How to implement multi-group bar chart and interact with highlighting by grouping dimension?
Tags: visactor, vchart, charts, visualization
Published: 2024-04-19 08:46:02

> 😊 I am a developer of [**VChart**](https://visactor.io/vchart), so I will introduce the solution in VChart.

## Description
Solution for implementing a multi-group bar chart similar to the following figure: 
1. Expect two groups to differentiate in style through color transparency.
2. When the mouse hovers over a column block, all blocks of the same color are highlighted in linkage.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/aioundbi00z9vpe9iln9.png)

## Solution

- Requires 4 data fields:

1. 3 grouping fields: There are 3 layers of grouping on the x-axis, corresponding to fields xField: ['type', 'type1', 'type2'] ;

2. series field: used to distinguish color series, seriesField: 'color'
![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/pq64v6xi04xra4v1qss9.png)

- Highlight interaction: You can configure the built-in `element-highlight-by-group` interaction in VChart, specify the interaction highlighting state to be named `'highligh'` , so as to add a stroke effect to the column in the graphic style:

```
  interactions:[
    {
       type: 'element-highlight-by-group',
       highlightState:'highlight'
    }
  ],
  bar:{
    state:{
      highlight:{
        stroke:"black",
        lineWidth:1,
        zIndex:100
      }
    }
  },
```

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/745mylyx83f29o6g086e.gif)
## Demo Code

