step_example_test.go

Documentation: gonum.org/v1/plot/plotter

     1  // Copyright ©2018 The Gonum Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package plotter_test
     6  
     7  import (
     8  	"image/color"
     9  	"log"
    10  
    11  	"golang.org/x/exp/rand"
    12  
    13  	"gonum.org/v1/plot"
    14  	"gonum.org/v1/plot/plotter"
    15  	"gonum.org/v1/plot/vg"
    16  	"gonum.org/v1/plot/vg/draw"
    17  )
    18  
    19  func ExampleLine_stepLine() {
    20  	rnd := rand.New(rand.NewSource(1))
    21  
    22  	// randomPoints returns some random x, y points
    23  	// with some interesting kind of trend.
    24  	randomPoints := func(n int, x float64) plotter.XYs {
    25  		pts := make(plotter.XYs, n)
    26  		for i := range pts {
    27  			pts[i].X = float64(i) + x
    28  			pts[i].Y = 5. + 10*rnd.Float64()
    29  		}
    30  		return pts
    31  	}
    32  
    33  	n := 4
    34  
    35  	p := plot.New()
    36  	p.Title.Text = "Step Example"
    37  	p.X.Label.Text = "X"
    38  	p.Y.Label.Text = "Y"
    39  	p.Add(plotter.NewGrid())
    40  
    41  	stepPre, err := plotter.NewLine(randomPoints(n, 0))
    42  	if err != nil {
    43  		log.Panic(err)
    44  	}
    45  	stepPre.StepStyle = plotter.PreStep
    46  	stepPre.FillColor = color.RGBA{R: 196, G: 255, B: 196, A: 255}
    47  
    48  	stepMid, err := plotter.NewLine(randomPoints(n, 3.5))
    49  	if err != nil {
    50  		log.Panic(err)
    51  	}
    52  	stepMid.StepStyle = plotter.MidStep
    53  	stepMid.LineStyle = draw.LineStyle{Color: color.RGBA{R: 196, B: 128, A: 255}, Width: vg.Points(1)}
    54  
    55  	stepMidFilled, err := plotter.NewLine(randomPoints(n, 7))
    56  	if err != nil {
    57  		log.Panic(err)
    58  	}
    59  	stepMidFilled.StepStyle = plotter.MidStep
    60  	stepMidFilled.LineStyle = draw.LineStyle{Color: color.RGBA{R: 196, B: 128, A: 255}, Width: vg.Points(1)}
    61  	stepMidFilled.FillColor = color.RGBA{R: 255, G: 196, B: 196, A: 255}
    62  
    63  	stepPost, err := plotter.NewLine(randomPoints(n, 10.5))
    64  	if err != nil {
    65  		log.Panic(err)
    66  	}
    67  	stepPost.StepStyle = plotter.PostStep
    68  	stepPost.LineStyle.Width = 0
    69  	stepPost.FillColor = color.RGBA{R: 196, G: 196, B: 255, A: 255}
    70  
    71  	p.Add(stepPre, stepMid, stepMidFilled, stepPost)
    72  	p.Legend.Add("pre", stepPre)
    73  	p.Legend.Add("mid", stepMid)
    74  	p.Legend.Add("midFilled", stepMidFilled)
    75  	p.Legend.Add("post", stepPost)
    76  	p.Legend.Top = true
    77  	p.Y.Max = 20
    78  	p.Y.Min = 0
    79  
    80  	err = p.Save(200, 200, "testdata/step.png")
    81  	if err != nil {
    82  		log.Panic(err)
    83  	}
    84  }
    85
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