api cleaup

_examples/linear_regression/main.go

@@ -10,7 +10,7 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 
 	/*
 		In this example we add a new type of series, a `SimpleMovingAverageSeries` that takes another series as a required argument.
-		InnerSeries only needs to implement `ValueProvider`, so really you could chain `SimpleMovingAverageSeries` together if you wanted.
+		InnerSeries only needs to implement `ValuesProvider`, so really you could chain `SimpleMovingAverageSeries` together if you wanted.
 	*/
 
 	mainSeries := chart.ContinuousSeries{

_examples/poly_regression/main.go

@@ -10,7 +10,7 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 
 	/*
 		In this example we add a new type of series, a `PolynomialRegressionSeries` that takes another series as a required argument.
-		InnerSeries only needs to implement `ValueProvider`, so really you could chain `PolynomialRegressionSeries` together if you wanted.
+		InnerSeries only needs to implement `ValuesProvider`, so really you could chain `PolynomialRegressionSeries` together if you wanted.
 	*/
 
 	mainSeries := chart.ContinuousSeries{

_examples/simple_moving_average/main.go

@@ -10,7 +10,7 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 
 	/*
 		In this example we add a new type of series, a `SimpleMovingAverageSeries` that takes another series as a required argument.
-		InnerSeries only needs to implement `ValueProvider`, so really you could chain `SimpleMovingAverageSeries` together if you wanted.
+		InnerSeries only needs to implement `ValuesProvider`, so really you could chain `SimpleMovingAverageSeries` together if you wanted.
 	*/
 
 	mainSeries := chart.ContinuousSeries{

bollinger_band_series.go

@@ -1,9 +1,6 @@
 package chart
 
-import (
+import "fmt"
-	"fmt"
-	"math"
-)
 
 // BollingerBandsSeries draws bollinger bands for an inner series.
 // Bollinger bands are defined by two lines, one at SMA+k*stddev, one at SMA-k*stdev.
@@ -14,9 +11,9 @@ type BollingerBandsSeries struct {
 
 	Period      int
 	K           float64
-	InnerSeries ValueProvider
+	InnerSeries ValuesProvider
 
-	valueBuffer *RingBuffer
+	valueBuffer *ValueBuffer
 }
 
 // GetName returns the name of the time series.
@@ -42,7 +39,9 @@ func (bbs BollingerBandsSeries) GetPeriod() int {
 	return bbs.Period
 }
 
-// GetK returns the K value.
+// GetK returns the K value, or the number of standard deviations above and below
+// to band the simple moving average with.
+// Typical K value is 2.0.
 func (bbs BollingerBandsSeries) GetK(defaults ...float64) float64 {
 	if bbs.K == 0 {
 		if len(defaults) > 0 {
@@ -54,35 +53,35 @@ func (bbs BollingerBandsSeries) GetK(defaults ...float64) float64 {
 }
 
 // Len returns the number of elements in the series.
-func (bbs *BollingerBandsSeries) Len() int {
+func (bbs BollingerBandsSeries) Len() int {
 	return bbs.InnerSeries.Len()
 }
 
-// GetBoundedValue gets the bounded value for the series.
+// GetBoundedValues gets the bounded value for the series.
-func (bbs *BollingerBandsSeries) GetBoundedValue(index int) (x, y1, y2 float64) {
+func (bbs *BollingerBandsSeries) GetBoundedValues(index int) (x, y1, y2 float64) {
 	if bbs.InnerSeries == nil {
 		return
 	}
 	if bbs.valueBuffer == nil || index == 0 {
-		bbs.valueBuffer = NewRingBufferWithCapacity(bbs.GetPeriod())
+		bbs.valueBuffer = NewValueBufferWithCapacity(bbs.GetPeriod())
 	}
 	if bbs.valueBuffer.Len() >= bbs.GetPeriod() {
 		bbs.valueBuffer.Dequeue()
 	}
-	px, py := bbs.InnerSeries.GetValue(index)
+	px, py := bbs.InnerSeries.GetValues(index)
 	bbs.valueBuffer.Enqueue(py)
 	x = px
 
-	ay := bbs.getAverage(bbs.valueBuffer)
+	ay := Sequence{bbs.valueBuffer}.Average()
-	std := bbs.getStdDev(bbs.valueBuffer)
+	std := Sequence{bbs.valueBuffer}.StdDev()
 
 	y1 = ay + (bbs.GetK() * std)
 	y2 = ay - (bbs.GetK() * std)
 	return
 }
 
-// GetBoundedLastValue returns the last bounded value for the series.
+// GetBoundedLastValues returns the last bounded value for the series.
-func (bbs *BollingerBandsSeries) GetBoundedLastValue() (x, y1, y2 float64) {
+func (bbs *BollingerBandsSeries) GetBoundedLastValues() (x, y1, y2 float64) {
 	if bbs.InnerSeries == nil {
 		return
 	}
@@ -93,15 +92,15 @@ func (bbs *BollingerBandsSeries) GetBoundedLastValue() (x, y1, y2 float64) {
 		startAt = 0
 	}
 
-	vb := NewRingBufferWithCapacity(period)
+	vb := NewValueBufferWithCapacity(period)
 	for index := startAt; index < seriesLength; index++ {
-		xn, yn := bbs.InnerSeries.GetValue(index)
+		xn, yn := bbs.InnerSeries.GetValues(index)
 		vb.Enqueue(yn)
 		x = xn
 	}
 
-	ay := bbs.getAverage(vb)
+	ay := Sequence{vb}.Average()
-	std := bbs.getStdDev(vb)
+	std := Sequence{vb}.StdDev()
 
 	y1 = ay + (bbs.GetK() * std)
 	y2 = ay - (bbs.GetK() * std)
@@ -120,37 +119,6 @@ func (bbs *BollingerBandsSeries) Render(r Renderer, canvasBox Box, xrange, yrang
 	Draw.BoundedSeries(r, canvasBox, xrange, yrange, s, bbs, bbs.GetPeriod())
 }
 
-func (bbs BollingerBandsSeries) getAverage(valueBuffer *RingBuffer) float64 {
-	var accum float64
-	valueBuffer.Each(func(v interface{}) {
-		if typed, isTyped := v.(float64); isTyped {
-			accum += typed
-		}
-	})
-	return accum / float64(valueBuffer.Len())
-}
-
-func (bbs BollingerBandsSeries) getVariance(valueBuffer *RingBuffer) float64 {
-	if valueBuffer.Len() == 0 {
-		return 0
-	}
-
-	var variance float64
-	m := bbs.getAverage(valueBuffer)
-
-	valueBuffer.Each(func(v interface{}) {
-		if n, isTyped := v.(float64); isTyped {
-			variance += (float64(n) - m) * (float64(n) - m)
-		}
-	})
-
-	return variance / float64(valueBuffer.Len())
-}
-
-func (bbs BollingerBandsSeries) getStdDev(valueBuffer *RingBuffer) float64 {
-	return math.Pow(bbs.getVariance(valueBuffer), 0.5)
-}
-
 // Validate validates the series.
 func (bbs BollingerBandsSeries) Validate() error {
 	if bbs.InnerSeries == nil {

bollinger_band_series_test.go

@@ -1,6 +1,7 @@
 package chart
 
 import (
+	"fmt"
 	"math"
 	"testing"
 
@@ -10,9 +11,9 @@ import (
 func TestBollingerBandSeries(t *testing.T) {
 	assert := assert.New(t)
 
-	s1 := mockValueProvider{
+	s1 := mockValuesProvider{
-		X: Sequence.Float64(1.0, 100.0),
+		X: Generate.Float64(1.0, 100.0),
-		Y: Sequence.Random(100, 1024),
+		Y: Generate.Random(100, 1024),
 	}
 
 	bbs := &BollingerBandsSeries{
@@ -24,27 +25,27 @@ func TestBollingerBandSeries(t *testing.T) {
 	y2values := make([]float64, 100)
 
 	for x := 0; x < 100; x++ {
-		xvalues[x], y1values[x], y2values[x] = bbs.GetBoundedValue(x)
+		xvalues[x], y1values[x], y2values[x] = bbs.GetBoundedValues(x)
 	}
 
 	for x := bbs.GetPeriod(); x < 100; x++ {
-		assert.True(y1values[x] > y2values[x])
+		assert.True(y1values[x] > y2values[x], fmt.Sprintf("%v vs. %v", y1values[x], y2values[x]))
 	}
 }
 
 func TestBollingerBandLastValue(t *testing.T) {
 	assert := assert.New(t)
 
-	s1 := mockValueProvider{
+	s1 := mockValuesProvider{
-		X: Sequence.Float64(1.0, 100.0),
+		X: Generate.Float64(1.0, 100.0),
-		Y: Sequence.Float64(1.0, 100.0),
+		Y: Generate.Float64(1.0, 100.0),
 	}
 
 	bbs := &BollingerBandsSeries{
 		InnerSeries: s1,
 	}
 
-	x, y1, y2 := bbs.GetBoundedLastValue()
+	x, y1, y2 := bbs.GetBoundedLastValues()
 	assert.Equal(100.0, x)
 	assert.Equal(101, math.Floor(y1))
 	assert.Equal(83, math.Floor(y2))

chart.go

@@ -177,10 +177,10 @@ func (c Chart) getRanges() (xrange, yrange, yrangeAlt Range) {
 	for _, s := range c.Series {
 		if s.GetStyle().IsZero() || s.GetStyle().Show {
 			seriesAxis := s.GetYAxis()
-			if bvp, isBoundedValueProvider := s.(BoundedValueProvider); isBoundedValueProvider {
+			if bvp, isBoundedValuesProvider := s.(BoundedValuesProvider); isBoundedValuesProvider {
 				seriesLength := bvp.Len()
 				for index := 0; index < seriesLength; index++ {
-					vx, vy1, vy2 := bvp.GetBoundedValue(index)
+					vx, vy1, vy2 := bvp.GetBoundedValues(index)
 
 					minx = math.Min(minx, vx)
 					maxx = math.Max(maxx, vx)
@@ -198,10 +198,10 @@ func (c Chart) getRanges() (xrange, yrange, yrangeAlt Range) {
 						seriesMappedToSecondaryAxis = true
 					}
 				}
-			} else if vp, isValueProvider := s.(ValueProvider); isValueProvider {
+			} else if vp, isValuesProvider := s.(ValuesProvider); isValuesProvider {
 				seriesLength := vp.Len()
 				for index := 0; index < seriesLength; index++ {
-					vx, vy := vp.GetValue(index)
+					vx, vy := vp.GetValues(index)
 
 					minx = math.Min(minx, vx)
 					maxx = math.Max(maxx, vx)

chart_test.go

@@ -391,8 +391,8 @@ func TestChartRegressionBadRangesByUser(t *testing.T) {
 		},
 		Series: []Series{
 			ContinuousSeries{
-				XValues: Sequence.Float64(1.0, 10.0),
+				XValues: Generate.Float64(1.0, 10.0),
-				YValues: Sequence.Float64(1.0, 10.0),
+				YValues: Generate.Float64(1.0, 10.0),
 			},
 		},
 	}
@@ -407,8 +407,8 @@ func TestChartValidatesSeries(t *testing.T) {
 	c := Chart{
 		Series: []Series{
 			ContinuousSeries{
-				XValues: Sequence.Float64(1.0, 10.0),
+				XValues: Generate.Float64(1.0, 10.0),
-				YValues: Sequence.Float64(1.0, 10.0),
+				YValues: Generate.Float64(1.0, 10.0),
 			},
 		},
 	}
@@ -418,7 +418,7 @@ func TestChartValidatesSeries(t *testing.T) {
 	c = Chart{
 		Series: []Series{
 			ContinuousSeries{
-				XValues: Sequence.Float64(1.0, 10.0),
+				XValues: Generate.Float64(1.0, 10.0),
 			},
 		},
 	}
@@ -504,8 +504,8 @@ func TestChartE2ELine(t *testing.T) {
 		},
 		Series: []Series{
 			ContinuousSeries{
-				XValues: Sequence.Float64(0, 4, 1),
+				XValues: Generate.Float64(0, 4, 1),
-				YValues: Sequence.Float64(0, 4, 1),
+				YValues: Generate.Float64(0, 4, 1),
 			},
 		},
 	}
@@ -549,8 +549,8 @@ func TestChartE2ELineWithFill(t *testing.T) {
 					StrokeColor: drawing.ColorBlue,
 					FillColor:   drawing.ColorRed,
 				},
-				XValues: Sequence.Float64(0, 4, 1),
+				XValues: Generate.Float64(0, 4, 1),
-				YValues: Sequence.Float64(0, 4, 1),
+				YValues: Generate.Float64(0, 4, 1),
 			},
 		},
 	}

