147 lines
3.6 KiB
Go
147 lines
3.6 KiB
Go
package chart
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import (
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"fmt"
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"time"
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"math"
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"github.com/wcharczuk/go-chart/util"
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)
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// CandleValue is a day's data for a candlestick plot.
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type CandleValue struct {
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Timestamp time.Time
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High float64
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Low float64
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Open float64
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Close float64
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}
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// String returns a string value for the candle value.
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func (cv CandleValue) String() string {
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return fmt.Sprintf("candle %s high: %.2f low: %.2f open: %.2f close: %.2f", cv.Timestamp.Format("2006-01-02"), cv.High, cv.Low, cv.Open, cv.Close)
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}
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// IsZero returns if the value is zero or not.
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func (cv CandleValue) IsZero() bool {
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return cv.Timestamp.IsZero()
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}
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// CandlestickSeries is a special type of series that takes a norma value provider
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// and maps it to day value stats (high, low, open, close).
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type CandlestickSeries struct {
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Name string
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Style Style
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YAxis YAxisType
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XValues []time.Time
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YValues []float64
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}
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// GetName implements Series.GetName.
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func (cs CandlestickSeries) GetName() string {
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return cs.Name
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}
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// GetStyle implements Series.GetStyle.
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func (cs CandlestickSeries) GetStyle() Style {
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return cs.Style
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}
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// GetYAxis returns which yaxis the series is mapped to.
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func (cs CandlestickSeries) GetYAxis() YAxisType {
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return cs.YAxis
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}
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// Len returns the length of the series.
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func (cs CandlestickSeries) Len() int {
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return util.Math.MinInt(len(cs.XValues), len(cs.YValues))
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}
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// GetValues returns the values at a given index.
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func (cs CandlestickSeries) GetValues(index int) (float64, float64) {
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return util.Time.ToFloat64(cs.XValues[index]), cs.YValues[index]
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}
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// GetRawValues returns the values at a given index.
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func (cs CandlestickSeries) GetRawValues(index int) (time.Time, float64) {
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return cs.XValues[index], cs.YValues[index]
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}
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// CandleValues returns the candlestick values for each day represented by the inner series.
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func (cs CandlestickSeries) CandleValues() []CandleValue {
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totalValues := cs.Len()
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if totalValues == 0 {
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return nil
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}
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var values []CandleValue
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var lastYear, lastMonth, lastDay int
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var year, month, day int
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var t time.Time
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var lv, v float64
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t, v = cs.GetRawValues(0)
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year, month, day = t.Year(), int(t.Month()), t.Day()
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lastYear, lastMonth, lastDay = year, month, day
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value := CandleValue{
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Timestamp: cs.newTimestamp(year, month, day),
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Open: v,
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Low: v,
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High: v,
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}
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lv = v
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for i := 1; i < totalValues; i++ {
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t, v = cs.GetRawValues(i)
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year, month, day = t.Year(), int(t.Month()), t.Day()
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// if we've transitioned to a new day or we're on the last value
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if lastYear != year || lastMonth != month || lastDay != day || i == (totalValues-1) {
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value.Close = lv
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values = append(values, value)
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value = CandleValue{
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Timestamp: cs.newTimestamp(year, month, day),
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Open: v,
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High: v,
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Low: v,
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}
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lastYear = year
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lastMonth = month
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lastDay = day
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} else {
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value.Low = math.Min(value.Low, v)
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value.High = math.Max(value.High, v)
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}
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lv = v
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}
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return values
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}
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func (cs CandlestickSeries) newTimestamp(year, month, day int) time.Time {
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return time.Date(year, time.Month(month), day, 12, 0, 0, 0, util.Date.Eastern())
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}
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// Render implements Series.Render.
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func (cs CandlestickSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) {
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style := cs.Style.InheritFrom(defaults)
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Draw.CandlestickSeries(r, canvasBox, xrange, yrange, style, cs)
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}
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// Validate validates the series.
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func (cs CandlestickSeries) Validate() error {
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if cs.XValues == nil {
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return fmt.Errorf("candlestick series requires `XValues` to be set")
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}
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if cs.YValues == nil {
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return fmt.Errorf("candlestick series requires `YValues` to be set")
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}
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return nil
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}
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