void VTTCue::line(DoubleOrAutoKeyword& result) const
{
if (lineIsAuto())
result.setAutoKeyword(autoKeyword());
else
result.setDouble(m_linePosition);
}
float VTTCue::calculateComputedLinePosition() const
{
// http://dev.w3.org/html5/webvtt/#dfn-text-track-cue-computed-line-position
// A text track cue has a text track cue computed line position whose value
// is that returned by the following algorithm, which is defined in terms
// of the other aspects of the cue:
// 1. If the text track cue line position is numeric, the text track cue
// snap-to-lines flag of the text track cue is not set, and the text
// track cue line position is negative or greater than 100, then return
// 100 and abort these steps.
if (!lineIsAuto() && !m_snapToLines && isInvalidPercentage(m_linePosition))
return 100;
// 2. If the text track cue line position is numeric, return the value of
// the text track cue line position and abort these steps. (Either the
// text track cue snap-to-lines flag is set, so any value, not just
// those in the range 0..100, is valid, or the value is in the range
// 0..100 and is thus valid regardless of the value of that flag.)
if (!lineIsAuto())
return m_linePosition;
// 3. If the text track cue snap-to-lines flag of the text track cue is not
// set, return the value 100 and abort these steps. (The text track cue
// line position is the special value auto.)
if (!m_snapToLines)
return 100;
// 4. Let cue be the text track cue.
// 5. If cue is not in a list of cues of a text track, or if that text
// track is not in the list of text tracks of a media element, return -1
// and abort these steps.
if (!track())
return -1;
// 6. Let track be the text track whose list of cues the cue is in.
// 7. Let n be the number of text tracks whose text track mode is showing
// and that are in the media element's list of text tracks before track.
int n = track()->trackIndexRelativeToRenderedTracks();
// 8. Increment n by one. / 9. Negate n. / 10. Return n.
n++;
n = -n;
return n;
}
void VTTCue::updateDisplay(HTMLDivElement& container)
{
ASSERT(track() && track()->isRendered() && isActive());
UseCounter::count(document(), UseCounter::VTTCueRender);
if (m_writingDirection != Horizontal)
UseCounter::count(document(), UseCounter::VTTCueRenderVertical);
if (!m_snapToLines)
UseCounter::count(document(), UseCounter::VTTCueRenderSnapToLinesFalse);
if (!lineIsAuto())
UseCounter::count(document(), UseCounter::VTTCueRenderLineNotAuto);
if (textPositionIsAuto())
UseCounter::count(document(), UseCounter::VTTCueRenderPositionNot50);
if (m_cueSize != 100)
UseCounter::count(document(), UseCounter::VTTCueRenderSizeNot100);
if (m_cueAlignment != Middle)
UseCounter::count(document(), UseCounter::VTTCueRenderAlignNotMiddle);
VTTCueBox* displayBox = getDisplayTree();
VTTRegion* region = 0;
if (track()->regions())
region = track()->regions()->getRegionById(regionId());
if (!region) {
// If cue has an empty region identifier or there is no WebVTT region
// whose region identifier is identical to cue's region identifier, run
// the following substeps:
if (displayBox->hasChildren() && !container.contains(displayBox)) {
// Note: the display tree of a cue is removed when the active flag of the cue is unset.
container.appendChild(displayBox);
}
} else {
// Let region be the WebVTT region whose region identifier matches the
// region identifier of cue.
