;
if (vttCue.lineAlign) {
cue.lineAlign = /** @type {shaka.text.Cue.lineAlign} */
(vttCue.lineAlign);
}
cue.lineInterpretation = vttCue.snapToLines ?
shaka.text.Cue.lineInterpretation.LINE_NUMBER :
shaka.text.Cue.lineInterpretation.PERCENTAGE;
cue.position = typeof vttCue.position === 'number' ?
vttCue.position : null;
if (vttCue.positionAlign) {
cue.positionAlign = /** @type {shaka.text.Cue.positionAlign} */
(vttCue.positionAlign);
}
cue.size = vttCue.size;
cue.textAlign = /** @type {shaka.text.Cue.textAlign} */ (vttCue.align);
if (vttCue.vertical === 'lr') {
cue.writingMode = shaka.text.Cue.writingMode.VERTICAL_LEFT_TO_RIGHT;
} else if (vttCue.vertical === 'rl') {
cue.writingMode = shaka.text.Cue.writingMode.VERTICAL_RIGHT_TO_LEFT;
}
if (vttCue.region) {
cue.region.id = vttCue.region.id;
cue.region.height = vttCue.region.lines;
cue.region.heightUnits = shaka.text.CueRegion.units.LINES;
cue.region.regionAnchorX = vttCue.region.regionAnchorX;
cue.region.regionAnchorY = vttCue.region.regionAnchorY;
cue.region.scroll = /** @type {shaka.text.CueRegion.scrollMode} */
(vttCue.region.scroll);
cue.region.viewportAnchorX = vttCue.region.viewportAnchorX;
cue.region.viewportAnchorY = vttCue.region.viewportAnchorY;
cue.region.viewportAnchorUnits = shaka.text.CueRegion.units.PERCENTAGE;
cue.region.width = vttCue.region.width;
cue.region.widthUnits = shaka.text.CueRegion.units.PERCENTAGE;
}
shaka.text.Cue.parseCuePayload(cue);
return cue;
}
};