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/*
* Copyright (C) 2011, 2013 Google Inc. All rights reserved.
* Copyright (C) 2011-2019 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
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* in the documentation and/or other materials provided with the
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#include "config.h"
#include "VTTCue.h"
#if ENABLE(VIDEO_TRACK)
#include "CSSPropertyNames.h"
#include "CSSValueKeywords.h"
#include "DocumentFragment.h"
#include "Event.h"
#include "HTMLDivElement.h"
#include "HTMLSpanElement.h"
#include "HTMLStyleElement.h"
#include "Logging.h"
#include "NodeTraversal.h"
#include "RenderVTTCue.h"
#include "ScriptDisallowedScope.h"
#include "Text.h"
#include "TextTrack.h"
#include "TextTrackCueGeneric.h"
#include "TextTrackCueList.h"
#include "VTTRegionList.h"
#include "VTTScanner.h"
#include "WebVTTElement.h"
#include "WebVTTParser.h"
#include <wtf/IsoMallocInlines.h>
#include <wtf/MathExtras.h>
#include <wtf/text/StringBuilder.h>
#include <wtf/text/StringConcatenateNumbers.h>
namespace WebCore {
WTF_MAKE_ISO_ALLOCATED_IMPL(VTTCue);
WTF_MAKE_ISO_ALLOCATED_IMPL(VTTCueBox);
// This constant should correspond with the percentage returned by CaptionUserPreferences::captionFontSizeScaleAndImportance.
static constexpr double DEFAULTCAPTIONFONTSIZEPERCENTAGE = 5;
static constexpr int undefinedPosition = -1;
static const CSSValueID displayWritingModeMap[] = {
CSSValueHorizontalTb, CSSValueVerticalRl, CSSValueVerticalLr
};
COMPILE_ASSERT(WTF_ARRAY_LENGTH(displayWritingModeMap) == VTTCue::NumberOfWritingDirections, displayWritingModeMap_has_wrong_size);
static const CSSValueID displayAlignmentMap[] = {
CSSValueStart, CSSValueCenter, CSSValueEnd, CSSValueLeft, CSSValueRight
};
COMPILE_ASSERT(WTF_ARRAY_LENGTH(displayAlignmentMap) == VTTCue::NumberOfAlignments, displayAlignmentMap_has_wrong_size);
static const String& startKeyword()
{
static NeverDestroyed<const String> start(MAKE_STATIC_STRING_IMPL("start"));
return start;
}
static const String& centerKeyword()
{
static NeverDestroyed<const String> center(MAKE_STATIC_STRING_IMPL("center"));
return center;
}
static const String& endKeyword()
{
static NeverDestroyed<const String> end(MAKE_STATIC_STRING_IMPL("end"));
return end;
}
static const String& leftKeyword()
{
static NeverDestroyed<const String> left(MAKE_STATIC_STRING_IMPL("left"));
return left;
}
static const String& rightKeyword()
{
static NeverDestroyed<const String> right(MAKE_STATIC_STRING_IMPL("right"));
return right;
}
static const String& horizontalKeyword()
{
return emptyString();
}
static const String& verticalGrowingLeftKeyword()
{
static NeverDestroyed<const String> verticalrl(MAKE_STATIC_STRING_IMPL("rl"));
return verticalrl;
}
static const String& verticalGrowingRightKeyword()
{
static NeverDestroyed<const String> verticallr(MAKE_STATIC_STRING_IMPL("lr"));
return verticallr;
}
// ----------------------------
VTTCueBox::VTTCueBox(Document& document, VTTCue& cue)
: TextTrackCueBox(document, cue)
{
}
void VTTCueBox::applyCSSProperties(const IntSize& videoSize)
{
auto textTrackCue = getCue();
if (!textTrackCue)
return;
ASSERT(is<VTTCue>(textTrackCue) || is<TextTrackCueGeneric>(textTrackCue));
auto cue = makeRef(*toVTTCue(textTrackCue));
// FIXME: Apply all the initial CSS positioning properties. http://wkb.ug/79916
if (!cue->regionId().isEmpty()) {
setInlineStyleProperty(CSSPropertyPosition, CSSValueRelative);
return;
}
// 3.5.1 On the (root) List of WebVTT Node Objects:
// the 'position' property must be set to 'absolute'
setInlineStyleProperty(CSSPropertyPosition, CSSValueAbsolute);
// the 'unicode-bidi' property must be set to 'plaintext'
setInlineStyleProperty(CSSPropertyUnicodeBidi, CSSValuePlaintext);
// the 'direction' property must be set to direction
setInlineStyleProperty(CSSPropertyDirection, cue->getCSSWritingDirection());
// the 'writing-mode' property must be set to writing-mode
setInlineStyleProperty(CSSPropertyWritingMode, cue->getCSSWritingMode(), false);
auto position = cue->getCSSPosition();
// the 'top' property must be set to top,
setInlineStyleProperty(CSSPropertyTop, position.second, CSSUnitType::CSS_PERCENTAGE);
// the 'left' property must be set to left
if (cue->vertical() == horizontalKeyword())
setInlineStyleProperty(CSSPropertyLeft, position.first, CSSUnitType::CSS_PERCENTAGE);
else if (cue->vertical() == verticalGrowingRightKeyword())
setInlineStyleProperty(CSSPropertyLeft, makeString("calc(-", FormattedNumber::fixedWidth(videoSize.width(), 2), "px - ", FormattedNumber::fixedWidth(cue->getCSSSize(), 2), "px)"));
double authorFontSize = std::min(videoSize.width(), videoSize.height()) * DEFAULTCAPTIONFONTSIZEPERCENTAGE / 100.0;
double multiplier = 1.0;
if (authorFontSize)
multiplier = m_fontSizeFromCaptionUserPrefs / authorFontSize;
double textPosition = cue->calculateComputedTextPosition();
double maxSize = 100.0;
CSSValueID alignment = cue->getCSSAlignment();
if (alignment == CSSValueEnd || alignment == CSSValueRight)
maxSize = textPosition;
else if (alignment == CSSValueStart || alignment == CSSValueLeft)
maxSize = 100.0 - textPosition;
