title: How to set minimum x-Axis instead of 0 in Vega d3 charts
body: <p>I am referring VEGA chart following code which is available in the <a href="https://trifacta.github.io/vega/editor/index.html?spec=image" rel="nofollow">preview</a>. There "domain": [0, 3] is used set range in x and y axis. Here if i set [-0.5, 3], x axis will start from -0.5 but if i want to have positive number such as 0.5 it, x-axis will not start from that value instead it starts from 0. Is there any alternative way to sort this matter?</p>
  
  <pre><code>{
    "name": "image",
    "width": 200,
    "height": 200,
    "padding": {"left":30, "top":10, "bottom":30, "right":10},
    "data": [
      {
        "name": "data",
        "values": [
          {"x":0.5, "y":0.5, "img":"data/ffox.png"},
          {"x":1.5, "y":1.5, "img":"data/gimp.png"},
          {"x":2.5, "y":2.5, "img":"data/7zip.png"}
        ]
      }
    ],
    "scales": [
      {"name": "x", "domain": [0, 3], "range": "width"},
      {"name": "y", "domain": [0, 3], "range": "height"}
    ],
    "axes": [
      {"type": "x", "scale": "x"},
      {"type": "y", "scale": "y"}
    ],
    "marks": [
      {
        "type": "image",
        "from": {"data": "data"},
        "properties": {
          "enter": {
            "url": {"field": "data.img"},
            "width": {"value": 50},
            "height": {"value": 50},
            "x": {"scale": "x", "field": "data.x"},
            "y": {"scale": "y", "field": "data.y"},
            "align": {"value": "center"},
            "baseline": {"value": "middle"}
          },
          "update": {
            "opacity": {"value": 1.0}
          },
          "hover": {
            "opacity": {"value": 0.5}
          }
        }
      }
    ]
  }
  </code></pre>