d3.js custom curve step round

Question

I\'m working on d3.js .v4 graph with x and y axis and I need your help.

Description:

xAxis is linear scaled with path on it like this image.

I\'m st

Answer 1

I finally found sometime to comeback to this question. This is a great opportunity to implement a custom curve. I essentially stole the source code to d3.curveStepBefore and modified to fit your requirements.

function Step(context, t) {
  this._context = context;
  this._t = t;
}

Step.prototype = {
  areaStart: function() {
    this._line = 0;
  },
  areaEnd: function() {
    this._line = NaN;
  },
  lineStart: function() {
    this._x = this._y = NaN;
    this._point = 0;
  },
  lineEnd: function() {
    if (0 < this._t && this._t < 1 && this._point === 2) this._context.lineTo(this._x, this._y);
    if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
    if (this._line >= 0) this._t = 1 - this._t, this._line = 1 - this._line;
  },
  point: function(x, y) {
    x = +x, y = +y;
    switch (this._point) {
      case 0:
      case 0:
        this._point = 1;
        this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y);
        break;
      case 1:
        this._point = 2; // proceed
      default:
        {
          var xN, yN, mYb, mYa;
          if (this._t <= 0) {
            xN = Math.abs(x - this._x) * 0.25;
            yN = Math.abs(y - this._y) * 0.25;
            mYb = (this._y < y) ? this._y + yN : this._y - yN;
            mYa = (this._y > y) ? y + yN : y - yN;

            this._context.quadraticCurveTo(this._x, this._y, this._x, mYb);
            this._context.lineTo(this._x, mYa);
            this._context.quadraticCurveTo(this._x, y, this._x + xN, y);
            this._context.lineTo(x - xN, y);

          } else {
            var x1 = this._x * (1 - this._t) + x * this._t;

            xN = Math.abs(x - x1) * 0.25;
            yN = Math.abs(y - this._y) * 0.25;
            mYb = (this._y < y) ? this._y + yN : this._y - yN;
            mYa = (this._y > y) ? y + yN : y - yN;

            this._context.quadraticCurveTo(x1, this._y, x1, mYb);
            this._context.lineTo(x1, mYa);
            this._context.quadraticCurveTo(x1, y, x1 + xN, y);
            this._context.lineTo(x - xN, y);
          }
          break;
        }
    }
    this._x = x, this._y = y;
  }
};

stepRound = function(context) {
  return new Step(context, 0.5);
};

stepRoundBefore = function(context) {
  return new Step(context, 0);
};

stepRoundAfter = function(context) {
  return new Step(context, 1);
};