A GVPR program to improve Graphviz edge labels

improveEdgeLabels.gvpr

/***********************************************
 1. save this file as improveEdgeLabels.gvpr
 2. what it does: it allows you to re-position Graphviz edge labels
 3. command line example (works with any Graphviz engine):
   dot myfile.gv |gvpr -cf improveEdgeLabels.gvpr |neato -n2 -Tpng >myfile.png
 4. how to use:
   improveEdgeLabels adds 3 new edge attributes to Graphviz:
   - labelOverlay, labelAdjust, label2Node
   - they can be used separately or in combination
   - if labelOverlay=true
      overlay label/xlabel on-top-of edge - centered
   - if labelOverlay=n% (n is integer)
      overlay label/xlabel on-top-of edge - n% of the way from tail-to-head
   - if labelAdjust (X,Y)
      adjust edge.lp by X,Y (either/both can be negative)
   - if label2Node = true
      delete the edge label
      replace the edge label with a node, where pos=edge.lp
      set node attributes
      #### future:
      - set/change various attributes of the new node
*************************************************/
BEGIN{
  int     i, cnt, LN=0;
  string  tStr, tok[int];
  graph_t Root;

  // do NOT call with direct output from sprintf - there is a bug - string will be empty
  void doError(string eString) {
    printf(2, "Error:: %s\n", eString);
  }
  ////////////////////////////////////////////////////////////////////
  int istrue(string checkme, int rc) {
    checkme = tolower(checkme);
    if (checkme == "@(1|yes|true)") // ksh syntax
      rc=1;
    else
      rc=0;
    return(rc);
  }
  /////////////////////////////////////////////////////////////////
  string overlayPos(string Pos, string cmd) {
    string p1, p2, pnew;
    float x1, y1, x2, y2, dx, dy, percent;
    p1="";
    if (cmd=="(+([0-9])\%)") {
      percent=.01 * (float)sub(cmd,"%");
    } else {
      percent=.5;
    }
    cnt=tokens(Pos, tok);
    for (i=0; i<cnt; i++) {
      if (tok[i]=="[es]*")
        continue;
      if (p1=="") {
        p1=tok[i];
      }
      if (i==cnt-1)
        p2=tok[i];
    }
    //print("//  cmd: ", cmd, "   p1: ", p1,"  p2: ",p2);
    //print("//  PERCENT: ", percent );
    x1=(float)xOf(p1);
    x2=(float)xOf(p2);
    y1=(float)yOf(p1);
    y2=(float)yOf(p2);
    dx=x2-x1;
    dy=y2-y1;
    return (string)(x1 + percent*dx) + ", " + (string)(y1 + percent*dy);
  }
  ///////////////////////////////////////////////////////////////////
  string adjustPos(string Pos, string adj) {
    string newPt;
    newPt=(string)((float)xOf(Pos) + (float)xOf(adj)) + ", " + (string)((float)yOf(Pos) + (float)yOf(adj));
    return newPt;
  }
}
BEG_G{
  Root=$G;
  $G.notranslate="true"; // fighting pos changes for created nodes
  if (!(hasAttr(Root, "splines") && Root.splines!=""))
    Root.splines="true";
}
N{
  $.REALLY_USE_THIS_pos=$.pos;
}
E{
  if (hasAttr($, "labelOverlay")) {
    if (istrue($.labelOverlay) || $.labelOverlay=="(+([0-9])\%)") {
      if (hasAttr($, "lp") && $.lp!="") {
        $.preOverlaylp=$.lp;
        $.lp=overlayPos($.pos, $.labelOverlay);
      }
    } else {
      doError("For edge " + $.name + ", invalid value (" + $.labelOverlay + ") for labelOverlay attribute");
    }
  }
  if (hasAttr($, "labelAdjust") && ($.labelAdjust!="")) {
    if (hasAttr($, "lp") && $.lp!="") {
      $.preAdjustlp=$.lp;
      $.lp=adjustPos($.lp, $.labelAdjust);
    }
  }
  if (hasAttr($, "label2node") && istrue($.label2node))  {
    node_t aNode;
    string lbl, rep, s1, s2;
    if (hasAttr($, "lp") && $.lp!="") {
      $.preL2Nlp=$.lp;
      $.preL2Nlabel=$.label;
      //// create node
      tStr="__labelNODE__" +  (string)++LN;
      aNode=node($G, tStr);
      lbl=$.label;
      rep=$.tail.name;
      /**********   problem w/ gsub, so roll our own ***********/
      print ("//  escape stuff >", lbl);
      while (i=index(lbl,"\\T"), i!=-1) {
        //print ("// x ", lbl, "  ",i);
        if (i>0)
          s1=substr(lbl,0,i-1);
        else
          s1="";
        if (i<(length(lbl)-2))
          s2=substr(lbl,i+1);
        else
          s2="";
        lbl=s1 + rep + s2;
      }
      print("// lbl:", lbl);
      while (i=index(lbl,"\H"), i!=-1) {
        //print ("// y ", lbl, "  ",i);
        lbl=substr(lbl,0,i-1) + rep + substr(lbl,i+1);
      }
      //print("// lbl:", lbl);
      while (i=index(lbl,"\E"), i!=-1) {
        //print ("// z ", lbl, "  ",i);
        lbl=substr(lbl,0,i-1) + rep + substr(lbl,i+1);
      }
      //print("// lbl:", lbl);
      aNode.label=lbl;
      aNode.shape="plaintext";
      aNode.style="filled";
      aNode.width=".05";
      aNode.height=".05";
      aNode.margin="0.01,0.01";
      aNode.fillcolor="white";
      aNode.pos=$.lp;
      // clean-up edge attributes
      $.label="";
      $.lp="";
      $._comment="edge label replaced by " + tStr;
    }
  }
}

/******************* test graph **************************

graph straight {
  splines=false
  edge [label="\T" labelOverlay=true color=purple]
  node [shape=rect style=filled fillcolor=lightblue]

    a1 -- b1
    c1 -- d1  [labelOverlay="15%" label=high]
    e1 -- f1  [label2node=true labelOverlay="75%" label=low]
    g1:sw -- h1:nw  
    g1:s -- h1:n  [labelOverlay="20%"]
    g1:se -- h1:ne  
    j1 -- k1  [ label2node=true]

  node[shape=square style=filled fillcolor=lightgreen]
    {rank=sink
    edge [fontcolor=red]
    Aaa -- B3  [labelOverlay="33%"]
    C98 -- D3  [labelOverlay="80%" label2node=true]
    Eee -- F6  [label="adjust me" labelAdjust="45,-25"]
    G12 -- H3  [label2node=true]
    node [shape=plain fontcolor=blue style=""]
    Lxx -- M123
    Noo -- Ooo [label2node=true]
    node [shape=oval fontcolor=blue style=""]
    P  -- Q
    }

    node[shape=circle style=filled fillcolor=pink]
    edge [label2node=true label="aeiou" labelOverlay="78%"]
    10 -- {11 12}
    10 -- 13 [labelOverlay="38%"]    
    10 -- 14 [labelOverlay="62%"]    
    edge [label="three"]
    node [shape=Mrecord]
    13 --  21
    edge [labelOverlay="55%" label="T\nh\nr\ne\ne\n \n33"] 13 -- 22
    edge [labelOverlay="60%"] 13 -- 23
}
*************************************************/