double newCueSize = std::min(cue->getCSSSize() * multiplier, 100.0);
// the 'width' property must be set to width, and the 'height' property must be set to height
if (cue->vertical() == horizontalKeyword()) {
setInlineStyleProperty(CSSPropertyWidth, newCueSize, CSSUnitType::CSS_PERCENTAGE);
setInlineStyleProperty(CSSPropertyHeight, CSSValueAuto);
setInlineStyleProperty(CSSPropertyMinWidth, "min-content");
setInlineStyleProperty(CSSPropertyMaxWidth, maxSize, CSSUnitType::CSS_PERCENTAGE);
if ((alignment == CSSValueMiddle || alignment == CSSValueCenter) && multiplier != 1.0)
setInlineStyleProperty(CSSPropertyLeft, static_cast<double>(position.first - (newCueSize - cue->getCSSSize()) / 2), CSSUnitType::CSS_PERCENTAGE);
} else {
setInlineStyleProperty(CSSPropertyWidth, CSSValueAuto);
setInlineStyleProperty(CSSPropertyHeight, newCueSize, CSSUnitType::CSS_PERCENTAGE);
setInlineStyleProperty(CSSPropertyMinHeight, "min-content");
setInlineStyleProperty(CSSPropertyMaxHeight, maxSize, CSSUnitType::CSS_PERCENTAGE);
if ((alignment == CSSValueMiddle || alignment == CSSValueCenter) && multiplier != 1.0)
setInlineStyleProperty(CSSPropertyTop, static_cast<double>(position.second - (newCueSize - cue->getCSSSize()) / 2), CSSUnitType::CSS_PERCENTAGE);
}
// The 'text-align' property on the (root) List of WebVTT Node Objects must
// be set to the value in the second cell of the row of the table below
// whose first cell is the value of the corresponding cue's text track cue
// alignment:
setInlineStyleProperty(CSSPropertyTextAlign, cue->getCSSAlignment());
if (!cue->snapToLines()) {
// 10.13.1 Set up x and y:
// Note: x and y are set through the CSS left and top above.
// 10.13.2 Position the boxes in boxes such that the point x% along the
// width of the bounding box of the boxes in boxes is x% of the way
// across the width of the video's rendering area, and the point y%
// along the height of the bounding box of the boxes in boxes is y%
// of the way across the height of the video's rendering area, while
// maintaining the relative positions of the boxes in boxes to each
// other.
setInlineStyleProperty(CSSPropertyTransform,
makeString("translate(", FormattedNumber::fixedWidth(-position.first, 2), "%, ", FormattedNumber::fixedWidth(-position.second, 2), "%)"));
setInlineStyleProperty(CSSPropertyWhiteSpace, CSSValuePre);
}
// Make sure shadow or stroke is not clipped.
setInlineStyleProperty(CSSPropertyOverflow, CSSValueVisible);
cue->element().setInlineStyleProperty(CSSPropertyOverflow, CSSValueVisible);
}
RenderPtr<RenderElement> VTTCueBox::createElementRenderer(RenderStyle&& style, const RenderTreePosition&)
{
return createRenderer<RenderVTTCue>(*this, WTFMove(style));
}
// ----------------------------
Ref<VTTCue> VTTCue::create(ScriptExecutionContext& context, const WebVTTCueData& data)
{
return adoptRef(*new VTTCue(context, data));
}
VTTCue::VTTCue(ScriptExecutionContext& context, const MediaTime& start, const MediaTime& end, const String& content)
: TextTrackCue(context, start, end)
, m_content(content)
{
initialize(context);
}
VTTCue::VTTCue(ScriptExecutionContext& context, const WebVTTCueData& cueData)
: TextTrackCue(context, MediaTime::zeroTime(), MediaTime::zeroTime())
{
initialize(context);
setText(cueData.content());
setStartTime(cueData.startTime());
setEndTime(cueData.endTime());
setId(cueData.id());
setCueSettings(cueData.settings());
m_originalStartTime = cueData.originalStartTime();
}
VTTCue::~VTTCue()
{
}
void VTTCue::initialize(ScriptExecutionContext& context)
{
m_linePosition = undefinedPosition;
m_computedLinePosition = undefinedPosition;
m_textPosition = std::numeric_limits<double>::quiet_NaN();
m_cueSize = 100;
m_writingDirection = Horizontal;
m_cueAlignment = Center;
m_webVTTNodeTree = nullptr;
m_cueBackdropBox = HTMLDivElement::create(downcast<Document>(context));
m_cueHighlightBox = HTMLSpanElement::create(spanTag, downcast<Document>(context));
m_displayDirection = CSSValueLtr;
m_displaySize = 0;
m_snapToLines = true;
m_displayTreeShouldChange = true;
m_notifyRegion = true;
m_originalStartTime = MediaTime::zeroTime();
}
Ref<VTTCueBox> VTTCue::createDisplayTree()
{
return VTTCueBox::create(ownerDocument(), *this);
}
VTTCueBox& VTTCue::displayTreeInternal()
{
if (!m_displayTree)
m_displayTree = createDisplayTree();
return *m_displayTree;
}
void VTTCue::didChange()
{
TextTrackCue::didChange();
m_displayTreeShouldChange = true;
}
const String& VTTCue::vertical() const
{
switch (m_writingDirection) {
case Horizontal:
return horizontalKeyword();
case VerticalGrowingLeft:
return verticalGrowingLeftKeyword();
case VerticalGrowingRight:
return verticalGrowingRightKeyword();
default:
ASSERT_NOT_REACHED();
return emptyString();
}
}
ExceptionOr<void> VTTCue::setVertical(const String& value)
{
// http://www.whatwg.org/specs/web-apps/current-work/multipage/the-video-element.html#dom-texttrackcue-vertical
// On setting, the text track cue writing direction must be set to the value given
// in the first cell of the row in the table above whose second cell is a
// case-sensitive match for the new value, if any. If none of the values match, then
// the user agent must instead throw a SyntaxError exception.