concat_series.go

@@ -7,7 +7,7 @@ type ConcatSeries []Series
 func (cs ConcatSeries) Len() int {
 	total := 0
 	for _, s := range cs {
-		if typed, isValueProvider := s.(ValueProvider); isValueProvider {
+		if typed, isValuesProvider := s.(ValuesProvider); isValuesProvider {
 			total += typed.Len()
 		}
 	}
@@ -19,10 +19,10 @@ func (cs ConcatSeries) Len() int {
 func (cs ConcatSeries) GetValue(index int) (x, y float64) {
 	cursor := 0
 	for _, s := range cs {
-		if typed, isValueProvider := s.(ValueProvider); isValueProvider {
+		if typed, isValuesProvider := s.(ValuesProvider); isValuesProvider {
 			len := typed.Len()
 			if index < cursor+len {
-				x, y = typed.GetValue(index - cursor) //FENCEPOSTS.
+				x, y = typed.GetValues(index - cursor) //FENCEPOSTS.
 				return
 			}
 			cursor += typed.Len()

concat_series_test.go

@@ -10,18 +10,18 @@ func TestConcatSeries(t *testing.T) {
 	assert := assert.New(t)
 
 	s1 := ContinuousSeries{
-		XValues: Sequence.Float64(1.0, 10.0),
+		XValues: Generate.Float64(1.0, 10.0),
-		YValues: Sequence.Float64(1.0, 10.0),
+		YValues: Generate.Float64(1.0, 10.0),
 	}
 
 	s2 := ContinuousSeries{
-		XValues: Sequence.Float64(11, 20.0),
+		XValues: Generate.Float64(11, 20.0),
-		YValues: Sequence.Float64(10.0, 1.0),
+		YValues: Generate.Float64(10.0, 1.0),
 	}
 
 	s3 := ContinuousSeries{
-		XValues: Sequence.Float64(21, 30.0),
+		XValues: Generate.Float64(21, 30.0),
-		YValues: Sequence.Float64(1.0, 10.0),
+		YValues: Generate.Float64(1.0, 10.0),
 	}
 
 	cs := ConcatSeries([]Series{s1, s2, s3})

continuous_series.go

@@ -31,13 +31,13 @@ func (cs ContinuousSeries) Len() int {
 	return len(cs.XValues)
 }
 
-// GetValue gets a value at a given index.
+// GetValues gets the x,y values at a given index.
-func (cs ContinuousSeries) GetValue(index int) (float64, float64) {
+func (cs ContinuousSeries) GetValues(index int) (float64, float64) {
 	return cs.XValues[index], cs.YValues[index]
 }
 
-// GetLastValue gets the last value.
+// GetLastValues gets the last x,y values.
-func (cs ContinuousSeries) GetLastValue() (float64, float64) {
+func (cs ContinuousSeries) GetLastValues() (float64, float64) {
 	return cs.XValues[len(cs.XValues)-1], cs.YValues[len(cs.YValues)-1]
 }
 

continuous_series_test.go

@@ -12,21 +12,21 @@ func TestContinuousSeries(t *testing.T) {
 
 	cs := ContinuousSeries{
 		Name:    "Test Series",
-		XValues: Sequence.Float64(1.0, 10.0),
+		XValues: Generate.Float64(1.0, 10.0),
-		YValues: Sequence.Float64(1.0, 10.0),
+		YValues: Generate.Float64(1.0, 10.0),
 	}
 
 	assert.Equal("Test Series", cs.GetName())
 	assert.Equal(10, cs.Len())
-	x0, y0 := cs.GetValue(0)
+	x0, y0 := cs.GetValues(0)
 	assert.Equal(1.0, x0)
 	assert.Equal(1.0, y0)
 
-	xn, yn := cs.GetValue(9)
+	xn, yn := cs.GetValues(9)
 	assert.Equal(10.0, xn)
 	assert.Equal(10.0, yn)
 
-	xn, yn = cs.GetLastValue()
+	xn, yn = cs.GetLastValues()
 	assert.Equal(10.0, xn)
 	assert.Equal(10.0, yn)
 }
@@ -53,20 +53,20 @@ func TestContinuousSeriesValidate(t *testing.T) {
 
 	cs := ContinuousSeries{
 		Name:    "Test Series",
-		XValues: Sequence.Float64(1.0, 10.0),
+		XValues: Generate.Float64(1.0, 10.0),
-		YValues: Sequence.Float64(1.0, 10.0),
+		YValues: Generate.Float64(1.0, 10.0),
 	}
 	assert.Nil(cs.Validate())
 
 	cs = ContinuousSeries{
 		Name:    "Test Series",
-		XValues: Sequence.Float64(1.0, 10.0),
+		XValues: Generate.Float64(1.0, 10.0),
 	}
 	assert.NotNil(cs.Validate())
 
 	cs = ContinuousSeries{
 		Name:    "Test Series",
-		YValues: Sequence.Float64(1.0, 10.0),
+		YValues: Generate.Float64(1.0, 10.0),
 	}
 	assert.NotNil(cs.Validate())
 }

draw.go

@@ -10,7 +10,7 @@ var (
 type draw struct{}
 
 // LineSeries draws a line series with a renderer.
-func (d draw) LineSeries(r Renderer, canvasBox Box, xrange, yrange Range, style Style, vs ValueProvider) {
+func (d draw) LineSeries(r Renderer, canvasBox Box, xrange, yrange Range, style Style, vs ValuesProvider) {
 	if vs.Len() == 0 {
 		return
 	}
@@ -18,7 +18,7 @@ func (d draw) LineSeries(r Renderer, canvasBox Box, xrange, yrange Range, style
 	cb := canvasBox.Bottom
 	cl := canvasBox.Left
 
-	v0x, v0y := vs.GetValue(0)
+	v0x, v0y := vs.GetValues(0)
 	x0 := cl + xrange.Translate(v0x)
 	y0 := cb - yrange.Translate(v0y)
 
@@ -31,7 +31,7 @@ func (d draw) LineSeries(r Renderer, canvasBox Box, xrange, yrange Range, style
 		style.GetFillOptions().WriteDrawingOptionsToRenderer(r)
 		r.MoveTo(x0, y0)
 		for i := 1; i < vs.Len(); i++ {
-			vx, vy = vs.GetValue(i)
+			vx, vy = vs.GetValues(i)
 			x = cl + xrange.Translate(vx)
 			y = cb - yrange.Translate(vy)
 			r.LineTo(x, y)
@@ -47,7 +47,7 @@ func (d draw) LineSeries(r Renderer, canvasBox Box, xrange, yrange Range, style
 
 		r.MoveTo(x0, y0)
 		for i := 1; i < vs.Len(); i++ {
-			vx, vy = vs.GetValue(i)
+			vx, vy = vs.GetValues(i)
 			x = cl + xrange.Translate(vx)
 			y = cb - yrange.Translate(vy)
 			r.LineTo(x, y)
@@ -60,7 +60,7 @@ func (d draw) LineSeries(r Renderer, canvasBox Box, xrange, yrange Range, style
 
 		style.GetDotOptions().WriteDrawingOptionsToRenderer(r)
 		for i := 0; i < vs.Len(); i++ {
-			vx, vy = vs.GetValue(i)
+			vx, vy = vs.GetValues(i)
 			x = cl + xrange.Translate(vx)
 			y = cb - yrange.Translate(vy)
 
@@ -82,8 +82,8 @@ func (d draw) LineSeries(r Renderer, canvasBox Box, xrange, yrange Range, style
 	}
 }
 
-// BoundedSeries draws a series that implements BoundedValueProvider.
+// BoundedSeries draws a series that implements BoundedValuesProvider.
-func (d draw) BoundedSeries(r Renderer, canvasBox Box, xrange, yrange Range, style Style, bbs BoundedValueProvider, drawOffsetIndexes ...int) {
+func (d draw) BoundedSeries(r Renderer, canvasBox Box, xrange, yrange Range, style Style, bbs BoundedValuesProvider, drawOffsetIndexes ...int) {
 	drawOffsetIndex := 0
 	if len(drawOffsetIndexes) > 0 {
 		drawOffsetIndex = drawOffsetIndexes[0]
@@ -92,7 +92,7 @@ func (d draw) BoundedSeries(r Renderer, canvasBox Box, xrange, yrange Range, sty
 	cb := canvasBox.Bottom
 	cl := canvasBox.Left
 
-	v0x, v0y1, v0y2 := bbs.GetBoundedValue(0)
+	v0x, v0y1, v0y2 := bbs.GetBoundedValues(0)
 	x0 := cl + xrange.Translate(v0x)
 	y0 := cb - yrange.Translate(v0y1)
 
@@ -107,7 +107,7 @@ func (d draw) BoundedSeries(r Renderer, canvasBox Box, xrange, yrange Range, sty
 	style.GetFillAndStrokeOptions().WriteToRenderer(r)
 	r.MoveTo(x0, y0)
 	for i := 1; i < bbs.Len(); i++ {
-		vx, vy1, vy2 = bbs.GetBoundedValue(i)
+		vx, vy1, vy2 = bbs.GetBoundedValues(i)
 
 		xvalues[i] = vx
 		y2values[i] = vy2
@@ -133,7 +133,7 @@ func (d draw) BoundedSeries(r Renderer, canvasBox Box, xrange, yrange Range, sty
 }
 
 // HistogramSeries draws a value provider as boxes from 0.
-func (d draw) HistogramSeries(r Renderer, canvasBox Box, xrange, yrange Range, style Style, vs ValueProvider, barWidths ...int) {
+func (d draw) HistogramSeries(r Renderer, canvasBox Box, xrange, yrange Range, style Style, vs ValuesProvider, barWidths ...int) {
 	if vs.Len() == 0 {
 		return
 	}
@@ -150,7 +150,7 @@ func (d draw) HistogramSeries(r Renderer, canvasBox Box, xrange, yrange Range, s
 
 	//foreach datapoint, draw a box.
 	for index := 0; index < seriesLength; index++ {
-		vx, vy := vs.GetValue(index)
+		vx, vy := vs.GetValues(index)
 		y0 := yrange.Translate(0)
 		x := cl + xrange.Translate(vx)
 		y := yrange.Translate(vy)

ema_series.go

@@ -14,7 +14,7 @@ type EMASeries struct {
 	YAxis YAxisType
 
 	Period      int
-	InnerSeries ValueProvider
+	InnerSeries ValuesProvider
 
 	cache []float64
 }
@@ -52,23 +52,23 @@ func (ema EMASeries) GetSigma() float64 {
 	return 2.0 / (float64(ema.GetPeriod()) + 1)
 }
 
-// GetValue gets a value at a given index.
+// GetValues gets a value at a given index.
-func (ema *EMASeries) GetValue(index int) (x, y float64) {
+func (ema *EMASeries) GetValues(index int) (x, y float64) {
 	if ema.InnerSeries == nil {
 		return
 	}
 	if len(ema.cache) == 0 {
 		ema.ensureCachedValues()
 	}
-	vx, _ := ema.InnerSeries.GetValue(index)
+	vx, _ := ema.InnerSeries.GetValues(index)
 	x = vx
 	y = ema.cache[index]
 	return
 }
 
