// Example_boxPlots draws vertical boxplots.
func Example_boxPlots() *plot.Plot {
rand.Seed(int64(0))
n := 100
uniform := make(plotter.Values, n)
normal := make(plotter.Values, n)
expon := make(plotter.Values, n)
for i := 0; i < n; i++ {
uniform[i] = rand.Float64()
normal[i] = rand.NormFloat64()
expon[i] = rand.ExpFloat64()
}
p, err := plot.New()
if err != nil {
panic(err)
}
p.Title.Text = "Box Plot"
p.Y.Label.Text = "plotter.Values"
// Make boxes for our data and add them to the plot.
p.Add(must(plotter.NewBoxPlot(vg.Points(20), 0, uniform)).(*plotter.BoxPlot),
must(plotter.NewBoxPlot(vg.Points(20), 1, normal)).(*plotter.BoxPlot),
must(plotter.NewBoxPlot(vg.Points(20), 2, expon)).(*plotter.BoxPlot))
// Set the X axis of the plot to nominal with
// the given names for x=0, x=1 and x=2.
p.NominalX("Uniform\nDistribution", "Normal\nDistribution",
"Exponential\nDistribution")
return p
}
// NewBoxPlot returns a new BoxPlot that represents
// the distribution of the given values. The style of
// the box plot is that used for Tukey's schematic
// plots is ``Exploratory Data Analysis.''
//
// An error is returned if the boxplot is created with
// no values.
//
// The fence values are 1.5x the interquartile before
// the first quartile and after the third quartile. Any
// value that is outside of the fences are drawn as
// Outside points. The adjacent values (to which the
// whiskers stretch) are the minimum and maximum
// values that are not outside the fences.
func NewBoxPlot(w vg.Length, loc float64, values Valuer) (*BoxPlot, error) {
if w < 0 {
return nil, errors.New("Negative boxplot width")
}
b := new(BoxPlot)
var err error
if b.fiveStatPlot, err = newFiveStat(w, loc, values); err != nil {
return nil, err
}
b.Width = w
b.CapWidth = 3 * w / 4
b.GlyphStyle = DefaultGlyphStyle
b.BoxStyle = DefaultLineStyle
b.MedianStyle = DefaultLineStyle
b.WhiskerStyle = plot.LineStyle{
Width: vg.Points(0.5),
Dashes: []vg.Length{vg.Points(4), vg.Points(2)},
}
if len(b.Values) == 0 {
b.Width = 0
b.GlyphStyle.Radius = 0
b.BoxStyle.Width = 0
b.MedianStyle.Width = 0
b.WhiskerStyle.Width = 0
}
return b, nil
}
// Example_groupedHorizontalBoxPlots draws vertical boxplots.
func Example_groupedHorizontalBoxPlots() *plot.Plot {
rand.Seed(int64(0))
n := 100
uniform := make(plotter.Values, n)
normal := make(plotter.Values, n)
expon := make(plotter.Values, n)
for i := 0; i < n; i++ {
uniform[i] = rand.Float64()
normal[i] = rand.NormFloat64()
expon[i] = rand.ExpFloat64()
}
p, err := plot.New()
if err != nil {
panic(err)
}
p.Title.Text = "Box Plot"
p.Y.Label.Text = "plotter.Values"
w := vg.Points(20)
for y := 0.0; y < 3.0; y++ {
b0 := must(plotter.MakeHorizBoxPlot(w, y, uniform)).(plotter.HorizBoxPlot)
b0.Offset = -w - vg.Points(3)
b1 := must(plotter.MakeHorizBoxPlot(w, y, normal)).(plotter.HorizBoxPlot)
b2 := must(plotter.MakeHorizBoxPlot(w, y, expon)).(plotter.HorizBoxPlot)
b2.Offset = w + vg.Points(3)
p.Add(b0, b1, b2)
}
p.NominalY("Group 0", "Group 1", "Group 2")
return p
}
// Draw the plotinum logo.
