fix ticks on x axis

hdiet.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"git.gutmet.org/go-chart.git"
 	"git.gutmet.org/go-chart.git/drawing"
+	util "git.gutmet.org/go-chart.git/util"
 	"git.gutmet.org/goutil.git"
 	"math"
 	"os"
@@ -157,18 +158,18 @@ func show(args showFlags) error {
 
 	fromTo := dateInterval{from, to}
 	s1 := timeSeries("weight", chart.ColorCyan)
-	yRange1 := addPointsGetRange(&s1, points, fromTo, func(p point) float64 { return p.weight })
+	xRange, yRange1 := addPointsGetRange(&s1, points, fromTo, func(p point) float64 { return p.weight })
 	s2 := timeSeries("trend", drawing.Color{R: 255, A: 255})
-	yRange2 := addPointsGetRange(&s2, points, fromTo, func(p point) float64 { return p.trend })
+	_, yRange2 := addPointsGetRange(&s2, points, xRange, func(p point) float64 { return p.trend })
 	s3 := timeSeries("diet", drawing.Color{R: 255, G: 211, A: 255})
 	yRange3 := yRange2
 	if dietpoints != nil {
-		yRange3 = addPointsGetRange(&s3, dietpoints, fromTo, func(p point) float64 { return p.weight })
+		_, yRange3 = addPointsGetRange(&s3, dietpoints, xRange, func(p point) float64 { return p.weight })
 	}
 	YRange := yRange{math.Min(math.Min(yRange1.min, yRange2.min), yRange3.min), math.Max(math.Max(yRange1.max, yRange2.max), yRange3.max)}
 	YRange.min = math.Floor(YRange.min) - 1.0
 	YRange.max = math.Ceil(YRange.max) + 1.0
-	graph := graph(s1, s2, s3, YRange)
+	graph := graph(xticks(xRange), s1, s2, s3, YRange)
 	err = writeGraphToFile(graph)
 	if err != nil {
 		return err
@@ -249,11 +250,35 @@ func main() {
 
 /*****************************/
 
-func addPointsGetRange(s *chart.TimeSeries, points []point, di dateInterval, project func(point) float64) yRange {
+func xticks(d dateInterval) []chart.Tick {
+	ticks := []chart.Tick{}
+	start := d.min
+	end := d.max
+	stepDays := int(end.Sub(start).Hours() / 24 / 10)
+	if stepDays < 1 {
+		stepDays = 1
+	}
+	for i := 0; start.AddDate(0, 0, i).Before(end.AddDate(0, 0, stepDays)); i += stepDays {
+		val := start.AddDate(0, 0, i)
+		label := val.Format(dateLayout)
+		ticks = append(ticks, chart.Tick{util.Time.ToFloat64(val), label})
+	}
+	return ticks
+}
+
+func addPointsGetRange(s *chart.TimeSeries, points []point, di dateInterval, project func(point) float64) (dateInterval, yRange) {
+	XRange := dateInterval{time.Now().AddDate(10000, 0, 0), time.Now().AddDate(-10000, 0, 0)}
 	YRange := yRange{math.MaxFloat64, -math.MaxFloat64}
 	for _, p := range points {
 		if (p.date.After(di.min) || p.date.Equal(di.min)) && (p.date.Before(di.max) || p.date.Equal(di.max)) && !math.IsNaN(project(p)) {
-			s.XValues = append(s.XValues, p.date)
+			xVal := p.date
+			s.XValues = append(s.XValues, xVal)
+			if xVal.Before(XRange.min) {
+				XRange.min = xVal
+			}
+			if xVal.After(XRange.max) {
+				XRange.max = xVal
+			}
 			yVal := project(p)
 			s.YValues = append(s.YValues, yVal)
 			if yVal < YRange.min {
@@ -264,14 +289,14 @@ func addPointsGetRange(s *chart.TimeSeries, points []point, di dateInterval, pro
 			}
 		}
 	}
-	return YRange
+	return XRange, YRange
 }
 
 func timeSeries(name string, color drawing.Color) chart.TimeSeries {
 	return chart.TimeSeries{Name: name, Style: chart.Style{Show: true, StrokeColor: color}}
 }
 
-func graph(s1 chart.TimeSeries, s2 chart.TimeSeries, s3 chart.TimeSeries, YRange yRange) chart.Chart {
+func graph(xticks []chart.Tick, s1 chart.TimeSeries, s2 chart.TimeSeries, s3 chart.TimeSeries, YRange yRange) chart.Chart {
 	graph := chart.Chart{
 		Width:  width,
 		Height: height,
@@ -280,6 +305,7 @@ func graph(s1 chart.TimeSeries, s2 chart.TimeSeries, s3 chart.TimeSeries, YRange
 			NameStyle:      chart.StyleShow(),
 			Style:          chart.StyleShow(),
 			ValueFormatter: chart.TimeDateValueFormatter,
+			Ticks:          xticks,
 		},
 		YAxis: chart.YAxis{
 			Name:      "kg",