rolling_plot_xy.go

package rolling

import "gonum.org/v1/plot/plotter"

type XYs struct {
	size   int
	start  int
	length int
	data   plotter.XYs
}

func NewXYs(size int) *XYs {
	return &XYs{
		size: size,
		data: make(plotter.XYs, size),
	}
}

var _ plotter.XYer = &XYs{}

func (xy *XYs) Len() int { return xy.length }

func (xy *XYs) XY(i int) (float64, float64) {
	idx := (xy.start + i) % xy.size
	return xy.data.XY(idx)
}

func (xy *XYs) Add(x plotter.XY) {
	end := (xy.start + xy.length) % xy.size
	if xy.length < xy.size {
		xy.length++
	} else {
		xy.start = (xy.start + 1) % xy.size
	}
	xy.data[end] = x
}