func Example_logo() *plot.Plot {
p, err := plot.New()
if err != nil {
panic(err)
}
plotter.DefaultLineStyle.Width = vg.Points(1)
plotter.DefaultGlyphStyle.Radius = vg.Points(3)
p.Y.Tick.Marker = plot.ConstantTicks([]plot.Tick{
{0, "0"}, {0.25, ""}, {0.5, "0.5"}, {0.75, ""}, {1, "1"},
})
p.X.Tick.Marker = plot.ConstantTicks([]plot.Tick{
{0, "0"}, {0.25, ""}, {0.5, "0.5"}, {0.75, ""}, {1, "1"},
})
pts := plotter.XYs{{0, 0}, {0, 1}, {0.5, 1}, {0.5, 0.6}, {0, 0.6}}
line := must(plotter.NewLine(pts)).(*plotter.Line)
scatter := must(plotter.NewScatter(pts)).(*plotter.Scatter)
p.Add(line, scatter)
pts = plotter.XYs{{1, 0}, {0.75, 0}, {0.75, 0.75}}
line = must(plotter.NewLine(pts)).(*plotter.Line)
scatter = must(plotter.NewScatter(pts)).(*plotter.Scatter)
p.Add(line, scatter)
pts = plotter.XYs{{0.5, 0.5}, {1, 0.5}}
line = must(plotter.NewLine(pts)).(*plotter.Line)
scatter = must(plotter.NewScatter(pts)).(*plotter.Scatter)
p.Add(line, scatter)
return p
}
// Example_groupedBoxPlots draws vertical boxplots.
func Example_groupedBoxPlots() *plot.Plot {
rand.Seed(int64(0))
n := 100
uniform := make(plotter.Values, n)
normal := make(plotter.Values, n)
expon := make(plotter.Values, n)
for i := 0; i < n; i++ {
uniform[i] = rand.Float64()
normal[i] = rand.NormFloat64()
expon[i] = rand.ExpFloat64()
}
p, err := plot.New()
if err != nil {
panic(err)
}
p.Title.Text = "Box Plot"
p.Y.Label.Text = "plotter.Values"
w := vg.Points(20)
for x := 0.0; x < 3.0; x++ {
b0 := must(plotter.NewBoxPlot(w, x, uniform)).(*plotter.BoxPlot)
b0.Offset = -w - vg.Points(3)
b1 := must(plotter.NewBoxPlot(w, x, normal)).(*plotter.BoxPlot)
b2 := must(plotter.NewBoxPlot(w, x, expon)).(*plotter.BoxPlot)
b2.Offset = w + vg.Points(3)
p.Add(b0, b1, b2)
}
// Set the X axis of the plot to nominal with
// the given names for x=0, x=1 and x=2.
p.NominalX("Group 0", "Group 1", "Group 2")
return p
}
// makeLegend returns a legend with the default
// parameter settings.
func makeLegend() (Legend, error) {
font, err := vg.MakeFont(DefaultFont, vg.Points(12))
if err != nil {
return Legend{}, err
}
return Legend{
ThumbnailWidth: vg.Points(20),
TextStyle: TextStyle{Font: font},
}, nil
}
// Example_horizontalBoxPlots draws horizontal boxplots
// with some labels on their points.
func Example_horizontalBoxPlots() *plot.Plot {
rand.Seed(int64(0))
n := 100
uniform := make(valueLabels, n)
normal := make(valueLabels, n)
expon := make(valueLabels, n)
for i := 0; i < n; i++ {
uniform[i].Value = rand.Float64()
uniform[i].Label = fmt.Sprintf("%4.4f", uniform[i].Value)
normal[i].Value = rand.NormFloat64()
normal[i].Label = fmt.Sprintf("%4.4f", normal[i].Value)
expon[i].Value = rand.ExpFloat64()
expon[i].Label = fmt.Sprintf("%4.4f", expon[i].Value)
}
p, err := plot.New()
if err != nil {
panic(err)
}
p.Title.Text = "Horizontal Box Plot"
p.X.Label.Text = "plotter.Values"
// Make boxes for our data and add them to the plot.
