public void Draw(TextView textView, DrawingContext drawingContext)
{
var typeface = textView.GetValue(TextBlock.FontFamilyProperty);
var emSize = textView.GetValue(TextBlock.FontSizeProperty);
var formattedText = TextFormatterFactory.CreateFormattedText(
textView,
"9",
typeface,
emSize,
Brushes.Black
);
var charSize = formattedText.Measure();
var pixelSize = PixelSnapHelpers.GetPixelSize(textView);
foreach (var entry in markers.Where(e => e.Length > 0))
{
if (entry.StartOffset <= textView.Document.TextLength)
{
var startLine = textView.Document.GetLineByOffset(entry.StartOffset);
var start = entry.StartOffset;
var startChar = textView.Document.GetCharAt(startLine.Offset);
if (char.IsWhiteSpace(startChar))
{
start = TextUtilities.GetNextCaretPosition(textView.Document, startLine.Offset, LogicalDirection.Forward,
CaretPositioningMode.WordBorder);
}
var endLine = textView.Document.GetLineByOffset(entry.EndOffset <= textView.Document.TextLength ? entry.EndOffset : textView.Document.TextLength);
if (endLine.EndOffset > start && startLine != endLine)
{
var newEntry = new TextSegment()
{
StartOffset = start, EndOffset = endLine.EndOffset
};
var rects = BackgroundGeometryBuilder.GetRectsForSegment(textView, newEntry);
var rect = GetRectForRange(rects);
if (!rect.IsEmpty)
{
var startColumn = textView.Document.GetLocation(newEntry.StartOffset).Column - 1;
var endColumn = textView.Document.GetLocation(newEntry.EndOffset).Column - 2;
var xPos = charSize.Width * Math.Min(startColumn, endColumn);
rect = rect.WithX(xPos + (charSize.Width / 2));
rect = rect.WithX(PixelSnapHelpers.PixelAlign(rect.X, pixelSize.Width));
rect = rect.WithY(PixelSnapHelpers.PixelAlign(rect.Y, pixelSize.Height));
drawingContext.DrawLine(_pen, rect.TopLeft, rect.BottomLeft);
}
}
}
}
}