examples, some fixes

examples/custom_ranges/main.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"net/http"
+
+	"github.com/wcharczuk/go-chart"
+)
+
+func drawChart(res http.ResponseWriter, req *http.Request) {
+	/*
+	   In this example we set a custom range for the y-axis, overriding the automatic range generation.
+	   Note: the chart will still generate the ticks automatically based on the custom range, so the intervals may be a bit weird.
+	*/
+
+	graph := chart.Chart{
+		YAxis: chart.YAxis{
+			Style: chart.Style{
+				Show: true,
+			},
+			Range: chart.Range{
+				Min: 0.0,
+				Max: 10.0,
+			},
+		},
+		Series: []chart.Series{
+			chart.ContinuousSeries{
+				XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
+				YValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
+			},
+		},
+	}
+
+	res.Header().Set("Content-Type", "image/png")
+	graph.Render(chart.PNG, res)
+}
+
+func main() {
+	http.HandleFunc("/", drawChart)
+	http.ListenAndServe(":8080", nil)
+}