uniBox := must(plotter.MakeHorizBoxPlot(vg.Points(20), 0, uniform)).(plotter.HorizBoxPlot)
uniLabels, err := uniBox.OutsideLabels(uniform)
if err != nil {
panic(err)
}
normBox := must(plotter.MakeHorizBoxPlot(vg.Points(20), 1, normal)).(plotter.HorizBoxPlot)
normLabels, err := normBox.OutsideLabels(normal)
if err != nil {
panic(err)
}
expBox := must(plotter.MakeHorizBoxPlot(vg.Points(20), 2, expon)).(plotter.HorizBoxPlot)
expLabels, err := expBox.OutsideLabels(expon)
if err != nil {
panic(err)
}
p.Add(uniBox, uniLabels, normBox, normLabels, expBox, expLabels)
// Add a GlyphBox plotter for debugging.
p.Add(plotter.NewGlyphBoxes())
// Set the Y axis of the plot to nominal with
// the given names for y=0, y=1 and y=2.
p.NominalY("Uniform\nDistribution", "Normal\nDistribution",
"Exponential\nDistribution")
return p
}
// An example of making a histogram.
func Example_histogram() *plot.Plot {
rand.Seed(int64(0))
n := 10000
vals := make(plotter.Values, n)
for i := 0; i < n; i++ {
vals[i] = rand.NormFloat64()
}
p, err := plot.New()
if err != nil {
panic(err)
}
p.Title.Text = "Histogram"
h, err := plotter.NewHist(vals, 16)
if err != nil {
panic(err)
}
h.Normalize(1)
p.Add(h)
// The normal distribution function
norm := plotter.NewFunction(stdNorm)
norm.Color = color.RGBA{R: 255, A: 255}
norm.Width = vg.Points(2)
p.Add(norm)
return p
}
func Example_groupedQuartPlots() *plot.Plot {
rand.Seed(int64(0))
n := 100
uniform := make(plotter.Values, n)
normal := make(plotter.Values, n)
expon := make(plotter.Values, n)
for i := 0; i < n; i++ {
uniform[i] = rand.Float64()
normal[i] = rand.NormFloat64()
expon[i] = rand.ExpFloat64()
}
p, err := plot.New()
if err != nil {
panic(err)
}
p.Title.Text = "Box Plot"
p.Y.Label.Text = "plotter.Values"
w := vg.Points(10)
for x := 0.0; x < 3.0; x++ {
b0 := must(plotter.NewQuartPlot(x, uniform)).(*plotter.QuartPlot)
b0.Offset = -w
b1 := must(plotter.NewQuartPlot(x, normal)).(*plotter.QuartPlot)
b2 := must(plotter.NewQuartPlot(x, expon)).(*plotter.QuartPlot)
b2.Offset = w
p.Add(b0, b1, b2)
}
p.Add(plotter.NewGlyphBoxes())
p.NominalX("Group 0", "Group 1", "Group 2")
return p
}
// DrawGlyph implements the Glyph interface.
func (RingGlyph) DrawGlyph(da *DrawArea, sty GlyphStyle, pt Point) {
da.SetLineStyle(LineStyle{Color: sty.Color, Width: vg.Points(0.5)})
var p vg.Path
p.Move(pt.X+sty.Radius, pt.Y)
p.Arc(pt.X, pt.Y, sty.Radius, 0, 2*math.Pi)
p.Close()
da.Stroke(p)
}
// DrawGlyph implements the Glyph interface.
func (TriangleGlyph) DrawGlyph(da *DrawArea, sty GlyphStyle, pt Point) {
da.SetLineStyle(LineStyle{Color: sty.Color, Width: vg.Points(0.5)})
r := sty.Radius + (sty.Radius-sty.Radius*sinπover6)/2
var p vg.Path
p.Move(pt.X, pt.Y+r)
p.Line(pt.X-r*cosπover6, pt.Y-r*sinπover6)
p.Line(pt.X+r*cosπover6, pt.Y-r*sinπover6)
p.Close()
da.Stroke(p)
}
// DrawGlyph implements the Glyph interface.
