//-------------------------------------------------------------------
//
// Protected Methods
//
//-------------------------------------------------------------------
#region Protected Methods
/// <summary>
/// Fetch the next run at text position.
/// </summary>
/// <param name="position">
/// Current position in text array
/// </param>
/// <returns></returns>
protected TextRun HandleText(StaticTextPointer position)
{
DependencyObject element;
StaticTextPointer endOfRunPosition;
Invariant.Assert(position.GetPointerContext(LogicalDirection.Forward) == TextPointerContext.Text, "TextPointer does not point to characters.");
if (position.Parent != null)
{
element = position.Parent;
}
else
{
element = _paraClient.Paragraph.Element;
}
// Extract the aggregated properties into something that the textrun can use.
//
TextProperties textProps = new TextProperties(element, position, false /* inline objects */, true /* get background */);
// Calculate the end of the run by finding either:
// a) the next intersection of highlight ranges, or
// b) the natural end of this textrun
endOfRunPosition = position.TextContainer.Highlights.GetNextPropertyChangePosition(position, LogicalDirection.Forward);
// Clamp the text run at an arbitrary limit, so we don't make
// an unbounded allocation.
if (position.GetOffsetToPosition(endOfRunPosition) > 4096)
{
endOfRunPosition = position.CreatePointer(4096);
}
// Get character buffer for the text run.
char[] textBuffer = new char[position.GetOffsetToPosition(endOfRunPosition)];
// Copy characters from text run into buffer. Note the actual number of characters copied,
// which may be different than the buffer's length. Buffer length only specifies the maximum
// number of characters
int charactersCopied = position.GetTextInRun(LogicalDirection.Forward, textBuffer, 0, textBuffer.Length);
// Create text run using the actual number of characters copied
return new TextCharacters(textBuffer, 0, charactersCopied, textProps);
}
//-------------------------------------------------------------------
//
// Private Methods
//
//-------------------------------------------------------------------
#region Private Methods
/// <summary>
/// Fetch the next run at text position.
/// </summary>
private TextRun HandleText(StaticTextPointer position)
{
// Calculate the end of the run by finding either:
// a) the next intersection of highlight ranges, or
// b) the natural end of this textrun
StaticTextPointer endOfRunPosition = _owner.Host.TextContainer.Highlights.GetNextPropertyChangePosition(position, LogicalDirection.Forward);
// Clamp the text run at an arbitrary limit, so we don't make
// an unbounded allocation.
if (position.GetOffsetToPosition(endOfRunPosition) > 4096)
{
endOfRunPosition = position.CreatePointer(4096);
}
// Factor in any speller error squiggles on the run.
TextDecorationCollection highlightDecorations = position.TextContainer.Highlights.GetHighlightValue(position, LogicalDirection.Forward, typeof(SpellerHighlightLayer)) as TextDecorationCollection;
TextRunProperties properties;
if (highlightDecorations == null)
{
properties = _lineProperties.DefaultTextRunProperties;
}
else
{
if (_spellerErrorProperties == null)
{
_spellerErrorProperties = new TextProperties((TextProperties)_lineProperties.DefaultTextRunProperties, highlightDecorations);
}
properties = _spellerErrorProperties;
}
// Get character buffer for the text run.
char[] textBuffer = new char[position.GetOffsetToPosition(endOfRunPosition)];
// Copy characters from text run into buffer. Since we are dealing with plain text content,
// we expect to get all the characters from position to endOfRunPosition.
int charactersCopied = position.GetTextInRun(LogicalDirection.Forward, textBuffer, 0, textBuffer.Length);
Invariant.Assert(charactersCopied == textBuffer.Length);
// Create text run, using characters copied as length
return new TextCharacters(textBuffer, 0, charactersCopied, properties);
}