-// GetLastValue computes the last moving average value but walking back window size samples,
+// GetLastValues computes the last moving average value but walking back window size samples,
 // and recomputing the last moving average chunk.
-func (ema *EMASeries) GetLastValue() (x, y float64) {
+func (ema *EMASeries) GetLastValues() (x, y float64) {
 	if ema.InnerSeries == nil {
 		return
 	}
@@ -76,7 +76,7 @@ func (ema *EMASeries) GetLastValue() (x, y float64) {
 		ema.ensureCachedValues()
 	}
 	lastIndex := ema.InnerSeries.Len() - 1
-	x, _ = ema.InnerSeries.GetValue(lastIndex)
+	x, _ = ema.InnerSeries.GetValues(lastIndex)
 	y = ema.cache[lastIndex]
 	return
 }
@@ -86,7 +86,7 @@ func (ema *EMASeries) ensureCachedValues() {
 	ema.cache = make([]float64, seriesLength)
 	sigma := ema.GetSigma()
 	for x := 0; x < seriesLength; x++ {
-		_, y := ema.InnerSeries.GetValue(x)
+		_, y := ema.InnerSeries.GetValues(x)
 		if x == 0 {
 			ema.cache[x] = y
 			continue

ema_series_test.go

@@ -7,7 +7,7 @@ import (
 )
 
 var (
-	emaXValues = Sequence.Float64(1.0, 50.0)
+	emaXValues = Generate.Float64(1.0, 50.0)
 	emaYValues = []float64{
 		1, 2, 3, 4, 5, 4, 3, 2,
 		1, 2, 3, 4, 5, 4, 3, 2,
@@ -75,7 +75,7 @@ var (
 func TestEMASeries(t *testing.T) {
 	assert := assert.New(t)
 
-	mockSeries := mockValueProvider{
+	mockSeries := mockValuesProvider{
 		emaXValues,
 		emaYValues,
 	}
@@ -91,7 +91,7 @@ func TestEMASeries(t *testing.T) {
 
 	var yvalues []float64
 	for x := 0; x < ema.Len(); x++ {
-		_, y := ema.GetValue(x)
+		_, y := ema.GetValues(x)
 		yvalues = append(yvalues, y)
 	}
 
@@ -99,7 +99,7 @@ func TestEMASeries(t *testing.T) {
 		assert.InDelta(yv, emaExpected[index], emaDelta)
 	}
 
-	lvx, lvy := ema.GetLastValue()
+	lvx, lvy := ema.GetLastValues()
 	assert.Equal(50.0, lvx)
 	assert.InDelta(lvy, emaExpected[49], emaDelta)
 }

generate.go

@@ -0,0 +1,190 @@
+package chart
+
+import (
+	"math/rand"
+	"time"
+)
+
+var (
+	// Generate contains some sequence generation utilities.
+	// These utilities can be useful for generating test data.
+	Generate = &generate{
+		rnd: rand.New(rand.NewSource(time.Now().Unix())),
+	}
+)
+
+type generate struct {
+	rnd *rand.Rand
+}
+
+// Float64 produces an array of floats from [start,end] by optional steps.
+func (g generate) Float64(start, end float64, steps ...float64) []float64 {
+	var values []float64
+	step := 1.0
+	if len(steps) > 0 {
+		step = steps[0]
+	}
+
+	if start < end {
+		for x := start; x <= end; x += step {
+			values = append(values, x)
+		}
+	} else {
+		for x := start; x >= end; x = x - step {
+			values = append(values, x)
+		}
+	}
+	return values
+}
+
+// Random generates a fixed length sequence of random values between (0, scale).
+func (g generate) Random(samples int, scale float64) []float64 {
+	values := make([]float64, samples)
+
+	for x := 0; x < samples; x++ {
+		values[x] = g.rnd.Float64() * scale
+	}
+
+	return values
+}
+
+// Random generates a fixed length sequence of random values with a given average, above and below that average by (-scale, scale)
+func (g generate) RandomWithAverage(samples int, average, scale float64) []float64 {
+	values := make([]float64, samples)
+
+	for x := 0; x < samples; x++ {
+		jitter := scale - (g.rnd.Float64() * (2 * scale))
+		values[x] = average + jitter
+	}
+
+	return values
+}
+
+// Days generates a sequence of timestamps by day, from -days to today.
+func (g generate) Days(days int) []time.Time {
+	var values []time.Time
+	for day := days; day >= 0; day-- {
+		values = append(values, time.Now().AddDate(0, 0, -day))
+	}
+	return values
+}
+
+func (g generate) MarketHours(from, to time.Time, marketOpen, marketClose time.Time, isHoliday HolidayProvider) []time.Time {
+	var times []time.Time
+	cursor := Date.On(marketOpen, from)
+	toClose := Date.On(marketClose, to)
+	for cursor.Before(toClose) || cursor.Equal(toClose) {
+		todayOpen := Date.On(marketOpen, cursor)
+		todayClose := Date.On(marketClose, cursor)
+		isValidTradingDay := !isHoliday(cursor) && Date.IsWeekDay(cursor.Weekday())
+
+		if (cursor.Equal(todayOpen) || cursor.After(todayOpen)) && (cursor.Equal(todayClose) || cursor.Before(todayClose)) && isValidTradingDay {
+			times = append(times, cursor)
+		}
+		if cursor.After(todayClose) {
+			cursor = Date.NextMarketOpen(cursor, marketOpen, isHoliday)
+		} else {
+			cursor = Date.NextHour(cursor)
+		}
+	}
+	return times
+}
+
+func (g generate) MarketHourQuarters(from, to time.Time, marketOpen, marketClose time.Time, isHoliday HolidayProvider) []time.Time {
+	var times []time.Time
+	cursor := Date.On(marketOpen, from)
+	toClose := Date.On(marketClose, to)
+	for cursor.Before(toClose) || cursor.Equal(toClose) {
+
+		isValidTradingDay := !isHoliday(cursor) && Date.IsWeekDay(cursor.Weekday())
+
+		if isValidTradingDay {
+			todayOpen := Date.On(marketOpen, cursor)
+			todayNoon := Date.NoonOn(cursor)
+			today2pm := Date.On(Date.Time(14, 0, 0, 0, cursor.Location()), cursor)
+			todayClose := Date.On(marketClose, cursor)
+			times = append(times, todayOpen, todayNoon, today2pm, todayClose)
+		}
+
+		cursor = Date.NextDay(cursor)
+	}
+	return times
+}
+
+func (g generate) MarketDayCloses(from, to time.Time, marketOpen, marketClose time.Time, isHoliday HolidayProvider) []time.Time {
+	var times []time.Time
+	cursor := Date.On(marketOpen, from)
+	toClose := Date.On(marketClose, to)
+	for cursor.Before(toClose) || cursor.Equal(toClose) {
+		isValidTradingDay := !isHoliday(cursor) && Date.IsWeekDay(cursor.Weekday())
+		if isValidTradingDay {
+			todayClose := Date.On(marketClose, cursor)
+			times = append(times, todayClose)
+		}
+
+		cursor = Date.NextDay(cursor)
+	}
+	return times
+}
+
+func (g generate) MarketDayAlternateCloses(from, to time.Time, marketOpen, marketClose time.Time, isHoliday HolidayProvider) []time.Time {
+	var times []time.Time
+	cursor := Date.On(marketOpen, from)
+	toClose := Date.On(marketClose, to)
+	for cursor.Before(toClose) || cursor.Equal(toClose) {
+		isValidTradingDay := !isHoliday(cursor) && Date.IsWeekDay(cursor.Weekday())
+		if isValidTradingDay {
+			todayClose := Date.On(marketClose, cursor)
+			times = append(times, todayClose)
+		}
+
+		cursor = cursor.AddDate(0, 0, 2)
+	}
+	return times
+}
+
+func (g generate) MarketDayMondayCloses(from, to time.Time, marketOpen, marketClose time.Time, isHoliday HolidayProvider) []time.Time {
+	var times []time.Time
+	cursor := Date.On(marketClose, from)
+	toClose := Date.On(marketClose, to)
+
+	for cursor.Equal(toClose) || cursor.Before(toClose) {
+		isValidTradingDay := !isHoliday(cursor) && Date.IsWeekDay(cursor.Weekday())
+		if isValidTradingDay {
+			times = append(times, cursor)
+		}
+		cursor = Date.NextDayOfWeek(cursor, time.Monday)
+	}
+	return times
+}
+
+func (g generate) Hours(start time.Time, totalHours int) []time.Time {
+	times := make([]time.Time, totalHours)
+
+	last := start
+	for i := 0; i < totalHours; i++ {
+		times[i] = last
+		last = last.Add(time.Hour)
+	}
+
+	return times
+}
+
+// HoursFilled adds zero values for the data bounded by the start and end of the xdata array.
+func (g generate) HoursFilled(xdata []time.Time, ydata []float64) ([]time.Time, []float64) {
+	start := Date.Start(xdata)
+	end := Date.End(xdata)
+
+	totalHours := Math.AbsInt(Date.DiffHours(start, end))
+
+	finalTimes := g.Hours(start, totalHours+1)
+	finalValues := make([]float64, totalHours+1)
+
+	var hoursFromStart int
+	for i, xd := range xdata {
+		hoursFromStart = Date.DiffHours(start, xd)
+		finalValues[hoursFromStart] = ydata[i]
+	}
+
+	return finalTimes, finalValues
+}

generate_test.go

@@ -10,10 +10,10 @@ import (
 func TestSequenceFloat64(t *testing.T) {
 	assert := assert.New(t)
 
-	asc := Sequence.Float64(1.0, 10.0)
+	asc := Generate.Float64(1.0, 10.0)
 	assert.Len(asc, 10)
 
-	desc := Sequence.Float64(10.0, 1.0)
+	desc := Generate.Float64(10.0, 1.0)
 	assert.Len(desc, 10)
 }
 
@@ -21,7 +21,7 @@ func TestSequenceMarketHours(t *testing.T) {
 	assert := assert.New(t)
 
 	today := time.Date(2016, 07, 01, 12, 0, 0, 0, Date.Eastern())
-	mh := Sequence.MarketHours(today, today, NYSEOpen(), NYSEClose(), Date.IsNYSEHoliday)
+	mh := Generate.MarketHours(today, today, NYSEOpen(), NYSEClose(), Date.IsNYSEHoliday)
 	assert.Len(mh, 8)
 	assert.Equal(Date.Eastern(), mh[0].Location())
 }
@@ -29,7 +29,7 @@ func TestSequenceMarketHours(t *testing.T) {
 func TestSequenceMarketQuarters(t *testing.T) {
 	assert := assert.New(t)
 	today := time.Date(2016, 07, 01, 12, 0, 0, 0, Date.Eastern())
-	mh := Sequence.MarketHourQuarters(today, today, NYSEOpen(), NYSEClose(), Date.IsNYSEHoliday)
+	mh := Generate.MarketHourQuarters(today, today, NYSEOpen(), NYSEClose(), Date.IsNYSEHoliday)
 	assert.Len(mh, 4)
 	assert.Equal(9, mh[0].Hour())
 	assert.Equal(30, mh[0].Minute())
@@ -48,7 +48,7 @@ func TestSequenceHours(t *testing.T) {
 	assert := assert.New(t)
 
 	today := time.Date(2016, 07, 01, 12, 0, 0, 0, time.UTC)
-	seq := Sequence.Hours(today, 24)
+	seq := Generate.Hours(today, 24)
 
 	end := Date.End(seq)
 	assert.Len(seq, 24)
@@ -81,7 +81,7 @@ func TestSequenceHoursFill(t *testing.T) {
 		0.6,
 	}
 