func (SquareGlyph) DrawGlyph(da *DrawArea, sty GlyphStyle, pt Point) {
da.SetLineStyle(LineStyle{Color: sty.Color, Width: vg.Points(0.5)})
x := (sty.Radius-sty.Radius*cosπover4)/2 + sty.Radius*cosπover4
var p vg.Path
p.Move(pt.X-x, pt.Y-x)
p.Line(pt.X+x, pt.Y-x)
p.Line(pt.X+x, pt.Y+x)
p.Line(pt.X-x, pt.Y+x)
p.Close()
da.Stroke(p)
}
// Example_points draws some scatter points, a line,
// and a line with points.
func Example_points() *plot.Plot {
rand.Seed(int64(0))
n := 15
scatterData := randomPoints(n)
lineData := randomPoints(n)
linePointsData := randomPoints(n)
p, err := plot.New()
if err != nil {
panic(err)
}
p.Title.Text = "Points Example"
p.X.Label.Text = "X"
p.Y.Label.Text = "Y"
p.Add(plotter.NewGrid())
s := must(plotter.NewScatter(scatterData)).(*plotter.Scatter)
s.GlyphStyle.Color = color.RGBA{R: 255, B: 128, A: 255}
s.GlyphStyle.Radius = vg.Points(3)
l := must(plotter.NewLine(lineData)).(*plotter.Line)
l.LineStyle.Width = vg.Points(1)
l.LineStyle.Dashes = []vg.Length{vg.Points(5), vg.Points(5)}
l.LineStyle.Color = color.RGBA{B: 255, A: 255}
lpLine, lpPoints, err := plotter.NewLinePoints(linePointsData)
if err != nil {
panic(err)
}
lpLine.Color = color.RGBA{G: 255, A: 255}
lpPoints.Shape = plot.CircleGlyph{}
lpPoints.Color = color.RGBA{R: 255, A: 255}
p.Add(s, l, lpLine, lpPoints)
p.Legend.Add("scatter", s)
p.Legend.Add("line", l)
p.Legend.Add("line points", lpLine, lpPoints)
return p
}
// DrawGlyph implements the Glyph interface.
func (CrossGlyph) DrawGlyph(da *DrawArea, sty GlyphStyle, pt Point) {
da.SetLineStyle(LineStyle{Color: sty.Color, Width: vg.Points(0.5)})
r := sty.Radius * cosπover4
var p vg.Path
p.Move(pt.X-r, pt.Y-r)
p.Line(pt.X+r, pt.Y+r)
da.Stroke(p)
p = vg.Path{}
p.Move(pt.X-r, pt.Y+r)
p.Line(pt.X+r, pt.Y-r)
da.Stroke(p)
}
// Example_functions draws some functions.
func Example_functions() *plot.Plot {
p, err := plot.New()
if err != nil {
panic(err)
}
p.Title.Text = "Functions"
p.X.Label.Text = "X"
p.Y.Label.Text = "Y"
quad := plotter.NewFunction(func(x float64) float64 { return x * x })
quad.Color = color.RGBA{B: 255, A: 255}
exp := plotter.NewFunction(func(x float64) float64 { return math.Pow(2, x) })
exp.Dashes = []vg.Length{vg.Points(2), vg.Points(2)}
exp.Width = vg.Points(2)
exp.Color = color.RGBA{G: 255, A: 255}
sin := plotter.NewFunction(func(x float64) float64 { return 10*math.Sin(x) + 50 })
sin.Dashes = []vg.Length{vg.Points(4), vg.Points(5)}
sin.Width = vg.Points(4)
sin.Color = color.RGBA{R: 255, A: 255}
p.Add(quad, exp, sin)
p.Legend.Add("x^2", quad)
p.Legend.Add("2^x", exp)
p.Legend.Add("10*sin(x)+50", sin)
p.Legend.ThumbnailWidth = vg.Inches(0.5)
p.X.Min = 0
p.X.Max = 10
p.Y.Min = 0
p.Y.Max = 100
return p
}
func Example_bubbles() *plot.Plot {
rand.Seed(int64(0))
n := 10
bubbleData := randomTriples(n)
p, err := plot.New()
if err != nil {
panic(err)
}
p.Title.Text = "Bubbles"
p.X.Label.Text = "X"
p.Y.Label.Text = "Y"
bs, err := plotter.NewBubbles(bubbleData, vg.Points(1), vg.Points(20))
if err != nil {
panic(err)
}
bs.Color = color.RGBA{R: 196, B: 128, A: 255}
p.Add(bs)
return p
}
// AddStackedAreaPlots adds stacked area plot plotters to a plot.
