/// <inheritdoc cref="TextFormatter.FormatLine"/>
public override TextLine FormatLine(ITextSource textSource, int firstTextSourceIndex, double paragraphWidth,
TextParagraphProperties paragraphProperties, TextLineBreak previousLineBreak = null)
{
var textTrimming = paragraphProperties.TextTrimming;
var textWrapping = paragraphProperties.TextWrapping;
TextLine textLine = null;
var textRuns = FetchTextRuns(textSource, firstTextSourceIndex, previousLineBreak, out var nextLineBreak);
var textRange = GetTextRange(textRuns);
if (textTrimming != TextTrimming.None)
{
textLine = PerformTextTrimming(textRuns, textRange, paragraphWidth, paragraphProperties);
}
else
{
switch (textWrapping)
{
case TextWrapping.NoWrap:
{
var textLineMetrics =
TextLineMetrics.Create(textRuns, textRange, paragraphWidth, paragraphProperties);
textLine = new TextLineImpl(textRuns, textLineMetrics, nextLineBreak);
break;
}
case TextWrapping.WrapWithOverflow:
case TextWrapping.Wrap:
{
textLine = PerformTextWrapping(textRuns, textRange, paragraphWidth, paragraphProperties);
break;
}
}
}
return(textLine);
}
/// <summary>
/// Fetches text runs.
/// </summary>
/// <param name="textSource">The text source.</param>
/// <param name="firstTextSourceIndex">The first text source index.</param>
/// <param name="previousLineBreak">Previous line break. Can be null.</param>
/// <param name="nextLineBreak">Next line break. Can be null.</param>
/// <returns>
/// The formatted text runs.
/// </returns>
private static List <ShapedTextCharacters> FetchTextRuns(ITextSource textSource,
int firstTextSourceIndex, TextLineBreak previousLineBreak, out TextLineBreak nextLineBreak)
{
nextLineBreak = default;
var currentLength = 0;
var textRuns = new List <ShapedTextCharacters>();
if (previousLineBreak != null)
{
for (var index = 0; index < previousLineBreak.RemainingCharacters.Count; index++)
{
var shapedCharacters = previousLineBreak.RemainingCharacters[index];
if (shapedCharacters == null)
{
continue;
}
textRuns.Add(shapedCharacters);
if (TryGetLineBreak(shapedCharacters, out var runLineBreak))
{
var splitResult = SplitTextRuns(textRuns, currentLength + runLineBreak.PositionWrap);
if (++index < previousLineBreak.RemainingCharacters.Count)
{
for (; index < previousLineBreak.RemainingCharacters.Count; index++)
{
splitResult.Second.Add(previousLineBreak.RemainingCharacters[index]);
}
}
nextLineBreak = new TextLineBreak(splitResult.Second);
return(splitResult.First);
}
currentLength += shapedCharacters.Text.Length;
}
}
firstTextSourceIndex += currentLength;
var textRunEnumerator = new TextRunEnumerator(textSource, firstTextSourceIndex);
while (textRunEnumerator.MoveNext())
{
var textRun = textRunEnumerator.Current;
switch (textRun)
{
case TextCharacters textCharacters:
{
var shapeableRuns = textCharacters.GetShapeableCharacters();
foreach (var run in shapeableRuns)
{
var glyphRun = TextShaper.Current.ShapeText(run.Text, run.Properties.Typeface,
run.Properties.FontRenderingEmSize, run.Properties.CultureInfo);
var shapedCharacters = new ShapedTextCharacters(glyphRun, run.Properties);
textRuns.Add(shapedCharacters);
}
break;
}
case TextEndOfLine textEndOfLine:
nextLineBreak = new TextLineBreak(textEndOfLine);
break;
}
if (TryGetLineBreak(textRun, out var runLineBreak))
{
var splitResult = SplitTextRuns(textRuns, currentLength + runLineBreak.PositionWrap);
nextLineBreak = new TextLineBreak(splitResult.Second);
return(splitResult.First);
}
currentLength += textRun.Text.Length;
}
return(textRuns);
}
/// <summary>
/// Performs text wrapping returns a list of text lines.
