C++ cueDidChange函数代码示例

void TextTrackCue::setVertical(const String& value, ExceptionCode& ec)
{
    // 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
        ec = SYNTAX_ERR;
    
    if (direction == m_writingDirection)
        return;

    cueWillChange();
    m_writingDirection = direction;
    cueDidChange();
}

void TextTrackCue::setId(const AtomicString& id) {
  if (m_id == id)
    return;

  cueWillChange();
  m_id = id;
  cueDidChange();
}

void VTTCue::setSnapToLines(bool value)
{
    if (m_snapToLines == value)
        return;

    cueWillChange();
    m_snapToLines = value;
    cueDidChange();
}

void TextTrackCue::setEndTime(double value)
{
    if (m_endTime == value)
        return;
    
    cueWillChange();
    m_endTime = value;
    cueDidChange();
}

void TextTrackCue::setText(const String& text)
{
    if (m_content == text)
        return;
    
    cueWillChange();
    // 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 = 0;
    m_content = text;
    cueDidChange();
}

void TextTrackCue::setStartTime(double value, ExceptionState& exceptionState)
{
    // NaN, Infinity and -Infinity values should trigger a TypeError.
    if (isInfiniteOrNonNumber(value, exceptionState))
        return;

    // TODO(93143): Add spec-compliant behavior for negative time values.
    if (m_startTime == value || value < 0)
        return;

    cueWillChange();
    m_startTime = value;
    cueDidChange();
}

void VTTCue::setLine(int position, ExceptionState& exceptionState)
{
    // 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)) {
        exceptionState.throwDOMException(IndexSizeError, "The snap-to-lines flag is not set, and the value provided (" + String::number(position) + ") is not between 0 and 100.");
        return;
    }

    // Otherwise, set the text track cue line position to the new value.
    if (m_linePosition == position)
        return;

    cueWillChange();
    m_linePosition = position;
    m_computedLinePosition = calculateComputedLinePosition();
    cueDidChange();
}

void VTTCue::setVertical(const String& value)
{
    WritingDirection direction = m_writingDirection;
    if (value == horizontalKeyword())
        direction = Horizontal;
    else if (value == verticalGrowingLeftKeyword())
        direction = VerticalGrowingLeft;
    else if (value == verticalGrowingRightKeyword())
        direction = VerticalGrowingRight;
    else
        ASSERT_NOT_REACHED();

    if (direction == m_writingDirection)
        return;

    cueWillChange();
    m_writingDirection = direction;
    cueDidChange();
}