HTMLDivElement* regionNode = region->getDisplayTree(document());
// Append the region to the viewport, if it was not already.
if (!container.contains(regionNode))
container.appendChild(regionNode);
region->appendVTTCueBox(displayBox);
}
}
void VTTCue::setLine(const DoubleOrAutoKeyword& position)
{
// http://dev.w3.org/html5/webvtt/#dfn-vttcue-line
// On setting, the WebVTT cue line 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. ("auto" is translated to NaN.)
float floatPosition;
if (position.isAutoKeyword()) {
if (lineIsAuto())
return;
floatPosition = std::numeric_limits<float>::quiet_NaN();
} else {
ASSERT(position.isDouble());
floatPosition = narrowPrecisionToFloat(position.getAsDouble());
if (m_linePosition == floatPosition)
return;
}
cueWillChange();
m_linePosition = floatPosition;
cueDidChange();
}
void VTTCue::parseSettings(const String& inputString)
{
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<VTTParser::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<VTTParser::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 WebVTT 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 WebVTT cue writing direction be
// vertical growing right.
else if (input.scanRun(valueRun, verticalGrowingRightKeyword()))
m_writingDirection = VerticalGrowingRight;
break;
}
case Line: {
// If name is a case-sensitive match for "line"
// Steps 1 - 2 skipped.
float number;
// 3. If linepos does not contain at least one ASCII digit, then
// jump to the step labeled next setting.
// 4. If the last character in linepos is a U+0025 PERCENT SIGN character (%)
//
// If parse a percentage string from linepos doesn't fail, let
// number be the returned percentage, otherwise jump to the step
// labeled next setting.
bool isPercentage = scanPercentage(input, number);
if (!isPercentage) {
// Otherwise
//
// 1. If linepos contains any characters other than U+002D
// HYPHEN-MINUS characters (-) and ASCII digits, then jump to
// the step labeled next setting.
// 2. If any character in linepos other than the first character is
// a U+002D HYPHEN-MINUS character (-), then jump to the step
// labeled next setting.
bool isNegative = input.scan('-');
int intLinePosition;
if (!input.scanDigits(intLinePosition))
break;
// 3. Interpret linepos as a (potentially signed) integer, and let
// number be that number.
number = isNegative ? -intLinePosition : intLinePosition;
}
if (!input.isAt(valueRun.end()))
break;
// 5. Let cue's WebVTT cue line be number.
m_linePosition = number;
// 6. If the last character in linepos is a U+0025 PERCENT SIGN
// character (%), then let cue's WebVTT cue snap-to-lines
// flag be false. Otherwise, let it be true.
m_snapToLines = !isPercentage;
// Steps 7 - 9 skipped.
break;
}
case Position: {
// If name is a case-sensitive match for "position".
float number;
// Steps 1 - 2 skipped.
// 3. If parse a percentage string from colpos doesn't fail, let
// number be the returned percentage, otherwise jump to the step
// labeled next setting (text track cue text position's value
// remains the special value auto).
if (!scanPercentage(input, number))
break;
if (!input.isAt(valueRun.end()))
break;
// 4. Let cue's cue position be number.
m_textPosition = number;
// Steps 5 - 7 skipped.
break;
}
case Size: {
// If name is a case-sensitive match for "size"
float number;
// 1. If parse a percentage string from value doesn't fail, let
// number be the returned percentage, otherwise jump to the step
// labeled next setting.
if (!scanPercentage(input, number))
break;
if (!input.isAt(valueRun.end()))
break;
// 2. Let cue's WebVTT cue size be number.
m_cueSize = number;
break;
}
case Align: {
// If name is a case-sensitive match for "align"
// 1. If value is a case-sensitive match for the string "start",
// then let cue's WebVTT cue text alignment be start alignment.
if (input.scanRun(valueRun, startKeyword()))
m_cueAlignment = Start;
// 2. If value is a case-sensitive match for the string "middle",
// then let cue's WebVTT cue text alignment be middle alignment.
else if (input.scanRun(valueRun, middleKeyword()))
m_cueAlignment = Middle;
// 3. If value is a case-sensitive match for the string "end", then
// let cue's WebVTT cue text 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 WebVTT cue text 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 WebVTT cue text alignment be right alignment.
else if (input.scanRun(valueRun, rightKeyword()))
m_cueAlignment = Right;
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 (!lineIsAuto() || m_cueSize != 100 || m_writingDirection != Horizontal)
m_regionId = emptyString();
}
