/// <summary>
/// format text line using LS
/// </summary>
/// <param name="fullText">state of the full text backing store</param>
/// <param name="cpFirst">first cp to format</param>
/// <param name="lineLength">character length of the line</param>
/// <param name="formatWidth">width used to format</param>
/// <param name="finiteFormatWidth">width used to detect overflowing of format result</param>
/// <param name="paragraphWidth">paragraph width</param>
/// <param name="lineFlags">line formatting control flags</param>
/// <param name="collapsingSymbol">line end collapsing symbol</param>
private void FormatLine(
FullTextState fullText,
int cpFirst,
int lineLength,
int formatWidth,
int finiteFormatWidth,
int paragraphWidth,
LineFlags lineFlags,
FormattedTextSymbols collapsingSymbol
)
{
_fullText = fullText;
_paragraphWidth = paragraphWidth;
TextStore store = fullText.TextStore;
FormatSettings settings = store.Settings;
ParaProp pap = settings.Pap;
_paragraphTextDecorations = pap.TextDecorations;
if (_paragraphTextDecorations != null)
{
if (_paragraphTextDecorations.Count != 0)
{
_defaultTextDecorationsBrush = pap.DefaultTextDecorationsBrush;
}
else
{
_paragraphTextDecorations = null;
}
}
_metrics = GetLineMetrics(fullText, cpFirst, lineLength, formatWidth, finiteFormatWidth, paragraphWidth, lineFlags, collapsingSymbol);
lineLength = _metrics._cchLength;
if (lineLength > _metrics._cchNewline)
{
var lineBreakpoints = store.FindLineBreakpoints(cpFirst, lineLength);
// check for line wrap
if (pap.Wrap && _metrics._textStart + _metrics._textWidthAtTrailing > finiteFormatWidth)
{
for (int i = lineLength - 1; i > 0; i--)
{
if (lineBreakpoints.GetBreakConditionBefore(i + cpFirst) == DWriteBreakCondition.CanBreak)
{
var trailingWhitespace = lineBreakpoints.WhitespaceLengthBefore(i + cpFirst);
var trimmedMetrics = GetLineMetrics(fullText, cpFirst, i - trailingWhitespace, formatWidth, finiteFormatWidth, paragraphWidth, lineFlags, collapsingSymbol);
if (trimmedMetrics._textStart + trimmedMetrics._textWidthAtTrailing <= finiteFormatWidth)
{
_metrics = GetLineMetrics(fullText, cpFirst, i, formatWidth, finiteFormatWidth, paragraphWidth, lineFlags, collapsingSymbol);
_metrics._cchTrailing = trailingWhitespace;
_metrics._textWidthAtTrailing = trimmedMetrics._textWidth;
break;
}
}
}
}
}
if (collapsingSymbol == null)
{
// overflow detection for potential collapsible line
if (_metrics._textStart + _metrics._textWidthAtTrailing > finiteFormatWidth)
{
bool hasOverflowed = true;
if (_textFormattingMode == TextFormattingMode.Display)
{
// apply display-mode rounding before checking for overflow
double realWidth = Width;
double realFormatWidth = _metrics._formatter.IdealToReal(finiteFormatWidth, PixelsPerDip);
hasOverflowed = (TextFormatterImp.CompareReal(realWidth, realFormatWidth, PixelsPerDip, _textFormattingMode) > 0);
}
if (hasOverflowed)
{
// line has overflowed
_statusFlags |= StatusFlags.HasOverflowed;
}
}
}
}
// For a given line length, return TextMetrics for as manu characters fit in the width
private TextMetrics GetLineMetrics(
FullTextState fullText,
int cpFirst,
int lineLength,
int formatWidth,
int finiteFormatWidth,
int paragraphWidth,
LineFlags lineFlags,
FormattedTextSymbols collapsingSymbol
)
{
TextMetrics result = new TextMetrics();
result._formatter = fullText.Formatter;
Debug.Assert(result._formatter != null);
TextStore store = fullText.TextStore;
FormatSettings settings = store.Settings;
ParaProp pap = settings.Pap;
var pixelsPerDip = settings.TextSource.PixelsPerDip;
int pos = cpFirst;
int content_ascent = 0;
int content_descent = 0;
while (lineLength <= 0 || cpFirst + lineLength > pos)
{
TextRun textRun;
int runLength;
CharacterBufferRange chars = settings.FetchTextRun(pos, cpFirst, out textRun, out runLength);
if (lineLength > 0 && pos + runLength > cpFirst + lineLength)
{
runLength = cpFirst + lineLength - pos;
chars = new CharacterBufferRange(chars, 0, runLength);
}
if (textRun is TextEndOfParagraph || textRun is TextEndOfLine)
{
pos += runLength;
result._cchNewline = runLength;
break;
}
TextMetrics runMetrics = GetRunMetrics(fullText, textRun, chars);
if (content_ascent < runMetrics._textAscent)
{
content_ascent = runMetrics._textAscent;
}
if (content_descent < runMetrics._textHeight - runMetrics._textAscent)
{
content_descent = runMetrics._textHeight - runMetrics._textAscent;
}
result._textWidth += runMetrics._textWidth;
pos += runLength;
}
result._pixelsPerDip = pixelsPerDip;
result._cchLength = pos - cpFirst;
result._textWidthAtTrailing = result._textWidth; // will be set later by FormatLine
if (pap.LineHeight > 0)
{
// Host specifies line height, honor it.
result._height = pap.LineHeight;
result._baselineOffset = (int)Math.Round(
result._height
* pap.DefaultTypeface.Baseline(pap.EmSize, Constants.DefaultIdealToReal, pixelsPerDip, _textFormattingMode)
/ pap.DefaultTypeface.LineSpacing(pap.EmSize, Constants.DefaultIdealToReal, pixelsPerDip, _textFormattingMode)
);
}
if (content_ascent > 0)
{
result._textAscent = content_ascent;
result._textHeight = content_ascent + content_descent;
// TODO: VerticalAdjust
}
else
{
// Line is empty so text height and text baseline are based on the default typeface;
// it doesn't make sense even for an emtpy line to have zero text height
result._textAscent = (int)Math.Round(pap.DefaultTypeface.Baseline(pap.EmSize, Constants.DefaultIdealToReal, pixelsPerDip, _textFormattingMode));
result._textHeight = (int)Math.Round(pap.DefaultTypeface.LineSpacing(pap.EmSize, Constants.DefaultIdealToReal, pixelsPerDip, _textFormattingMode));
}
if (result._height <= 0)
{
result._height = result._textHeight;
result._baselineOffset = result._textAscent;
}
return(result);
}