// AddLinePoints adds Line and Scatter plotters to a
// plot. The variadic arguments must be either strings
// or plotter.XYers. Each plotter.XYer is added to
// the plot using the next color, dashes, and glyph
// shape via the Color, Dashes, and Shape functions.
// If a plotter.XYer is immediately preceeded by
// a string then a legend entry is added to the plot
// using the string as the name.
//
// If an error occurs then none of the plotters are added
// to the plot, and the error is returned.
func AddLinePoints(plt *plot.Plot, vs ...interface{}) error {
var ps []plot.Plotter
names := make(map[[2]plot.Thumbnailer]string)
name := ""
var i int
for _, v := range vs {
switch t := v.(type) {
case string:
name = t
case plotter.XYer:
l, s, err := plotter.NewLinePoints(t)
if err != nil {
return err
}
l.Color = Color(i)
l.Dashes = Dashes(i)
s.Color = Color(i)
s.Shape = Shape(i)
i++
ps = append(ps, l, s)
if name != "" {
names[[2]plot.Thumbnailer{l, s}] = name
name = ""
}
default:
panic(fmt.Sprintf("AddLinePoints handles strings and plotter.XYers, got %T", t))
}
}
plt.Add(ps...)
for ps, n := range names {
plt.Legend.Add(n, ps[0], ps[1])
}
return nil
}
func TestPersistency(t *testing.T) {
// Get some random points
rand.Seed(0) // The default random seed is 1.
n := 15
scatterData := randomPoints(n)
lineData := randomPoints(n)
linePointsData := randomPoints(n)
p, err := plot.New()
if err != nil {
t.Fatalf("error creating plot: %v\n", err)
}
p.Title.Text = "Plot Example"
p.X.Label.Text = "X"
p.Y.Label.Text = "Y"
// Use a custom tick marker function that computes the default
// tick marks and re-labels the major ticks with commas.
p.Y.Tick.Marker = commaTicks{}
// Draw a grid behind the data
p.Add(plotter.NewGrid())
// Make a scatter plotter and set its style.
s, err := plotter.NewScatter(scatterData)
if err != nil {
panic(err)
}
s.GlyphStyle.Color = color.RGBA{R: 255, B: 128, A: 255}
// Make a line plotter and set its style.
l, err := plotter.NewLine(lineData)
if err != nil {
panic(err)
}
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}
// Make a line plotter with points and set its style.
lpLine, lpPoints, err := plotter.NewLinePoints(linePointsData)
if err != nil {
panic(err)
}
lpLine.Color = color.RGBA{G: 255, A: 255}
lpPoints.Shape = draw.PyramidGlyph{}
lpPoints.Color = color.RGBA{R: 255, A: 255}
// Add the plotters to the plot, with a legend
// entry for each
p.Add(s, l, lpLine, lpPoints)
p.Legend.Add("scatter", s)
p.Legend.Add("line", l)
p.Legend.Add("line points", lpLine, lpPoints)
// Save the plot to a PNG file.
err = p.Save(4, 4, "test-persistency.png")
if err != nil {
t.Fatalf("error saving to PNG: %v\n", err)
}
defer os.Remove("test-persistency.png")
buf := new(bytes.Buffer)
enc := gob.NewEncoder(buf)
err = enc.Encode(p)
if err != nil {
t.Fatalf("error gob-encoding plot: %v\n", err)
}
// TODO(sbinet): impl. BinaryMarshal for plot.Plot and vg.Font
// {
// dec := gob.NewDecoder(buf)
// var p plot.Plot
// err = dec.Decode(&p)
// if err != nil {
// t.Fatalf("error gob-decoding plot: %v\n", err)
// }
// // Save the plot to a PNG file.
// err = p.Save(4, 4, "test-persistency-readback.png")
// if err != nil {
// t.Fatalf("error saving to PNG: %v\n", err)
// }
// defer os.Remove("test-persistency-readback.png")
// }
}