// The variadic arguments must be either strings
// or plotter.Valuers. Each valuer adds a stacked area
// plot to the plot below the stacked area plots added
// before it. If a plotter.Valuer is immediately
// preceeded by a string then the string value is used to
// label the legend.
// Plots should be added in order of tallest to shortest,
// because they will be drawn in the order they are added
// (i.e. later plots will be painted over earlier plots).
//
// If an error occurs then none of the plotters are added
// to the plot, and the error is returned.
func AddStackedAreaPlots(plt *plot.Plot, xs plotter.Valuer, vs ...interface{}) error {
var ps []plot.Plotter
names := make(map[*plotter.Line]string)
name := ""
var i int
for _, v := range vs {
switch t := v.(type) {
case string:
name = t
case plotter.Valuer:
if xs.Len() != t.Len() {
return errors.New("X/Y length mismatch")
}
// Make a line plotter and set its style.
l, err := plotter.NewLine(combineXYs{xs: xs, ys: t})
if err != nil {
return err
}
l.LineStyle.Width = vg.Points(0)
color := Color(i)
i++
l.ShadeColor = &color
ps = append(ps, l)
if name != "" {
names[l] = name
name = ""
}
default:
panic(fmt.Sprintf("AddStackedAreaPlots handles strings and plotter.Valuers, got %T", t))
}
}
plt.Add(ps...)
for p, n := range names {
plt.Legend.Add(n, p)
}
return nil
}
// 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
}
// makeAxis returns a default Axis.
//
// The default range is (∞, ∞), and thus any finite
// value is less than Min and greater than Max.
func makeAxis() (Axis, error) {
labelFont, err := vg.MakeFont(DefaultFont, vg.Points(12))
if err != nil {
return Axis{}, err
}
tickFont, err := vg.MakeFont(DefaultFont, vg.Points(10))
if err != nil {
return Axis{}, err
}
a := Axis{
Min: math.Inf(1),
Max: math.Inf(-1),
LineStyle: LineStyle{
Color: color.Black,
Width: vg.Points(0.5),
},
Padding: vg.Points(5),
Scale: LinearScale,
}
a.Label.TextStyle = TextStyle{
Color: color.Black,
Font: labelFont,
}
a.Tick.Label = TextStyle{
Color: color.Black,
Font: tickFont,
}
a.Tick.LineStyle = LineStyle{
Color: color.Black,
Width: vg.Points(0.5),
}
a.Tick.Length = vg.Points(8)
a.Tick.Marker = DefaultTicks
return a, nil
}
// than the max number of GlyphDrawers
// in the DefaultGlyphShapes slice.
func Shape(i int) plot.GlyphDrawer {
n := len(DefaultGlyphShapes)
if i < 0 {
return DefaultGlyphShapes[i%n+n]
}
return DefaultGlyphShapes[i%n]
}
// DefaultDashes is a set of dash patterns used by
// the Dashes function.
var DefaultDashes = [][]vg.Length{
{},
{vg.Points(6), vg.Points(2)},
{vg.Points(2), vg.Points(2)},
{vg.Points(1), vg.Points(1)},
{vg.Points(5), vg.Points(2), vg.Points(1), vg.Points(2)},
{vg.Points(10), vg.Points(2), vg.Points(2), vg.Points(2),
vg.Points(2), vg.Points(2), vg.Points(2), vg.Points(2)},
{vg.Points(10), vg.Points(2), vg.Points(2), vg.Points(2)},
{vg.Points(5), vg.Points(2), vg.Points(5), vg.Points(2),
vg.Points(2), vg.Points(2), vg.Points(2), vg.Points(2)},
// that can be found in the LICENSE file.
package plotter
import (
"github.com/Tradnaiofh/plotinum/plot"
"github.com/Tradnaiofh/plotinum/vg"
"image/color"
)
var (
// DefaultQuartMedianStyle is a fat dot.
