如何在 Vega-Lite 中用特定颜色为线条着色？

Posted 2023-02-16

【中文标题】如何在 Vega-Lite 中用特定颜色为线条着色？

【英文标题】：How to color lines with specific colors in Vega-Lite?

【发布时间】：2020-04-16 01:28:14

【问题描述】：

VegaLite 自动分配颜色。黄金价格是蓝色的，白银价格是橙色的，感觉不对。

我如何分配明确的颜色 - #F1C40F 代表金色，#95A5A6 代表银色？

我还想将data.values 保留在下面的示例代码中 - 作为一组单独的数组。

代码和Playground

  "$schema": "https://vega.github.io/schema/vega-lite/v4.json",
  "description": "Stock prices of 5 Tech Companies over Time.",
  "data": 
    "values": [
      
        "dates": ["2000-01", "2000-02", "2000-03"], 
        "gold": [1, 2, 1], 
        "silver": [1.5, 1, 2]
      
    ]
  ,
  "transform": [
    "flatten": ["dates", "gold", "silver"],
    "fold": ["gold", "silver"], "as": ["symbol", "price"],
    "calculate": "datetime(datum.dates)", "as": "dates"
  ],
  "mark": "type": "line", "point": "filled": false, "fill": "white",
  "encoding": 
    "x": "field": "dates", "type": "temporal", "timeUnit": "yearmonth",
    "y": "field": "price", "type": "quantitative",
    "color": "field": "symbol", "type": "nominal"
  

【参考方案1】：

您可以使用scale.domain 和scale.range 参数设置自定义Color Scheme：

"color": 
  "field": "symbol",
  "type": "nominal",
  "scale": "domain": ["gold", "silver"], "range": ["#F1C40F", "#95A5A6"]

无论如何指定数据源，这都有效。

这是应用于图表时的结果 (Vega Editor)：