adding timeseries example.

This commit is contained in:
Will Charczuk 2016-07-16 23:03:01 -07:00
parent ed452c5a7a
commit 3432bd9443
2 changed files with 57 additions and 0 deletions

View file

@ -0,0 +1,48 @@
package main
import (
"net/http"
"time"
"github.com/wcharczuk/go-chart"
)
func drawChart(res http.ResponseWriter, req *http.Request) {
/*
This is an example of using the `TimeSeries` to automatically coerce time.Time values into a continuous xrange.
Note: chart.TimeSeries implements `ValueFormatterProvider` and as a result gives the XAxis the appropariate formatter to use for the ticks.
*/
graph := chart.Chart{
XAxis: chart.XAxis{
Style: chart.Style{
Show: true,
},
},
Series: []chart.Series{
chart.TimeSeries{
XValues: []time.Time{
time.Now().AddDate(0, 0, -10),
time.Now().AddDate(0, 0, -9),
time.Now().AddDate(0, 0, -8),
time.Now().AddDate(0, 0, -7),
time.Now().AddDate(0, 0, -6),
time.Now().AddDate(0, 0, -5),
time.Now().AddDate(0, 0, -4),
time.Now().AddDate(0, 0, -3),
time.Now().AddDate(0, 0, -2),
time.Now().AddDate(0, 0, -1),
time.Now(),
},
YValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0},
},
},
}
res.Header().Set("Content-Type", "image/png")
graph.Render(chart.PNG, res)
}
func main() {
http.HandleFunc("/", drawChart)
http.ListenAndServe(":8080", nil)
}

View file

@ -156,6 +156,15 @@ func SeqRand(samples int, scale float64) []float64 {
return values return values
} }
// SeqDays generates a sequence of timestamps by day, from -days to today.
func SeqDays(days int) []time.Time {
var values []time.Time
for day := days; day >= 0; day-- {
values = append(values, time.Now().AddDate(0, 0, -day))
}
return values
}
// PercentDifference computes the percentage difference between two values. // PercentDifference computes the percentage difference between two values.
// The formula is (v2-v1)/v1. // The formula is (v2-v1)/v1.
func PercentDifference(v1, v2 float64) float64 { func PercentDifference(v1, v2 float64) float64 {