> You can paste the code in editor: https://visactor.io/vchart/demo/line-chart/basic-line

```
const spec = {
  type: 'bar',
  height:400,
  data: [
    {
      values: [
        { type: 'Category One', min: 80,  color: 'A', type1: 'p', type2: 'T' },
        { type: 'Category One', min: 40,  color: 'B', type1: 'p', type2: 'T' },
        { type: 'Category One', min: 40,  color: 'D', type1: 'p', type2: 'T' },
        { type: 'Category One', min: 75,  color: 'C', type1: 'p', type2: 'T' },
        { type: 'Category One', min: 30,  color: 'E', type1: 'p', type2: 'T' },

        { type: 'Category One', min: 70,  color: 'A', type1: 'p', type2: 'T1' },
        { type: 'Category One', min: 40,  color: 'B', type1: 'p', type2: 'T1' },
        { type: 'Category One', min: 40,  color: 'D', type1: 'p', type2: 'T1' },
        { type: 'Category One', min: 50,  color: 'C', type1: 'p', type2: 'T1' },
        { type: 'Category One', min: 30,  color: 'E', type1: 'p', type2: 'T1' },

        { type: 'Category One', min: 70,  color: 'A', type1: 'p', type2: 'T2' },
        { type: 'Category One', min: 40,  color: 'B', type1: 'p', type2: 'T2' },
        { type: 'Category One', min: 40,  color: 'D', type1: 'p', type2: 'T2' },
        { type: 'Category One', min: 50,  color: 'C', type1: 'p', type2: 'T2' },
        { type: 'Category One', min: 30,  color: 'E', type1: 'p', type2: 'T2' },

        { type: 'Category One', min: 70,  color: 'A', type1: 'p', type2: 'T3' },
        { type: 'Category One', min: 40,  color: 'B', type1: 'p', type2: 'T3' },
        { type: 'Category One', min: 40,  color: 'D', type1: 'p', type2: 'T3' },
        { type: 'Category One', min: 50,  color: 'C', type1: 'p', type2: 'T3' },
        { type: 'Category One', min: 30,  color: 'E', type1: 'p', type2: 'T3' },

        { type: 'Category One', min: 70,  color: 'A', type1: 'p', type2: 'T4' },
        { type: 'Category One', min: 40,  color: 'B', type1: 'p', type2: 'T4' },
        { type: 'Category One', min: 40,  color: 'D', type1: 'p', type2: 'T4' },
        { type: 'Category One', min: 50,  color: 'C', type1: 'p', type2: 'T4' },
        { type: 'Category One', min: 30,  color: 'E', type1: 'p', type2: 'T4' },
        
        { type: 'Category One', min: 80,  color: 'A', type1: 'p1', type2: 'T' },
        { type: 'Category One', min: 40,  color: 'B', type1: 'p1', type2: 'T' },
        { type: 'Category One', min: 40,  color: 'D', type1: 'p1', type2: 'T' },
        { type: 'Category One', min: 75,  color: 'C', type1: 'p1', type2: 'T' },
        { type: 'Category One', min: 30,  color: 'E', type1: 'p1', type2: 'T' },

        { type: 'Category One', min: 70,  color: 'A', type1: 'p1', type2: 'T1' },
        { type: 'Category One', min: 40,  color: 'B', type1: 'p1', type2: 'T1' },
        { type: 'Category One', min: 40,  color: 'D', type1: 'p1', type2: 'T1' },
        { type: 'Category One', min: 50,  color: 'C', type1: 'p1', type2: 'T1' },
        { type: 'Category One', min: 30,  color: 'E', type1: 'p1', type2: 'T1' },

        { type: 'Category One', min: 70,  color: 'A', type1: 'p1', type2: 'T2' },
        { type: 'Category One', min: 40,  color: 'B', type1: 'p1', type2: 'T2' },
        { type: 'Category One', min: 40,  color: 'D', type1: 'p1', type2: 'T2' },
        { type: 'Category One', min: 50,  color: 'C', type1: 'p1', type2: 'T2' },
        { type: 'Category One', min: 30,  color: 'E', type1: 'p1', type2: 'T2' },

        { type: 'Category One', min: 70,  color: 'A', type1: 'p1', type2: 'T3' },
        { type: 'Category One', min: 40,  color: 'B', type1: 'p1', type2: 'T3' },
        { type: 'Category One', min: 40,  color: 'D', type1: 'p1', type2: 'T3' },
        { type: 'Category One', min: 50,  color: 'C', type1: 'p1', type2: 'T3' },
        { type: 'Category One', min: 30,  color: 'E', type1: 'p1', type2: 'T3' },

        { type: 'Category One', min: 70,  color: 'A', type1: 'p1', type2: 'T4' },
        { type: 'Category One', min: 40,  color: 'B', type1: 'p1', type2: 'T4' },
        { type: 'Category One', min: 40,  color: 'D', type1: 'p1', type2: 'T4' },
        { type: 'Category One', min: 50,  color: 'C', type1: 'p1', type2: 'T4' },
        { type: 'Category One', min: 30,  color: 'E', type1: 'p1', type2: 'T4' },

        

        { type: 'Category Two', min: 76,  color: 'A', type1: 'p', type2: 'T' },
        { type: 'Category Two', min: 40,  color: 'B', type1: 'p', type2: 'T' },
        { type: 'Category Two', min: 40,  color: 'D', type1: 'p', type2: 'T' },
        { type: 'Category Two', min: 65,  color: 'C', type1: 'p', type2: 'T' },