-	filledTimes, filledValues := Sequence.HoursFill(xdata, ydata)
+	filledTimes, filledValues := Generate.HoursFilled(xdata, ydata)
 	assert.Len(filledTimes, Date.DiffHours(Date.Start(xdata), Date.End(xdata))+1)
 	assert.Equal(len(filledValues), len(filledTimes))
 

histogram_series.go

@@ -9,7 +9,7 @@ type HistogramSeries struct {
 	Name        string
 	Style       Style
 	YAxis       YAxisType
-	InnerSeries ValueProvider
+	InnerSeries ValuesProvider
 }
 
 // GetName implements Series.GetName.
@@ -27,19 +27,19 @@ func (hs HistogramSeries) GetYAxis() YAxisType {
 	return hs.YAxis
 }
 
-// Len implements BoundedValueProvider.Len.
+// Len implements BoundedValuesProvider.Len.
 func (hs HistogramSeries) Len() int {
 	return hs.InnerSeries.Len()
 }
 
-// GetValue implements ValueProvider.GetValue.
+// GetValues implements ValuesProvider.GetValues.
-func (hs HistogramSeries) GetValue(index int) (x, y float64) {
+func (hs HistogramSeries) GetValues(index int) (x, y float64) {
-	return hs.InnerSeries.GetValue(index)
+	return hs.InnerSeries.GetValues(index)
 }
 
-// GetBoundedValue implements BoundedValueProvider.GetBoundedValue
+// GetBoundedValues implements BoundedValuesProvider.GetBoundedValue
-func (hs HistogramSeries) GetBoundedValue(index int) (x, y1, y2 float64) {
+func (hs HistogramSeries) GetBoundedValues(index int) (x, y1, y2 float64) {
-	vx, vy := hs.InnerSeries.GetValue(index)
+	vx, vy := hs.InnerSeries.GetValues(index)
 
 	x = vx
 

histogram_series_test.go

@@ -11,8 +11,8 @@ func TestHistogramSeries(t *testing.T) {
 
 	cs := ContinuousSeries{
 		Name:    "Test Series",
-		XValues: Sequence.Float64(1.0, 20.0),
+		XValues: Generate.Float64(1.0, 20.0),
-		YValues: Sequence.Float64(10.0, -10.0),
+		YValues: Generate.Float64(10.0, -10.0),
 	}
 
 	hs := HistogramSeries{
@@ -20,8 +20,8 @@ func TestHistogramSeries(t *testing.T) {
 	}
 
 	for x := 0; x < hs.Len(); x++ {
-		csx, csy := cs.GetValue(0)
+		csx, csy := cs.GetValues(0)
-		hsx, hsy1, hsy2 := hs.GetBoundedValue(0)
+		hsx, hsy1, hsy2 := hs.GetBoundedValues(0)
 		assert.Equal(csx, hsx)
 		assert.True(hsy1 > 0)
 		assert.True(hsy2 <= 0)

last_value_annotation_series.go

@@ -3,7 +3,7 @@ package chart
 import "fmt"
 
 // LastValueAnnotation returns an annotation series of just the last value of a value provider.
-func LastValueAnnotation(innerSeries ValueProvider, vfs ...ValueFormatter) AnnotationSeries {
+func LastValueAnnotation(innerSeries ValuesProvider, vfs ...ValueFormatter) AnnotationSeries {
 	var vf ValueFormatter
 	if len(vfs) > 0 {
 		vf = vfs[0]
@@ -14,11 +14,11 @@ func LastValueAnnotation(innerSeries ValueProvider, vfs ...ValueFormatter) Annot
 	}
 
 	var lastValue Value2
-	if typed, isTyped := innerSeries.(LastValueProvider); isTyped {
+	if typed, isTyped := innerSeries.(LastValuesProvider); isTyped {
-		lastValue.XValue, lastValue.YValue = typed.GetLastValue()
+		lastValue.XValue, lastValue.YValue = typed.GetLastValues()
 		lastValue.Label = vf(lastValue.YValue)
 	} else {
-		lastValue.XValue, lastValue.YValue = innerSeries.GetValue(innerSeries.Len() - 1)
+		lastValue.XValue, lastValue.YValue = innerSeries.GetValues(innerSeries.Len() - 1)
 		lastValue.Label = vf(lastValue.YValue)
 	}
 

linear_regression_series.go

@@ -11,7 +11,7 @@ type LinearRegressionSeries struct {
 
 	Limit       int
 	Offset      int
-	InnerSeries ValueProvider
+	InnerSeries ValuesProvider
 
 	m       float64
 	b       float64
@@ -62,8 +62,8 @@ func (lrs LinearRegressionSeries) GetOffset() int {
 	return lrs.Offset
 }
 
-// GetValue gets a value at a given index.
+// GetValues gets a value at a given index.
-func (lrs *LinearRegressionSeries) GetValue(index int) (x, y float64) {
+func (lrs *LinearRegressionSeries) GetValues(index int) (x, y float64) {
 	if lrs.InnerSeries == nil || lrs.InnerSeries.Len() == 0 {
 		return
 	}
@@ -72,13 +72,13 @@ func (lrs *LinearRegressionSeries) GetValue(index int) (x, y float64) {
 	}
 	offset := lrs.GetOffset()
 	effectiveIndex := Math.MinInt(index+offset, lrs.InnerSeries.Len())
-	x, y = lrs.InnerSeries.GetValue(effectiveIndex)
+	x, y = lrs.InnerSeries.GetValues(effectiveIndex)
 	y = (lrs.m * lrs.normalize(x)) + lrs.b
 	return
 }
 
-// GetLastValue computes the last linear regression value.
+// GetLastValues computes the last linear regression value.
-func (lrs *LinearRegressionSeries) GetLastValue() (x, y float64) {
+func (lrs *LinearRegressionSeries) GetLastValues() (x, y float64) {
 	if lrs.InnerSeries == nil || lrs.InnerSeries.Len() == 0 {
 		return
 	}
@@ -86,7 +86,7 @@ func (lrs *LinearRegressionSeries) GetLastValue() (x, y float64) {
 		lrs.computeCoefficients()
 	}
 	endIndex := lrs.GetEndIndex()
-	x, y = lrs.InnerSeries.GetValue(endIndex)
+	x, y = lrs.InnerSeries.GetValues(endIndex)
 	y = (lrs.m * lrs.normalize(x)) + lrs.b
 	return
 }
@@ -102,18 +102,18 @@ func (lrs *LinearRegressionSeries) computeCoefficients() {
 
 	p := float64(endIndex - startIndex)
 
-	xvalues := NewRingBufferWithCapacity(lrs.Len())
+	xvalues := NewValueBufferWithCapacity(lrs.Len())
 	for index := startIndex; index < endIndex; index++ {
-		x, _ := lrs.InnerSeries.GetValue(index)
+		x, _ := lrs.InnerSeries.GetValues(index)
 		xvalues.Enqueue(x)
 	}
 
-	lrs.avgx = xvalues.Average()
+	lrs.avgx = Sequence{xvalues}.Average()
-	lrs.stddevx = xvalues.StdDev()
+	lrs.stddevx = Sequence{xvalues}.StdDev()
 
 	var sumx, sumy, sumxx, sumxy float64
 	for index := startIndex; index < endIndex; index++ {
-		x, y := lrs.InnerSeries.GetValue(index)
+		x, y := lrs.InnerSeries.GetValues(index)
 
 		x = lrs.normalize(x)
 

linear_regression_series_test.go

@@ -11,19 +11,19 @@ func TestLinearRegressionSeries(t *testing.T) {
 
 	mainSeries := ContinuousSeries{
 		Name:    "A test series",
-		XValues: Sequence.Float64(1.0, 100.0),
+		XValues: Generate.Float64(1.0, 100.0),
-		YValues: Sequence.Float64(1.0, 100.0),
+		YValues: Generate.Float64(1.0, 100.0),
 	}
 
 	linRegSeries := &LinearRegressionSeries{
 		InnerSeries: mainSeries,
 	}
 
-	lrx0, lry0 := linRegSeries.GetValue(0)
+	lrx0, lry0 := linRegSeries.GetValues(0)
 	assert.InDelta(1.0, lrx0, 0.0000001)
 	assert.InDelta(1.0, lry0, 0.0000001)
 
-	lrxn, lryn := linRegSeries.GetLastValue()
+	lrxn, lryn := linRegSeries.GetLastValues()
 	assert.InDelta(100.0, lrxn, 0.0000001)
 	assert.InDelta(100.0, lryn, 0.0000001)
 }
@@ -33,19 +33,19 @@ func TestLinearRegressionSeriesDesc(t *testing.T) {
 
 	mainSeries := ContinuousSeries{
 		Name:    "A test series",
-		XValues: Sequence.Float64(100.0, 1.0),
+		XValues: Generate.Float64(100.0, 1.0),
-		YValues: Sequence.Float64(100.0, 1.0),
+		YValues: Generate.Float64(100.0, 1.0),
 	}
 
 	linRegSeries := &LinearRegressionSeries{
 		InnerSeries: mainSeries,
 	}
 
-	lrx0, lry0 := linRegSeries.GetValue(0)
+	lrx0, lry0 := linRegSeries.GetValues(0)
 	assert.InDelta(100.0, lrx0, 0.0000001)
 	assert.InDelta(100.0, lry0, 0.0000001)
 
-	lrxn, lryn := linRegSeries.GetLastValue()
+	lrxn, lryn := linRegSeries.GetLastValues()
 	assert.InDelta(1.0, lrxn, 0.0000001)
 	assert.InDelta(1.0, lryn, 0.0000001)
 }
@@ -55,8 +55,8 @@ func TestLinearRegressionSeriesWindowAndOffset(t *testing.T) {
 
 	mainSeries := ContinuousSeries{
 		Name:    "A test series",
-		XValues: Sequence.Float64(100.0, 1.0),
+		XValues: Generate.Float64(100.0, 1.0),
-		YValues: Sequence.Float64(100.0, 1.0),
+		YValues: Generate.Float64(100.0, 1.0),
 	}
 
 	linRegSeries := &LinearRegressionSeries{
@@ -67,11 +67,11 @@ func TestLinearRegressionSeriesWindowAndOffset(t *testing.T) {
 
 	assert.Equal(10, linRegSeries.Len())
 
-	lrx0, lry0 := linRegSeries.GetValue(0)
+	lrx0, lry0 := linRegSeries.GetValues(0)
 	assert.InDelta(90.0, lrx0, 0.0000001)
 	assert.InDelta(90.0, lry0, 0.0000001)
 
-	lrxn, lryn := linRegSeries.GetLastValue()
+	lrxn, lryn := linRegSeries.GetLastValues()
 	assert.InDelta(80.0, lrxn, 0.0000001)
 	assert.InDelta(80.0, lryn, 0.0000001)
 }

macd_series.go

@@ -17,7 +17,7 @@ type MACDSeries struct {
 	Name        string
 	Style       Style
 	YAxis       YAxisType
-	InnerSeries ValueProvider
+	InnerSeries ValuesProvider
 
 	PrimaryPeriod   int
 	SecondaryPeriod int
@@ -89,8 +89,8 @@ func (macd MACDSeries) Len() int {
 	return macd.InnerSeries.Len()
 }
 
-// GetValue gets a value at a given index. For MACD it is the signal value.
+// GetValues gets a value at a given index. For MACD it is the signal value.
-func (macd *MACDSeries) GetValue(index int) (x float64, y float64) {
+func (macd *MACDSeries) GetValues(index int) (x float64, y float64) {
 	if macd.InnerSeries == nil {
 		return
 	}
@@ -99,10 +99,10 @@ func (macd *MACDSeries) GetValue(index int) (x float64, y float64) {
 		macd.ensureChildSeries()
 	}
 
-	_, lv := macd.macdl.GetValue(index)
+	_, lv := macd.macdl.GetValues(index)
-	_, sv := macd.signal.GetValue(index)
+	_, sv := macd.signal.GetValues(index)
 
-	x, _ = macd.InnerSeries.GetValue(index)
+	x, _ = macd.InnerSeries.GetValues(index)
 	y = lv - sv
 
 	return
@@ -130,7 +130,7 @@ type MACDSignalSeries struct {
 	Name        string
 	Style       Style
 	YAxis       YAxisType
-	InnerSeries ValueProvider
+	InnerSeries ValuesProvider
 