WritingDirection direction = m_writingDirection;
if (value == horizontalKeyword())
direction = Horizontal;
else if (value == verticalGrowingLeftKeyword())
direction = VerticalGrowingLeft;
else if (value == verticalGrowingRightKeyword())
direction = VerticalGrowingRight;
else
return Exception { SyntaxError };
if (direction == m_writingDirection)
return { };
willChange();
m_writingDirection = direction;
didChange();
return { };
}
void VTTCue::setSnapToLines(bool value)
{
if (m_snapToLines == value)
return;
willChange();
m_snapToLines = value;
didChange();
}
ExceptionOr<void> VTTCue::setLine(double position)
{
// http://www.whatwg.org/specs/web-apps/current-work/multipage/the-video-element.html#dom-texttrackcue-line
// On setting, if the text track cue snap-to-lines flag is not set, and the new
// value is negative or greater than 100, then throw an IndexSizeError exception.
if (!m_snapToLines && !(position >= 0 && position <= 100))
return Exception { IndexSizeError };
// Otherwise, set the text track cue line position to the new value.
if (m_linePosition == position)
return { };
willChange();
m_linePosition = position;
m_computedLinePosition = calculateComputedLinePosition();
didChange();
return { };
}
VTTCue::LineAndPositionSetting VTTCue::position() const
{
if (textPositionIsAuto())
return Auto;
return m_textPosition;
}
ExceptionOr<void> VTTCue::setPosition(const LineAndPositionSetting& position)
{
// http://dev.w3.org/html5/webvtt/#dfn-vttcue-position
// On setting, if the new value is negative or greater than 100, then an
// IndexSizeError exception must be thrown. Otherwise, the WebVTT cue
// position must be set to the new value; if the new value is the string
// "auto", then it must be interpreted as the special value auto.
double textPosition = 0;
if (WTF::holds_alternative<AutoKeyword>(position)) {
if (textPositionIsAuto())
return { };
textPosition = std::numeric_limits<double>::quiet_NaN();
} else {
if (!(WTF::get<double>(position) >= 0 && WTF::get<double>(position) <= 100))
return Exception { IndexSizeError };
// Otherwise, set the text track cue line position to the new value.
textPosition = WTF::get<double>(position);
if (m_textPosition == textPosition)
return { };
}
willChange();
m_textPosition = textPosition;
didChange();
return { };
}
ExceptionOr<void> VTTCue::setSize(int size)
{
// http://www.whatwg.org/specs/web-apps/current-work/multipage/the-video-element.html#dom-texttrackcue-size
// On setting, if the new value is negative or greater than 100, then throw an IndexSizeError
// exception. Otherwise, set the text track cue size to the new value.
if (!(size >= 0 && size <= 100))
return Exception { IndexSizeError };
// Otherwise, set the text track cue line position to the new value.
if (m_cueSize == size)
return { };
willChange();
m_cueSize = size;
didChange();
return { };
}
const String& VTTCue::align() const
{
switch (m_cueAlignment) {
case Start:
return startKeyword();
case Center:
return centerKeyword();
case End:
return endKeyword();
case Left:
return leftKeyword();
case Right:
return rightKeyword();
default:
ASSERT_NOT_REACHED();
return emptyString();
}
}
ExceptionOr<void> VTTCue::setAlign(const String& value)
{
// http://www.whatwg.org/specs/web-apps/current-work/multipage/the-video-element.html#dom-texttrackcue-align
// On setting, the text track cue alignment must be set to the value given in the
// first cell of the row in the table above whose second cell is a case-sensitive
// match for the new value, if any. If none of the values match, then the user
// agent must instead throw a SyntaxError exception.
