/// <summary>
/// Add something to the line. Return true if we should keep trying to add more. (That is, all of the current thing fit,
/// and there is still room left; this routine is not responsible to determine whether there IS anything else to add.)
/// If there is not yet anything in the line, this routine MUST add something; otherwise, it is allowed to fail,
/// returning false without changing anything.
/// </summary>
private bool AddSomethingToLine()
{
m_currentRenderRun = m_renderRuns[m_renderRunIndex];
Box boxToAdd = m_currentRenderRun.Box;
if (boxToAdd != null)
{
// The current run works out to a single box; add it if it fits. Add it anyway if the line
// is currently empty.
boxToAdd.Layout(m_layoutInfo);
if (m_currentLine.FirstBox != null && boxToAdd.Width > m_spaceLeftOnCurrentLine)
{
return(false);
}
m_spaceLeftOnCurrentLine -= boxToAdd.Width;
AddBoxToLine(boxToAdd, LgEndSegmentType.kestOkayBreak); // always OK to break after non-string.
boxToAdd.Container = m_para;
m_ichRendered = m_currentRenderRun.RenderLim;
m_renderRunIndex++;
}
else
{
// current run is not a simple box. Make a text box out of part or all of it, or possibly also subsequent
// runs that are not boxes and use the same renderer.
IRenderEngine renderer = m_layoutInfo.GetRenderer(m_currentRenderRun.Ws);
// If our text source doesn't yet know about the writing system factory, make sure it does.
if (m_para.Source.GetWsFactory() == null)
{
m_para.Source.SetWsFactory(renderer.WritingSystemFactory);
}
int ichRunLim = GetLimitOfRunWithSameRenderer(renderer, m_renderRunIndex);
ILgSegment seg;
int dichLim, dxWidth;
LgEndSegmentType est;
bool mustGetSomeSeg = m_currentLine.FirstBox == null;
var twsh = GetNextTwsh();
renderer.FindBreakPoint(m_layoutInfo.VwGraphics, m_para.Source, null, m_ichRendered,
ichRunLim, ichRunLim, false, mustGetSomeSeg, m_spaceLeftOnCurrentLine, (mustGetSomeSeg ? LgLineBreak.klbClipBreak : LgLineBreak.klbWordBreak),
m_currentLine.FirstBox == null ? LgLineBreak.klbClipBreak : LgLineBreak.klbWordBreak, twsh,
false, out seg, out dichLim, out dxWidth, out est, null);
if (est == LgEndSegmentType.kestNothingFit && twsh != LgTrailingWsHandling.ktwshAll)
{
// Nothing of the one we were trying for, try for the other.
twsh = GetNextTwsh();
renderer.FindBreakPoint(m_layoutInfo.VwGraphics, m_para.Source, null, m_ichRendered,
ichRunLim, ichRunLim, false, mustGetSomeSeg, m_spaceLeftOnCurrentLine, (mustGetSomeSeg ? LgLineBreak.klbClipBreak : LgLineBreak.klbWordBreak),
m_currentLine.FirstBox == null ? LgLineBreak.klbClipBreak : LgLineBreak.klbWordBreak, twsh,
false, out seg, out dichLim, out dxWidth, out est, null);
}
switch (est)
{
case LgEndSegmentType.kestNoMore:
case LgEndSegmentType.kestOkayBreak:
case LgEndSegmentType.kestMoreLines:
case LgEndSegmentType.kestWsBreak:
case LgEndSegmentType.kestMoreWhtsp:
boxToAdd = new StringBox(m_para.Style, seg, m_ichRendered);
boxToAdd.Layout(m_layoutInfo);
m_spaceLeftOnCurrentLine -= boxToAdd.Width;
m_ichRendered += dichLim;
boxToAdd.Container = m_para;
// If we get NoMore, we should also check, because it might really be a ws break at the end
// of the run.
if (est == LgEndSegmentType.kestNoMore && ichRunLim < m_para.Source.Length && ichRunLim > 0 &&
WsInSource(ichRunLim - 1, m_para.Source) != WsInSource(ichRunLim, m_para.Source))
{
// The renderer failed to detect it because not told to look further in the source,
// but there is in fact a writing system break.
// However, if the next character is a box, we want to treat it as a definitely good break.
if (m_para.Source.IsThereABoxAt(ichRunLim))
{
est = LgEndSegmentType.kestOkayBreak;
}
else
{
est = LgEndSegmentType.kestWsBreak;
}
}
AddBoxToLine(boxToAdd, est);
m_renderRunIndex = AdvanceRenderRunIndexToIch(m_ichRendered, m_renderRunIndex);
// We want to return true if more could be put on this line.
// Of the cases that take this branch, NoMore means no more input at all, so we can't add any more;
// MoreLines means this line is full. So for both of those we return false. OkayBreak allows us to try
// to put more segments on this line, as does ws break, and moreWhtsp.
return(est == LgEndSegmentType.kestOkayBreak || est == LgEndSegmentType.kestWsBreak || est == LgEndSegmentType.kestMoreWhtsp);
case LgEndSegmentType.kestNothingFit:
Debug.Assert(m_currentLine.FirstBox != null, "Making segment must not return kestNothingFit if line contains nothing");
return(false);
//case LgEndSegmentType.kestHardBreak:
// if()
// return true;
default:
Debug.Assert(false);
break;
}
}
return(true);
}
