# go-charts

[![license](https://img.shields.io/badge/license-MIT-blue.svg)](https://github.com/vicanso/go-charts/blob/master/LICENSE)
[![Build Status](https://github.com/vicanso/go-charts/workflows/Test/badge.svg)](https://github.com/vicanso/go-charts/actions)

[中文](./README_zh.md)

`go-charts` base on [go-chart](https://github.com/wcharczuk/go-chart)，it is simpler way for generating charts, which supports `svg` and `png` format and three themes: `light`, `dark` and `grafana`.

`Apache ECharts` is popular among Front-end developers, so `go-charts` supports the option of `Apache ECharts`. Developers can generate charts almost the same as `Apache ECharts`. 

Screenshot of common charts, the left part is light theme, the right part is grafana theme.

![go-charts](./assets/go-charts.png)

## Chart Type

Support three chart types: `line`, `bar` and `pie`.

## Example

The example is for `golang option` and `echarts option`, more examples can be found in the `./examples/` directory.

```go
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

```bash
BenchmarkMultiChartPNGRender-8                78          15216336 ns/op         2298308 B/op       1148 allocs/op
BenchmarkMultiChartSVGRender-8               367           3356325 ns/op        20597282 B/op       3088 allocs/op
```