CueAlignment alignment;
if (value == startKeyword())
alignment = Start;
else if (value == centerKeyword())
alignment = Center;
else if (value == endKeyword())
alignment = End;
else if (value == leftKeyword())
alignment = Left;
else if (value == rightKeyword())
alignment = Right;
else
return Exception { SyntaxError };
if (alignment == m_cueAlignment)
return { };
willChange();
m_cueAlignment = alignment;
didChange();
return { };
}
void VTTCue::setText(const String& text)
{
if (m_content == text)
return;
willChange();
// Clear the document fragment but don't bother to create it again just yet as we can do that
// when it is requested.
m_webVTTNodeTree = nullptr;
m_content = text;
didChange();
}
void VTTCue::createWebVTTNodeTree()
{
if (!m_webVTTNodeTree)
m_webVTTNodeTree = WebVTTParser::createDocumentFragmentFromCueText(ownerDocument(), m_content);
}
void VTTCue::copyWebVTTNodeToDOMTree(ContainerNode* webVTTNode, ContainerNode* parent)
{
for (RefPtr<Node> node = webVTTNode->firstChild(); node; node = node->nextSibling()) {
RefPtr<Node> clonedNode;
if (is<WebVTTElement>(*node))
clonedNode = downcast<WebVTTElement>(*node).createEquivalentHTMLElement(ownerDocument());
else
clonedNode = node->cloneNode(false);
parent->appendChild(*clonedNode);
if (is<ContainerNode>(*node))
copyWebVTTNodeToDOMTree(downcast<ContainerNode>(node.get()), downcast<ContainerNode>(clonedNode.get()));
}
}
RefPtr<DocumentFragment> VTTCue::getCueAsHTML()
{
createWebVTTNodeTree();
if (!m_webVTTNodeTree)
return nullptr;
auto clonedFragment = DocumentFragment::create(ownerDocument());
copyWebVTTNodeToDOMTree(m_webVTTNodeTree.get(), clonedFragment.ptr());
return clonedFragment;
}
RefPtr<DocumentFragment> VTTCue::createCueRenderingTree()
{
createWebVTTNodeTree();
if (!m_webVTTNodeTree)
return nullptr;
auto clonedFragment = DocumentFragment::create(ownerDocument());
// The cloned fragment is never exposed to author scripts so it's safe to dispatch events here.
ScriptDisallowedScope::EventAllowedScope allowedScope(clonedFragment);
m_webVTTNodeTree->cloneChildNodes(clonedFragment);
return clonedFragment;
}
void VTTCue::setRegionId(const String& regionId)
{
if (m_regionId == regionId)
return;
willChange();
m_regionId = regionId;
didChange();
}
void VTTCue::notifyRegionWhenRemovingDisplayTree(bool notifyRegion)
{
m_notifyRegion = notifyRegion;
}
void VTTCue::setIsActive(bool active)
{
TextTrackCue::setIsActive(active);
if (!active) {
if (!hasDisplayTree())
return;
// Remove the display tree as soon as the cue becomes inactive.
removeDisplayTree();
}
}
int VTTCue::calculateComputedLinePosition()
{
// http://www.whatwg.org/specs/web-apps/current-work/multipage/the-video-element.html#text-track-cue-computed-line-position
// If the text track cue line position is numeric, then that is the text
// track cue computed line position.
if (m_linePosition != undefinedPosition)
return m_linePosition;
// If the text track cue snap-to-lines flag of the text track cue is not
// set, the text track cue computed line position is the value 100;
if (!m_snapToLines)
return 100;
// Otherwise, it is the value returned by the following algorithm:
// If cue is not associated with a text track, return -1 and abort these
// steps.
if (!track())
return -1;
// Let n be the number of text tracks whose text track mode is showing or
// showing by default and that are in the media element's list of text
// tracks before track.
int n = track()->trackIndexRelativeToRenderedTracks();
// Increment n by one.
n++;
// Negate n.
n = -n;
return n;
}
static bool isCueParagraphSeparator(UChar character)
{
// Within a cue, paragraph boundaries are only denoted by Type B characters,
// such as U+000A LINE FEED (LF), U+0085 NEXT LINE (NEL), and U+2029 PARAGRAPH SEPARATOR.
return u_charType(character) == U_PARAGRAPH_SEPARATOR;
}
bool VTTCue::textPositionIsAuto() const
{
return std::isnan(m_textPosition);
}
void VTTCue::determineTextDirection()
{
static NeverDestroyed<const String> rtTag(MAKE_STATIC_STRING_IMPL("rt"));
createWebVTTNodeTree();
if (!m_webVTTNodeTree)
return;
// Apply the Unicode Bidirectional Algorithm's Paragraph Level steps to the
// concatenation of the values of each WebVTT Text Object in nodes, in a
// pre-order, depth-first traversal, excluding WebVTT Ruby Text Objects and
// their descendants.
StringBuilder paragraphBuilder;
for (RefPtr<Node> node = m_webVTTNodeTree->firstChild(); node; node = NodeTraversal::next(*node, m_webVTTNodeTree.get())) {
// FIXME: The code does not match the comment above. This does not actually exclude Ruby Text Object descendant.
if (!node->isTextNode() || node->localName() == rtTag)
continue;
paragraphBuilder.append(node->nodeValue());
}
String paragraph = paragraphBuilder.toString();
if (!paragraph.length())
return;
for (size_t i = 0; i < paragraph.length(); ++i) {
UChar current = paragraph[i];
if (!current || isCueParagraphSeparator(current))
return;
if (UChar current = paragraph[i]) {
UCharDirection charDirection = u_charDirection(current);
if (charDirection == U_LEFT_TO_RIGHT) {
m_displayDirection = CSSValueLtr;
return;
}
if (charDirection == U_RIGHT_TO_LEFT || charDirection == U_RIGHT_TO_LEFT_ARABIC) {
m_displayDirection = CSSValueRtl;
return;
}
}
}
}
double VTTCue::calculateComputedTextPosition() const
{
// http://dev.w3.org/html5/webvtt/#dfn-cue-computed-position
// 1. If the position is numeric, then return the value of the position and
// abort these steps. (Otherwise, the position is the special value auto.)
