public override VisualLineElement ConstructElement(int offset)
{
char c = CurrentContext.Document.GetCharAt(offset);
if (ShowSpaces && c == ' ')
{
return(new SpaceTextElement(CurrentContext.TextView.cachedElements.GetTextForNonPrintableCharacter("\u00B7", CurrentContext)));
}
else if (ShowTabs && c == '\t')
{
return(new TabTextElement(CurrentContext.TextView.cachedElements.GetTextForNonPrintableCharacter("\u00BB", CurrentContext)));
}
else if (ShowBoxForControlCharacters && char.IsControl(c))
{
var p = new VisualLineElementTextRunProperties(CurrentContext.GlobalTextRunProperties);
p.SetForegroundBrush(Brushes.White);
var textFormatter = TextFormatterFactory.Create(CurrentContext.TextView);
var text = FormattedTextElement.PrepareText(textFormatter,
TextUtilities.GetControlCharacterName(c), p);
return(new SpecialCharacterBoxElement(text));
}
else
{
return(null);
}
}
public TextLine GetTextForNonPrintableCharacter(string text, ITextRunConstructionContext context)
{
if (nonPrintableCharacterTexts == null)
{
nonPrintableCharacterTexts = new Dictionary <string, TextLine>();
}
TextLine textLine;
if (!nonPrintableCharacterTexts.TryGetValue(text, out textLine))
{
var p = new VisualLineElementTextRunProperties(context.GlobalTextRunProperties);
p.SetForegroundBrush(context.TextView.NonPrintableCharacterBrush);
if (formatter == null)
{
formatter = TextFormatterFactory.Create(context.TextView);
}
textLine = FormattedTextElement.PrepareText(formatter, text, p);
nonPrintableCharacterTexts[text] = textLine;
}
return(textLine);
}