void TextImplementor.GetCharacterExtents(int offset, out int x, out int y, out int width, out int height, CoordType coords)
        {
            var point = editor.DocumentToVisualLocation(Document.OffsetToLocation(offset));

            x      = point.X + editor.TextViewMargin.XOffset;
            y      = point.Y;
            width  = editor.TextViewMargin.CharWidth;
            height = editor.LineHeight;
            switch (coords)
            {
            case Atk.CoordType.Screen:
                int ox, oy;
                editor.GdkWindow.GetOrigin(out ox, out oy);
                x += ox; y += oy;
                break;

            case Atk.CoordType.Window:
                // nothing
                break;
            }
        }