/// <summary>
/// Measures the number of characters that fits into available width.
/// </summary>
/// <param name="textRun">The text run.</param>
/// <param name="availableWidth">The available width.</param>
/// <returns></returns>
private int MeasureText(ShapedTextRun textRun, double availableWidth)
{
if (textRun.GlyphRun.Bounds.Width < availableWidth)
{
return(textRun.Text.Length);
}
var measuredWidth = 0.0;
var index = 0;
for (; index < textRun.GlyphRun.GlyphAdvances.Length; index++)
{
var advance = textRun.GlyphRun.GlyphAdvances[index];
if (measuredWidth + advance > availableWidth)
{
break;
}
measuredWidth += advance;
}
var cluster = textRun.GlyphRun.GlyphClusters[index];
var characterHit = textRun.GlyphRun.FindNearestCharacterHit(cluster, out _);
return(characterHit.FirstCharacterIndex - textRun.GlyphRun.Characters.Start +
(textRun.GlyphRun.IsLeftToRight ? characterHit.TrailingLength : 0));
}
/// <summary>
/// Measures the number of characters that fits into available width.
/// </summary>
/// <param name="textRun">The text run.</param>
/// <param name="availableWidth">The available width.</param>
/// <returns></returns>
private static int MeasureText(ShapedTextRun textRun, double availableWidth)
{
var glyphRun = textRun.GlyphRun;
var characterHit = glyphRun.GetCharacterHitFromDistance(availableWidth, out _);
return(characterHit.FirstCharacterIndex + characterHit.TrailingLength - textRun.Text.Start);
}
/// <summary>
/// Formats text runs with optional text style overrides.
/// </summary>
/// <param name="textSource">The text source.</param>
/// <param name="firstTextSourceIndex">The first text source index.</param>
/// <param name="textPointer">The text pointer that covers the formatted text runs.</param>
/// <returns>
/// The formatted text runs.
/// </returns>
private List <ShapedTextRun> FormatTextRuns(ITextSource textSource, int firstTextSourceIndex, out TextPointer textPointer)
{
var start = -1;
var length = 0;
var textRuns = new List <ShapedTextRun>();
while (true)
{
var textRun = textSource.GetTextRun(firstTextSourceIndex + length);
if (start == -1)
{
start = textRun.Text.Start;
}
if (textRun is TextEndOfLine)
{
break;
}
switch (textRun)
{
case TextCharacters textCharacters:
var runText = textCharacters.Text;
while (!runText.IsEmpty)
{
var shapableTextStyleRun = CreateShapableTextStyleRun(runText, textRun.Style);
var shapedRun = new ShapedTextRun(runText.Take(shapableTextStyleRun.TextPointer.Length),
shapableTextStyleRun.Style);
textRuns.Add(shapedRun);
runText = runText.Skip(shapedRun.Text.Length);
}
break;
default:
throw new NotSupportedException("Run type not supported by the formatter.");
}
length += textRun.Text.Length;
}
textPointer = new TextPointer(start, length);
return(textRuns);
}
/// <summary>
/// Splits the <see cref="TextRun"/> at specified length.
/// </summary>
/// <param name="length">The length.</param>
/// <returns>The split result.</returns>
public SplitTextCharactersResult Split(int length)
{
var glyphCount = 0;
var firstCharacters = GlyphRun.Characters.Take(length);
var codepointEnumerator = new CodepointEnumerator(firstCharacters);
while (codepointEnumerator.MoveNext())
{
glyphCount++;
}
if (GlyphRun.Characters.Length == length)
{
return(new SplitTextCharactersResult(this, null));
}
if (GlyphRun.GlyphIndices.Length == glyphCount)
{
return(new SplitTextCharactersResult(this, null));
}
var firstGlyphRun = new GlyphRun(
Style.TextFormat.Typeface.GlyphTypeface,
Style.TextFormat.FontRenderingEmSize,
GlyphRun.GlyphIndices.Take(glyphCount),
GlyphRun.GlyphAdvances.Take(glyphCount),
GlyphRun.GlyphOffsets.Take(glyphCount),
GlyphRun.Characters.Take(length),
GlyphRun.GlyphClusters.Take(length));
var firstTextRun = new ShapedTextRun(firstGlyphRun, Style);
var secondGlyphRun = new GlyphRun(
Style.TextFormat.Typeface.GlyphTypeface,
Style.TextFormat.FontRenderingEmSize,
GlyphRun.GlyphIndices.Skip(glyphCount),
GlyphRun.GlyphAdvances.Skip(glyphCount),
GlyphRun.GlyphOffsets.Skip(glyphCount),
GlyphRun.Characters.Skip(length),
GlyphRun.GlyphClusters.Skip(length));
var secondTextRun = new ShapedTextRun(secondGlyphRun, Style);
return(new SplitTextCharactersResult(firstTextRun, secondTextRun));
}
/// <summary>
/// Formats text runs with optional text style overrides.