if (!textPositionIsAuto())
return m_textPosition;
switch (m_cueAlignment) {
case Start:
case Left:
// 2. If the cue text alignment is start or left, return 0 and abort these
// steps.
return 0;
case End:
case Right:
// 3. If the cue text alignment is end or right, return 100 and abort these
// steps.
return 100;
case Center:
// 4. If the cue text alignment is center, return 50 and abort these steps.
return 50;
default:
ASSERT_NOT_REACHED();
return 0;
}
}
void VTTCue::calculateDisplayParameters()
{
// Steps 10.2, 10.3
determineTextDirection();
// 10.4 If the text track cue writing direction is horizontal, then let
// block-flow be 'tb'. Otherwise, if the text track cue writing direction is
// vertical growing left, then let block-flow be 'lr'. Otherwise, the text
// track cue writing direction is vertical growing right; let block-flow be
// 'rl'.
// The above step is done through the writing direction static map.
// 10.5 Determine the value of maximum size for cue as per the appropriate
// rules from the following list:
double computedTextPosition = calculateComputedTextPosition();
int maximumSize = computedTextPosition;
if ((m_writingDirection == Horizontal && m_cueAlignment == Start && m_displayDirection == CSSValueLtr)
|| (m_writingDirection == Horizontal && m_cueAlignment == End && m_displayDirection == CSSValueRtl)
|| (m_writingDirection == Horizontal && m_cueAlignment == Left)
|| (m_writingDirection == VerticalGrowingLeft && (m_cueAlignment == Start || m_cueAlignment == Left))
|| (m_writingDirection == VerticalGrowingRight && (m_cueAlignment == Start || m_cueAlignment == Left))) {
maximumSize = 100 - computedTextPosition;
} else if ((m_writingDirection == Horizontal && m_cueAlignment == End && m_displayDirection == CSSValueLtr)
|| (m_writingDirection == Horizontal && m_cueAlignment == Start && m_displayDirection == CSSValueRtl)
|| (m_writingDirection == Horizontal && m_cueAlignment == Right)
|| (m_writingDirection == VerticalGrowingLeft && (m_cueAlignment == End || m_cueAlignment == Right))
|| (m_writingDirection == VerticalGrowingRight && (m_cueAlignment == End || m_cueAlignment == Right))) {
maximumSize = computedTextPosition;
} else if (m_cueAlignment == Center) {
maximumSize = computedTextPosition <= 50 ? computedTextPosition : (100 - computedTextPosition);
maximumSize = maximumSize * 2;
} else
ASSERT_NOT_REACHED();
// 10.6 If the text track cue size is less than maximum size, then let size
// be text track cue size. Otherwise, let size be maximum size.
m_displaySize = std::min(m_cueSize, maximumSize);
// FIXME: Understand why step 10.7 is missing (just a copy/paste error?)
// Could be done within a spec implementation check - http://crbug.com/301580
// 10.8 Determine the value of x-position or y-position for cue as per the
// appropriate rules from the following list:
if (m_writingDirection == Horizontal) {
switch (m_cueAlignment) {
case Start:
if (m_displayDirection == CSSValueLtr)
m_displayPosition.first = computedTextPosition;
else
m_displayPosition.first = 100 - computedTextPosition - m_displaySize;
break;
case End:
if (m_displayDirection == CSSValueRtl)
m_displayPosition.first = 100 - computedTextPosition;
else
m_displayPosition.first = computedTextPosition - m_displaySize;
break;
case Left:
if (m_displayDirection == CSSValueLtr)
m_displayPosition.first = computedTextPosition;
else
m_displayPosition.first = 100 - computedTextPosition;
break;
case Right:
if (m_displayDirection == CSSValueLtr)
m_displayPosition.first = computedTextPosition - m_displaySize;
else
m_displayPosition.first = 100 - computedTextPosition - m_displaySize;
break;
case Center:
if (m_displayDirection == CSSValueLtr)
m_displayPosition.first = computedTextPosition - m_displaySize / 2;
else
m_displayPosition.first = 100 - computedTextPosition - m_displaySize / 2;
break;
case NumberOfAlignments:
ASSERT_NOT_REACHED();
}
}
// A text track cue has a text track cue computed line position whose value
// is defined in terms of the other aspects of the cue.
