go-chart/testserver/main.go

package main

import (
	"image/color"
	"log"
	"net/http"

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

func chartHandler(rc *web.RequestContext) web.ControllerResult {
	format, err := rc.RouteParameter("format")
	if err != nil {
		format = "png"
	}

	if format == "png" {
		rc.Response.Header().Set("Content-Type", "image/png")
	} else {
		rc.Response.Header().Set("Content-Type", "image/svg+xml")
	}

	c := chart.Chart{
		Title: "A Test Chart",
		TitleStyle: chart.Style{
			Show:     true,
			FontSize: 26.0,
		},
		Width:  640,
		Height: 480,
		Axes: chart.Style{
			Show:        true,
			StrokeWidth: 1.0,
		},
		YRange: chart.Range{
			Min: 0.0,
			Max: 7.0,
		},
		FinalValueLabel: chart.Style{
			Show: true,
		},
		Series: []chart.Series{
			chart.ContinuousSeries{
				Name:    "a",
				XValues: []float64{1.0, 2.0, 3.0, 4.0},
				YValues: []float64{2.5, 5.0, 2.0, 3.3},
				Style: chart.Style{
					FillColor: color.RGBA{R: 0, G: 116, B: 217, A: 255},
				},
			},
			chart.ContinuousSeries{
				Name:    "b",
				XValues: []float64{3.0, 4.0, 5.0, 6.0},
				YValues: []float64{6.0, 5.0, 4.0, 1.0},
			},
		},
	}

	if format == "png" {
		err = c.Render(chart.PNG, rc.Response)
	} else {
		err = c.Render(chart.SVG, rc.Response)
	}
	if err != nil {
		return rc.API().InternalError(err)
	}
	rc.Response.WriteHeader(http.StatusOK)
	return nil
}

func main() {
	app := web.New()
	app.SetName("Chart Test Server")
	app.SetLogger(web.NewStandardOutputLogger())
	app.GET("/", chartHandler)
	app.GET("/:format", chartHandler)
	log.Fatal(app.Start())
}