legendHighlight

Getting Started

The legendHighlight interaction targets the chart component legend.

• Trigger: Mouse hover over legend items.
• End: Mouse leaves legend items.
• Affected States:

Elements within the selection range become active.

Elements outside the selection range become inactive.

Built-in interaction states:

({
  // Define inactive state element opacity as 0.5
  state: { inactive: { opacity: 0.5 } },
});

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

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

chart.options({
  type: 'interval',
  interaction: { legendHighlight: true },
  data: profit,
  axis: { y: { labelFormatter: '~s' } },
  encode: {
    x: 'month',
    y: ['end', 'start'],
    color:
      d.month === 'Total' ? 'Total' : d.profit > 0 ? 'Increase' : 'Decrease',
  },
  state: { inactive: { opacity: 0.5 } },
  legend: {
    color: {
      state: { inactive: { labelOpacity: 0.5, markerOpacity: 0.5 } },
    },
  },
});

chart.render();

Usage

Pass a boolean to enable or disable the interaction.

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

Configuration Level

Legend highlight interaction can be configured at the View level:

chart.options({ type: 'view', interaction: { legendHighlight: true } });

Configuration Options

The current version of LegendHighlight interaction has no configurable parameters.

To set the inactive state, refer to Element State

Legend Component Configuration

For detailed documentation, see Legend

Events

Listening to Events

• legend:highlight - Triggered when mouse hovers over legend items
• legend:unhighlight - Triggered when mouse leaves legend

chart.on('legend:highlight', (e) => {
  const { nativeEvent, data } = e;
  if (!nativeEvent) return;
  console.log(data);
});

chart.on('legend:unhighlight', (e) => {
  const { nativeEvent } = e;
  if (!nativeEvent) return;
  console.log('unhighlight');
});

Triggering Interaction

• legend:highlight - Highlight data corresponding to legend values
• legend:unhighlight - Cancel highlight state

chart.emit('legend:highlight', {
  data: { channel: 'color', value: 'Increase' },
});

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

Examples

The following example demonstrates the basic interaction functionality of legendHighlight.

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

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

chart.options({
  type: 'interval',
  autoFit: true,
  height: 300,
  data: [
    { name: 'London', month: 'Jan.', value: 18.9 },
    { name: 'London', month: 'Feb.', value: 28.8 },
    { name: 'London', month: 'Mar.', value: 39.3 },
    { name: 'London', month: 'Apr.', value: 81.4 },
    { name: 'London', month: 'May', value: 47 },
    { name: 'London', month: 'Jun.', value: 20.3 },
    { name: 'London', month: 'Jul.', value: 24 },
    { name: 'London', month: 'Aug.', value: 35.6 },
    { name: 'Berlin', month: 'Jan.', value: 12.4 },
    { name: 'Berlin', month: 'Feb.', value: 23.2 },
    { name: 'Berlin', month: 'Mar.', value: 34.5 },
    { name: 'Berlin', month: 'Apr.', value: 99.7 },
    { name: 'Berlin', month: 'May', value: 52.6 },
    { name: 'Berlin', month: 'Jun.', value: 35.5 },
    { name: 'Berlin', month: 'Jul.', value: 37.4 },
    { name: 'Berlin', month: 'Aug.', value: 42.4 },
  ],
  encode: {
    x: 'month',
    y: 'value',
    color: 'name',
  },
  transform: [
    {
      type: 'dodgeX',
      groupBy: 'x',
      orderBy: 'value',
      padding: 0.1,
    },
  ],
  interaction: {
    legendHighlight: {
      series: true,
    },
  },
  state: { inactive: { opacity: 0.5 } },
});

chart.render();