chart.js•2.68 kB
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
import * as echarts from 'echarts';
import { createCanvas/*, registerFont */ } from 'canvas';
import { getNameValueData, getXData, getYData } from './util.js';
// This is an example of how to register a custom font.
// registerFont('./font/xxx.otf', {
// family: 'xxx',
// weight: 'bold',
// });
// This is an example of how to use a custom theme.
// echarts.registerTheme('custom', {
// backgroundColor: '#ccc',
// ...
// });
export function getChartOption(type, data, title, seriesName, xAxisName, yAxisName) {
const option = {
title: {
text: title || 'Chart',
},
series: [
{
type,
data,
name: seriesName,
},
],
};
const series = option.series[0];
switch (type) {
case 'pie':
case 'funnel':
series.data = getNameValueData(data);
break;
}
if (['line', 'bar', 'scatter'].includes(type)) {
const xAxis = getXData(data, xAxisName);
const yAxis = getYData(data, yAxisName);
option.xAxis = xAxis;
option.yAxis = yAxis;
series.label =
data.length < 16
? {
show: true,
}
: null;
}
series.animation = false;
return option;
}
export function getChartBase64(type, data, title, seriesName, xAxisName, yAxisName) {
// Create canvas
const canvas = createCanvas(800, 600);
// Initialize ECharts
let chart = echarts.init(canvas, 'custom');
// Set chart options
const option = getChartOption(type, data, title, seriesName, xAxisName, yAxisName);
chart.setOption(option);
// Return base64 image
const url = canvas.toDataURL();
// Dispose the chart instance
chart.dispose();
chart = null;
return url;
}