Trend should not go below 0

graph

@@ -474,24 +474,25 @@ else
 	(( end > 0 )) && end="+$end"
 	(( datastart > 0 )) && datastart="+$datastart"
 
-	rrdtool graph - 					\
-		-a PNG 						\
-		-w $graph_width					\
-		-v $graph					\
-		-s $start -e $end				\
+	rrdtool graph - 												\
+		-a PNG 													\
+		-w $graph_width												\
+		-v $graph												\
+		-s $start -e $end											\
 		DEF:data=$rrdfile:$graph:AVERAGE:step=3600${datastart+:start=$datastart}${dataend+:end=$dataend}	\
-		DEF:fail=$rrdfile:$graph:FAILURES		\
-		VDEF:last=data,LAST				\
-		VDEF:intercept=data,LSLINT			\
-		VDEF:growth=data,LSLSLOPE			\
-		CDEF:trend=data,POP,COUNT,growth,*,intercept,+	\
-		CDEF:pred=TIME,NOW,GE,trend,UNKN,IF		\
-		LINE1:trend#FFFF00:Trend\\t			\
-		"${draw[@]:-AREA:data#00BD27}"			\
-		"${thresholds[@]}"				\
-		TICK:fail#ffffa0:1.0				\
-		VRULE:$now#000000				\
-		'GPRINT:data:MIN:min %6.2lf%S'			\
-		'GPRINT:data:MAX:\tmax %6.2lf%S'		\
+		DEF:fail=$rrdfile:$graph:FAILURES									\
+		VDEF:last=data,LAST											\
+		VDEF:intercept=data,LSLINT										\
+		VDEF:growth=data,LSLSLOPE										\
+		CDEF:trend=data,POP,COUNT,growth,*,intercept,+								\
+		CDEF:trendline=trend,0,GT,trend,UNKN,IF									\
+		CDEF:pred=TIME,NOW,GE,trend,UNKN,IF									\
+		LINE1:trendline#FFFF00:Trend\\t										\
+		"${draw[@]:-AREA:data#00BD27}"										\
+		"${thresholds[@]}"											\
+		TICK:fail#ffffa0:1.0											\
+		VRULE:$now#000000											\
+		'GPRINT:data:MIN:min %6.2lf%S'										\
+		'GPRINT:data:MAX:\tmax %6.2lf%S'									\
 		"${next[@]}"
 fi