//------------------------------------------------------
//
// Internal Methods
//
//------------------------------------------------------
#region Internal Methods
// returns the range that is visible in the RichEdit window
internal ITextRange GetVisibleRange()
{
// get a range from the center point of the client rectangle
Rect rect = BoundingRectangle;
int x = ((int)rect.Left + (int)rect.Right) / 2;
int y = ((int)rect.Top + (int)rect.Bottom) / 2;
ITextRange range = _document.RangeFromPoint(x, y);
// expand it to fill the window.
range.Expand(TomUnit.tomWindow);
// There is a bug with RichEdit 3.0. The expand to tomWindow may gets 0 as the range's cpBegin (Start).
// So need to trim off what is outside of the window.
int start = range.Start;
// 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.
range.SetRange(range.End, range.Start);
bool gotPoint = WindowsRichEditRange.RangeGetPoint(range, TomGetPoint.tomStart, out x, out y);
while (!gotPoint || !Misc.PtInRect(ref rect, x, y))
{
range.MoveStart(TomUnit.tomWord, 1);
gotPoint = WindowsRichEditRange.RangeGetPoint(range, TomGetPoint.tomStart, out x, out y);
}
if (start != range.Start)
{
// The trimming was done based on the left edge of the range. The last visiable partial
// character/word has been also added back into the range, need to remove it. Do the comparing
// against the characters right edge and the window rectangle.
ITextRange rangeAdjust = _document.Range(0, range.Start - 1);
gotPoint = WindowsRichEditRange.RangeGetPoint(rangeAdjust, TomGetPoint.TA_BOTTOM | TomGetPoint.TA_RIGHT, out x, out y);
while (gotPoint && Misc.PtInRect(ref rect, x, y) && rangeAdjust.Start != rangeAdjust.End)
{
rangeAdjust.MoveEnd(TomUnit.tomCharacter, -1);
range.MoveStart(TomUnit.tomCharacter, -1);
gotPoint = WindowsRichEditRange.RangeGetPoint(rangeAdjust, TomGetPoint.TA_BOTTOM | TomGetPoint.TA_RIGHT, out x, out y);
}
}
// There is a bug with RichEdit 3.0. The expand to tomWindow gets the last cp of the bottom
// line in the window as the range's cpLim (End). The cpLim may be passed the right side of
// the window.
// So need to trim off what is on the right side of the window.
int end = range.End;
gotPoint = WindowsRichEditRange.RangeGetPoint(range, TomGetPoint.TA_RIGHT, out x, out y);
while (!gotPoint || !Misc.PtInRect(ref rect, x, y))
{
range.MoveEnd(TomUnit.tomWord, -1);
gotPoint = WindowsRichEditRange.RangeGetPoint(range, TomGetPoint.TA_RIGHT, out x, out y);
}
if (end != range.End)
{
// The trimming was done based on the right edge of the range. The last visiable partial
// character/word has been also trimmed so add it back to the range. Do the comparing
// against the characters left edge and the window rectangle.
ITextRange rangeAdjust = _document.Range(range.End, end);
do
{
if (range.MoveEnd(TomUnit.tomCharacter, 1) == 0)
{
break;
}
rangeAdjust.MoveStart(TomUnit.tomCharacter, 1);
gotPoint = WindowsRichEditRange.RangeGetPoint(rangeAdjust, TomGetPoint.tomStart, out x, out y);
} while (gotPoint && Misc.PtInRect(ref rect, x, y));
}
return(range);
}
