feat: support horizontal bar chart

examples/horizontal_bar_chart/main.go

@@ -0,0 +1,94 @@
+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, "horizontal-bar-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.NewHorizontalBarChart(p, charts.HorizontalBarChartOption{
+		Title: charts.TitleOption{
+			Text: "World Population",
+		},
+		Padding: charts.Box{
+			Top:    20,
+			Right:  40,
+			Bottom: 20,
+			Left:   20,
+		},
+		Legend: charts.NewLegendOption([]string{
+			"2011",
+			"2012",
+		}),
+		YAxisOptions: charts.NewYAxisOptions([]string{
+			"Brazil",
+			"Indonesia",
+			"USA",
+			"India",
+			"China",
+			"World",
+		}),
+		SeriesList: []charts.Series{
+			{
+				Type: charts.ChartTypeHorizontalBar,
+				Data: charts.NewSeriesDataFromValues([]float64{
+					18203,
+					23489,
+					29034,
+					104970,
+					131744,
+					630230,
+				}),
+			},
+			{
+				Type: charts.ChartTypeHorizontalBar,
+				Data: charts.NewSeriesDataFromValues([]float64{
+					19325,
+					23438,
+					31000,
+					121594,
+					134141,
+					681807,
+				}),
+			},
+		},
+	}).Render()
+	if err != nil {
+		panic(err)
+	}
+
+	buf, err := p.Bytes()
+	if err != nil {
+		panic(err)
+	}
+	err = writeFile(buf)
+	if err != nil {
+		panic(err)
+	}
+}