lightweight-graph.js

/* USAGE

    var graph = new Graph(paper.get(0), 800, 500);

    graph.max(maxx, maxy)
         .min(minx, miny)
         .ticks(4, function(x, y){
            var attrs = {stroke: "#ffffff", 'stroke-width': '1'};
            graph.hor(y, attrs)
                 .ver(x, attrs);
            graph.xLabel(x, "Label:" + x);
            graph.yLabel(y, "Label:" + y);
         });

    graph.data(data, function(next, prev){
      graph.line(prev.x, prev.y, next.x, next.y, {});
    });

*/



(function(){
  var extend = function(to, source){
    for(var i in source) to[i] = source[i];
    return to;
  };

  var each = function(obj, cb, context){
    if(obj.forEach) {
      obj.forEach(cb, context);
    } else {
      for(var i in obj)
        if(obj.hasOwnProperty(i))
          cb.call(context, obj[i], key, obj);
    }
  };

  var Bounds = function(){
    this.minx = Math.min();
    this.miny = Math.min();
    this.maxx = Math.max();
    this.maxy = Math.max();
  };

  Bounds.prototype = extend(Bounds.prototype, {
    extend : function(x, y){
      if(this.minx > x) this.minx = x;
      if(this.maxx < x) this.maxx = x;
      if(this.miny > y) this.miny = y;
      if(this.maxy < y) this.maxy = y;
    },

    shrink : function(factor){
      var iter = ['minx', 'miny', 'maxx', 'maxy'];
      for(var i in iter)
        if(this[iter[i]] < 0)
          this[iter[i]] = this[iter[i]] + factor;
        else
          this[tter[i]] = this[iter[i]] - factor;
    },

    grow : function(factor){
      this.shrink(factor * -1);
    },

    width : function(){
      return Math.abs(this.maxx - this.minx);
    },

    height : function(){
      return Math.abs(this.maxy - this.miny);
    },

    setProject : function(w, h){
      this.matrix = Raphael.matrix(1, 0, 0, -1, 0, 0);
      this.matrix.scale(w / this.width(), h / this.height());
      this.matrix.translate(-this.minx, -this.maxy);
    },

    projString : function(){
      return this.matrix.toTransformString();
    }
  });


  var Graph = this.Graph = function(canvas, w, h){
    this.canvas   = Raphael(canvas, w, h);
    this.el       = $(canvas).css({width: w, height: h});
    this.width    = w;
    this.height   = h;
    this.bounds   = new Bounds();
  };

  Graph.prototype = extend(Graph.prototype, {
    data: function(data, cb){
      var last;
      var that = this;
      each(data, function(it){
        cb.call(that, it, last);
        last = it;
      })
      return this;
    },

    max : function(maxx, maxy) {
      this.bounds.extend(maxx, maxy);
      this.bounds.setProject(this.width, this.height);
      return this;
    },

    min : function(minx, miny) {
      this.max(minx, miny);
      return this;
    },

    ticks : function(num, cb){
      var xStep = (this.bounds.maxx - this.bounds.minx) / num;
      var yStep = (this.bounds.maxy - this.bounds.miny) / num;

      for(var i = 0; i < num + 1; i++)
        cb.call(this, i * xStep + this.bounds.minx, i * yStep + this.bounds.miny);

      return this;
    },

    point : function(x, y, attr){
      this.canvas.circle(this.x(x), this.y(y), 1).attr(attr);
      return this;
    },

    line : function(x1, y1, x2, y2, attr){
      this.canvas
        .path(Raphael.format("M{0},{1}L{2},{3}", this.x(x1), this.y(y1), this.x(x2), this.y(y2)))
        .attr(attr);
      return this;
    },

    hor : function(y, attr){
      this.line(this.bounds.minx, y, this.bounds.maxx, y, attr);
      return this;
    },

    ver : function(x, attr){
      this.line(x, this.bounds.miny, x, this.bounds.maxy, attr);
      return this;
    },

    x : function(x){
      return this.bounds.matrix.x(x, 0);
    },

    y : function(y){
      return this.bounds.matrix.y(0, y);
    },

    xLabel : function(x, text){
      var div = $("<div />")
                  .addClass("graph-label-x")
                  .css({
                    "top": this.y(this.bounds.miny)
                  }).text(text).appendTo(this.el);
      div.css({left: this.x(x, 0) - div.width() / 2});
    },

    yLabel : function(y, text){
      var div = $("<div />")
                  .addClass("graph-label-y")
                  .css({
                    "left": this.x(this.bounds.maxx)
                  }).text(text).appendTo(this.el);
      div.css({top: this.y(y) - div.height() / 2});
    }
  });
})();