moving averages! dashes!

This commit is contained in:
Will Charczuk 2016-07-14 09:27:23 -07:00
parent e4c410621d
commit 96e957daaf
6 changed files with 483 additions and 7 deletions

View file

@ -33,6 +33,9 @@ func DrawLineSeries(r Renderer, canvasBox Box, xrange, yrange Range, s Style, vs
}
r.SetStrokeColor(s.GetStrokeColor())
if len(s.GetStrokeDashArray()) > 0 {
r.SetStrokeDashArray(s.GetStrokeDashArray())
}
r.SetStrokeWidth(s.GetStrokeWidth(DefaultStrokeWidth))
r.MoveTo(x0, y0)

81
moving_average_series.go Normal file
View file

@ -0,0 +1,81 @@
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)
}

217
ring_buffer.go Normal file
View file

@ -0,0 +1,217 @@
package chart
import (
"fmt"
"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, " <= ")
}
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]
}
}

162
ring_buffer_test.go Normal file
View file

@ -0,0 +1,162 @@
package chart
import (
"testing"
"github.com/blendlabs/go-assert"
)
func TestRingBuffer(t *testing.T) {
assert := assert.New(t)
buffer := NewRingBuffer()
buffer.Enqueue(1)
assert.Equal(1, buffer.Len())
assert.Equal(1, buffer.Peek())
assert.Equal(1, buffer.PeekBack())
buffer.Enqueue(2)
assert.Equal(2, buffer.Len())
assert.Equal(1, buffer.Peek())
assert.Equal(2, buffer.PeekBack())
buffer.Enqueue(3)
assert.Equal(3, buffer.Len())
assert.Equal(1, buffer.Peek())
assert.Equal(3, buffer.PeekBack())
buffer.Enqueue(4)
assert.Equal(4, buffer.Len())
assert.Equal(1, buffer.Peek())
assert.Equal(4, buffer.PeekBack())
buffer.Enqueue(5)
assert.Equal(5, buffer.Len())
assert.Equal(1, buffer.Peek())
assert.Equal(5, buffer.PeekBack())
buffer.Enqueue(6)
assert.Equal(6, buffer.Len())
assert.Equal(1, buffer.Peek())
assert.Equal(6, buffer.PeekBack())
buffer.Enqueue(7)
assert.Equal(7, buffer.Len())
assert.Equal(1, buffer.Peek())
assert.Equal(7, buffer.PeekBack())
buffer.Enqueue(8)
assert.Equal(8, buffer.Len())
assert.Equal(1, buffer.Peek())
assert.Equal(8, buffer.PeekBack())
value := buffer.Dequeue()
assert.Equal(1, value)
assert.Equal(7, buffer.Len())
assert.Equal(2, buffer.Peek())
assert.Equal(8, buffer.PeekBack())
value = buffer.Dequeue()
assert.Equal(2, value)
assert.Equal(6, buffer.Len())
assert.Equal(3, buffer.Peek())
assert.Equal(8, buffer.PeekBack())
value = buffer.Dequeue()
assert.Equal(3, value)
assert.Equal(5, buffer.Len())
assert.Equal(4, buffer.Peek())
assert.Equal(8, buffer.PeekBack())
value = buffer.Dequeue()
assert.Equal(4, value)
assert.Equal(4, buffer.Len())
assert.Equal(5, buffer.Peek())
assert.Equal(8, buffer.PeekBack())
value = buffer.Dequeue()
assert.Equal(5, value)
assert.Equal(3, buffer.Len())
assert.Equal(6, buffer.Peek())
assert.Equal(8, buffer.PeekBack())
value = buffer.Dequeue()
assert.Equal(6, value)
assert.Equal(2, buffer.Len())
assert.Equal(7, buffer.Peek())
assert.Equal(8, buffer.PeekBack())
value = buffer.Dequeue()
assert.Equal(7, value)
assert.Equal(1, buffer.Len())
assert.Equal(8, buffer.Peek())
assert.Equal(8, buffer.PeekBack())
value = buffer.Dequeue()
assert.Equal(8, value)
assert.Equal(0, buffer.Len())
assert.Nil(buffer.Peek())
assert.Nil(buffer.PeekBack())
}
func TestRingBufferClear(t *testing.T) {
assert := assert.New(t)
buffer := NewRingBuffer()
buffer.Enqueue(1)
buffer.Enqueue(1)
buffer.Enqueue(1)
buffer.Enqueue(1)
buffer.Enqueue(1)
buffer.Enqueue(1)
buffer.Enqueue(1)
buffer.Enqueue(1)
assert.Equal(8, buffer.Len())
buffer.Clear()
assert.Equal(0, buffer.Len())
assert.Nil(buffer.Peek())
assert.Nil(buffer.PeekBack())
}
func TestRingBufferAsSlice(t *testing.T) {
assert := assert.New(t)
buffer := NewRingBuffer()
buffer.Enqueue(1)
buffer.Enqueue(2)
buffer.Enqueue(3)
buffer.Enqueue(4)
buffer.Enqueue(5)
contents := buffer.AsSlice()
assert.Len(contents, 5)
assert.Equal(1, contents[0])
assert.Equal(2, contents[1])
assert.Equal(3, contents[2])
assert.Equal(4, contents[3])
assert.Equal(5, contents[4])
}
func TestRingBufferEach(t *testing.T) {
assert := assert.New(t)
buffer := NewRingBuffer()
for x := 1; x < 17; x++ {
buffer.Enqueue(x)
}
called := 0
buffer.Each(func(v interface{}) {
if typed, isTyped := v.(int); isTyped {
if typed == (called + 1) {
called++
}
}
})
assert.Equal(16, called)
}

View file

@ -120,6 +120,7 @@ func (s Style) GetPadding(defaults ...Box) Box {
func (s Style) WithDefaultsFrom(defaults Style) (final Style) {
final.StrokeColor = s.GetStrokeColor(defaults.StrokeColor)
final.StrokeWidth = s.GetStrokeWidth(defaults.StrokeWidth)
final.StrokeDashArray = s.GetStrokeDashArray(defaults.StrokeDashArray)
final.FillColor = s.GetFillColor(defaults.FillColor)
final.FontColor = s.GetFontColor(defaults.FontColor)
final.Font = s.GetFont(defaults.Font)

View file

@ -35,6 +35,16 @@ func chartHandler(rc *web.RequestContext) web.ControllerResult {
s1y = append(s1y, rnd.Float64()*1024)
}
s1 := chart.TimeSeries{
Name: "a",
XValues: s1x,
YValues: s1y,
Style: chart.Style{
Show: true,
FillColor: chart.GetDefaultSeriesStrokeColor(0).WithAlpha(64),
},
}
c := chart.Chart{
Title: "A Test Chart",
TitleStyle: chart.Style{
@ -65,17 +75,19 @@ func chartHandler(rc *web.RequestContext) web.ControllerResult {
},
},
Series: []chart.Series{
chart.TimeSeries{
Name: "a",
XValues: s1x,
YValues: s1y,
s1,
&chart.MovingAverageSeries{
Name: "Average",
Style: chart.Style{
Show: true,
FillColor: chart.GetDefaultSeriesStrokeColor(0).WithAlpha(64),
Show: true,
StrokeColor: drawing.ColorRed,
StrokeDashArray: []float64{5, 1, 1},
},
WindowSize: 10,
InnerSeries: s1,
},
chart.AnnotationSeries{
Name: fmt.Sprintf("%s - Last Value", "Test"),
Name: fmt.Sprintf("Last Value"),
Style: chart.Style{
Show: true,
StrokeColor: chart.GetDefaultSeriesStrokeColor(0),