m_computedLinePosition = calculateComputedLinePosition();
// 10.9 Determine the value of whichever of x-position or y-position is not
// yet calculated for cue as per the appropriate rules from the following
// list:
if (m_snapToLines && m_displayPosition.second == undefinedPosition && m_writingDirection == Horizontal)
m_displayPosition.second = 0;
if (!m_snapToLines && m_displayPosition.second == undefinedPosition && m_writingDirection == Horizontal)
m_displayPosition.second = m_computedLinePosition;
if (m_snapToLines && m_displayPosition.first == undefinedPosition
&& (m_writingDirection == VerticalGrowingLeft || m_writingDirection == VerticalGrowingRight))
m_displayPosition.first = 0;
if (!m_snapToLines && (m_writingDirection == VerticalGrowingLeft || m_writingDirection == VerticalGrowingRight))
m_displayPosition.first = m_computedLinePosition;
}
void VTTCue::markFutureAndPastNodes(ContainerNode* root, const MediaTime& previousTimestamp, const MediaTime& movieTime)
{
static NeverDestroyed<const String> timestampTag(MAKE_STATIC_STRING_IMPL("timestamp"));
bool isPastNode = true;
MediaTime currentTimestamp = previousTimestamp;
if (currentTimestamp > movieTime)
isPastNode = false;
for (RefPtr<Node> child = root->firstChild(); child; child = NodeTraversal::next(*child, root)) {
if (child->nodeName() == timestampTag) {
MediaTime currentTimestamp;
bool check = WebVTTParser::collectTimeStamp(child->nodeValue(), currentTimestamp);
ASSERT_UNUSED(check, check);
currentTimestamp += m_originalStartTime;
if (currentTimestamp > movieTime)
isPastNode = false;
}
if (is<WebVTTElement>(*child)) {
downcast<WebVTTElement>(*child).setIsPastNode(isPastNode);
// Make an elemenet id match a cue id for style matching purposes.
if (!id().isEmpty())
downcast<WebVTTElement>(*child).setIdAttribute(id());
}
}
}
void VTTCue::updateDisplayTree(const MediaTime& movieTime)
{
// The display tree may contain WebVTT timestamp objects representing
// timestamps (processing instructions), along with displayable nodes.
if (!track()->isRendered())
return;
// Mutating the VTT contents is safe because it's never exposed to author scripts.
ScriptDisallowedScope::EventAllowedScope allowedScopeForCueHighlightBox(*m_cueHighlightBox);
// Clear the contents of the set.
m_cueHighlightBox->removeChildren();
// Update the two sets containing past and future WebVTT objects.
RefPtr<DocumentFragment> referenceTree = createCueRenderingTree();
if (!referenceTree)
return;
ScriptDisallowedScope::EventAllowedScope allowedScopeForReferenceTree(*referenceTree);
markFutureAndPastNodes(referenceTree.get(), startMediaTime(), movieTime);
m_cueHighlightBox->appendChild(*referenceTree);
}
RefPtr<TextTrackCueBox> VTTCue::getDisplayTree(const IntSize& videoSize, int fontSize)
{
Ref<VTTCueBox> displayTree = displayTreeInternal();
if (!m_displayTreeShouldChange || !track()->isRendered())
return displayTree;
// 10.1 - 10.10
calculateDisplayParameters();
// 10.11. Apply the terms of the CSS specifications to nodes within the
// following constraints, thus obtaining a set of CSS boxes positioned
// relative to an initial containing block:
displayTree->removeChildren();
// The document tree is the tree of WebVTT Node Objects rooted at nodes.
// The children of the nodes must be wrapped in an anonymous box whose
// 'display' property has the value 'inline'. This is the WebVTT cue
// background box.
// Note: This is contained by default in m_cueHighlightBox.
m_cueHighlightBox->setPseudo(cueShadowPseudoId());
m_cueBackdropBox->setPseudo(cueBackdropShadowPseudoId());
m_cueBackdropBox->appendChild(*m_cueHighlightBox);
displayTree->appendChild(*m_cueBackdropBox);
// FIXME(BUG 79916): Runs of children of WebVTT Ruby Objects that are not
// WebVTT Ruby Text Objects must be wrapped in anonymous boxes whose
// 'display' property has the value 'ruby-base'.
displayTree->setFontSizeFromCaptionUserPrefs(fontSize);
displayTree->applyCSSProperties(videoSize);
if (displayTree->document().page()) {
auto cssString = displayTree->document().page()->captionUserPreferencesStyleSheet();
auto style = HTMLStyleElement::create(HTMLNames::styleTag, displayTree->document(), false);
style->setTextContent(cssString);
displayTree->appendChild(style);
}
const auto& styleSheets = track()->styleSheets();
if (styleSheets) {
for (const auto& cssString : *styleSheets) {
auto style = HTMLStyleElement::create(HTMLNames::styleTag, displayTree->document(), false);
style->setTextContent(cssString);
displayTree->appendChild(style);
}
}
if (m_fontSize)
displayTree->setInlineStyleProperty(CSSPropertyFontSize, m_fontSize, CSSUnitType::CSS_PX, m_fontSizeIsImportant);
m_displayTreeShouldChange = false;
if (track()) {
if (auto* regions = track()->regions()) {
if (auto region = regions->getRegionById(m_regionId))
region->cueStyleChanged();
}
}
// 10.15. Let cue's text track cue display state have the CSS boxes in
// boxes.
return displayTree;
}
void VTTCue::removeDisplayTree()
{
if (!hasDisplayTree())
return;
// The region needs to be informed about the cue removal.
if (m_notifyRegion && track()) {
if (VTTRegionList* regions = track()->regions()) {
if (RefPtr<VTTRegion> region = regions->getRegionById(m_regionId)) {
if (hasDisplayTree())
region->willRemoveTextTrackCueBox(m_displayTree.get());
}
}
}
// The display tree is never exposed to author scripts so it's safe to dispatch events here.
