Merge pull request #184 from lyricnz/feature/x-labels

Show X axis labels on charts

cointop/chart.go

@@ -172,23 +172,28 @@ func (ct *Cointop) ChartPoints(symbol string, name string) error {
 		}
 	}
 
-	// Resample cachedata
-	timeQuantum := timedata.CalculateTimeQuantum(cacheData)
-	newStart := time.Unix(start, 0).Add(timeQuantum)
-	newEnd := time.Unix(end, 0).Add(-timeQuantum)
-	timeData := timedata.ResampleTimeSeriesData(cacheData, float64(newStart.UnixMilli()), float64(newEnd.UnixMilli()), chart.GetChartDataSize(maxX))
-
-	// Extract just the values from the data
+	var labels []string
 	var data []float64
-	for i := range timeData {
-		value := timeData[i][1]
-		if math.IsNaN(value) {
-			value = 0.0
+	timeQuantum := timedata.CalculateTimeQuantum(cacheData) // will be 0 if <2 points
+	if timeQuantum > 0 {
+		// Resample cachedata
+		newStart := cacheData[0][0] // use the first data point
+		newEnd := time.Unix(end, 0).Add(-timeQuantum)
+		timeData := timedata.ResampleTimeSeriesData(cacheData, newStart, float64(newEnd.UnixMilli()), chart.GetChartDataSize(maxX))
+		labels = timedata.BuildTimeSeriesLabels(timeData)
+
+		// Extract just the values from the data
+		for i := range timeData {
+			value := timeData[i][1]
+			if math.IsNaN(value) {
+				value = 0.0
+			}
+			data = append(data, value)
 		}
-		data = append(data, value)
 	}
 
 	chart.SetData(data)
+	chart.SetDataLabels(labels)
 	ct.State.chartPoints = chart.GetChartPoints(maxX)
 
 	return nil
@@ -280,39 +285,48 @@ func (ct *Cointop) PortfolioChart() error {
 			break // use the first one
 		}
 	}
-	newStart := time.Unix(start, 0).Add(timeQuantum)
-	newEnd := time.Unix(end, 0).Add(-timeQuantum)
 
-	// Resample and sum data
+	// If there is data, resample and sum
 	var data []float64
-	for _, cacheData := range allCacheData {
-		coinData := timedata.ResampleTimeSeriesData(cacheData.data, float64(newStart.UnixMilli()), float64(newEnd.UnixMilli()), chart.GetChartDataSize(maxX))
-		// sum (excluding NaN)
-		for i := range coinData {
-			price := coinData[i][1]
-			if math.IsNaN(price) {
-				price = 0.0
+	var labels []string
+	if timeQuantum > 0 {
+		newStart := time.Unix(start, 0).Add(timeQuantum)
+		newEnd := time.Unix(end, 0).Add(-timeQuantum)
+
+		// Resample and sum data
+		for i, cacheData := range allCacheData {
+			coinData := timedata.ResampleTimeSeriesData(cacheData.data, float64(newStart.UnixMilli()), float64(newEnd.UnixMilli()), chart.GetChartDataSize(maxX))
+			if i == 0 {
+				labels = timedata.BuildTimeSeriesLabels(coinData)
 			}
-			sum := cacheData.coin.Holdings * price
-			if i < len(data) {
-				data[i] += sum
-			} else {
-				data = append(data, sum)
+			// sum (excluding NaN)
+			for i := range coinData {
+				price := coinData[i][1]
+				if math.IsNaN(price) {
+					price = 0.0
+				}
+				sum := cacheData.coin.Holdings * price
+				if i < len(data) {
+					data[i] += sum
+				} else {
+					data = append(data, sum)
+				}
 			}
 		}
-	}
 
-	// Scale Portfolio Balances to hide value
-	if ct.State.hidePortfolioBalances {
-		var lastPrice = data[len(data)-1]
-		if lastPrice > 0.0 {
-			for i, price := range data {
-				data[i] = 100 * price / lastPrice
+		// Scale Portfolio Balances to hide value
+		if ct.State.hidePortfolioBalances {
+			var lastPrice = data[len(data)-1]
+			if lastPrice > 0.0 {
+				for i, price := range data {
+					data[i] = 100 * price / lastPrice
+				}
 			}
 		}
 	}
 
 	chart.SetData(data)
+	chart.SetDataLabels(labels)
 	ct.State.chartPoints = chart.GetChartPoints(maxX)
 
 	return nil

pkg/chartplot/chartplot.go

@@ -55,6 +55,11 @@ func (c *ChartPlot) SetData(data []float64) {
 	c.t.Data = data
 }
 
+// SetDataLabels ...
+func (c *ChartPlot) SetDataLabels(labels []string) {
+	c.t.DataLabels = labels
+}
+
 // GetChartDataSize ...
 func (c *ChartPlot) GetChartDataSize(width int) int {
 	axisYWidth := 30

pkg/timedata/timedata.go

@@ -4,11 +4,9 @@ import (
 	"math"
 	"sort"
 	"time"
-
-	log "github.com/sirupsen/logrus"
 )
 
-// Resample the [timestamp,value] data given to numsteps between start-end (returns numSteps+1 points).
+// ResampleTimeSeriesData resamples the given [timestamp,value] data to numsteps between start-end (returns numSteps+1 points).
 // If the data does not extend past start/end then there will likely be NaN in the output data.
 func ResampleTimeSeriesData(data [][]float64, start float64, end float64, numSteps int) [][]float64 {
 	var newData [][]float64
@@ -33,7 +31,7 @@ func ResampleTimeSeriesData(data [][]float64, start float64, end float64, numSte
 	return newData
 }
 
-// Assuming that the [timestamp,value] data provided is roughly evenly spaced, calculate that interval.
+// CalculateTimeQuantum determines the given [timestamp,value] data
 func CalculateTimeQuantum(data [][]float64) time.Duration {
 	if len(data) > 1 {
 		minTime := time.UnixMilli(int64(data[0][0]))
@@ -43,9 +41,25 @@ func CalculateTimeQuantum(data [][]float64) time.Duration {
 	return 0
 }
 
-// Print out all the [timestamp,value] data provided
-func DebugLogPriceData(data [][]float64) {
+// BuildTimeSeriesLabels returns a list of short labels representing time values from the given [timestamp,value] data
+func BuildTimeSeriesLabels(data [][]float64) []string {
+	minTime := time.UnixMilli(int64(data[0][0]))
+	maxTime := time.UnixMilli(int64(data[len(data)-1][0]))
+	timeRange := maxTime.Sub(minTime)
+
+	var timeFormat string
+	if timeRange.Hours() < 24 {
+		timeFormat = "15:04"
+	} else if timeRange.Hours() < 24*7 {
+		timeFormat = "Mon 15:04"
+	} else if timeRange.Hours() < 24*365 {
+		timeFormat = "02-Jan"
+	} else {
+		timeFormat = "Jan 2006"
+	}
+	var labels []string
 	for i := range data {
-		log.Debugf("%s %.2f", time.Unix(int64(data[i][0]/1000), 0), data[i][1])
+		labels = append(labels, time.UnixMilli(int64(data[i][0])).Format(timeFormat))
 	}
+	return labels
 }