 	PrimaryPeriod   int
 	SecondaryPeriod int
@@ -191,8 +191,8 @@ func (macds *MACDSignalSeries) Len() int {
 	return macds.InnerSeries.Len()
 }
 
-// GetValue gets a value at a given index. For MACD it is the signal value.
+// GetValues gets a value at a given index. For MACD it is the signal value.
-func (macds *MACDSignalSeries) GetValue(index int) (x float64, y float64) {
+func (macds *MACDSignalSeries) GetValues(index int) (x float64, y float64) {
 	if macds.InnerSeries == nil {
 		return
 	}
@@ -200,8 +200,8 @@ func (macds *MACDSignalSeries) GetValue(index int) (x float64, y float64) {
 	if macds.signal == nil {
 		macds.ensureSignal()
 	}
-	x, _ = macds.InnerSeries.GetValue(index)
+	x, _ = macds.InnerSeries.GetValues(index)
-	_, y = macds.signal.GetValue(index)
+	_, y = macds.signal.GetValues(index)
 	return
 }
 
@@ -229,7 +229,7 @@ type MACDLineSeries struct {
 	Name        string
 	Style       Style
 	YAxis       YAxisType
-	InnerSeries ValueProvider
+	InnerSeries ValuesProvider
 
 	PrimaryPeriod   int
 	SecondaryPeriod int
@@ -300,8 +300,8 @@ func (macdl *MACDLineSeries) Len() int {
 	return macdl.InnerSeries.Len()
 }
 
-// GetValue gets a value at a given index. For MACD it is the signal value.
+// GetValues gets a value at a given index. For MACD it is the signal value.
-func (macdl *MACDLineSeries) GetValue(index int) (x float64, y float64) {
+func (macdl *MACDLineSeries) GetValues(index int) (x float64, y float64) {
 	if macdl.InnerSeries == nil {
 		return
 	}
@@ -309,10 +309,10 @@ func (macdl *MACDLineSeries) GetValue(index int) (x float64, y float64) {
 		macdl.ensureEMASeries()
 	}
 
-	x, _ = macdl.InnerSeries.GetValue(index)
+	x, _ = macdl.InnerSeries.GetValues(index)
 
-	_, emav1 := macdl.ema1.GetValue(index)
+	_, emav1 := macdl.ema1.GetValues(index)
-	_, emav2 := macdl.ema2.GetValue(index)
+	_, emav2 := macdl.ema2.GetValues(index)
 
 	y = emav2 - emav1
 	return

macd_series_test.go

@@ -65,7 +65,7 @@ var (
 func TestMACDSeries(t *testing.T) {
 	assert := assert.New(t)
 
-	mockSeries := mockValueProvider{
+	mockSeries := mockValuesProvider{
 		emaXValues,
 		emaYValues,
 	}
@@ -77,7 +77,7 @@ func TestMACDSeries(t *testing.T) {
 
 	var yvalues []float64
 	for x := 0; x < mas.Len(); x++ {
-		_, y := mas.GetValue(x)
+		_, y := mas.GetValues(x)
 		yvalues = append(yvalues, y)
 	}
 

market_hours_range.go

@@ -112,31 +112,31 @@ func (mhr MarketHoursRange) GetMarketClose() time.Time {
 // GetTicks returns the ticks for the range.
 // This is to override the default continous ticks that would be generated for the range.
 func (mhr *MarketHoursRange) GetTicks(r Renderer, defaults Style, vf ValueFormatter) []Tick {
-	times := Sequence.MarketHours(mhr.Min, mhr.Max, mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
+	times := Generate.MarketHours(mhr.Min, mhr.Max, mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
 	timesWidth := mhr.measureTimes(r, defaults, vf, times)
 	if timesWidth <= mhr.Domain {
 		return mhr.makeTicks(vf, times)
 	}
 
-	times = Sequence.MarketHourQuarters(mhr.Min, mhr.Max, mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
+	times = Generate.MarketHourQuarters(mhr.Min, mhr.Max, mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
 	timesWidth = mhr.measureTimes(r, defaults, vf, times)
 	if timesWidth <= mhr.Domain {
 		return mhr.makeTicks(vf, times)
 	}
 
-	times = Sequence.MarketDayCloses(mhr.Min, mhr.Max, mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
+	times = Generate.MarketDayCloses(mhr.Min, mhr.Max, mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
 	timesWidth = mhr.measureTimes(r, defaults, vf, times)
 	if timesWidth <= mhr.Domain {
 		return mhr.makeTicks(vf, times)
 	}
 
-	times = Sequence.MarketDayAlternateCloses(mhr.Min, mhr.Max, mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
+	times = Generate.MarketDayAlternateCloses(mhr.Min, mhr.Max, mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
 	timesWidth = mhr.measureTimes(r, defaults, vf, times)
 	if timesWidth <= mhr.Domain {
 		return mhr.makeTicks(vf, times)
 	}
 
-	times = Sequence.MarketDayMondayCloses(mhr.Min, mhr.Max, mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
+	times = Generate.MarketDayMondayCloses(mhr.Min, mhr.Max, mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
 	timesWidth = mhr.measureTimes(r, defaults, vf, times)
 	if timesWidth <= mhr.Domain {
 		return mhr.makeTicks(vf, times)

min_max_series.go

@@ -10,7 +10,7 @@ type MinSeries struct {
 	Name        string
 	Style       Style
 	YAxis       YAxisType
-	InnerSeries ValueProvider
+	InnerSeries ValuesProvider
 
 	minValue *float64
 }
@@ -35,10 +35,10 @@ func (ms MinSeries) Len() int {
 	return ms.InnerSeries.Len()
 }
 
-// GetValue gets a value at a given index.
+// GetValues gets a value at a given index.
-func (ms *MinSeries) GetValue(index int) (x, y float64) {
+func (ms *MinSeries) GetValues(index int) (x, y float64) {
 	ms.ensureMinValue()
-	x, _ = ms.InnerSeries.GetValue(index)
+	x, _ = ms.InnerSeries.GetValues(index)
 	y = *ms.minValue
 	return
 }
@@ -54,7 +54,7 @@ func (ms *MinSeries) ensureMinValue() {
 		minValue := math.MaxFloat64
 		var y float64
 		for x := 0; x < ms.InnerSeries.Len(); x++ {
-			_, y = ms.InnerSeries.GetValue(x)
+			_, y = ms.InnerSeries.GetValues(x)
 			if y < minValue {
 				minValue = y
 			}
@@ -76,7 +76,7 @@ type MaxSeries struct {
 	Name        string
 	Style       Style
 	YAxis       YAxisType
-	InnerSeries ValueProvider
+	InnerSeries ValuesProvider
 
 	maxValue *float64
 }
@@ -101,10 +101,10 @@ func (ms MaxSeries) Len() int {
 	return ms.InnerSeries.Len()
 }
 
-// GetValue gets a value at a given index.
+// GetValues gets a value at a given index.
-func (ms *MaxSeries) GetValue(index int) (x, y float64) {
+func (ms *MaxSeries) GetValues(index int) (x, y float64) {
 	ms.ensureMaxValue()
-	x, _ = ms.InnerSeries.GetValue(index)
+	x, _ = ms.InnerSeries.GetValues(index)
 	y = *ms.maxValue
 	return
 }
@@ -120,7 +120,7 @@ func (ms *MaxSeries) ensureMaxValue() {
 		maxValue := -math.MaxFloat64
 		var y float64
 		for x := 0; x < ms.InnerSeries.Len(); x++ {
-			_, y = ms.InnerSeries.GetValue(x)
+			_, y = ms.InnerSeries.GetValues(x)
 			if y > maxValue {
 				maxValue = y
 			}

polynomial_regression_series.go

@@ -17,7 +17,7 @@ type PolynomialRegressionSeries struct {
 	Limit       int
 	Offset      int
 	Degree      int
-	InnerSeries ValueProvider
+	InnerSeries ValuesProvider
 
 	coeffs []float64
 }
@@ -79,8 +79,8 @@ func (prs *PolynomialRegressionSeries) Validate() error {
 	return nil
 }
 
-// GetValue returns the series value for a given index.
+// GetValues returns the series value for a given index.
-func (prs *PolynomialRegressionSeries) GetValue(index int) (x, y float64) {
+func (prs *PolynomialRegressionSeries) GetValues(index int) (x, y float64) {
 	if prs.InnerSeries == nil || prs.InnerSeries.Len() == 0 {
 		return
 	}
@@ -95,13 +95,13 @@ func (prs *PolynomialRegressionSeries) GetValue(index int) (x, y float64) {
 
 	offset := prs.GetOffset()
 	effectiveIndex := Math.MinInt(index+offset, prs.InnerSeries.Len())
-	x, y = prs.InnerSeries.GetValue(effectiveIndex)
+	x, y = prs.InnerSeries.GetValues(effectiveIndex)
 	y = prs.apply(x)
 	return
 }
 
-// GetLastValue computes the last poly regression value.
+// GetLastValues computes the last poly regression value.
-func (prs *PolynomialRegressionSeries) GetLastValue() (x, y float64) {
+func (prs *PolynomialRegressionSeries) GetLastValues() (x, y float64) {
 	if prs.InnerSeries == nil || prs.InnerSeries.Len() == 0 {
 		return
 	}
@@ -113,7 +113,7 @@ func (prs *PolynomialRegressionSeries) GetLastValue() (x, y float64) {
 		prs.coeffs = coeffs
 	}
 	endIndex := prs.GetEndIndex()
-	x, y = prs.InnerSeries.GetValue(endIndex)
+	x, y = prs.InnerSeries.GetValues(endIndex)
 	y = prs.apply(x)
 	return
 }
@@ -138,7 +138,7 @@ func (prs *PolynomialRegressionSeries) values() (xvalues, yvalues []float64) {
 	yvalues = make([]float64, endIndex-startIndex)
 
 	for index := startIndex; index < endIndex; index++ {
-		x, y := prs.InnerSeries.GetValue(index)
+		x, y := prs.InnerSeries.GetValues(index)
 		xvalues[index-startIndex] = x
 		yvalues[index-startIndex] = y
 	}

polynomial_regression_test.go

@@ -29,7 +29,7 @@ func TestPolynomialRegression(t *testing.T) {
 	}
 
 	for i := 0; i < 100; i++ {
-		_, y := poly.GetValue(i)
+		_, y := poly.GetValues(i)
 		assert.InDelta(float64(i*i), y, matrix.DefaultEpsilon)
 	}
 }