/// </summary>
/// <param name="textSource">The text source.</param>
/// <param name="firstTextSourceIndex">The first text source index.</param>
/// <param name="textPointer">The text pointer that covers the formatted text runs.</param>
/// <returns>
/// The formatted text runs.
/// </returns>
private List <ShapedTextRun> FormatTextRuns(ITextSource textSource, int firstTextSourceIndex, out TextPointer textPointer)
{
var start = firstTextSourceIndex;
var textRuns = new List <ShapedTextRun>();
while (true)
{
var textRun = textSource.GetTextRun(firstTextSourceIndex);
if (textRun.Text.IsEmpty)
{
break;
}
if (textRun is TextEndOfLine)
{
break;
}
if (!(textRun is TextCharacters))
{
throw new NotSupportedException("Run type not supported by the formatter.");
}
var runText = textRun.Text;
while (!runText.IsEmpty)
{
var shapableTextStyleRun = CreateShapableTextStyleRun(runText, textRun.Style);
var shapedRun = new ShapedTextRun(runText.Take(shapableTextStyleRun.TextPointer.Length),
shapableTextStyleRun.Style);
textRuns.Add(shapedRun);
runText = runText.Skip(shapedRun.Text.Length);
}
firstTextSourceIndex += textRun.Text.Length;
}
textPointer = new TextPointer(start, firstTextSourceIndex - start);
return(textRuns);
}
/// <summary>
/// Split a sequence of runs into two segments at specified length.
/// </summary>
/// <param name="textRuns">The text run's.</param>
/// <param name="length">The length to split at.</param>
/// <returns></returns>
private static SplitTextRunsResult SplitTextRuns(IReadOnlyList <ShapedTextRun> textRuns, int length)
{
var currentLength = 0;
for (var i = 0; i < textRuns.Count; i++)
{
var currentRun = textRuns[i];
if (currentLength + currentRun.GlyphRun.Characters.Length < length)
{
currentLength += currentRun.GlyphRun.Characters.Length;
continue;
}
var firstCount = currentRun.GlyphRun.Characters.Length >= 1 ? i + 1 : i;
var first = new ShapedTextRun[firstCount];
if (firstCount > 1)
{
for (var j = 0; j < i; j++)
{
first[j] = textRuns[j];
}
}
var secondCount = textRuns.Count - firstCount;
if (currentLength + currentRun.GlyphRun.Characters.Length == length)
{
var second = new ShapedTextRun[secondCount];
var offset = currentRun.GlyphRun.Characters.Length > 1 ? 1 : 0;
if (secondCount > 0)
{
for (var j = 0; j < secondCount; j++)
{
second[j] = textRuns[i + j + offset];
}
}
first[i] = currentRun;
return(new SplitTextRunsResult(first, second));
}
else
{
secondCount++;
var second = new ShapedTextRun[secondCount];
if (secondCount > 0)
{
for (var j = 1; j < secondCount; j++)
{
second[j] = textRuns[i + j];
}
}
var split = currentRun.Split(length - currentLength);
first[i] = split.First;
second[0] = split.Second;
return(new SplitTextRunsResult(first, second));
}
}
return(new SplitTextRunsResult(textRuns, null));
}
public SplitTextCharactersResult(ShapedTextRun first, ShapedTextRun second)
{
First = first;
Second = second;
}
