go-chart/moving_average_series.go
2016-07-14 09:27:23 -07:00

82 lines
2.0 KiB
Go

package chart
const (
// DefaultMovingAverageWindowSize is the default number of values to average.
DefaultMovingAverageWindowSize = 5
)
// MovingAverageSeries is a computed series.
type MovingAverageSeries struct {
Name string
Style Style
YAxis YAxisType
WindowSize int
InnerSeries ValueProvider
valueBuffer *RingBuffer
}
// GetName returns the name of the time series.
func (mas MovingAverageSeries) GetName() string {
return mas.Name
}
// GetStyle returns the line style.
func (mas MovingAverageSeries) GetStyle() Style {
return mas.Style
}
// GetYAxis returns which YAxis the series draws on.
func (mas MovingAverageSeries) GetYAxis() YAxisType {
return mas.YAxis
}
// Len returns the number of elements in the series.
func (mas *MovingAverageSeries) Len() int {
return mas.InnerSeries.Len()
}
// GetValue gets a value at a given index.
func (mas *MovingAverageSeries) GetValue(index int) (x float64, y float64) {
if mas.valueBuffer == nil {
mas.valueBuffer = NewRingBufferWithCapacity(mas.GetWindowSize())
}
if mas.valueBuffer.Len() >= mas.GetWindowSize() {
mas.valueBuffer.Dequeue()
}
x, y = mas.InnerSeries.GetValue(index)
mas.valueBuffer.Enqueue(y)
if mas.valueBuffer.Len() < mas.GetWindowSize() {
return
}
y = mas.getAverage()
return
}
// GetWindowSize returns the window size.
func (mas MovingAverageSeries) GetWindowSize(defaults ...int) int {
if mas.WindowSize == 0 {
if len(defaults) > 0 {
return defaults[0]
}
return DefaultMovingAverageWindowSize
}
return mas.WindowSize
}
func (mas MovingAverageSeries) getAverage() float64 {
var accum float64
mas.valueBuffer.Each(func(v interface{}) {
if typed, isTyped := v.(float64); isTyped {
accum += typed
}
})
return accum / float64(mas.valueBuffer.Len())
}
// Render renders the series.
func (mas *MovingAverageSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) {
style := mas.Style.WithDefaultsFrom(defaults)
DrawLineSeries(r, canvasBox, xrange, yrange, style, mas)
}