ring_buffer.go

@@ -1,252 +0,0 @@
-package chart
-
-import (
-	"fmt"
-	"math"
-	"strings"
-)
-
-const (
-	ringBufferMinimumGrow     = 4
-	ringBufferShrinkThreshold = 32
-	ringBufferGrowFactor      = 200
-	ringBufferDefaultCapacity = 4
-)
-
-var (
-	emptyArray = make([]interface{}, 0)
-)
-
-// NewRingBuffer creates a new, empty, RingBuffer.
-func NewRingBuffer() *RingBuffer {
-	return &RingBuffer{
-		array: make([]interface{}, ringBufferDefaultCapacity),
-		head:  0,
-		tail:  0,
-		size:  0,
-	}
-}
-
-// NewRingBufferWithCapacity creates a new RingBuffer pre-allocated with the given capacity.
-func NewRingBufferWithCapacity(capacity int) *RingBuffer {
-	return &RingBuffer{
-		array: make([]interface{}, capacity),
-		head:  0,
-		tail:  0,
-		size:  0,
-	}
-}
-
-// NewRingBufferFromSlice createsa  ring buffer out of a slice.
-func NewRingBufferFromSlice(values []interface{}) *RingBuffer {
-	return &RingBuffer{
-		array: values,
-		head:  0,
-		tail:  len(values) - 1,
-		size:  len(values),
-	}
-}
-
-// RingBuffer is a fifo buffer that is backed by a pre-allocated array, instead of allocating
-// a whole new node object for each element (which saves GC churn).
-// Enqueue can be O(n), Dequeue can be O(1).
-type RingBuffer struct {
-	array []interface{}
-	head  int
-	tail  int
-	size  int
-}
-
-// Len returns the length of the ring buffer (as it is currently populated).
-// Actual memory footprint may be different.
-func (rb *RingBuffer) Len() int {
-	return rb.size
-}
-
-// TotalLen returns the total size of the ring bufffer, including empty elements.
-func (rb *RingBuffer) TotalLen() int {
-	return len(rb.array)
-}
-
-// Clear removes all objects from the RingBuffer.
-func (rb *RingBuffer) Clear() {
-	if rb.head < rb.tail {
-		arrayClear(rb.array, rb.head, rb.size)
-	} else {
-		arrayClear(rb.array, rb.head, len(rb.array)-rb.head)
-		arrayClear(rb.array, 0, rb.tail)
-	}
-
-	rb.head = 0
-	rb.tail = 0
-	rb.size = 0
-}
-
-// Enqueue adds an element to the "back" of the RingBuffer.
-func (rb *RingBuffer) Enqueue(object interface{}) {
-	if rb.size == len(rb.array) {
-		newCapacity := int(len(rb.array) * int(ringBufferGrowFactor/100))
-		if newCapacity < (len(rb.array) + ringBufferMinimumGrow) {
-			newCapacity = len(rb.array) + ringBufferMinimumGrow
-		}
-		rb.setCapacity(newCapacity)
-	}
-
-	rb.array[rb.tail] = object
-	rb.tail = (rb.tail + 1) % len(rb.array)
-	rb.size++
-}
-
-// Dequeue removes the first element from the RingBuffer.
-func (rb *RingBuffer) Dequeue() interface{} {
-	if rb.size == 0 {
-		return nil
-	}
-
-	removed := rb.array[rb.head]
-	rb.head = (rb.head + 1) % len(rb.array)
-	rb.size--
-	return removed
-}
-
-// Peek returns but does not remove the first element.
-func (rb *RingBuffer) Peek() interface{} {
-	if rb.size == 0 {
-		return nil
-	}
-	return rb.array[rb.head]
-}
-
-// PeekBack returns but does not remove the last element.
-func (rb *RingBuffer) PeekBack() interface{} {
-	if rb.size == 0 {
-		return nil
-	}
-	if rb.tail == 0 {
-		return rb.array[len(rb.array)-1]
-	}
-	return rb.array[rb.tail-1]
-}
-
-func (rb *RingBuffer) setCapacity(capacity int) {
-	newArray := make([]interface{}, capacity)
-	if rb.size > 0 {
-		if rb.head < rb.tail {
-			arrayCopy(rb.array, rb.head, newArray, 0, rb.size)
-		} else {
-			arrayCopy(rb.array, rb.head, newArray, 0, len(rb.array)-rb.head)
-			arrayCopy(rb.array, 0, newArray, len(rb.array)-rb.head, rb.tail)
-		}
-	}
-	rb.array = newArray
-	rb.head = 0
-	if rb.size == capacity {
-		rb.tail = 0
-	} else {
-		rb.tail = rb.size
-	}
-}
-
-// TrimExcess resizes the buffer to better fit the contents.
-func (rb *RingBuffer) TrimExcess() {
-	threshold := float64(len(rb.array)) * 0.9
-	if rb.size < int(threshold) {
-		rb.setCapacity(rb.size)
-	}
-}
-
-// AsSlice returns the ring buffer, in order, as a slice.
-func (rb *RingBuffer) AsSlice() []interface{} {
-	newArray := make([]interface{}, rb.size)
-
-	if rb.size == 0 {
-		return newArray
-	}
-
-	if rb.head < rb.tail {
-		arrayCopy(rb.array, rb.head, newArray, 0, rb.size)
-	} else {
-		arrayCopy(rb.array, rb.head, newArray, 0, len(rb.array)-rb.head)
-		arrayCopy(rb.array, 0, newArray, len(rb.array)-rb.head, rb.tail)
-	}
-
-	return newArray
-}
-
-// Each calls the consumer for each element in the buffer.
-func (rb *RingBuffer) Each(consumer func(value interface{})) {
-	if rb.size == 0 {
-		return
-	}
-
-	if rb.head < rb.tail {
-		for cursor := rb.head; cursor < rb.tail; cursor++ {
-			consumer(rb.array[cursor])
-		}
-	} else {
-		for cursor := rb.head; cursor < len(rb.array); cursor++ {
-			consumer(rb.array[cursor])
-		}
-		for cursor := 0; cursor < rb.tail; cursor++ {
-			consumer(rb.array[cursor])
-		}
-	}
-}
-
-func (rb *RingBuffer) String() string {
-	var values []string
-	for _, elem := range rb.AsSlice() {
-		values = append(values, fmt.Sprintf("%v", elem))
-	}
-	return strings.Join(values, " <= ")
-}
-
-// Average returns the float average of the values in the buffer.
-func (rb *RingBuffer) Average() float64 {
-	var accum float64
-	rb.Each(func(v interface{}) {
-		if typed, isTyped := v.(float64); isTyped {
-			accum += typed
-		}
-	})
-	return accum / float64(rb.Len())
-}
-
-// Variance computes the variance of the buffer.
-func (rb *RingBuffer) Variance() float64 {
-	if rb.Len() == 0 {
-		return 0
-	}
-
-	var variance float64
-	m := rb.Average()
-
-	rb.Each(func(v interface{}) {
-		if n, isTyped := v.(float64); isTyped {
-			variance += (float64(n) - m) * (float64(n) - m)
-		}
-	})
-
-	return variance / float64(rb.Len())
-}
-
-// StdDev returns the standard deviation.
-func (rb *RingBuffer) StdDev() float64 {
-	return math.Pow(rb.Variance(), 0.5)
-}
-
-func arrayClear(source []interface{}, index, length int) {
-	for x := 0; x < length; x++ {
-		absoluteIndex := x + index
-		source[absoluteIndex] = nil
-	}
-}
-
-func arrayCopy(source []interface{}, sourceIndex int, destination []interface{}, destinationIndex, length int) {
-	for x := 0; x < length; x++ {
-		from := sourceIndex + x
-		to := destinationIndex + x
-
-		destination[to] = source[from]
-	}
-}

sequence.go

@@ -1,190 +1,82 @@
 package chart
 
-import (
+import "math"
-	"math/rand"
-	"time"
-)
 
-var (
+// SequenceProvider is a provider for values for a sequence.
-	// Sequence contains some sequence utilities.
+type SequenceProvider interface {
-	// These utilities can be useful for generating test data.
+	Len() int
-	Sequence = &sequence{
+	GetValue(int) float64
-		rnd: rand.New(rand.NewSource(time.Now().Unix())),
-	}
-)
-
-type sequence struct {
-	rnd *rand.Rand
 }
 
-// Float64 produces an array of floats from [start,end] by optional steps.
+// Sequence is a utility wrapper for sequence providers.
-func (s sequence) Float64(start, end float64, steps ...float64) []float64 {
+type Sequence struct {
-	var values []float64
+	SequenceProvider
-	step := 1.0
-	if len(steps) > 0 {
-		step = steps[0]
-	}
-
-	if start < end {
-		for x := start; x <= end; x += step {
-			values = append(values, x)
-		}
-	} else {
-		for x := start; x >= end; x = x - step {
-			values = append(values, x)
-		}
-	}
-	return values
 }
 
-// Random generates a fixed length sequence of random values between (0, scale).
+// Each applies the `mapfn` to all values in the value provider.
-func (s sequence) Random(samples int, scale float64) []float64 {
+func (s Sequence) Each(mapfn func(int, float64)) {
-	values := make([]float64, samples)
+	for i := 0; i < s.Len(); i++ {
-
+		mapfn(i, s.GetValue(i))
-	for x := 0; x < samples; x++ {
-		values[x] = s.rnd.Float64() * scale
 	}
-
-	return values
 }
 
-// Random generates a fixed length sequence of random values with a given average, above and below that average by (-scale, scale)
+// Map applies the `mapfn` to all values in the value provider,
-func (s sequence) RandomWithAverage(samples int, average, scale float64) []float64 {
+// returning a new sequence.
-	values := make([]float64, samples)
+func (s Sequence) Map(mapfn func(i int, v float64) float64) Sequence {
-
+	output := make([]float64, s.Len())
-	for x := 0; x < samples; x++ {
+	for i := 0; i < s.Len(); i++ {
-		jitter := scale - (s.rnd.Float64() * (2 * scale))
+		mapfn(i, s.GetValue(i))
-		values[x] = average + jitter
 	}
-
+	return Sequence{Array(output)}
-	return values
 }
 
-// Days generates a sequence of timestamps by day, from -days to today.
+// Average returns the float average of the values in the buffer.
-func (s sequence) Days(days int) []time.Time {
+func (s Sequence) Average() float64 {
-	var values []time.Time
+	if s.Len() == 0 {
-	for day := days; day >= 0; day-- {
+		return 0
-		values = append(values, time.Now().AddDate(0, 0, -day))
-	}
-	return values
-}
-
-func (s sequence) MarketHours(from, to time.Time, marketOpen, marketClose time.Time, isHoliday HolidayProvider) []time.Time {
-	var times []time.Time
-	cursor := Date.On(marketOpen, from)
-	toClose := Date.On(marketClose, to)
-	for cursor.Before(toClose) || cursor.Equal(toClose) {
-		todayOpen := Date.On(marketOpen, cursor)
-		todayClose := Date.On(marketClose, cursor)
-		isValidTradingDay := !isHoliday(cursor) && Date.IsWeekDay(cursor.Weekday())
-
-		if (cursor.Equal(todayOpen) || cursor.After(todayOpen)) && (cursor.Equal(todayClose) || cursor.Before(todayClose)) && isValidTradingDay {
-			times = append(times, cursor)
-		}
-		if cursor.After(todayClose) {
-			cursor = Date.NextMarketOpen(cursor, marketOpen, isHoliday)
-		} else {
-			cursor = Date.NextHour(cursor)
-		}
-	}
-	return times
-}
-
-func (s sequence) MarketHourQuarters(from, to time.Time, marketOpen, marketClose time.Time, isHoliday HolidayProvider) []time.Time {
-	var times []time.Time
-	cursor := Date.On(marketOpen, from)
-	toClose := Date.On(marketClose, to)
-	for cursor.Before(toClose) || cursor.Equal(toClose) {
-
-		isValidTradingDay := !isHoliday(cursor) && Date.IsWeekDay(cursor.Weekday())
-
-		if isValidTradingDay {
-			todayOpen := Date.On(marketOpen, cursor)
-			todayNoon := Date.NoonOn(cursor)
-			today2pm := Date.On(Date.Time(14, 0, 0, 0, cursor.Location()), cursor)
-			todayClose := Date.On(marketClose, cursor)
-			times = append(times, todayOpen, todayNoon, today2pm, todayClose)
-		}
-
-		cursor = Date.NextDay(cursor)
-	}
-	return times
-}
-
-func (s sequence) MarketDayCloses(from, to time.Time, marketOpen, marketClose time.Time, isHoliday HolidayProvider) []time.Time {
-	var times []time.Time
-	cursor := Date.On(marketOpen, from)
-	toClose := Date.On(marketClose, to)
-	for cursor.Before(toClose) || cursor.Equal(toClose) {
-		isValidTradingDay := !isHoliday(cursor) && Date.IsWeekDay(cursor.Weekday())
-		if isValidTradingDay {
-			todayClose := Date.On(marketClose, cursor)
-			times = append(times, todayClose)
-		}
-
-		cursor = Date.NextDay(cursor)
-	}
-	return times
-}
-
-func (s sequence) MarketDayAlternateCloses(from, to time.Time, marketOpen, marketClose time.Time, isHoliday HolidayProvider) []time.Time {
-	var times []time.Time
-	cursor := Date.On(marketOpen, from)
-	toClose := Date.On(marketClose, to)
-	for cursor.Before(toClose) || cursor.Equal(toClose) {
-		isValidTradingDay := !isHoliday(cursor) && Date.IsWeekDay(cursor.Weekday())
-		if isValidTradingDay {
-			todayClose := Date.On(marketClose, cursor)
-			times = append(times, todayClose)
-		}
-
-		cursor = cursor.AddDate(0, 0, 2)
-	}
-	return times
-}
-
-func (s sequence) MarketDayMondayCloses(from, to time.Time, marketOpen, marketClose time.Time, isHoliday HolidayProvider) []time.Time {
-	var times []time.Time
-	cursor := Date.On(marketClose, from)
-	toClose := Date.On(marketClose, to)
-
-	for cursor.Equal(toClose) || cursor.Before(toClose) {
-		isValidTradingDay := !isHoliday(cursor) && Date.IsWeekDay(cursor.Weekday())
-		if isValidTradingDay {
-			times = append(times, cursor)
-		}
-		cursor = Date.NextDayOfWeek(cursor, time.Monday)
-	}
-	return times
-}
-
-func (s sequence) Hours(start time.Time, totalHours int) []time.Time {
-	times := make([]time.Time, totalHours)
-
-	last := start
-	for i := 0; i < totalHours; i++ {
-		times[i] = last
-		last = last.Add(time.Hour)
 	}
 
