go-charts/charts.go

// MIT License

// Copyright (c) 2021 Tree Xie

// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

package charts

import (
	"bytes"
	"errors"
	"io"

	"github.com/wcharczuk/go-chart/v2"
)

const (
	ThemeLight = "light"
	ThemeDark  = "dark"
)

type (
	Title struct {
		Text string
	}
	Legend struct {
		Data []string
	}
	Option struct {
		Width  int
		Height int
		Theme  string
		XAxis  XAxis
		// YAxis  Axis
		Series       []Series
		Title        Title
		Legend       Legend
		TickPosition chart.TickPosition
	}
)

type Chart interface {
	Render(rp chart.RendererProvider, w io.Writer) error
}

type ECharOption struct {
	Title struct {
		Text      string
		TextStyle struct {
			Color      string
			FontFamily string
		}
	}
	XAxis struct {
		Type        string
		BoundaryGap *bool
		SplitNumber int
		Data        []string
	}
}

func (o *Option) validate() error {
	xAxisCount := len(o.XAxis.Data)
	if len(o.Series) == 0 {
		return errors.New("series can not be empty")
	}

	for _, item := range o.Series {
		if len(item.Data) != xAxisCount {
			return errors.New("series and xAxis is not matched")
		}
	}
	return nil
}

func render(c Chart, rp chart.RendererProvider) ([]byte, error) {
	buf := bytes.Buffer{}
	err := c.Render(rp, &buf)
	if err != nil {
		return nil, err
	}
	return buf.Bytes(), nil
}

func ToPNG(c Chart) ([]byte, error) {
	return render(c, chart.PNG)
}

func ToSVG(c Chart) ([]byte, error) {
	return render(c, chart.SVG)
}
func New(opt Option) (Chart, error) {
	err := opt.validate()
	if err != nil {
		return nil, err
	}
	tickPosition := opt.TickPosition

	xAxis, xValues := GetXAxisAndValues(opt.XAxis, tickPosition, opt.Theme)

	legendSize := len(opt.Legend.Data)
	for index, item := range opt.Series {
		if len(item.XValues) == 0 {
			opt.Series[index].XValues = xValues
		}
		if index < legendSize && opt.Series[index].Name == "" {
			opt.Series[index].Name = opt.Legend.Data[index]
		}
	}
	if opt.Series[0].Type == SeriesPie {
		values := make(chart.Values, len(opt.Series))
		for index, item := range opt.Series {
			values[index] = chart.Value{
				Value: item.Data[0].Value,
				Label: item.Name,
			}
		}
		c := &chart.PieChart{
			Title:  opt.Title.Text,
			Width:  opt.Width,
			Height: opt.Height,
			Values: values,
			ColorPalette: &ThemeColorPalette{
				Theme: opt.Theme,
			},
		}
		return c, nil
	}

	c := &chart.Chart{
		Title:  opt.Title.Text,
		Width:  opt.Width,
		Height: opt.Height,
		XAxis:  xAxis,
		YAxis:  GetYAxis(opt.Theme),
		Series: GetSeries(opt.Series, tickPosition, opt.Theme),
	}

	// 设置secondary的样式
	c.YAxisSecondary.Style = c.YAxis.Style
	if legendSize != 0 {
		c.Elements = []chart.Renderable{
			DefaultLegend(c),
		}
	}
	return c, nil
}