// An example of making a bar chart.
func Example_barChart() *plot.Plot {
groupA := plotter.Values{20, 35, 30, 35, 27}
groupB := plotter.Values{25, 32, 34, 20, 25}
groupC := plotter.Values{12, 28, 15, 21, 8}
groupD := plotter.Values{30, 42, 6, 9, 12}
p, err := plot.New()
if err != nil {
panic(err)
}
p.Title.Text = "Bar chart"
p.Y.Label.Text = "Heights"
w := vg.Points(8)
barsA := must(plotter.NewBarChart(groupA, w)).(*plotter.BarChart)
barsA.Color = color.RGBA{R: 255, A: 255}
barsA.Offset = -w / 2
barsB := must(plotter.NewBarChart(groupB, w)).(*plotter.BarChart)
barsB.Color = color.RGBA{R: 196, G: 196, A: 255}
barsB.Offset = w / 2
barsC := must(plotter.NewBarChart(groupC, w)).(*plotter.BarChart)
barsC.Color = color.RGBA{B: 255, A: 255}
barsC.XMin = 6
barsC.Offset = -w / 2
barsD := must(plotter.NewBarChart(groupD, w)).(*plotter.BarChart)
barsD.Color = color.RGBA{B: 255, R: 255, A: 255}
barsD.XMin = 6
barsD.Offset = w / 2
p.Add(barsA, barsB, barsC, barsD)
p.Legend.Add("A", barsA)
p.Legend.Add("B", barsB)
p.Legend.Add("C", barsC)
p.Legend.Add("D", barsD)
p.Legend.Top = true
p.NominalX("Zero", "One", "Two", "Three", "Four", "",
"Six", "Seven", "Eight", "Nine", "Ten")
return p
}
func barchart(path string, data set) error {
font, err := vg.MakeFont("Helvetica", 10)
if err != nil {
return err
}
titleFont, err := vg.MakeFont("Helvetica", 12)
if err != nil {
return err
}
style := plot.TextStyle{Color: color.Gray{0}, Font: font}
p, err := plot.New()
if err != nil {
return err
}
p.Title.Text = titles[filter]
p.Title.TextStyle = plot.TextStyle{Color: color.Gray{0}, Font: titleFont}
p.X.Label.Text = "Length Offset"
p.Y.Label.Text = "Relative Frequency"
p.X.Label.TextStyle = style
p.Y.Label.TextStyle = style
p.X.Tick.Label = style
p.Y.Tick.Label = style
p.Legend.TextStyle = style
barsFivePrime, err := plotter.NewBarChart(&normalised{vals: data.fiveEnd}, 1) // A non-zero width is required to prevent the creation failing.
if err != nil {
return err
}
barsFivePrime.LineStyle.Width = vg.Length(0)
barsFivePrime.Color = plotutil.Color(0)
barsThreePrime, err := plotter.NewBarChart(&normalised{vals: data.threeEnd}, 1) // A non-zero width is required to prevent the creation failing.
if err != nil {
return err
}
barsThreePrime.LineStyle.Width = vg.Length(0)
barsThreePrime.Color = plotutil.Color(1)
p.Add(barsFivePrime, barsThreePrime)
p.Legend.Add("5'-end", barsFivePrime)
p.Legend.Add("3'-end", barsThreePrime)
p.Legend.Top = true
p.NominalX(func() []string {
n := make([]string, len(data.fiveEnd))
for i := range data.fiveEnd {
if v := i - maxLength; v%5 == 0 {
n[i] = fmt.Sprint(v)
}
}
return n
}()...)
c := vgsvg.New(vg.Centimeters(19), vg.Centimeters(10))
da := plot.MakeDrawArea(c)
trX, _ := p.Transforms(&da)
w := ((trX(float64(2*maxLength)) - trX(float64(0))) / vg.Length(2*maxLength)) / 3
barsFivePrime.Width = w
barsFivePrime.Offset = -w / 2
barsThreePrime.Width = w
barsThreePrime.Offset = w / 2
p.Draw(da)
f, err := os.Create(decorate(path, "barchart.svg", filter))
if err != nil {
return err
}
defer f.Close()
_, err = c.WriteTo(f)
return err
}