go-charts: Go Library for Generating SVG/PNG Charts with Apache ECharts Compatibility

go-charts is a Go library built on go-chart that simplifies the creation of data visualizations, supporting SVG and PNG output and three themes (light, dark, grafana).

It offers compatibility with Apache ECharts, allowing developers to generate charts using either go-charts parameters or ECharts JSON configuration, and provides examples for line, bar, and pie charts.

The documentation lists supported chart types (line, bar, pie) and details the extensive configuration options, including canvas type, theme, font, padding, box, dimensions, title, axes, legend, series, and nested children.

Example Go code demonstrates rendering a line chart to PNG and rendering the same chart via ECharts JSON to PNG, with a benchmark showing PNG rendering around 20 ms and SVG even faster.

package main

import (
    "os"
    "path/filepath"

    charts "github.com/vicanso/go-charts"
)

func writeFile(file string, buf []byte) error {
    tmpPath := "./tmp"
    err := os.MkdirAll(tmpPath, 0700)
    if err != nil {
        return err
    }

    file = filepath.Join(tmpPath, file)
    err = os.WriteFile(file, buf, 0600)
    if err != nil {
        return err
    }
    return nil
}

func chartsRender() ([]byte, error) {
    d, err := charts.Render(charts.ChartOption{
        Type: charts.ChartOutputPNG,
        Title: charts.TitleOption{Text: "Line"},
        XAxis: charts.NewXAxisOption([]string{"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"}),
        SeriesList: charts.SeriesList{charts.NewSeriesFromValues([]float64{150, 230, 224, 218, 135, 147, 260})},
    })
    if err != nil {
        return nil, err
    }
    return d.Bytes()
}

func echartsRender() ([]byte, error) {
    return charts.RenderEChartsToPNG(`{
        "title": {"text": "Line"},
        "xAxis": {"data": ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"]},
        "series": [{"data": [150, 230, 224, 218, 135, 147, 260]}]
    }`)
}

type Render func() ([]byte, error)

func main() {
    m := map[string]Render{"charts-line.png": chartsRender, "echarts-line.png": echartsRender}
    for name, fn := range m {
        buf, err := fn()
        if err != nil {
            panic(err)
        }
        err = writeFile(name, buf)
        if err != nil {
            panic(err)
        }
    }
}

Performance benchmarks indicate that generating a simple PNG chart takes about 20 ms, while SVG rendering is faster, offering a significant speed advantage over headless‑Chrome screenshot approaches.

Notes on Chinese character support explain that the default font (Roboto) lacks Chinese glyphs, requiring additional font installation and setting the title text style font family to display Chinese correctly.