/// <summary>
/// Constructs a <code>LineBreakMeasurer</code> for the specified text.
/// </summary>
/// <param name="text"> the text for which this <code>LineBreakMeasurer</code>
/// produces <code>TextLayout</code> objects; the text must contain
/// at least one character; if the text available through
/// <code>iter</code> changes, further calls to this
/// <code>LineBreakMeasurer</code> instance are undefined (except,
/// in some cases, when <code>insertChar</code> or
/// <code>deleteChar</code> are invoked afterward - see below) </param>
/// <param name="breakIter"> the <seealso cref="BreakIterator"/> which defines line
/// breaks </param>
/// <param name="frc"> contains information about a graphics device which is
/// needed to measure the text correctly;
/// text measurements can vary slightly depending on the
/// device resolution, and attributes such as antialiasing; this
/// parameter does not specify a translation between the
/// <code>LineBreakMeasurer</code> and user space </param>
/// <exception cref="IllegalArgumentException"> if the text has less than one character </exception>
/// <seealso cref= LineBreakMeasurer#insertChar </seealso>
/// <seealso cref= LineBreakMeasurer#deleteChar </seealso>
public LineBreakMeasurer(AttributedCharacterIterator text, BreakIterator breakIter, FontRenderContext frc)
{
if (text.EndIndex - text.BeginIndex < 1)
{
throw new IllegalArgumentException("Text must contain at least one character.");
}
this.BreakIter = breakIter;
this.Measurer = new TextMeasurer(text, frc);
this.Limit = text.EndIndex;
this.Pos = this.Start = text.BeginIndex;
CharIter = new CharArrayIterator(Measurer.Chars, this.Start);
this.BreakIter.SetText(CharIter);
}
private void MakeLayoutWindow(int localStart)
{
int compStart = localStart;
int compLimit = FChars.Length;
// If we've already gone past the layout window, format to end of paragraph
if (LayoutCount > 0 && !HaveLayoutWindow)
{
float avgLineLength = System.Math.Max(LayoutCharCount / LayoutCount, 1);
compLimit = System.Math.Min(localStart + (int)(avgLineLength * EST_LINES), FChars.Length);
}
if (localStart > 0 || compLimit < FChars.Length)
{
if (CharIter == null)
{
CharIter = new CharArrayIterator(FChars);
}
else
{
CharIter.Reset(FChars);
}
if (FLineBreak == null)
{
FLineBreak = BreakIterator.LineInstance;
}
FLineBreak.SetText(CharIter);
if (localStart > 0)
{
if (!FLineBreak.IsBoundary(localStart))
{
compStart = FLineBreak.Preceding(localStart);
}
}
if (compLimit < FChars.Length)
{
if (!FLineBreak.IsBoundary(compLimit))
{
compLimit = FLineBreak.Following(compLimit);
}
}
}
EnsureComponents(compStart, compLimit);
HaveLayoutWindow = true;
}
