// ------------------------------------------------------------------
// Get collapsing properties.
//
// wrappingWidth - wrapping width for collapsed line.
// paraProperties - paragraph properties.
//
// Returns: Line collapsing properties.
// ------------------------------------------------------------------
protected TextCollapsingProperties GetCollapsingProps(double wrappingWidth, LineProperties paraProperties)
{
Debug.Assert(paraProperties.TextTrimming != TextTrimming.None, "Text trimming must be enabled.");
TextCollapsingProperties collapsingProps;
if (paraProperties.TextTrimming == TextTrimming.CharacterEllipsis)
{
collapsingProps = new TextTrailingCharacterEllipsis(wrappingWidth, paraProperties.DefaultTextRunProperties);
}
else
{
collapsingProps = new TextTrailingWordEllipsis(wrappingWidth, paraProperties.DefaultTextRunProperties);
}
return collapsingProps;
}
/// <summary>
/// Wrapper of TextFormatter.FormatLine that auto-collapses the line if needed.
/// </summary>
private TextLine FormatLine(TextSource textSource, int textSourcePosition, double maxLineLength, TextParagraphProperties paraProps, TextLineBreak lineBreak)
{
TextLine line = _formatter.FormatLine(
textSource,
textSourcePosition,
maxLineLength,
paraProps,
lineBreak
);
if (_that._trimming != TextTrimming.None && line.HasOverflowed && line.Length > 0)
{
// what I really need here is the last displayed text run of the line
// textSourcePosition + line.Length - 1 works except the end of paragraph case,
// where line length includes the fake paragraph break run
Debug.Assert(_that._text.Length > 0 && textSourcePosition + line.Length <= _that._text.Length + 1);
SpanRider thatFormatRider = new SpanRider(
_that._formatRuns,
_that._latestPosition,
Math.Min(textSourcePosition + line.Length - 1, _that._text.Length - 1)
);
GenericTextRunProperties lastRunProps = thatFormatRider.CurrentElement as GenericTextRunProperties;
TextCollapsingProperties trailingEllipsis;
if (_that._trimming == TextTrimming.CharacterEllipsis)
trailingEllipsis = new TextTrailingCharacterEllipsis(maxLineLength, lastRunProps);
else
{
Debug.Assert(_that._trimming == TextTrimming.WordEllipsis);
trailingEllipsis = new TextTrailingWordEllipsis(maxLineLength, lastRunProps);
}
TextLine collapsedLine = line.Collapse(trailingEllipsis);
if (collapsedLine != line)
{
line.Dispose();
line = collapsedLine;
}
}
return line;
}