/// </summary>
/// <param name="textRuns"></param>
/// <param name="textRange">The text range that is covered by the text runs.</param>
/// <param name="paragraphWidth">The paragraph width.</param>
/// <param name="paragraphProperties">The text paragraph properties.</param>
/// <param name="flowDirection"></param>
/// <param name="currentLineBreak">The current line break if the line was explicitly broken.</param>
/// <returns>The wrapped text line.</returns>
private static TextLineImpl PerformTextWrapping(List <ShapedTextCharacters> textRuns, TextRange textRange,
double paragraphWidth, TextParagraphProperties paragraphProperties, FlowDirection flowDirection,
TextLineBreak?currentLineBreak)
{
var measuredLength = MeasureLength(textRuns, textRange, paragraphWidth);
var currentLength = 0;
var lastWrapPosition = 0;
var currentPosition = 0;
for (var index = 0; index < textRuns.Count; index++)
{
var currentRun = textRuns[index];
var lineBreaker = new LineBreakEnumerator(currentRun.Text);
var breakFound = false;
while (lineBreaker.MoveNext())
{
if (lineBreaker.Current.Required &&
currentLength + lineBreaker.Current.PositionMeasure <= measuredLength)
{
//Explicit break found
breakFound = true;
currentPosition = currentLength + lineBreaker.Current.PositionWrap;
break;
}
if (currentLength + lineBreaker.Current.PositionMeasure > measuredLength)
{
if (paragraphProperties.TextWrapping == TextWrapping.WrapWithOverflow)
{
if (lastWrapPosition > 0)
{
currentPosition = lastWrapPosition;
breakFound = true;
break;
}
//Find next possible wrap position (overflow)
if (index < textRuns.Count - 1)
{
if (lineBreaker.Current.PositionWrap != currentRun.Text.Length)
{
//We already found the next possible wrap position.
breakFound = true;
currentPosition = currentLength + lineBreaker.Current.PositionWrap;
break;
}
while (lineBreaker.MoveNext() && index < textRuns.Count)
{
currentPosition += lineBreaker.Current.PositionWrap;
if (lineBreaker.Current.PositionWrap != currentRun.Text.Length)
{
break;
}
index++;
if (index >= textRuns.Count)
{
break;
}
currentRun = textRuns[index];
lineBreaker = new LineBreakEnumerator(currentRun.Text);
}
}
else
{
currentPosition = currentLength + lineBreaker.Current.PositionWrap;
}
breakFound = true;
break;
}
//We overflowed so we use the last available wrap position.
currentPosition = lastWrapPosition == 0 ? measuredLength : lastWrapPosition;
breakFound = true;
break;
}
if (lineBreaker.Current.PositionMeasure != lineBreaker.Current.PositionWrap)
{
lastWrapPosition = currentLength + lineBreaker.Current.PositionWrap;
}
}
if (!breakFound)
{
currentLength += currentRun.Text.Length;
continue;
}
measuredLength = currentPosition;
break;
}
var splitResult = SplitShapedRuns(textRuns, measuredLength);
textRange = new TextRange(textRange.Start, measuredLength);
var remainingCharacters = splitResult.Second;
var lineBreak = remainingCharacters?.Count > 0 ?
new TextLineBreak(currentLineBreak?.TextEndOfLine, flowDirection, remainingCharacters) :
null;
if (lineBreak is null && currentLineBreak?.TextEndOfLine != null)
{
lineBreak = new TextLineBreak(currentLineBreak.TextEndOfLine, flowDirection);
}
TextLineImpl.SortRuns(splitResult.First);
var textLine = new TextLineImpl(splitResult.First, textRange, paragraphWidth, paragraphProperties, flowDirection,
lineBreak);
return(textLine.FinalizeLine());
}
/// <inheritdoc cref="TextFormatter.FormatLine"/>
public override TextLine FormatLine(ITextSource textSource, int firstTextSourceIndex, double paragraphWidth,
TextParagraphProperties paragraphProperties, TextLineBreak previousLineBreak = null)
{
var textWrapping = paragraphProperties.TextWrapping;
var textRuns = FetchTextRuns(textSource, firstTextSourceIndex, previousLineBreak,
out var nextLineBreak);
var textRange = GetTextRange(textRuns);
TextLine textLine;
switch (textWrapping)
{
case TextWrapping.NoWrap:
{
textLine = new TextLineImpl(textRuns, textRange, paragraphWidth, paragraphProperties,
nextLineBreak);
break;
}
case TextWrapping.WrapWithOverflow:
case TextWrapping.Wrap:
{
textLine = PerformTextWrapping(textRuns, textRange, paragraphWidth, paragraphProperties,
nextLineBreak);
break;
}
default:
throw new ArgumentOutOfRangeException();
}
return(textLine);
}
/// <summary>
/// Performs text wrapping returns a list of text lines.