ScriptDisallowedScope::EventAllowedScope allowedScope(displayTreeInternal());
displayTreeInternal().remove();
}
std::pair<double, double> VTTCue::getPositionCoordinates() const
{
// This method is used for setting x and y when snap to lines is not set.
std::pair<double, double> coordinates;
auto textPosition = calculateComputedTextPosition();
if (m_writingDirection == Horizontal && m_displayDirection == CSSValueLtr) {
coordinates.first = textPosition;
coordinates.second = m_computedLinePosition;
return coordinates;
}
if (m_writingDirection == Horizontal && m_displayDirection == CSSValueRtl) {
coordinates.first = 100 - textPosition;
coordinates.second = m_computedLinePosition;
return coordinates;
}
if (m_writingDirection == VerticalGrowingLeft) {
coordinates.first = 100 - m_computedLinePosition;
coordinates.second = textPosition;
return coordinates;
}
if (m_writingDirection == VerticalGrowingRight) {
coordinates.first = m_computedLinePosition;
coordinates.second = textPosition;
return coordinates;
}
ASSERT_NOT_REACHED();
return coordinates;
}
VTTCue::CueSetting VTTCue::settingName(VTTScanner& input)
{
CueSetting parsedSetting = None;
if (input.scan("vertical"))
parsedSetting = Vertical;
else if (input.scan("line"))
parsedSetting = Line;
else if (input.scan("position"))
parsedSetting = Position;
else if (input.scan("size"))
parsedSetting = Size;
else if (input.scan("align"))
parsedSetting = Align;
else if (input.scan("region"))
parsedSetting = RegionId;
// Verify that a ':' follows.
if (parsedSetting != None && input.scan(':'))
return parsedSetting;
return None;
}
void VTTCue::setCueSettings(const String& inputString)
{
if (inputString.isEmpty())
return;
VTTScanner input(inputString);
while (!input.isAtEnd()) {
// The WebVTT cue settings part of a WebVTT cue consists of zero or more of the following components, in any order,
// separated from each other by one or more U+0020 SPACE characters or U+0009 CHARACTER TABULATION (tab) characters.
input.skipWhile<WebVTTParser::isValidSettingDelimiter>();
if (input.isAtEnd())
break;
// When the user agent is to parse the WebVTT settings given by a string input for a text track cue cue,
// the user agent must run the following steps:
// 1. Let settings be the result of splitting input on spaces.
// 2. For each token setting in the list settings, run the following substeps:
// 1. If setting does not contain a U+003A COLON character (:), or if the first U+003A COLON character (:)
// in setting is either the first or last character of setting, then jump to the step labeled next setting.
// 2. Let name be the leading substring of setting up to and excluding the first U+003A COLON character (:) in that string.
CueSetting name = settingName(input);
// 3. Let value be the trailing substring of setting starting from the character immediately after the first U+003A COLON character (:) in that string.
VTTScanner::Run valueRun = input.collectUntil<WebVTTParser::isValidSettingDelimiter>();
// 4. Run the appropriate substeps that apply for the value of name, as follows:
switch (name) {
case Vertical: {
// If name is a case-sensitive match for "vertical"
// 1. If value is a case-sensitive match for the string "rl", then let cue's text track cue writing direction
// be vertical growing left.
if (input.scanRun(valueRun, verticalGrowingLeftKeyword()))
m_writingDirection = VerticalGrowingLeft;
// 2. Otherwise, if value is a case-sensitive match for the string "lr", then let cue's text track cue writing
// direction be vertical growing right.
else if (input.scanRun(valueRun, verticalGrowingRightKeyword()))
m_writingDirection = VerticalGrowingRight;
else
LOG(Media, "VTTCue::setCueSettings, invalid Vertical");
break;
}
case Line: {
bool isValid = false;
do {
// 1-2 - Collect chars that are either '-', '%', or a digit.
// 1. If value contains any characters other than U+002D HYPHEN-MINUS characters (-), U+0025 PERCENT SIGN
// characters (%), and characters in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), then jump
// to the step labeled next setting.
float linePosition;
bool isNegative;
if (!input.scanFloat(linePosition, &isNegative))
break;
bool isPercentage = input.scan('%');
if (!input.isAt(valueRun.end())) {
if (!input.scan(','))
break;
// FIXME: implement handling of line setting alignment.
if (!input.scan(startKeyword().characters8(), startKeyword().length())
&& !input.scan(centerKeyword().characters8(), centerKeyword().length())
&& !input.scan(endKeyword().characters8(), endKeyword().length())) {
LOG(Media, "VTTCue::setCueSettings, invalid line setting alignment");
break;
}
}
// 2. If value does not contain at least one character in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT
// NINE (9), then jump to the step labeled next setting.
// 3. If any character in value other than the first character is a U+002D HYPHEN-MINUS character (-), then
// jump to the step labeled next setting.
// 4. If any character in value other than the last character is a U+0025 PERCENT SIGN character (%), then
// jump to the step labeled next setting.
// 5. If the first character in value is a U+002D HYPHEN-MINUS character (-) and the last character in value is a
// U+0025 PERCENT SIGN character (%), then jump to the step labeled next setting.
if (isPercentage && isNegative)
break;
// 6. Ignoring the trailing percent sign, if any, interpret value as a (potentially signed) integer, and
// let number be that number.
// 7. If the last character in value is a U+0025 PERCENT SIGN character (%), but number is not in the range
// 0 ≤ number ≤ 100, then jump to the step labeled next setting.
// 8. Let cue's text track cue line position be number.
