static Rect GetCharacterBounds(this TextView textView, TextViewPosition pos, HwndSource source)
{
VisualLine vl = textView.GetVisualLine(pos.Line);
if (vl == null)
{
return(EMPTY_RECT);
}
// this may happen during layout changes in AvalonDock, so we just return an empty rectangle
// in those cases. It should be refreshed immediately.
if (source.RootVisual == null || !source.RootVisual.IsAncestorOf(textView))
{
return(EMPTY_RECT);
}
TextLine line = vl.GetTextLine(pos.VisualColumn);
Rect displayRect;
// calculate the display rect for the current character
if (pos.VisualColumn < vl.VisualLengthWithEndOfLineMarker)
{
displayRect = line.GetTextBounds(pos.VisualColumn, 1).First().Rectangle;
displayRect.Offset(0, vl.GetTextLineVisualYPosition(line, VisualYPosition.LineTop));
}
else
{
// if we are in virtual space, we just use one wide-space as character width
displayRect = new Rect(vl.GetVisualPosition(pos.VisualColumn, VisualYPosition.TextTop),
new Size(textView.WideSpaceWidth, textView.DefaultLineHeight));
}
// adjust to current scrolling
displayRect.Offset(-textView.ScrollOffset);
return(textView
.TransformToAncestor(source.RootVisual).TransformBounds(displayRect) // rect on root visual
.TransformToDevice(source.RootVisual)); // rect on HWND
}