-	return times
+	var accum float64
+	for i := 0; i < s.Len(); i++ {
+		accum += s.GetValue(i)
+	}
+	return accum / float64(s.Len())
 }
 
-// HoursFill adds zero values for the data bounded by the start and end of the xdata array.
+// Variance computes the variance of the buffer.
-func (s sequence) HoursFill(xdata []time.Time, ydata []float64) ([]time.Time, []float64) {
+func (s Sequence) Variance() float64 {
-	start := Date.Start(xdata)
+	if s.Len() == 0 {
-	end := Date.End(xdata)
+		return 0
-
-	totalHours := Math.AbsInt(Date.DiffHours(start, end))
-
-	finalTimes := s.Hours(start, totalHours+1)
-	finalValues := make([]float64, totalHours+1)
-
-	var hoursFromStart int
-	for i, xd := range xdata {
-		hoursFromStart = Date.DiffHours(start, xd)
-		finalValues[hoursFromStart] = ydata[i]
 	}
 
-	return finalTimes, finalValues
+	m := s.Average()
+	var variance, v float64
+	for i := 0; i < s.Len(); i++ {
+		v = s.GetValue(i)
+		variance += (v - m) * (v - m)
+	}
+
+	return variance / float64(s.Len())
+}
+
+// StdDev returns the standard deviation.
+func (s Sequence) StdDev() float64 {
+	if s.Len() == 0 {
+		return 0
+	}
+
+	return math.Pow(s.Variance(), 0.5)
+}
+
+// Array is a wrapper for an array of floats that implements `ValuesProvider`.
+type Array []float64
+
+// Len returns the value provider length.
+func (a Array) Len() int {
+	return len(a)
+}
+
+// GetValue returns the value at a given index.
+func (a Array) GetValue(index int) float64 {
+	return a[index]
 }

sma_series.go

@@ -14,7 +14,7 @@ type SMASeries struct {
 	YAxis YAxisType
 
 	Period      int
-	InnerSeries ValueProvider
+	InnerSeries ValuesProvider
 }
 
 // GetName returns the name of the time series.
@@ -48,25 +48,25 @@ func (sma SMASeries) GetPeriod(defaults ...int) int {
 	return sma.Period
 }
 
-// GetValue gets a value at a given index.
+// GetValues gets a value at a given index.
-func (sma SMASeries) GetValue(index int) (x, y float64) {
+func (sma SMASeries) GetValues(index int) (x, y float64) {
 	if sma.InnerSeries == nil || sma.InnerSeries.Len() == 0 {
 		return
 	}
-	px, _ := sma.InnerSeries.GetValue(index)
+	px, _ := sma.InnerSeries.GetValues(index)
 	x = px
 	y = sma.getAverage(index)
 	return
 }
 
-// GetLastValue computes the last moving average value but walking back window size samples,
+// GetLastValues computes the last moving average value but walking back window size samples,
 // and recomputing the last moving average chunk.
-func (sma SMASeries) GetLastValue() (x, y float64) {
+func (sma SMASeries) GetLastValues() (x, y float64) {
 	if sma.InnerSeries == nil || sma.InnerSeries.Len() == 0 {
 		return
 	}
 	seriesLen := sma.InnerSeries.Len()
-	px, _ := sma.InnerSeries.GetValue(seriesLen - 1)
+	px, _ := sma.InnerSeries.GetValues(seriesLen - 1)
 	x = px
 	y = sma.getAverage(seriesLen - 1)
 	return
@@ -78,7 +78,7 @@ func (sma SMASeries) getAverage(index int) float64 {
 	var accum float64
 	var count float64
 	for x := index; x >= floor; x-- {
-		_, vy := sma.InnerSeries.GetValue(x)
+		_, vy := sma.InnerSeries.GetValues(x)
 		accum += vy
 		count += 1.0
 	}

sma_series_test.go

@@ -6,16 +6,16 @@ import (
 	"github.com/blendlabs/go-assert"
 )
 
-type mockValueProvider struct {
+type mockValuesProvider struct {
 	X []float64
 	Y []float64
 }
 
-func (m mockValueProvider) Len() int {
+func (m mockValuesProvider) Len() int {
 	return Math.MinInt(len(m.X), len(m.Y))
 }
 
-func (m mockValueProvider) GetValue(index int) (x, y float64) {
+func (m mockValuesProvider) GetValues(index int) (x, y float64) {
 	if index < 0 {
 		panic("negative index at GetValue()")
 	}
@@ -30,9 +30,9 @@ func (m mockValueProvider) GetValue(index int) (x, y float64) {
 func TestSMASeriesGetValue(t *testing.T) {
 	assert := assert.New(t)
 
-	mockSeries := mockValueProvider{
+	mockSeries := mockValuesProvider{
-		Sequence.Float64(1.0, 10.0),
+		Generate.Float64(1.0, 10.0),
-		Sequence.Float64(10, 1.0),
+		Generate.Float64(10, 1.0),
 	}
 	assert.Equal(10, mockSeries.Len())
 
@@ -43,7 +43,7 @@ func TestSMASeriesGetValue(t *testing.T) {
 
 	var yvalues []float64
 	for x := 0; x < mas.Len(); x++ {
-		_, y := mas.GetValue(x)
+		_, y := mas.GetValues(x)
 		yvalues = append(yvalues, y)
 	}
 
@@ -61,9 +61,9 @@ func TestSMASeriesGetValue(t *testing.T) {
 func TestSMASeriesGetLastValueWindowOverlap(t *testing.T) {
 	assert := assert.New(t)
 
-	mockSeries := mockValueProvider{
+	mockSeries := mockValuesProvider{
-		Sequence.Float64(1.0, 10.0),
+		Generate.Float64(1.0, 10.0),
-		Sequence.Float64(10, 1.0),
+		Generate.Float64(10, 1.0),
 	}
 	assert.Equal(10, mockSeries.Len())
 
@@ -74,11 +74,11 @@ func TestSMASeriesGetLastValueWindowOverlap(t *testing.T) {
 
 	var yvalues []float64
 	for x := 0; x < mas.Len(); x++ {
-		_, y := mas.GetValue(x)
+		_, y := mas.GetValues(x)
 		yvalues = append(yvalues, y)
 	}
 
-	lx, ly := mas.GetLastValue()
+	lx, ly := mas.GetLastValues()
 	assert.Equal(10.0, lx)
 	assert.Equal(5.5, ly)
 	assert.Equal(yvalues[len(yvalues)-1], ly)
@@ -87,9 +87,9 @@ func TestSMASeriesGetLastValueWindowOverlap(t *testing.T) {
 func TestSMASeriesGetLastValue(t *testing.T) {
 	assert := assert.New(t)
 
-	mockSeries := mockValueProvider{
+	mockSeries := mockValuesProvider{
-		Sequence.Float64(1.0, 100.0),
+		Generate.Float64(1.0, 100.0),
-		Sequence.Float64(100, 1.0),
+		Generate.Float64(100, 1.0),
 	}
 	assert.Equal(100, mockSeries.Len())
 
@@ -100,11 +100,11 @@ func TestSMASeriesGetLastValue(t *testing.T) {
 
 	var yvalues []float64
 	for x := 0; x < mas.Len(); x++ {
-		_, y := mas.GetValue(x)
+		_, y := mas.GetValues(x)
 		yvalues = append(yvalues, y)
 	}
 
-	lx, ly := mas.GetLastValue()
+	lx, ly := mas.GetLastValues()
 	assert.Equal(100.0, lx)
 	assert.Equal(6, ly)
 	assert.Equal(yvalues[len(yvalues)-1], ly)

stacked_bar_chart.go

@@ -200,7 +200,7 @@ func (sbc StackedBarChart) drawYAxis(r Renderer, canvasBox Box) {
 		r.LineTo(canvasBox.Right+DefaultHorizontalTickWidth, canvasBox.Bottom)
 		r.Stroke()
 
-		ticks := Sequence.Float64(1.0, 0.0, 0.2)
+		ticks := Generate.Float64(1.0, 0.0, 0.2)
 		for _, t := range ticks {
 			axisStyle.GetStrokeOptions().WriteToRenderer(r)
 			ty := canvasBox.Bottom - int(t*float64(canvasBox.Height()))

time_series.go

@@ -31,15 +31,15 @@ func (ts TimeSeries) Len() int {
 	return len(ts.XValues)
 }
 
-// GetValue gets a value at a given index.
+// GetValues gets a value at a given index.
-func (ts TimeSeries) GetValue(index int) (x, y float64) {
+func (ts TimeSeries) GetValues(index int) (x, y float64) {
 	x = Time.ToFloat64(ts.XValues[index])
 	y = ts.YValues[index]
 	return
 }
 
-// GetLastValue gets the last value.
+// GetLastValues gets the last value.
-func (ts TimeSeries) GetLastValue() (x, y float64) {
+func (ts TimeSeries) GetLastValues() (x, y float64) {
 	x = Time.ToFloat64(ts.XValues[len(ts.XValues)-1])
 	y = ts.YValues[len(ts.YValues)-1]
 	return

time_series_test.go

@@ -24,7 +24,7 @@ func TestTimeSeriesGetValue(t *testing.T) {
 		},
 	}
 
-	x0, y0 := ts.GetValue(0)
+	x0, y0 := ts.GetValues(0)
 	assert.NotZero(x0)
 	assert.Equal(1.0, y0)
 }

