// this function gets the bounding rectangle for a range that does not wrap lines.
private static Rect CalculateOneLineRangeRectangle(ITextRange lineRange, Rect clientRect)
{
int start = lineRange.Start;
int end = lineRange.End;
if (start < end)
{
// make a working copy of the range. shrink it by one character since
// ITextRange.GetPoint returns the coordinates of the character *after* the end of the
// range rather than the one immediately *before* the end of the range.
ITextRange range = lineRange.GetDuplicate();
range.MoveEnd(TomUnit.tomCharacter, -1);
end--;
// The ITextRange::SetRange method sets this range’s Start = min(cp1, cp2) and End = max(cp1, cp2).
// If the range is a nondegenerate selection, cp2 is the active end; if it’s a degenerate selection,
// the ambiguous cp is displayed at the start of the line (rather than at the end of the previous line).
// Set the end to the start and the start to the end to create an ambiguous cp. This was added to
// resolve Windows OS Bug 1030882.
range.SetRange(range.End, range.Start);
Rect rect = new Rect(clientRect.Location, clientRect.Size);
bool trimmed = TrimRectangleByRangeCorners(range, ref rect);
if (!trimmed)
{
while (!trimmed && start < end)
{
// shrink the range
range.MoveStart(TomUnit.tomCharacter, 1);
// If the character just moved over was a '\r' the start will be out of sink with range.Start
start++;
if (start < end)
{
range.MoveEnd(TomUnit.tomCharacter, -1);
// If the character just moved over was a '\r' the end will be out of sink with range.End
end--;
}
//Debug.Assert(start == range.Start);
//Debug.Assert(end == range.End);
trimmed = TrimRectangleByRangeCorners(range, ref rect);
}
if (trimmed)
{
rect.X = clientRect.X;
rect.Width = clientRect.Width;
}
}
if (!trimmed)
{
rect = Rect.Empty;
}
return rect;
}
else
{
// degenerate range. return empty rectangle.
// it might be nice to return a zero-width rectangle with the appropriate height and location.
// however, when the degenerate range is at a line wrapping point then it is ambiguous as to
// whether the rectangle should be at the end of one line or the beginning of the next. clients
// can always extend a degenerate range by one character in either direction before getting a bounding
// rectangle if they want.
return Rect.Empty;
}
}
private static ITextRange LastUnit(ITextRange range)
{
// get a degenerate subrange positioned at the end of the range
ITextRange subrange = range.GetDuplicate();
subrange.Collapse(TomStartEnd.tomEnd);
return subrange;
}