DefaultQuartMedianStyle = plot.GlyphStyle{
Color: color.Black,
Radius: vg.Points(1.5),
Shape: plot.CircleGlyph{},
}
// DefaultQuartWhiskerStyle is a hairline.
DefaultQuartWhiskerStyle = plot.LineStyle{
Color: color.Black,
Width: vg.Points(0.5),
Dashes: []vg.Length{},
DashOffs: 0,
}
)
// QuartPlot implements the Plotter interface, drawing
// a plot to represent the distribution of values.
//
func NewGlyphBoxes() *GlyphBoxes {
g := new(GlyphBoxes)
g.Color = color.RGBA{R: 255, A: 255}
g.Width = vg.Points(0.25)
return g
}
import (
"errors"
"image/color"
"math"
"github.com/Tradnaiofh/plotinum/plot"
"github.com/Tradnaiofh/plotinum/vg"
)
var (
// DefaultLineStyle is the default style for drawing
// lines.
DefaultLineStyle = plot.LineStyle{
Color: color.Black,
Width: vg.Points(1),
Dashes: []vg.Length{},
DashOffs: 0,
}
// DefaultGlyphStyle is the default style used
// for gyph marks.
DefaultGlyphStyle = plot.GlyphStyle{
Color: color.Black,
Radius: vg.Points(2.5),
Shape: plot.RingGlyph{},
}
)
// Valuer wraps the Len and Value methods.
type Valuer interface {
// Copyright 2012 The Plotinum Authors. All rights reserved.
// Use of this source code is governed by an MIT-style license
// that can be found in the LICENSE file.
package plotter
import (
"github.com/Tradnaiofh/plotinum/plot"
"github.com/Tradnaiofh/plotinum/vg"
"math"
)
// DefaultCapWidth is the default width of error bar caps.
var DefaultCapWidth = vg.Points(5)
// YErrorBars implements the plot.Plotter, plot.DataRanger,
// and plot.GlyphBoxer interfaces, drawing vertical error
// bars, denoting error in Y values.
type YErrorBars struct {
XYs
// YErrors is a copy of the Y errors for each point.
YErrors
// LineStyle is the style used to draw the error bars.
plot.LineStyle
// CapWidth is the width of the caps drawn at the top
// of each error bar.
CapWidth vg.Length
}
// Use of this source code is governed by an MIT-style license
// that can be found in the LICENSE file.
package plotter
import (
"github.com/Tradnaiofh/plotinum/plot"
"github.com/Tradnaiofh/plotinum/vg"
"image/color"
)
var (
// DefaultGridLineStyle is the default style for grid lines.
DefaultGridLineStyle = plot.LineStyle{
Color: color.Gray{128},
Width: vg.Points(0.25),
}
)
// Grid implements the plot.Plotter interface, drawing
// a set of grid lines at the major tick marks.
type Grid struct {
// Vertical is the style of the vertical lines.
Vertical plot.LineStyle
// Horizontal is the style of the horizontal lines.
Horizontal plot.LineStyle
}
// NewGrid returns a new grid with both vertical and
// horizontal lines using the default grid line style.
package plotter
import (
"errors"
"github.com/Tradnaiofh/plotinum/plot"
"github.com/Tradnaiofh/plotinum/vg"
)
var (
// DefaultFont is the default font for label text.
DefaultFont = plot.DefaultFont
// DefaultFontSize is the default font.
DefaultFontSize = vg.Points(10)
)
// Labels implements the Plotter interface,
// drawing a set of labels at specified points.
type Labels struct {
XYs
// Labels is the set of labels corresponding
// to each point.
Labels []string
// TextStyle is the style of the label text.
plot.TextStyle
// XAlign and YAlign are multiplied by the width