From e129cbbec6f6fd7d3b9c8f0bdfbb9e28dd670f1b Mon Sep 17 00:00:00 2001
From: dooglus <dooglus@1f10aa63-cdf2-0310-b900-c93c546f37ac>
Date: Fri, 31 Aug 2007 22:40:01 +0000
Subject: [PATCH 1/1] Fix 1785598: studio crash when marking all Bline vertices
 as Off.  The previous fix wasn't enough.  More work is needed on this file,
 but it's not exactly clear how best to interpolate the appearance and
 disappearance of bline points.

git-svn-id: http://svn.voria.com/code@570 1f10aa63-cdf2-0310-b900-c93c546f37ac
---
 synfig-core/trunk/src/synfig/valuenode_bline.cpp | 50 ++++++++++--------------
 1 file changed, 21 insertions(+), 29 deletions(-)

diff --git a/synfig-core/trunk/src/synfig/valuenode_bline.cpp b/synfig-core/trunk/src/synfig/valuenode_bline.cpp
index ee0d831..87e8702 100644
--- a/synfig-core/trunk/src/synfig/valuenode_bline.cpp
+++ b/synfig-core/trunk/src/synfig/valuenode_bline.cpp
@@ -340,13 +340,16 @@ ValueNode_BLine::operator()(Time t)const
 	BLinePoint prev,first;
 	first.set_origin(100.0f);
 
+	// loop through all the list's entries
 	for(iter=list.begin();iter!=list.end();++iter,index++)
 	{
+		// how 'on' is this vertex?
 		float amount(iter->amount_at_time(t,&rising));
 
 		assert(amount>=0.0f);
 		assert(amount<=1.0f);
 
+		// it's fully on
 		if(amount==1.0f)
 		{
 			if(first_flag)
@@ -381,8 +384,8 @@ ValueNode_BLine::operator()(Time t)const
 
 			prev=curr;
 		}
-		else
-		if(amount>0.0f)
+		// it's partly on
+		else if(amount>0.0f)
 		{
 			std::vector<ListEntry>::const_iterator begin_iter,end_iter;
 
@@ -417,34 +420,28 @@ ValueNode_BLine::operator()(Time t)const
 			blp_here_on=(*iter->value_node)(on_time).get(blp_here_on);
 //			blp_here_on=(*iter->value_node)(t).get(blp_here_on);
 
-			// Find "end" of dynamic group
+			// Find "end" of dynamic group - ie. search forward along
+			// the bline from the current point until we find a point
+			// which is more 'on'than the current one
 			end_iter=iter;
 //			for(++end_iter;begin_iter!=list.end();++end_iter)
 			for(++end_iter;end_iter!=list.end();++end_iter)
 				if(end_iter->amount_at_time(t)>amount)
-				{
-					blp_next_off=(*end_iter->value_node)(off_time).get(prev);
 					break;
-				}
 
 			// If we did not find an end of the dynamic group...
+			// Writeme!  at least now it doesn't crash if first_iter
+			// isn't set yet
 			if(end_iter==list.end())
 			{
-				if(get_loop())
-				{
+				if(get_loop() && !first_flag)
 					end_iter=first_iter;
-					blp_next_off=(*end_iter->value_node)(off_time).get(prev);
-//					end=first;
-				}
 				else
-				{
-					// Writeme!
-					end_iter=first_iter;
-					blp_next_off=(*end_iter->value_node)(off_time).get(prev);
-//					end=first;
-				}
+					end_iter=--list.end();
 			}
 
+			blp_next_off=(*end_iter->value_node)(off_time).get(prev);
+
 			// Find "begin" of dynamic group
 			begin_iter=iter;
 			blp_prev_off.set_origin(100.0f); // set the origin to 100 (which is crazy) so that we can check to see if it was found
@@ -461,6 +458,7 @@ ValueNode_BLine::operator()(Time t)const
 				--begin_iter;
 				dist_from_begin++;
 
+				// if we've gone all around the loop, give up
 				if(begin_iter==iter)
 					break;
 
@@ -469,24 +467,18 @@ ValueNode_BLine::operator()(Time t)const
 					blp_prev_off=(*begin_iter->value_node)(off_time).get(prev);
 					break;
 				}
-			}while(begin_iter!=iter);
+			}while(true);
 
 			// If we did not find a begin
 			if(blp_prev_off.get_origin()==100.0f)
 			{
-				if(get_loop())
-				{
-					begin_iter=first_iter;
-					blp_prev_off=(*begin_iter->value_node)(off_time).get(prev);
-//					blp_prev_off=first;
-				}
+				// Writeme! - this needs work, but at least now it
+				// doesn't crash
+				if(first_flag)
+					begin_iter=list.begin();
 				else
-				{
-					// Writeme!
 					begin_iter=first_iter;
-					blp_prev_off=(*begin_iter->value_node)(off_time).get(prev);
-//					blp_prev_off=first;
-				}
+				blp_prev_off=(*begin_iter->value_node)(off_time).get(prev);
 			}
 
 			// this is how the curve looks when we have completely vanished
-- 
2.7.4