package chart import ( "fmt" "time" "math" "github.com/wcharczuk/go-chart/util" ) // CandleValue is a day's data for a candlestick plot. type CandleValue struct { Timestamp time.Time High float64 Low float64 Open float64 Close float64 } // String returns a string value for the candle value. func (cv CandleValue) String() string { 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) } // IsZero returns if the value is zero or not. func (cv CandleValue) IsZero() bool { return cv.Timestamp.IsZero() } // CandlestickSeries is a special type of series that takes a norma value provider // and maps it to day value stats (high, low, open, close). type CandlestickSeries struct { Name string Style Style YAxis YAxisType // CandleValues will be used in place of creating them from the `InnerSeries`. CandleValues []CandleValue // InnerSeries is used if the `CandleValues` are not set. InnerSeries ValuesProvider } // GetName implements Series.GetName. func (cs *CandlestickSeries) GetName() string { return cs.Name } // GetStyle implements Series.GetStyle. func (cs *CandlestickSeries) GetStyle() Style { return cs.Style } // GetYAxis returns which yaxis the series is mapped to. func (cs *CandlestickSeries) GetYAxis() YAxisType { return cs.YAxis } // Len returns the length of the series. func (cs *CandlestickSeries) Len() int { return len(cs.GetCandleValues()) } // GetBoundedValues returns the bounded values at a given index. func (cs *CandlestickSeries) GetBoundedValues(index int) (x, y0, y1 float64) { value := cs.GetCandleValues()[index] return util.Time.ToFloat64(value.Timestamp), value.Low, value.High } // GetCandleValues returns the candle values. func (cs CandlestickSeries) GetCandleValues() []CandleValue { if cs.CandleValues == nil { cs.CandleValues = cs.GenerateCandleValues() } return cs.CandleValues } // GenerateCandleValues returns the candlestick values for each day represented by the inner series. func (cs CandlestickSeries) GenerateCandleValues() []CandleValue { totalValues := cs.InnerSeries.Len() if totalValues == 0 { return nil } var values []CandleValue var lastYear, lastMonth, lastDay int var year, month, day int var t time.Time var tv, lv, v float64 tv, v = cs.InnerSeries.GetValues(0) t = util.Time.FromFloat64(tv) year, month, day = t.Year(), int(t.Month()), t.Day() lastYear, lastMonth, lastDay = year, month, day value := CandleValue{ Timestamp: cs.newTimestamp(year, month, day), Open: v, Low: v, High: v, } lv = v for i := 1; i < totalValues; i++ { tv, v = cs.InnerSeries.GetValues(0) t = util.Time.FromFloat64(tv) year, month, day = t.Year(), int(t.Month()), t.Day() // if we've transitioned to a new day or we're on the last value if lastYear != year || lastMonth != month || lastDay != day || i == (totalValues-1) { value.Close = lv values = append(values, value) value = CandleValue{ Timestamp: cs.newTimestamp(year, month, day), Open: v, High: v, Low: v, } lastYear = year lastMonth = month lastDay = day } else { value.Low = math.Min(value.Low, v) value.High = math.Max(value.High, v) } lv = v } return values } func (cs CandlestickSeries) newTimestamp(year, month, day int) time.Time { return time.Date(year, time.Month(month), day, 12, 0, 0, 0, util.Date.Eastern()) } // Render implements Series.Render. func (cs CandlestickSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) { style := cs.Style.InheritFrom(defaults) Draw.CandlestickSeries(r, canvasBox, xrange, yrange, style, cs) } // Validate validates the series. func (cs CandlestickSeries) Validate() error { if cs.CandleValues == nil && cs.InnerSeries == nil { return fmt.Errorf("candlestick series requires either `CandleValues` or `InnerSeries` to be set") } return nil }