Finished float positioning iteration.

1 files changed, 63 insertions, 21 deletions

diff --git a/dw/textblock_linebreaking.cc b/dw/textblock_linebreaking.cc
index e38d5377..44f7c2dc 100644
--- a/dw/textblock_linebreaking.cc
+++ b/dw/textblock_linebreaking.cc
@@ -619,8 +619,7 @@ bool Textblock::wrapWordInFlow (int wordIndex, bool wrapAll)
 
       bool regardBorder =  mustBorderBeRegarded (lines->size ());
       bool thereWillBeMoreSpace = regardBorder ?
-         newLineHasFloatLeft || newLineHasFloatRight :
-         false;
+         newLineHasFloatLeft || newLineHasFloatRight : false;
 
       DBG_OBJ_MSGF ("construct.word", 1,
                     "thereWillBeMoreSpace = %s ? %s || %s : false = %s",
@@ -740,6 +739,7 @@ bool Textblock::wrapWordInFlow (int wordIndex, bool wrapAll)
             int startSearch = misc::max (firstIndex, lastFloatPos + 1);
             int newFloatPos = -1;
 
+            // Step 1: search for the next float.
             DBG_OBJ_MSGF ("construct.word", 2, "searching from %d to %d",
                           startSearch, breakPos);
             for (int i = startSearch; newFloatPos == -1 && i <= breakPos; i++) {
@@ -759,30 +759,72 @@ bool Textblock::wrapWordInFlow (int wordIndex, bool wrapAll)
             if (newFloatPos == -1)
                floatHandled = false;
             else {
+               // Step 2: position the float and re-calculate the line.
                lastFloatPos = newFloatPos;
 
                containingBlock->outOfFlowMgr->tellPosition
                   (words->getRef(lastFloatPos)->content.widget, yNewLine);
 
-               calcBorders (lastFloatPos, height);
-               bool thereWillBeMoreSpace = regardBorder ?
-                  newLineHasFloatLeft || newLineHasFloatRight :
-                  false;
-
-               DBG_OBJ_MSGF ("construct.word", 2, "thereWillBeMoreSpace = %s",
-                             thereWillBeMoreSpace ? "true" : "false");
-
-               for(int i = firstIndex; i <= wordIndexEnd; i++)
-                  accumulateWordData (i);
-                              
-               breakPos =
-                  searchBreakPos (wordIndex, firstIndex, &searchUntil,
-                                  tempNewLine, penaltyIndex,
-                                  thereWillBeMoreSpace, wrapAll,
-                                  &wordListChanged, &wordIndexEnd);
-               height = calcLinePartHeight (firstIndex, breakPos);
-
-               // TODO: Iterate until the height converges?
+               // The height of this part of the line (until the new
+               // break position) may change with the break position,
+               // but the break position may depend on the height. We
+               // try to let these values converge.
+               //
+               // The height, as a function of the break position, is
+               // monotonically (but not strictly) increasing, since
+               // more words may make the line higher (but not
+               // flatter). The break position, as a function of the
+               // height, is, however, monotonically (but not
+               // strictly) *de*creasing, since flatter lines may fit
+               // easier between floats (although this is a rare
+               // case). So a convergence is not necessary.
+               //
+               // For this reason, we iterate only as long as the
+               // height does not increase again, and stop if it
+               // remains the same. As the minimum is 1, this approach
+               // will force the iteration to stop.
+               //
+               // (As a side effect, this will lead to a larger break
+               // position, and so place as much words as possible in
+               // the line.)
+
+               bool firstRun = true;
+               while (true) {
+                  calcBorders (lastFloatPos, height);
+                  thereWillBeMoreSpace = regardBorder ?
+                     newLineHasFloatLeft || newLineHasFloatRight : false;
+
+                  DBG_OBJ_MSGF ("construct.word", 2,
+                                "thereWillBeMoreSpace = %s",
+                                thereWillBeMoreSpace ? "true" : "false");
+
+                  for(int i = firstIndex; i <= wordIndexEnd; i++)
+                     accumulateWordData (i);
+
+                  int newBreakPos =
+                     searchBreakPos (wordIndex, firstIndex, &searchUntil,
+                                     tempNewLine, penaltyIndex,
+                                     thereWillBeMoreSpace, wrapAll,
+                                     &wordListChanged, &wordIndexEnd);
+                  int newHeight = calcLinePartHeight (firstIndex, newBreakPos);
+                  
+                  if (!firstRun && newHeight >= height)
+                     // - newHeight > height: do not proceed, discard
+                     //   new values, which are less desirable than
+                     //   the old ones (see above).
+                     // - newHeight == height: convergence, stop
+                     //   here. New values can be discarded, since
+                     //   they are the same.
+                     // (Since *some* value are needed, the results
+                     // from the first run are never discarded.)
+                     break;
+                  else {
+                     height = newHeight;
+                     breakPos = newBreakPos;
+                  }
+
+                  firstRun = false;
+               }
             }
 
             DBG_OBJ_MSG_END ();