/// </summary>
/// <param name="textRuns">The text run's.</param>
/// <param name="textRange">The text range that is covered by the text runs.</param>
/// <param name="paragraphWidth">The paragraph width.</param>
/// <param name="paragraphProperties">The text paragraph properties.</param>
/// <param name="currentLineBreak">The current line break if the line was explicitly broken.</param>
/// <returns>The wrapped text line.</returns>
private static TextLine PerformTextWrapping(List <ShapedTextCharacters> textRuns, TextRange textRange,
double paragraphWidth, TextParagraphProperties paragraphProperties, TextLineBreak currentLineBreak)
{
var availableWidth = paragraphWidth;
var currentWidth = 0.0;
var measuredLength = 0;
foreach (var currentRun in textRuns)
{
if (currentWidth + currentRun.Size.Width > availableWidth)
{
if (TryMeasureCharacters(currentRun, paragraphWidth - currentWidth, out var count))
{
measuredLength += count;
}
break;
}
currentWidth += currentRun.Size.Width;
measuredLength += currentRun.Text.Length;
}
var currentLength = 0;
var lastWrapPosition = 0;
var currentPosition = 0;
if (measuredLength == 0 && paragraphProperties.TextWrapping != TextWrapping.WrapWithOverflow)
{
measuredLength = 1;
}
else
{
for (var index = 0; index < textRuns.Count; index++)
{
var currentRun = textRuns[index];
var lineBreaker = new LineBreakEnumerator(currentRun.Text);
var breakFound = false;
while (lineBreaker.MoveNext())
{
if (lineBreaker.Current.Required &&
currentLength + lineBreaker.Current.PositionMeasure <= measuredLength)
{
breakFound = true;
currentPosition = currentLength + lineBreaker.Current.PositionWrap;
break;
}
if ((paragraphProperties.TextWrapping != TextWrapping.WrapWithOverflow || lastWrapPosition != 0) &&
currentLength + lineBreaker.Current.PositionMeasure > measuredLength)
{
if (lastWrapPosition > 0)
{
currentPosition = lastWrapPosition;
}
else
{
currentPosition = currentLength + measuredLength;
}
breakFound = true;
break;
}
if (currentLength + lineBreaker.Current.PositionWrap >= measuredLength)
{
currentPosition = currentLength + lineBreaker.Current.PositionWrap;
if (index < textRuns.Count - 1 &&
lineBreaker.Current.PositionWrap == currentRun.Text.Length)
{
var nextRun = textRuns[index + 1];
lineBreaker = new LineBreakEnumerator(nextRun.Text);
if (lineBreaker.MoveNext() &&
lineBreaker.Current.PositionMeasure == 0)
{
currentPosition += lineBreaker.Current.PositionWrap;
}
}
breakFound = true;
break;
}
lastWrapPosition = currentLength + lineBreaker.Current.PositionWrap;
}
if (!breakFound)
{
currentLength += currentRun.Text.Length;
continue;
}
measuredLength = currentPosition;
break;
}
}
var splitResult = SplitTextRuns(textRuns, measuredLength);
textRange = new TextRange(textRange.Start, measuredLength);
var remainingCharacters = splitResult.Second;
if (currentLineBreak?.RemainingCharacters != null)
{
if (remainingCharacters != null)
{
remainingCharacters.AddRange(currentLineBreak.RemainingCharacters);
}
else
{
remainingCharacters = new List <ShapedTextCharacters>(currentLineBreak.RemainingCharacters);
}
}
var lineBreak = remainingCharacters != null && remainingCharacters.Count > 0 ?
new TextLineBreak(remainingCharacters) :
null;
return(new TextLineImpl(splitResult.First, textRange, paragraphWidth, paragraphProperties,
lineBreak));
}
/// <summary>
/// Performs text wrapping returns a list of text lines.