value_buffer.go

@@ -0,0 +1,229 @@
+package chart
+
+import (
+	"fmt"
+	"strings"
+)
+
+const (
+	valueBufferMinimumGrow     = 4
+	valueBufferShrinkThreshold = 32
+	valueBufferGrowFactor      = 200
+	valueBufferDefaultCapacity = 4
+)
+
+var (
+	emptyArray = make([]float64, 0)
+)
+
+// NewValueBuffer creates a new value buffer with an optional set of values.
+func NewValueBuffer(values ...float64) *ValueBuffer {
+	var tail int
+	array := make([]float64, Math.MaxInt(len(values), valueBufferDefaultCapacity))
+	if len(values) > 0 {
+		copy(array, values)
+		tail = len(values)
+	}
+	return &ValueBuffer{
+		array: array,
+		head:  0,
+		tail:  tail,
+		size:  len(values),
+	}
+}
+
+// NewValueBufferWithCapacity creates a new ValueBuffer pre-allocated with the given capacity.
+func NewValueBufferWithCapacity(capacity int) *ValueBuffer {
+	return &ValueBuffer{
+		array: make([]float64, capacity),
+		head:  0,
+		tail:  0,
+		size:  0,
+	}
+}
+
+// ValueBuffer is a fifo buffer that is backed by a pre-allocated array, instead of allocating
+// a whole new node object for each element (which saves GC churn).
+// Enqueue can be O(n), Dequeue can be O(1).
+type ValueBuffer struct {
+	array []float64
+	head  int
+	tail  int
+	size  int
+}
+
+// Len returns the length of the ValueBuffer (as it is currently populated).
+// Actual memory footprint may be different.
+func (vb *ValueBuffer) Len() int {
+	return vb.size
+}
+
+// GetValue implements sequence provider.
+func (vb *ValueBuffer) GetValue(index int) float64 {
+	effectiveIndex := (vb.head + index) % len(vb.array)
+	return vb.array[effectiveIndex]
+}
+
+// Capacity returns the total size of the ValueBuffer, including empty elements.
+func (vb *ValueBuffer) Capacity() int {
+	return len(vb.array)
+}
+
+// SetCapacity sets the capacity of the ValueBuffer.
+func (vb *ValueBuffer) SetCapacity(capacity int) {
+	newArray := make([]float64, capacity)
+	if vb.size > 0 {
+		if vb.head < vb.tail {
+			arrayCopy(vb.array, vb.head, newArray, 0, vb.size)
+		} else {
+			arrayCopy(vb.array, vb.head, newArray, 0, len(vb.array)-vb.head)
+			arrayCopy(vb.array, 0, newArray, len(vb.array)-vb.head, vb.tail)
+		}
+	}
+	vb.array = newArray
+	vb.head = 0
+	if vb.size == capacity {
+		vb.tail = 0
+	} else {
+		vb.tail = vb.size
+	}
+}
+
+// Clear removes all objects from the ValueBuffer.
+func (vb *ValueBuffer) Clear() {
+	if vb.head < vb.tail {
+		arrayClear(vb.array, vb.head, vb.size)
+	} else {
+		arrayClear(vb.array, vb.head, len(vb.array)-vb.head)
+		arrayClear(vb.array, 0, vb.tail)
+	}
+
+	vb.head = 0
+	vb.tail = 0
+	vb.size = 0
+}
+
+// Enqueue adds an element to the "back" of the ValueBuffer.
+func (vb *ValueBuffer) Enqueue(value float64) {
+	if vb.size == len(vb.array) {
+		newCapacity := int(len(vb.array) * int(valueBufferGrowFactor/100))
+		if newCapacity < (len(vb.array) + valueBufferMinimumGrow) {
+			newCapacity = len(vb.array) + valueBufferMinimumGrow
+		}
+		vb.SetCapacity(newCapacity)
+	}
+
+	vb.array[vb.tail] = value
+	vb.tail = (vb.tail + 1) % len(vb.array)
+	vb.size++
+}
+
+// Dequeue removes the first element from the RingBuffer.
+func (vb *ValueBuffer) Dequeue() float64 {
+	if vb.size == 0 {
+		return 0
+	}
+
+	removed := vb.array[vb.head]
+	vb.head = (vb.head + 1) % len(vb.array)
+	vb.size--
+	return removed
+}
+
+// Peek returns but does not remove the first element.
+func (vb *ValueBuffer) Peek() float64 {
+	if vb.size == 0 {
+		return 0
+	}
+	return vb.array[vb.head]
+}
+
+// PeekBack returns but does not remove the last element.
+func (vb *ValueBuffer) PeekBack() float64 {
+	if vb.size == 0 {
+		return 0
+	}
+	if vb.tail == 0 {
+		return vb.array[len(vb.array)-1]
+	}
+	return vb.array[vb.tail-1]
+}
+
+// TrimExcess resizes the buffer to better fit the contents.
+func (vb *ValueBuffer) TrimExcess() {
+	threshold := float64(len(vb.array)) * 0.9
+	if vb.size < int(threshold) {
+		vb.SetCapacity(vb.size)
+	}
+}
+
+// Array returns the ring buffer, in order, as an array.
+func (vb *ValueBuffer) Array() Array {
+	newArray := make([]float64, vb.size)
+
+	if vb.size == 0 {
+		return newArray
+	}
+
+	if vb.head < vb.tail {
+		arrayCopy(vb.array, vb.head, newArray, 0, vb.size)
+	} else {
+		arrayCopy(vb.array, vb.head, newArray, 0, len(vb.array)-vb.head)
+		arrayCopy(vb.array, 0, newArray, len(vb.array)-vb.head, vb.tail)
+	}
+
+	return Array(newArray)
+}
+
+// Each calls the consumer for each element in the buffer.
+func (vb *ValueBuffer) Each(mapfn func(int, float64)) {
+	if vb.size == 0 {
+		return
+	}
+
+	var index int
+	if vb.head < vb.tail {
+		for cursor := vb.head; cursor < vb.tail; cursor++ {
+			mapfn(index, vb.array[cursor])
+			index++
+		}
+	} else {
+		for cursor := vb.head; cursor < len(vb.array); cursor++ {
+			mapfn(index, vb.array[cursor])
+			index++
+		}
+		for cursor := 0; cursor < vb.tail; cursor++ {
+			mapfn(index, vb.array[cursor])
+			index++
+		}
+	}
+}
+
+// String returns a string representation for value buffers.
+func (vb *ValueBuffer) String() string {
+	var values []string
+	for _, elem := range vb.Array() {
+		values = append(values, fmt.Sprintf("%v", elem))
+	}
+	return strings.Join(values, " <= ")
+}
+
+// --------------------------------------------------------------------------------
+// Util methods
+// --------------------------------------------------------------------------------
+
+func arrayClear(source []float64, index, length int) {
+	for x := 0; x < length; x++ {
+		absoluteIndex := x + index
+		source[absoluteIndex] = 0
+	}
+}
+
+func arrayCopy(source []float64, sourceIndex int, destination []float64, destinationIndex, length int) {
+	for x := 0; x < length; x++ {
+		from := sourceIndex + x
+		to := destinationIndex + x
+
+		destination[to] = source[from]
+	}
+}

value_buffer_test.go

@@ -6,10 +6,10 @@ import (
 	"github.com/blendlabs/go-assert"
 )
 
-func TestRingBuffer(t *testing.T) {
+func TestValueBuffer(t *testing.T) {
 	assert := assert.New(t)
 
-	buffer := NewRingBuffer()
+	buffer := NewValueBuffer()
 
 	buffer.Enqueue(1)
 	assert.Equal(1, buffer.Len())
@@ -96,14 +96,14 @@ func TestRingBuffer(t *testing.T) {
 	value = buffer.Dequeue()
 	assert.Equal(8, value)
 	assert.Equal(0, buffer.Len())
-	assert.Nil(buffer.Peek())
+	assert.Zero(buffer.Peek())
-	assert.Nil(buffer.PeekBack())
+	assert.Zero(buffer.PeekBack())
 }
 
 func TestRingBufferClear(t *testing.T) {
 	assert := assert.New(t)
 
-	buffer := NewRingBuffer()
+	buffer := NewValueBuffer()
 	buffer.Enqueue(1)
 	buffer.Enqueue(1)
 	buffer.Enqueue(1)
@@ -117,21 +117,21 @@ func TestRingBufferClear(t *testing.T) {
 
 	buffer.Clear()
 	assert.Equal(0, buffer.Len())
-	assert.Nil(buffer.Peek())
+	assert.Zero(buffer.Peek())
-	assert.Nil(buffer.PeekBack())
+	assert.Zero(buffer.PeekBack())
 }
 
 func TestRingBufferAsSlice(t *testing.T) {
 	assert := assert.New(t)
 
-	buffer := NewRingBuffer()
+	buffer := NewValueBuffer()
 	buffer.Enqueue(1)
 	buffer.Enqueue(2)
 	buffer.Enqueue(3)
 	buffer.Enqueue(4)
 	buffer.Enqueue(5)
 
-	contents := buffer.AsSlice()
+	contents := buffer.Array()
 	assert.Len(contents, 5)
 	assert.Equal(1, contents[0])
 	assert.Equal(2, contents[1])
@@ -143,20 +143,40 @@ func TestRingBufferAsSlice(t *testing.T) {
 func TestRingBufferEach(t *testing.T) {
 	assert := assert.New(t)
 
-	buffer := NewRingBuffer()
+	buffer := NewValueBuffer()
 
 	for x := 1; x < 17; x++ {
-		buffer.Enqueue(x)
+		buffer.Enqueue(float64(x))
 	}
 
 	called := 0
-	buffer.Each(func(v interface{}) {
+	buffer.Each(func(_ int, v float64) {
-		if typed, isTyped := v.(int); isTyped {
+		if v == float64(called+1) {
-			if typed == (called + 1) {
+			called++
-				called++
-			}
 		}
 	})
 
 	assert.Equal(16, called)
 }
+
+func TestNewValueBuffer(t *testing.T) {
+	assert := assert.New(t)
+
+	empty := NewValueBuffer()
+	assert.NotNil(empty)
+	assert.Zero(empty.Len())
+	assert.Equal(valueBufferDefaultCapacity, empty.Capacity())
+	assert.Zero(empty.Peek())
+	assert.Zero(empty.PeekBack())
+}
+
+func TestNewValueBufferWithValues(t *testing.T) {
+	assert := assert.New(t)
+
+	values := NewValueBuffer(1, 2, 3, 4)
+	assert.NotNil(values)
+	assert.Equal(4, values.Len())
+	assert.Equal(valueBufferDefaultCapacity, values.Capacity())
+	assert.Equal(1, values.Peek())
+	assert.Equal(4, values.PeekBack())
+}

value_provider.go

@@ -2,38 +2,38 @@ package chart
 
 import "github.com/wcharczuk/go-chart/drawing"
 
-// ValueProvider is a type that produces values.
+// ValuesProvider is a type that produces values.
-type ValueProvider interface {
+type ValuesProvider interface {
 	Len() int
-	GetValue(index int) (float64, float64)
+	GetValues(index int) (float64, float64)
 }
 
-// BoundedValueProvider allows series to return a range.
+// BoundedValuesProvider allows series to return a range.
-type BoundedValueProvider interface {
+type BoundedValuesProvider interface {
 	Len() int
-	GetBoundedValue(index int) (x, y1, y2 float64)
+	GetBoundedValues(index int) (x, y1, y2 float64)
 }
 
-// LastValueProvider is a special type of value provider that can return it's (potentially computed) last value.
+// LastValuesProvider is a special type of value provider that can return it's (potentially computed) last value.
-type LastValueProvider interface {
+type LastValuesProvider interface {
-	GetLastValue() (x, y float64)
+	GetLastValues() (x, y float64)
 }
 
-// BoundedLastValueProvider is a special type of value provider that can return it's (potentially computed) bounded last value.
+// BoundedLastValuesProvider is a special type of value provider that can return it's (potentially computed) bounded last value.
-type BoundedLastValueProvider interface {
+type BoundedLastValuesProvider interface {
-	GetBoundedLastValue() (x, y1, y2 float64)
+	GetBoundedLastValues() (x, y1, y2 float64)
 }
 
-// FullValueProvider is an interface that combines `ValueProvider` and `LastValueProvider`
+// FullValuesProvider is an interface that combines `ValuesProvider` and `LastValuesProvider`
-type FullValueProvider interface {
+type FullValuesProvider interface {
-	ValueProvider
+	ValuesProvider
-	LastValueProvider
+	LastValuesProvider
 }
 
-// FullBoundedValueProvider is an interface that combines `BoundedValueProvider` and `BoundedLastValueProvider`
+// FullBoundedValuesProvider is an interface that combines `BoundedValuesProvider` and `BoundedLastValuesProvider`
-type FullBoundedValueProvider interface {
+type FullBoundedValuesProvider interface {
-	BoundedValueProvider
+	BoundedValuesProvider
-	BoundedLastValueProvider
+	BoundedLastValuesProvider
 }
 
 // SizeProvider is a provider for integer size.