package main import ( "net/http" "github.com/wcharczuk/go-chart" ) func drawChart(res http.ResponseWriter, req *http.Request) { /* In this example we add a `Renderable` or a custom component to the `Elements` array. In this specific case it is a pre-built renderable (`CreateLegend`) that draws a legend for the chart's series. If you like, you can use `CreateLegend` as a template for writing your own renderable, or even your own legend. */ graph := chart.Chart{ XAxis: chart.XAxis{ Style: chart.Style{Show: true}, }, YAxis: chart.YAxis{ Style: chart.Style{Show: true}, }, Background: chart.Style{ Padding: chart.Box{ Top: 20, Left: 20, }, }, Series: []chart.Series{ chart.ContinuousSeries{ Name: "A test series", XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0}, YValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0}, }, }, } //note we have to do this as a separate step because we need a reference to graph graph.Elements = []chart.Renderable{ chart.CreateLegend(&graph), } res.Header().Set("Content-Type", "image/png") graph.Render(chart.PNG, res) } func main() { http.HandleFunc("/", drawChart) http.ListenAndServe(":8080", nil) }