/// <summary>
/// Utility method to write a single cue span into a buffer.
/// </summary>
/// <param name="span">Cue span to write.</param>
/// <param name="builder">String builder buffer to write into.</param>
private static void WriteSpan(
Span span,
StringBuilder builder)
{
if (span.Type == SpanType.Text)
{
if (string.IsNullOrEmpty(span.Text))
{
return;
}
if (span.Text.Contains(Constants.ArrowToken))
{
throw new ArgumentException("Cue text cannot contain '{0}'.", Constants.ArrowToken);
}
WebVttSerializer.WriteString(span.Text, true, builder);
return;
}
string tagName = WebVttSerializer.GetSpanTagName(span.Type);
builder.Append('<').Append(tagName);
if (span.Classes != null && span.Classes.Length > 0)
{
foreach (string cls in span.Classes)
{
if (false == string.IsNullOrWhiteSpace(cls))
{
if (WebVttSerializer.HasWhiteSpace(cls))
{
throw new ArgumentException("White space characters are not allowed in span class name.");
}
builder.Append('.').Append(cls);
}
}
}
if (false == string.IsNullOrWhiteSpace(span.Annotation))
{
builder.Append(' ');
WebVttSerializer.WriteString(span.Annotation, true, builder);
}
builder.Append('>');
if (span.Children != null && span.Children.Length > 0)
{
foreach (var child in span.Children)
{
if (child != null)
{
WebVttSerializer.WriteSpan(child, builder);
}
}
}
builder.Append("</").Append(tagName).Append('>');
}
/// <summary>
/// Utility method to write a caption cue into a buffer.
/// </summary>
/// <param name="cue">Cue to write.</param>
/// <param name="builder">String builder buffer to write into.</param>
private static void WriteCue(
Cue cue,
StringBuilder builder)
{
if (cue.End <= cue.Start)
{
throw new ArgumentException(string.Format("Cue start time '{0}' must be less than cue end time '{1}'.", cue.Start, cue.End));
}
builder.AppendLine();
if (false == string.IsNullOrWhiteSpace(cue.Id))
{
builder.AppendLine(cue.Id);
}
WebVttSerializer.WriteTimeSpanValue(cue.Start, builder);
builder
.Append(' ')
.Append(Constants.ArrowToken)
.Append(' ');
WebVttSerializer.WriteTimeSpanValue(cue.End, builder);
if (false == string.IsNullOrWhiteSpace(cue.Region))
{
if (WebVttSerializer.HasWhiteSpace(cue.Region))
{
throw new ArgumentException("White space characters are not allowed in cue region id.");
}
builder
.Append(' ')
.Append(Constants.RegionName).Append(':').Append(cue.Region);
}
if (cue.Alignment.HasValue)
{
builder
.Append(' ')
.Append(Constants.AlignName).Append(':').Append(WebVttSerializer.GetAlignmentValue(cue.Alignment.Value));
}
if (cue.Line.HasValue)
{
builder
.Append(' ')
.Append(Constants.LineName).Append(':');
if (cue.Line.Value.Percent.HasValue)
{
builder.Append(WebVttSerializer.GetPercentValue(cue.Line.Value.Percent.Value));
}
else if (cue.Line.Value.LineNumber.HasValue)
{
builder.Append(cue.Line.Value.LineNumber.Value);
}
else
{
throw new ArgumentException("Cue line setting must specify either percent or line number value.");
}
if (cue.Line.Value.Alignment.HasValue)
{
builder.Append(',').Append(WebVttSerializer.GetLineAlignmentValue(cue.Line.Value.Alignment.Value));
}
}
if (cue.Position.HasValue)
{
builder
.Append(' ')
.Append(Constants.PositionName).Append(':')
.Append(WebVttSerializer.GetPercentValue(
cue.Position.Value.PositionPercent.HasValue
? cue.Position.Value.PositionPercent.Value
: 0.0));
if (cue.Position.Value.Alignment.HasValue)
{
builder
.Append(',')
.Append(WebVttSerializer.GetPositionAlignmentValue(cue.Position.Value.Alignment.Value));
}
}
if (cue.SizePercent.HasValue)
{
builder
.Append(' ')
.Append(Constants.SizeName)
.Append(":")
.Append(WebVttSerializer.GetPercentValue(cue.SizePercent.Value));
}
if (cue.Vertical.HasValue)
{
builder
.Append(' ')
.Append(Constants.VerticalName)
.Append(":")
.Append(WebVttSerializer.GetVerticalAlignmentValue(cue.Vertical.Value));
}
builder.AppendLine();
if (cue.Content != null && cue.Content.Length > 0)
{
Span previousSpan = null;
foreach (var span in cue.Content)
{
if (span == null)
{
throw new ArgumentException("Cue content cannot be null.");
}
if (WebVttSerializer.NeedNewLine(previousSpan, span))
{
builder.AppendLine();
}
WebVttSerializer.WriteSpan(span, builder);
previousSpan = span;
}
builder.AppendLine();
}
}