go-charts

go-charts is a Go library for generating charts, based on go-chart. It provides a simpler way to generate various chart types and supports both svg and png formats.

Key features include:

• Supported Formats: svg and png (default is png).
• Themes: light (default), dark, grafana, and ant.
• ECharts Compatibility: Supports Apache ECharts options, allowing developers to generate charts using ECharts-style configurations.
• Supported Chart Types: line, bar, horizontal bar, pie, radar, funnel, and table.

To create an area chart effect using the line chart constructor, set the FillArea field to true in your LineChartOption. You can also control the transparency of the fill using the Opacity field (a uint8 value).

If Opacity is set to 0, the chart uses a default opacity of 200.

opt := LineChartOption{
    FillArea: true,
    Opacity:  128, // Semi-transparent fill
    // ... other options
}

The Formatter field in AxisOption allows you to inject custom text into your axis labels. The library performs a string replacement on the Data slice, replacing every instance of the literal {value} with the corresponding data string.

Example: If Data is []string{"10", "20"} and Formatter is "$ {value}", the rendered labels will be "$ 10" and "$ 20".

You can control the visual density and shape of the bars using BarWidth, BarMargin, and the RoundRadius property within the series data.

• Bar Width & Margin: Use BarWidth and BarMargin in the BarChartOption to override automatic spacing calculations.
• Rounded Bars: Within each series in the SeriesList, you can set RoundRadius. If RoundRadius > 0, the bars will be rendered as rounded rectangles instead of standard rectangles.
• Custom Colors: Individual data items can override the series color using item.Style.FillColor.

By default, line charts may show symbols (dots) at each data point. You can control this behavior using the SymbolShow field in LineChartOption. Because this field is a pointer to a boolean (*bool), you must pass the address of a boolean value.

• To show symbols: Pass a pointer to true.
• To hide symbols: Pass a pointer to false.

// Example of hiding symbols
showSymbols := false
opt := LineChartOption{
    SymbolShow: &showSymbols,
    // ... other options
}

Use charts.LineRender to create a line chart. You provide a 2D slice of float64 values representing the series data and use option functions to configure the title, X-axis data, and legend.

package main

import (
	charts "github.com/vicanso/go-charts/v2"
)

func main() {
	values := [][]float64{
		{
			120,
			132,
			101,
			134,
			90,
			230,
			210,
		},
		// ... other series
	}
	p, err := charts.LineRender(
		values,
		charts.TitleTextOptionFunc("Line"),
		charts.XAxisDataOptionFunc([]string{
			"Mon",
			"Tue",
			"Wed",
			"Thu",
			"Fri",
			"Sat",
			"Sun",
		}),
		charts.LegendLabelsOptionFunc([]string{
			"Email",
			"Union Ads",
			"Video Ads",
			"Direct",
			"Search Engine",
		}, charts.PositionCenter),
	)

	if err != nil {
		panic(err)
	}

	buf, err := p.Bytes()
	if err != nil {
		panic(err)
	}
	// Use buf...
}

Use charts.RadarRender to create radar charts. You must provide RadarIndicatorOptionFunc to define the dimensions (indicators) and their maximum values.

package main

import (
	"github.com/vicanso/go-charts/v2"
)

func main() {
	values := [][]float64{
		{
			4200, 3000, 20000, 35000, 50000, 18000,
		},
		// ... other series
	}
	p, err := charts.RadarRender(
		values,
		charts.TitleTextOptionFunc("Basic Radar Chart"),
		charts.LegendLabelsOptionFunc([]string{"Allocated Budget", "Actual Spending"}),
		charts.RadarIndicatorOptionFunc([]string{
			"Sales", "Administration", "Information Technology",
			"Customer Support", "Development", "Marketing",
		}, []float64{
			6500, 16000, 30000, 38000, 52000, 25000,
		}),
	)
	if err != nil {
		panic(err)
	}

	buf, err := p.Bytes()
	if err != nil {
		panic(err)
	}
}

Use charts.HorizontalBarRender to create a bar chart where bars are oriented horizontally. This is useful for long category names on the Y-axis.

package main

import (
	"github.com/vicanso/go-charts/v2"
)

func main() {
	values := [][]float64{
		{
			18203, 23489, 29034, 104970, 131744, 630230,
		},
		// ... other series
	}
	p, err := charts.HorizontalBarRender(
		values,
		charts.TitleTextOptionFunc("World Population"),
		charts.PaddingOptionFunc(charts.Box{
			Top:    20,
			Right:  40,
			Bottom: 20,
			Left:   20,
		}),
		charts.LegendLabelsOptionFunc([]string{"2011", "2012"}),
		charts.YAxisDataOptionFunc([]string{
			"Brazil", "Indonesia", "USA", "India", "China", "World",
		}),
	)
	if err != nil {
		panic(err)
	}

	buf, err := p.Bytes()
	if err != nil {
		panic(err)
	}
}

Use charts.FunnelRender to create funnel charts from a slice of float64 values.

package main

import (
	"github.com/vicanso/go-charts/v2"
)

func main() {
	values := []float64{100, 80, 60, 40, 20}
	p, err := charts.FunnelRender(
		values,
		charts.TitleTextOptionFunc("Funnel"),
		charts.LegendLabelsOptionFunc([]string{
			"Show", "Click", "Visit", "Inquiry", "Order",
		}),
	)
	if err != nil {
		panic(err)
	}

	buf, err := p.Bytes()
	if err != nil {
		panic(err)
	}
}