last annotation helper

examples/min_max/main.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"net/http"
+
+	"github.com/wcharczuk/go-chart"
+)
+
+func drawChart(res http.ResponseWriter, req *http.Request) {
+	mainSeries := chart.ContinuousSeries{
+		Name:    "A test series",
+		XValues: chart.Sequence.Float64(1.0, 100.0),
+		YValues: chart.Sequence.RandomWithAverage(100, 100, 50),
+	}
+
+	minSeries := &chart.MinSeries{
+		Style: chart.Style{
+			Show:            true,
+			StrokeColor:     chart.ColorAlternateGray,
+			StrokeDashArray: []float64{5.0, 5.0},
+		},
+		InnerSeries: mainSeries,
+	}
+
+	maxSeries := &chart.MaxSeries{
+		Style: chart.Style{
+			Show:            true,
+			StrokeColor:     chart.ColorAlternateGray,
+			StrokeDashArray: []float64{5.0, 5.0},
+		},
+		InnerSeries: mainSeries,
+	}
+
+	graph := chart.Chart{
+		YAxis: chart.YAxis{
+			Style: chart.StyleShow(),
+			Range: &chart.ContinuousRange{
+				Min: 25,
+				Max: 175,
+			},
+		},
+		XAxis: chart.XAxis{
+			Style: chart.StyleShow(),
+		},
+		Series: []chart.Series{
+			mainSeries,
+			minSeries,
+			maxSeries,
+			chart.LastValueAnnotation(minSeries),
+			chart.LastValueAnnotation(maxSeries),
+		},
+	}
+
+	res.Header().Set("Content-Type", "image/png")
+	graph.Render(chart.PNG, res)
+}
+
+func main() {
+	http.HandleFunc("/", drawChart)
+	http.ListenAndServe(":8080", nil)
+}