functions_example_test.go

Documentation: gonum.org/v1/plot/plotter

     1  // Copyright ©2015 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  	"math"
    11  
    12  	"gonum.org/v1/plot"
    13  	"gonum.org/v1/plot/plotter"
    14  	"gonum.org/v1/plot/vg"
    15  )
    16  
    17  // ExampleFunction draws some functions.
    18  func ExampleFunction() {
    19  	quad := plotter.NewFunction(func(x float64) float64 { return x * x })
    20  	quad.Color = color.RGBA{B: 255, A: 255}
    21  
    22  	exp := plotter.NewFunction(func(x float64) float64 { return math.Pow(2, x) })
    23  	exp.Dashes = []vg.Length{vg.Points(2), vg.Points(2)}
    24  	exp.Width = vg.Points(2)
    25  	exp.Color = color.RGBA{G: 255, A: 255}
    26  
    27  	sin := plotter.NewFunction(func(x float64) float64 { return 10*math.Sin(x) + 50 })
    28  	sin.Dashes = []vg.Length{vg.Points(4), vg.Points(5)}
    29  	sin.Width = vg.Points(4)
    30  	sin.Color = color.RGBA{R: 255, A: 255}
    31  
    32  	p := plot.New()
    33  	p.Title.Text = "Functions"
    34  	p.X.Label.Text = "X"
    35  	p.Y.Label.Text = "Y"
    36  
    37  	p.Add(quad, exp, sin)
    38  	p.Legend.Add("x^2", quad)
    39  	p.Legend.Add("2^x", exp)
    40  	p.Legend.Add("10*sin(x)+50", sin)
    41  	p.Legend.ThumbnailWidth = 0.5 * vg.Inch
    42  
    43  	p.X.Min = 0
    44  	p.X.Max = 10
    45  	p.Y.Min = 0
    46  	p.Y.Max = 100
    47  
    48  	err := p.Save(200, 200, "testdata/functions.png")
    49  	if err != nil {
    50  		log.Panic(err)
    51  	}
    52  }
    53
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