elementHighlightByX

Overview

The elementHighlightByX interaction targets chart elements. When the mouse hovers over an element, it highlights all elements with the same x channel value as the hovered element.

Trigger: Mouse hover over element.
End: Mouse leaves element.
Affected states:

Hovered elements change to active state.

Other elements change to inactive state.

Built-in interaction states:

({
  // Active state elements have 1px black border
  state: { active: { lineWidth: '1', stroke: '#000' } },
});

Getting Started

import { Chart } from '@antv/g2';

const chart = new Chart({ container: 'container' });

chart.options({
  type: 'interval',
  paddingLeft: 50,
  data: {
    type: 'fetch',
    value:
      'https://gw.alipayobjects.com/os/bmw-prod/f129b517-158d-41a9-83a3-3294d639b39e.csv',
    format: 'csv',
  },
  encode: { x: 'state', y: 'population', color: 'age' },
  transform: [
    { type: 'sortX', by: 'y', reverse: true, slice: 6 },
    { type: 'dodgeX' },
  ],
  state: { active: { fill: 'red' }, inactive: { opacity: 0.5 } },
  axis: { y: { labelFormatter: '~s' } },
  interaction: { elementHighlightByX: true },
});

chart.render();

Usage

There are two ways to configure the elementHighlightByX interaction:

First, pass a boolean to set whether to enable the interaction.

({
  type: 'interval',
  interaction: { elementHighlightByX: true }, // Use default configuration
});

Second, pass configuration options to configure the interaction.

({
  type: 'line',
  interaction: {
    elementHighlightByX: {
      background: true,
    },
  },
});

Configuration Level

Interaction can be configured at the Mark level:

({
  type: 'interval',
  interaction: { elementHighlightByX: true },
});

It can also be configured at the View level. Interactions declared on the view will be passed to marks declared in children. If the mark has declared the corresponding interaction, they will be merged; otherwise, it won’t be affected.

({
  type: 'view',
  interaction: { elementHighlightByX: true },
});

Configuration Options

Interaction configuration

Property	Description	Type	Default
background	Whether to highlight background	`boolean`	false
region	Whether to trigger highlight when mouse moves to empty area of element (see below)	`boolean`	false

Element highlight style configuration

Property	Description	Type	Default
offset	Offset in the main direction	`number`	0
background	Whether to highlight background	backgroundStyle	See backgroundStyle

Events

Listening to Events

The following events are supported:

element:highlight - Triggered when element is highlighted
element:unhighlight - Triggered when element highlight is removed

chart.on('element:highlight', (e) => {
  console.log(e.data.data);
  console.log(e.data.group);
  console.log(e.nativeEvent);
});

chart.on('element:unhighlight', (e) => {
  console.log(e.nativeEvent);
});

Triggering Interaction

The following events are supported:

element:highlight - Highlight data
element:unhighlight - Remove highlight

chart.emit('element:highlight', {
  data: { data: { population: 5038433 } },
});

chart.emit('element:unhighlight', {});

Examples

Basic Highlight

import { Chart } from '@antv/g2';

const chart = new Chart({
  container: 'container',
});
chart.options({
  type: 'interval',
  paddingLeft: 50,
  data: {
    type: 'fetch',
    value:
      'https://gw.alipayobjects.com/os/bmw-prod/f129b517-158d-41a9-83a3-3294d639b39e.csv',
    format: 'csv',
  },
  encode: { x: 'state', y: 'population', color: 'age' },
  transform: [
    { type: 'sortX', by: 'y', reverse: true, slice: 6 },
    { type: 'dodgeX' },
  ],
  axis: { y: { labelFormatter: '~s' } },
  interaction: { elementHighlightByX: true },
});

chart.render();

Custom Highlight

import { Chart } from '@antv/g2';

const chart = new Chart({
  container: 'container',
});
chart.options({
  type: 'interval',
  data: {
    type: 'fetch',
    value:
      'https://gw.alipayobjects.com/os/bmw-prod/f129b517-158d-41a9-83a3-3294d639b39e.csv',
    format: 'csv',
  },
  encode: { x: 'state', y: 'population', color: 'age' },
  transform: [
    { type: 'stackY' },
    { type: 'sortX', by: 'y', reverse: true, slice: 5 },
  ],
  state: {
    active: { fill: 'red', linkFillOpacity: 0.5 },
    inactive: { opacity: 0.5 },
  },
  axis: { y: { labelFormatter: '~s' } },
  interaction: { elementHighlightByX: true },
});

chart.render();