Adding upstream version 2.1.2.

Signed-off-by: Daniel Baumann <daniel@debian.org>

examples/timeseries/main.go

@@ -0,0 +1,79 @@
+package main
+
+import (
+	"net/http"
+	"time"
+
+	chart "github.com/wcharczuk/go-chart/v2"
+)
+
+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 appropriate formatter to use for the ticks.
+	*/
+	graph := chart.Chart{
+		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 drawCustomChart(res http.ResponseWriter, req *http.Request) {
+	/*
+	   This is basically the other timeseries example, except we switch to hour intervals and specify a different formatter from default for the xaxis tick labels.
+	*/
+	graph := chart.Chart{
+		XAxis: chart.XAxis{
+			ValueFormatter: chart.TimeHourValueFormatter,
+		},
+		Series: []chart.Series{
+			chart.TimeSeries{
+				XValues: []time.Time{
+					time.Now().Add(-10 * time.Hour),
+					time.Now().Add(-9 * time.Hour),
+					time.Now().Add(-8 * time.Hour),
+					time.Now().Add(-7 * time.Hour),
+					time.Now().Add(-6 * time.Hour),
+					time.Now().Add(-5 * time.Hour),
+					time.Now().Add(-4 * time.Hour),
+					time.Now().Add(-3 * time.Hour),
+					time.Now().Add(-2 * time.Hour),
+					time.Now().Add(-1 * time.Hour),
+					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.HandleFunc("/favicon.ico", func(res http.ResponseWriter, req *http.Request) {
+		res.Write([]byte{})
+	})
+	http.HandleFunc("/custom", drawCustomChart)
+	http.ListenAndServe(":8080", nil)
+}