        { type: 'Category Two', min: 30,  color: 'E', type1: 'p', type2: 'T' },

        { type: 'Category Two', min: 70,  color: 'A', type1: 'p', type2: 'T1' },
        { type: 'Category Two', min: 40,  color: 'B', type1: 'p', type2: 'T1' },
        { type: 'Category Two', min: 40,  color: 'D', type1: 'p', type2: 'T1' },
        { type: 'Category Two', min: 50,  color: 'C', type1: 'p', type2: 'T1' },
        { type: 'Category Two', min: 30,  color: 'E', type1: 'p', type2: 'T1' },

        { type: 'Category Two', min: 70,  color: 'A', type1: 'p', type2: 'T2' },
        { type: 'Category Two', min: 40,  color: 'B', type1: 'p', type2: 'T2' },
        { type: 'Category Two', min: 40,  color: 'D', type1: 'p', type2: 'T2' },
        { type: 'Category Two', min: 50,  color: 'C', type1: 'p', type2: 'T2' },
        { type: 'Category Two', min: 30,  color: 'E', type1: 'p', type2: 'T2' },

        { type: 'Category Two', min: 70,  color: 'A', type1: 'p', type2: 'T3' },
        { type: 'Category Two', min: 40,  color: 'B', type1: 'p', type2: 'T3' },
        { type: 'Category Two', min: 40,  color: 'D', type1: 'p', type2: 'T3' },
        { type: 'Category Two', min: 50,  color: 'C', type1: 'p', type2: 'T3' },
        { type: 'Category Two', min: 30,  color: 'E', type1: 'p', type2: 'T3' },

        { type: 'Category Two', min: 70,  color: 'A', type1: 'p', type2: 'T4' },
        { type: 'Category Two', min: 40,  color: 'B', type1: 'p', type2: 'T4' },
        { type: 'Category Two', min: 40,  color: 'D', type1: 'p', type2: 'T4' },
        { type: 'Category Two', min: 50,  color: 'C', type1: 'p', type2: 'T4' },
        { type: 'Category Two', min: 30,  color: 'E', type1: 'p', type2: 'T4' },
        
        { type: 'Category Two', min: 80,  color: 'A', type1: 'p1', type2: 'T' },
        { type: 'Category Two', min: 40,  color: 'B', type1: 'p1', type2: 'T' },
        { type: 'Category Two', min: 40,  color: 'D', type1: 'p1', type2: 'T' },
        { type: 'Category Two', min: 75,  color: 'C', type1: 'p1', type2: 'T' },
        { type: 'Category Two', min: 30,  color: 'E', type1: 'p1', type2: 'T' },

        { type: 'Category Two', min: 70,  color: 'A', type1: 'p1', type2: 'T1' },
        { type: 'Category Two', min: 40,  color: 'B', type1: 'p1', type2: 'T1' },
        { type: 'Category Two', min: 40,  color: 'D', type1: 'p1', type2: 'T1' },
        { type: 'Category Two', min: 50,  color: 'C', type1: 'p1', type2: 'T1' },
        { type: 'Category Two', min: 30,  color: 'E', type1: 'p1', type2: 'T1' },

        { type: 'Category Two', min: 70,  color: 'A', type1: 'p1', type2: 'T2' },
        { type: 'Category Two', min: 40,  color: 'B', type1: 'p1', type2: 'T2' },
        { type: 'Category Two', min: 40,  color: 'D', type1: 'p1', type2: 'T2' },
        { type: 'Category Two', min: 50,  color: 'C', type1: 'p1', type2: 'T2' },
        { type: 'Category Two', min: 30,  color: 'E', type1: 'p1', type2: 'T2' },

        { type: 'Category Two', min: 70,  color: 'A', type1: 'p1', type2: 'T3' },
        { type: 'Category Two', min: 40,  color: 'B', type1: 'p1', type2: 'T3' },
        { type: 'Category Two', min: 40,  color: 'D', type1: 'p1', type2: 'T3' },
        { type: 'Category Two', min: 50,  color: 'C', type1: 'p1', type2: 'T3' },
        { type: 'Category Two', min: 30,  color: 'E', type1: 'p1', type2: 'T3' },

        { type: 'Category Two', min: 70,  color: 'A', type1: 'p1', type2: 'T4' },
        { type: 'Category Two', min: 40,  color: 'B', type1: 'p1', type2: 'T4' },
        { type: 'Category Two', min: 40,  color: 'D', type1: 'p1', type2: 'T4' },
        { type: 'Category Two', min: 50,  color: 'C', type1: 'p1', type2: 'T4' },
        { type: 'Category Two', min: 30,  color: 'E', type1: 'p1', type2: 'T4' },
      ]
    }
  ],
  interactions:[
    {
       type: 'element-highlight-by-group',
       highlightState:'highlight'
    }
  ],
  bar:{
    style:{
      fillOpacity:(data) => data.type1 === 'p' ? 1: 0.5
    },
    state:{
      highlight:{
        stroke:"black",
        lineWidth:1,
        zIndex:100
      }
    }
  },
  xField: ['type', 'type1', 'type2'],
  yField: 'min',
  seriesField: 'color',
  axes: [
    {
      orient:"left",
      label:{ visible: false},
      grid:{ style:{ lineDash:[4,4], stroke:'#dddddd'} }
    },
    {
      orient:"bottom",
      paddingInner:[0.1,0.05,0.5]
    }
  ],
  tooltip:{
      visible:false
  }
};

const vchart = new VChart(spec, { dom: CONTAINER_ID });
vchart.renderSync();

// Just for the convenience of console debugging, DO NOT COPY!
window['vchart'] = vchart;
```