Charts I: components 101-120

area_chart.go

@@ -0,0 +1,74 @@
+package mujica
+
+import (
+	"math"
+	"time"
+
+	"github.com/egoist/mygo/ui"
+)
+
+// AreaChartOptions configure an AreaChart.
+type AreaChartOptions struct {
+	Frame ChartFrame
+	// X places point i at ascending X[i]; nil means i.
+	X []float64
+	// Times makes a time axis; set X or Times.
+	Times []time.Time
+	// Stacked piles visible series on each other.
+	Stacked bool
+	// Baseline is where areas start; zero by default.
+	Baseline float64
+	Format   func(v float64) string
+}
+
+// AreaChart fills series to the baseline, or stacked.
+func AreaChart(c *ui.Context, series []ChartSeries, opts AreaChartOptions) ChartResult {
+	n := chartCheckSeries(series)
+	ch := newChart(c, opts.Frame)
+	ax := chartMemo(ch, "x", [3]string{chartID(opts.X), chartID(opts.Times), chartID(series)}, func() chartX { return newChartX(n, opts.X, opts.Times) })
+	deps := struct {
+		id      string
+		stacked bool
+		base    float64
+	}{chartSeriesID(ch, series), opts.Stacked, opts.Baseline}
+	bands := chartMemo(ch, "bands", deps, func() [2][][]float64 { return areaBands(series, ch.hidden, opts.Stacked, opts.Baseline) })
+	lo, hi, ok := chartYRange(ch, series, false, bands[0])
+	if !ok {
+		n = 0
+	}
+	lo, hi = min(lo, opts.Baseline), max(hi, opts.Baseline)
+	return chartLines(ch, chartLineData{series: series, tops: bands[0], bases: bands[1], ax: ax, lo: lo, hi: hi, n: n, format: opts.Format})
+}
+
+// areaBands returns each series' top and bottom edges.
+func areaBands(series []ChartSeries, hidden func(string) bool, stacked bool, base float64) [2][][]float64 {
+	var tops, bases [][]float64
+	var run []float64
+	if len(series) > 0 {
+		run = make([]float64, len(series[0].Values))
+		for i := range run {
+			run[i] = base
+		}
+	}
+	for _, s := range series {
+		top, bot := make([]float64, len(s.Values)), make([]float64, len(s.Values))
+		for i, v := range s.Values {
+			bot[i], top[i] = base, v
+			if stacked {
+				bot[i], top[i] = run[i], run[i]+v
+			}
+			if stacked && !math.IsNaN(v) && !hidden(s.Name) {
+				run[i] += v
+			}
+		}
+		tops, bases = append(tops, top), append(bases, bot)
+	}
+	return [2][][]float64{tops, bases}
+}
+
+func chartBool(b bool) float64 {
+	if b {
+		return 1
+	}
+	return 0
+}