101 lines
2.9 KiB
Markdown
101 lines
2.9 KiB
Markdown
go-chart
|
|
========
|
|
|
|
Package `chart` is a very simple golang native charting library that supports timeseries and continuous
|
|
line charts.
|
|
|
|
# Installation
|
|
|
|
To install `chart` run the following:
|
|
|
|
```bash
|
|
> go get -u github.com/wcharczuk/go-chart
|
|
```
|
|
|
|
Most of the components are interchangeable so feel free to crib whatever you want.
|
|
|
|
# Usage
|
|
|
|
|
|
|
|
|
|
The chart code to produce the above is as follows:
|
|
|
|
```go
|
|
// note this assumes that xvalues and yvalues
|
|
// have been pulled from a pricing service.
|
|
graph := chart.Chart{
|
|
Width: 1024,
|
|
Height: 400,
|
|
YAxis: chart.YAxis {
|
|
Style: chart.Style{
|
|
Show: true,
|
|
},
|
|
},
|
|
XAxis: chart.XAxis {
|
|
Style: chart.Style{
|
|
Show: true,
|
|
},
|
|
},
|
|
Series: []chart.Series{
|
|
chart.TimeSeries{
|
|
XValues: xvalues,
|
|
YValues: yvalues,
|
|
Style: chart.Style {
|
|
FillColor: chart.DefaultSeriesStrokeColors[0].WithAlpha(64),
|
|
},
|
|
},
|
|
chart.AnnotationSeries{
|
|
Name: "Last Value",
|
|
Style: chart.Style{
|
|
Show: true,
|
|
StrokeColor: chart.DefaultSeriesStrokeColors[0],
|
|
},
|
|
Annotations: []chart.Annotation{
|
|
chart.Annotation{
|
|
X: float64(xvalues[len(xvalues)-1].Unix()), //todo: helpers for this.
|
|
Y: yvalues[len(yvalues)-1],
|
|
Label: chart.FloatValueFormatter(yvalues[len(yvalues)-1]),
|
|
},
|
|
},
|
|
},
|
|
},
|
|
}
|
|
graph.Render(chart.PNG, buffer) //thats it!
|
|
```
|
|
|
|
The key areas to note are that we have to explicitly turn on two features, the axes and add the last value label annotation series. When calling `.Render(..)` we add a parameter, `chart.PNG` that tells the renderer to use a raster renderer. Another option is to use `chart.SVG` which will use the vector renderer and create an svg representation of the chart.
|
|
|
|
# Alternate Usage
|
|
|
|
You can alternately turn a bunch of features off and constrain the proportions to something like a spark line:
|
|
|
|
|
|
|
|
The code to produce the above would be:
|
|
|
|
```go
|
|
// note this assumes that xvalues and yvalues
|
|
// have been pulled from a pricing service.
|
|
graph := chart.Chart{
|
|
Width: 1024,
|
|
Height: 100,
|
|
Series: []chart.Series{
|
|
chart.TimeSeries{
|
|
XValues: xvalues,
|
|
YValues: yvalues,
|
|
},
|
|
},
|
|
}
|
|
graph.Render(chart.PNG, buffer)
|
|
```
|
|
|
|
# Design Philosophy
|
|
|
|
I wanted to make a charting library that used only native golang, that could be stood up on a server (i.e. it had built in fonts).
|
|
|
|
The goal with the API itself is to have the "zero value be useful", and to require the user to not code more than they absolutely needed.
|
|
|
|
# Contributions
|
|
|
|
This library is super early but contributions are welcome.
|