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https://github.com/brentp/go-chartjs

golang library to make https://chartjs.org/ plots (this is vanilla #golang, not gopherjs)
https://github.com/brentp/go-chartjs

chart chartjs golang plot plotting

Last synced: 3 months ago
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golang library to make https://chartjs.org/ plots (this is vanilla #golang, not gopherjs)

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chartjs
-------

go wrapper for [chartjs](http://chartjs.org)

[![GoDoc](https://godoc.org/github.com/brentp/go-chartjs?status.png)](https://godoc.org/github.com/brentp/go-chartjs)
[![Build Status](https://travis-ci.org/brentp/go-chartjs.svg)](https://travis-ci.org/brentp/go-chartjs)

Chartjs charts are defined purely in JSON, so this library is mostly
structs and struct-tags that dictate how to marshal to JSON. None of the currently
implemented parts are stringly-typed in this library so it can avoid many errors.

The chartjs javascript/JSON api has a [lot of surface area](http://www.chartjs.org/docs/).
Currently, only the options that I use are provided. More can and will be added as I need
them (or via pull-requests).

There is a small amount of code to simplify creating charts.

data to be plotted by chartjs has to meet this interface.
```Go
type Values interface {
// X-axis values. If only these are specified then it must be a Bar plot.
Xs() []float64
// Optional Y values.
Ys() []float64
// Rs are used to size points for chartType `Bubble`. If this returns an
// empty slice then it's not used.
Rs() []float64
}
```

Example
-------

This longish example shows common use of the library.

```Go
package main

import (
"log"
"math"
"os"

chartjs "github.com/brentp/go-chartjs"
)

// satisfy the required interface with this struct and methods.
type xy struct {
x []float64
y []float64
r []float64
}

func (v xy) Xs() []float64 {
return v.x
}
func (v xy) Ys() []float64 {
return v.y
}
func (v xy) Rs() []float64 {
return v.r
}

func check(e error) {
if e != nil {
log.Fatal(e)
}
}

func main() {
var xys1 xy
var xys2 xy

// make some example data.
for i := float64(0); i < 9; i += 0.1 {
xys1.x = append(xys1.x, i)
xys2.x = append(xys2.x, i)

xys1.y = append(xys1.y, math.Sin(i))
xys2.y = append(xys2.y, 3*math.Cos(2*i))

}

// a set of colors to work with.
colors := []*types.RGBA{
&types.RGBA{102, 194, 165, 220},
&types.RGBA{250, 141, 98, 220},
&types.RGBA{141, 159, 202, 220},
&types.RGBA{230, 138, 195, 220},
}

// a Dataset contains the data and styling info.
d1 := chartjs.Dataset{Data: xys1, BorderColor: colors[1], Label: "sin(x)", Fill: chartjs.False,
PointRadius: 10, PointBorderWidth: 4, BackgroundColor: colors[0]}

d2 := chartjs.Dataset{Data: xys2, BorderWidth: 8, BorderColor: colors[3], Label: "3*cos(2*x)",
Fill: chartjs.False, PointStyle: chartjs.Star}

chart := chartjs.Chart{Label: "test-chart"}

var err error
_, err = chart.AddXAxis(chartjs.Axis{Type: chartjs.Linear, Position: chartjs.Bottom, ScaleLabel: &chartjs.ScaleLabel{FontSize: 22, LabelString: "X", Display: chartjs.True}})
check(err)
d1.YAxisID, err = chart.AddYAxis(chartjs.Axis{Type: chartjs.Linear, Position: chartjs.Left,
ScaleLabel: &chartjs.ScaleLabel{LabelString: "sin(x)", Display: chartjs.True}})
check(err)
chart.AddDataset(d1)

d2.YAxisID, err = chart.AddYAxis(chartjs.Axis{Type: chartjs.Linear, Position: chartjs.Right,
ScaleLabel: &chartjs.ScaleLabel{LabelString: "3*cos(2*x)", Display: chartjs.True}})
check(err)
chart.AddDataset(d2)

chart.Options.Responsive = chartjs.False

wtr, err := os.Create("example-chartjs-multi.html")
if err != nil {
}
if err := chart.SaveHTML(wtr, nil); err != nil {
log.Fatal(err)
}
wtr.Close()
}
```

The resulting html will have an interactive `` element that looks like this.

![plot](https://cloud.githubusercontent.com/assets/1739/20368217/5068a336-ac10-11e6-8d6c-f711c7c71df3.png "example plot")

Live Examples
-------------

[evaluating coverage on high throughput sequencing data](https://brentp.github.io/goleft/indexcov/ex-indexcov-roc.html)

[inferring sex from sequencing coverage on X and Y chroms](https://brentp.github.io/goleft/indexcov/ex-indexcov-sex.html)