Weeding functions

gistfile1.txt

// just a sketch to put away for now
// these are weeding functions 
// the goal is to remove lables on a graph that are too close together (ie weed out overlapping labels)
  function weed(array, x, y){
    var f = array[0]
      , l = array[array.length -1]
      , ex = d3.extent(array, function(d){ return d.y })
      , hiLo = array.filter(function(d){ return d.y == ex[0] || d.y == ex[1]});

    return _.uniq([f,l].concat(hiLo));
  }

  // filters out labels which will be too close together
  function weedValue(array, x, y){
    var threshold = 0.1;

    var ls = threshold+1 // last displayed x
      , skipped = false;

    return array.filter(function(d){
      var cy = y(d.y);

      var diffy = Math.abs(1 - (ls / cy));

      if(diffy > threshold){
        skipped = false;
        ls = cy;
      } else {
        skipped = true;
      }

      return ! skipped;
    })
  }

  // filters out labels which will be too close together
  function weedSpatial(array, x, y){
    var thresholdx = 24,
        thresholdy = 24;

    var lsx = thresholdx+1 // last displayed x
      , lsy = thresholdy+1 // last displayed y
      , skipped = false;

    return array.filter(function(d){
      var cx = x(d.x) // current positions
        , cy = y(d.y);

      var diffx = Math.abs(lsx - cx)
        , diffy = Math.abs(lsy - cy);

      if(diffx > thresholdx || diffy > thresholdy){
        skipped = false;
        lsx = cx;
        lst = cy;
      } else {
        skipped = true;
      }

      return ! skipped;
    })
  }