Make the need to use -s for position input to fdp or neato clearer;

update overlap attribute items

diff --git a/doc/info/attrs.html b/doc/info/attrs.html
index 0142aa6575490b4b75ee62a0872a379456a6327c..4e024392a71eef9ebb724fc94ed8df3e4653833b 100644 (file)
--- a/doc/info/attrs.html
+++ b/doc/info/attrs.html
@@ -317,7 +317,7 @@ This field indicates which graph component uses the attribute.
 </TD><TD>G</TD><TD>string<BR><A HREF=#k:bool>bool</A>
 </TD><TD ALIGN="CENTER">true</TD><TD></TD><TD>not dot</TD> </TR>
  <TR><TD><A NAME=a:overlap_scaling HREF=#d:overlap_scaling>overlap_scaling</A>
-</TD><TD>G</TD><TD>double</TD><TD ALIGN="CENTER">-4</TD><TD>-1.0e10</TD><TD>sfdp only</TD> </TR>
+</TD><TD>G</TD><TD>double</TD><TD ALIGN="CENTER">-4</TD><TD>-1.0e10</TD><TD>prism only</TD> </TR>
  <TR><TD><A NAME=a:pack HREF=#d:pack>pack</A>
 </TD><TD>G</TD><TD><A HREF=#k:bool>bool</A>
 <BR>int</TD><TD ALIGN="CENTER">false</TD><TD></TD><TD>not dot</TD> </TR>
@@ -1162,9 +1162,20 @@ This field indicates which graph component uses the attribute.
   Voronoi-based technique.
   If the value is "scalexy", x and y are separately
   scaled to remove overlaps.
-  If sfdp is available, one can set overlap=prism to use a proximity graph-
-  based algorithm for overlap removal. This last is the preferred technique,
-  though scale and false can work well with small graphs.
+  <P>
+  If sfdp is available, one can set overlap to "prism" to use a 
+  proximity graph-based algorithm for overlap removal. 
+  This last is the preferred technique,
+  though "scale" and "false" can work well with small graphs.
+  This technique starts with a
+  small scaling up, controlled by the 
+  <A HREF="#d:overlap_scaling"><TT>overlap_scaling</TT></A> attribute,
+  which can remove a significant portion of the overlap.
+  The prism option also accepts an optional non-negative integer suffix.
+  This can be used to control the number of attempts made at overlap
+  removal. By default, <TT>overlap="prism"</TT> is equivalent to
+  <TT>overlap="prism1000"</TT>. Setting <TT>overlap="prism0"</TT>
+  causes only the scaling phase to be run.
   <P>
   If the value is "compress", the layout will be scaled down as much as
   possible without introducing any overlaps, obviously assuming there are
@@ -1205,10 +1216,7 @@ This field indicates which graph component uses the attribute.
   <TT>overlap="0:true"</TT> and <TT>overlap="0:"</TT> all turn off all overlap
   removal.
   <P>
-  By default, sfdp uses <TT>overlap="prism"</TT>. This is preceded by a
-  small scaling up, controlled by the 
-  <A HREF="#d:overlap_scaling"><TT>overlap_scaling</TT></A> attribute,
-  which can remove a significant portion of the overlap.
+  By default, sfdp uses <TT>overlap="prism:0"</TT>.
   <P>
   Except for the Voronoi and prism methods, all of these transforms preserve the
   orthogonal ordering of the original layout. That is, if the x coordinates
@@ -1220,7 +1228,7 @@ This field indicates which graph component uses the attribute.
   ordering is only preserved among nodes related by an edge.
 
 <DT><A NAME=d:overlap_scaling HREF=#a:overlap_scaling><STRONG>overlap_scaling</STRONG></A>
-<DD>  When <TT>overlap=sfdp</TT>, the layout is scaled by this factor, thereby
+<DD>  When <TT>overlap=prism</TT>, the layout is scaled by this factor, thereby
   removing a fair amount of node overlap, and making node overlap removal
   faster and better able to retain the graph's shape.
   <P>
@@ -1228,6 +1236,7 @@ This field indicates which graph component uses the attribute.
   <TT>-1*overlap_scaling</TT> times the average label size.
   If <TT>overlap_scaling</TT> is positive, the layout is scaled by
   <TT>overlap_scaling</TT>.
+  If <TT>overlap_scaling</TT> is zero, no scaling is done.
 
 <DT><A NAME=d:pack HREF=#a:pack><STRONG>pack</STRONG></A>
 <DD>  This is true if the value of pack is "true" (case-insensitive) or a
@@ -1309,7 +1318,7 @@ This field indicates which graph component uses the attribute.
   Also, 1 is the maximum peripheries value for clusters.
 
 <DT><A NAME=d:pin HREF=#a:pin><STRONG>pin</STRONG></A>
-<DD>  If true and the node has a pos attribute on input, neato prevents the
+<DD>  If true and the node has a pos attribute on input, neato or fdp prevents the
   node from moving from the input position. This property can also be specified
   in the pos attribute itself (cf. the <A HREF=#d:point>point</A> type).
   <P>
@@ -1326,10 +1335,12 @@ This field indicates which graph component uses the attribute.
   For nodes, the position indicates the center of the node.
   On output, the coordinates are in <A HREF=#points>points</A>.
   <P>
-  In neato, fdp and sfdp, pos can be used to set the initial position of a node.
-  By default, the coordinates are assumed to be in points. However, the
+  In neato and fdp, pos can be used to set the initial position of a node.
+  By default, the coordinates are assumed to be in inches. However, the
   <A HREF=command.html#d:s>-s</A> command line flag can be used to specify
-  different units.
+  different units. As the output coordinates are in points, 
+  feeding the output of a graph laid out by a Graphviz program into
+  neato or fdp will almost always require the -s flag.
   <P>
   When the <A HREF=command.html#d:n>-n</A> command line flag is used with
   neato, it is assumed the positions have been set by one of the layout