/// </summary>
/// <param name="textRuns">The text run's.</param>
/// <param name="textRange">The text range that is covered by the text runs.</param>
/// <param name="paragraphWidth">The paragraph width.</param>
/// <param name="paragraphProperties">The text paragraph properties.</param>
/// <param name="currentLineBreak">The current line break if the line was explicitly broken.</param>
/// <returns>The wrapped text line.</returns>
private static TextLine PerformTextWrapping(List <ShapedTextCharacters> textRuns, TextRange textRange,
double paragraphWidth, TextParagraphProperties paragraphProperties, TextLineBreak currentLineBreak)
{
var availableWidth = paragraphWidth;
var currentWidth = 0.0;
var runIndex = 0;
var currentLength = 0;
while (runIndex < textRuns.Count)
{
var currentRun = textRuns[runIndex];
if (currentWidth + currentRun.GlyphRun.Bounds.Width > availableWidth)
{
var measuredLength = MeasureCharacters(currentRun, paragraphWidth - currentWidth);
var breakFound = false;
var currentBreakPosition = 0;
if (measuredLength < currentRun.Text.Length)
{
var lineBreaker = new LineBreakEnumerator(currentRun.Text);
while (currentBreakPosition < measuredLength && lineBreaker.MoveNext())
{
var nextBreakPosition = lineBreaker.Current.PositionWrap;
if (nextBreakPosition == 0 || nextBreakPosition > measuredLength)
{
break;
}
breakFound = lineBreaker.Current.Required ||
lineBreaker.Current.PositionWrap != currentRun.Text.Length;
currentBreakPosition = nextBreakPosition;
}
}
if (breakFound)
{
measuredLength = currentBreakPosition;
}
else
{
if (paragraphProperties.TextWrapping == TextWrapping.WrapWithOverflow)
{
var lineBreaker = new LineBreakEnumerator(currentRun.Text.Skip(currentBreakPosition));
if (lineBreaker.MoveNext())
{
measuredLength = currentBreakPosition + lineBreaker.Current.PositionWrap;
}
}
}
currentLength += measuredLength;
var splitResult = SplitTextRuns(textRuns, currentLength);
var textLineMetrics = TextLineMetrics.Create(splitResult.First,
new TextRange(textRange.Start, currentLength), paragraphWidth, paragraphProperties);
var remainingCharacters = splitResult.Second;
if (currentLineBreak?.RemainingCharacters != null)
{
if (remainingCharacters != null)
{
remainingCharacters.AddRange(currentLineBreak.RemainingCharacters);
}
else
{
remainingCharacters = new List <ShapedTextCharacters>(currentLineBreak.RemainingCharacters);
}
}
var lineBreak = remainingCharacters != null && remainingCharacters.Count > 0 ?
new TextLineBreak(remainingCharacters) :
null;
return(new TextLineImpl(splitResult.First, textLineMetrics, lineBreak));
}
currentWidth += currentRun.GlyphRun.Bounds.Width;
currentLength += currentRun.GlyphRun.Characters.Length;
runIndex++;
}
return(new TextLineImpl(textRuns,
TextLineMetrics.Create(textRuns, textRange, paragraphWidth, paragraphProperties),
currentLineBreak?.RemainingCharacters != null ?
new TextLineBreak(currentLineBreak.RemainingCharacters) :
null));
}
/// <summary>
/// Formats a text line.
/// </summary>
/// <param name="textSource">The text source.</param>
/// <param name="firstTextSourceIndex">The first character index to start the text line from.</param>
/// <param name="paragraphWidth">A <see cref="double"/> value that specifies the width of the paragraph that the line fills.</param>
/// <param name="paragraphProperties">A <see cref="TextParagraphProperties"/> value that represents paragraph properties,
/// such as TextWrapping, TextAlignment, or TextStyle.</param>
/// <param name="previousLineBreak">A <see cref="TextLineBreak"/> value that specifies the text formatter state,
/// in terms of where the previous line in the paragraph was broken by the text formatting process.</param>
/// <returns>The formatted line.</returns>
public abstract TextLine FormatLine(ITextSource textSource, int firstTextSourceIndex, double paragraphWidth,
TextParagraphProperties paragraphProperties, TextLineBreak previousLineBreak = null);