// 9. If the last character in value is a U+0025 PERCENT SIGN character (%), then let cue's text track cue
// snap-to-lines flag be false. Otherwise, let it be true.
if (isPercentage) {
if (linePosition < 0 || linePosition > 100)
break;
// 10 - If '%' then set snap-to-lines flag to false.
m_snapToLines = false;
} else {
if (linePosition - static_cast<int>(linePosition))
break;
m_snapToLines = true;
}
m_linePosition = linePosition;
isValid = true;
} while (0);
if (!isValid)
LOG(Media, "VTTCue::setCueSettings, invalid Line");
break;
}
case Position: {
float position;
if (WebVTTParser::parseFloatPercentageValue(input, position) && input.isAt(valueRun.end()))
m_textPosition = position;
else
LOG(Media, "VTTCue::setCueSettings, invalid Position");
break;
}
case Size: {
float cueSize;
if (WebVTTParser::parseFloatPercentageValue(input, cueSize) && input.isAt(valueRun.end()))
m_cueSize = cueSize;
else
LOG(Media, "VTTCue::setCueSettings, invalid Size");
break;
}
case Align: {
// 1. If value is a case-sensitive match for the string "start", then let cue's text track cue alignment be start alignment.
if (input.scanRun(valueRun, startKeyword()))
m_cueAlignment = Start;
// 2. If value is a case-sensitive match for the string "center", then let cue's text track cue alignment be center alignment.
else if (input.scanRun(valueRun, centerKeyword()))
m_cueAlignment = Center;
// 3. If value is a case-sensitive match for the string "end", then let cue's text track cue alignment be end alignment.
else if (input.scanRun(valueRun, endKeyword()))
m_cueAlignment = End;
// 4. If value is a case-sensitive match for the string "left", then let cue's text track cue alignment be left alignment.
else if (input.scanRun(valueRun, leftKeyword()))
m_cueAlignment = Left;
// 5. If value is a case-sensitive match for the string "right", then let cue's text track cue alignment be right alignment.
else if (input.scanRun(valueRun, rightKeyword()))
m_cueAlignment = Right;
else
LOG(Media, "VTTCue::setCueSettings, invalid Align");
break;
}
case RegionId:
m_regionId = input.extractString(valueRun);
break;
case None:
break;
}
// Make sure the entire run is consumed.
input.skipRun(valueRun);
}
// If cue's line position is not auto or cue's size is not 100 or cue's
// writing direction is not horizontal, but cue's region identifier is not
// the empty string, let cue's region identifier be the empty string.
if (m_regionId.isEmpty())
return;
if (m_linePosition != undefinedPosition || m_cueSize != 100 || m_writingDirection != Horizontal)
m_regionId = emptyString();
}
CSSValueID VTTCue::getCSSAlignment() const
{
return displayAlignmentMap[m_cueAlignment];
}
CSSValueID VTTCue::getCSSWritingDirection() const
{
return m_displayDirection;
}
CSSValueID VTTCue::getCSSWritingMode() const
{
return displayWritingModeMap[m_writingDirection];
}
int VTTCue::getCSSSize() const
{
return m_displaySize;
}
std::pair<double, double> VTTCue::getCSSPosition() const
{
if (!m_snapToLines)
return getPositionCoordinates();
return m_displayPosition;
}
bool VTTCue::cueContentsMatch(const TextTrackCue& cue) const
{
RefPtr<const VTTCue> vttCue = toVTTCue(&cue);
if (text() != vttCue->text())
return false;
if (cueSettings() != vttCue->cueSettings())
return false;
if (position() != vttCue->position())
return false;
if (line() != vttCue->line())
return false;
if (size() != vttCue->size())
return false;
if (align() != vttCue->align())
return false;
return true;
}
bool VTTCue::isEqual(const TextTrackCue& cue, TextTrackCue::CueMatchRules match) const
{
if (!TextTrackCue::isEqual(cue, match))
return false;
if (cue.cueType() != WebVTT)
return false;
return cueContentsMatch(cue);
}
bool VTTCue::doesExtendCue(const TextTrackCue& cue) const
{
if (!cueContentsMatch(cue))
return false;
return TextTrackCue::doesExtendCue(cue);
}
void VTTCue::setFontSize(int fontSize, const IntSize&, bool important)
{
if (fontSize == m_fontSize && important == m_fontSizeIsImportant)
return;
m_displayTreeShouldChange = true;
m_fontSizeIsImportant = important;
m_fontSize = fontSize;
}
VTTCue* toVTTCue(TextTrackCue* cue)
{
return const_cast<VTTCue*>(toVTTCue(const_cast<const TextTrackCue*>(cue)));
}
const VTTCue* toVTTCue(const TextTrackCue* cue)
{
RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(is<VTTCue>(cue) || is<TextTrackCueGeneric>(cue));
return static_cast<const VTTCue*>(cue);
}
String VTTCue::toJSONString() const
{
auto object = JSON::Object::create();
toJSON(object.get());
return object->toJSONString();
}
void VTTCue::toJSON(JSON::Object& object) const
{
TextTrackCue::toJSON(object);
#if !LOG_DISABLED
object.setString("text"_s, text());
#endif
object.setString("vertical"_s, vertical());
object.setBoolean("snapToLines"_s, snapToLines());
object.setDouble("line"_s, m_linePosition);
if (textPositionIsAuto())
object.setString("position"_s, "auto");
else
object.setDouble("position"_s, m_textPosition);
object.setInteger("size"_s, m_cueSize);
object.setString("align"_s, align());
object.setString("regionId"_s, regionId());
}
} // namespace WebCore
#endif