fixed dependencies

vendor/gonum.org/v1/plot/plotter/functions.go

@@ -0,0 +1,63 @@
+// Copyright ©2015 The Gonum Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package plotter
+
+import (
+	"gonum.org/v1/plot"
+	"gonum.org/v1/plot/vg"
+	"gonum.org/v1/plot/vg/draw"
+)
+
+// Function implements the Plotter interface,
+// drawing a line for the given function.
+type Function struct {
+	F func(x float64) (y float64)
+
+	// XMin and XMax specify the range
+	// of x values to pass to F.
+	XMin, XMax float64
+
+	Samples int
+
+	draw.LineStyle
+}
+
+// NewFunction returns a Function that plots F using
+// the default line style with 50 samples.
+func NewFunction(f func(float64) float64) *Function {
+	return &Function{
+		F:         f,
+		Samples:   50,
+		LineStyle: DefaultLineStyle,
+	}
+}
+
+// Plot implements the Plotter interface, drawing a line
+// that connects each point in the Line.
+func (f *Function) Plot(c draw.Canvas, p *plot.Plot) {
+	trX, trY := p.Transforms(&c)
+
+	min, max := f.XMin, f.XMax
+	if min == 0 && max == 0 {
+		min = p.X.Min
+		max = p.X.Max
+	}
+	d := (max - min) / float64(f.Samples-1)
+	line := make([]vg.Point, f.Samples)
+	for i := range line {
+		x := min + float64(i)*d
+		line[i].X = trX(x)
+		line[i].Y = trY(f.F(x))
+	}
+	c.StrokeLines(f.LineStyle, c.ClipLinesXY(line)...)
+}
+
+// Thumbnail draws a line in the given style down the
+// center of a DrawArea as a thumbnail representation
+// of the LineStyle of the function.
+func (f Function) Thumbnail(c *draw.Canvas) {
+	y := c.Center().Y
+	c.StrokeLine2(f.LineStyle, c.Min.X, y, c.Max.X, y)
+}