feat: support pie, radar and funnel chart

examples/pie_chart/main.go

@@ -0,0 +1,83 @@
+package main
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+
+	"github.com/vicanso/go-charts"
+)
+
+func writeFile(buf []byte) error {
+	tmpPath := "./tmp"
+	err := os.MkdirAll(tmpPath, 0700)
+	if err != nil {
+		return err
+	}
+
+	file := filepath.Join(tmpPath, "pie-chart.png")
+	err = ioutil.WriteFile(file, buf, 0600)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func main() {
+	p, err := charts.NewPainter(charts.PainterOptions{
+		Width:  800,
+		Height: 600,
+		Type:   charts.ChartOutputPNG,
+	})
+	if err != nil {
+		panic(err)
+	}
+	_, err = charts.NewPieChart(p, charts.PieChartOption{
+		Title: charts.TitleOption{
+			Text:    "Rainfall vs Evaporation",
+			Subtext: "Fake Data",
+			Left:    charts.PositionCenter,
+		},
+		Padding: charts.Box{
+			Top:    20,
+			Right:  20,
+			Bottom: 20,
+			Left:   20,
+		},
+		Legend: charts.LegendOption{
+			Orient: charts.OrientVertical,
+			Data: []string{
+				"Search Engine",
+				"Direct",
+				"Email",
+				"Union Ads",
+				"Video Ads",
+			},
+			Left: charts.PositionLeft,
+		},
+		SeriesList: charts.NewPieSeriesList([]float64{
+			1048,
+			735,
+			580,
+			484,
+			300,
+		}, charts.PieSeriesOption{
+			Label: charts.SeriesLabel{
+				Show: true,
+			},
+			Radius: "35%",
+		}),
+	}).Render()
+	if err != nil {
+		panic(err)
+	}
+
+	buf, err := p.Bytes()
+	if err != nil {
+		panic(err)
+	}
+	err = writeFile(buf)
+	if err != nil {
+		panic(err)
+	}
+}