gistfile1.txt

{
  "$schema": "https://vega.github.io/schema/vega/v3.json",
  "width": 300,
  "height": 240,
  "padding": 5,

  "data": [
    {
      "name": "table",
      "values": [
        {"category":"A", "position":0, "value":0.1},
        {"category":"A", "position":1, "value":0.6},
        {"category":"A", "position":2, "value":0.9},
        {"category":"A", "position":3, "value":0.4},
        {"category":"B", "position":0, "value":0.7},
        {"category":"B", "position":1, "value":0.2},
        {"category":"B", "position":2, "value":1.1},
        {"category":"B", "position":3, "value":0.8},
        {"category":"C", "position":0, "value":0.6},
        {"category":"C", "position":1, "value":0.1},
        {"category":"C", "position":2, "value":0.2},
        {"category":"C", "position":3, "value":0.7}
      ]
    }
  ],

  "scales": [
 
    {
      "name": "color",
      "type": "ordinal",
      "domain": {"data": "table", "field": "position"},
      "range": {"scheme": "category20"}
    }

  ],

 

   "legends": [
    {
      "title" : "Colors for me",
      "type" : "symbol",
      "orient" : "bottom",
      "fill": "color",
      "offset": 50,
      "direction": "horizontal",
     
      
      "encode": {
      
        "title": {  "update": {   "fontSize": {"value": 20}   }    },
        

        "symbols": {
          "update": {
            "shape" : {"value": "square" },
            "stroke": {"value": "transparent"}
          }
        },       
        
        "labels": { 
          "interactive": true,  
          "update": {  
            "fontSize": {"value": 30},   
            "fill":   { "scale": "color", "field" : "value"  }
          }
        }

  
      
      }
    }
  ]
}