Charts I: components 101-120

radar_chart.go

@@ -0,0 +1,141 @@
+package mujica
+
+import (
+	"math"
+	"strings"
+
+	"github.com/egoist/mygo/ui"
+
+	"mujicaui/internal"
+	"mujicaui/theme"
+)
+
+// RadarChartOptions configure a RadarChart.
+type RadarChartOptions struct {
+	Frame ChartFrame
+	// Max is the outer ring's value; 0 means automatic.
+	Max    float64
+	Format func(v float64) string
+}
+
+// RadarChart draws series as polygons over three or more axes.
+func RadarChart(c *ui.Context, axes []string, series []ChartSeries, opts RadarChartOptions) ChartResult {
+	if n := chartCheckSeries(series); len(axes) < 3 || n != len(axes) && len(series) > 0 || opts.Max < 0 {
+		panic("mujica: RadarChart needs three or more axes, one value per axis and Max ≥ 0")
+	}
+	ch := newChart(c, opts.Frame)
+	k := Tokens(c)
+	pal := internal.Palette(k)
+	size := FontSize(c, theme.CaptionSize)
+	keys := make([]chartKey, len(series))
+	top := opts.Max
+	for i, s := range series {
+		keys[i] = chartKey{Name: s.Name, Color: pal[i%len(pal)], Shape: i}
+		for _, v := range s.Values {
+			if v < 0 {
+				panic("mujica: RadarChart values must be ≥ 0")
+			}
+			if !ch.hidden(s.Name) && opts.Max == 0 && !math.IsNaN(v) {
+				top = max(top, v)
+			}
+		}
+	}
+	n := len(axes)
+	if top == 0 {
+		n = 0
+	}
+	var step float64
+	if n > 0 && opts.Max == 0 {
+		_, top, step = internal.Nice(0, top, 4)
+	} else if n > 0 {
+		_, _, step = internal.Nice(0, top, 4)
+	}
+	geom := func(r ui.Rect) (cx, cy, rad float32) {
+		return r.X + r.W/2, r.Y + r.H/2 + 4, min(r.W/2-70, r.H/2-24)
+	}
+	angle := func(i int) float64 { return 2 * math.Pi * float64(i) / float64(len(axes)) }
+	spec := chartSpec{n: n, keys: keys, toggle: len(series) > 1}
+	spec.readout = func(i int) string {
+		parts := []string{axes[i]}
+		for _, s := range series {
+			if !ch.hidden(s.Name) {
+				parts = append(parts, s.Name+" "+chartValue(c, s.Values[i], opts.Format))
+			}
+		}
+		return strings.Join(parts, " · ")
+	}
+	spec.pick = func(r ui.Rect, x, y float32) int {
+		cx, cy, rad := geom(r)
+		if math.Hypot(float64(x-cx), float64(y-cy)) > float64(rad)+16 {
+			return -1
+		}
+		return internal.Nearest(len(axes), func(i int) (float32, float32) { return internal.Polar(cx, cy, rad, angle(i)) }, x, y, 2*rad+32, false)
+	}
+	spec.draw = func(p *ui.Painter, r ui.Rect, active int) {
+		cx, cy, rad := geom(r)
+		for _, t := range internal.Ticks(step, top, step) {
+			var ring ui.Path
+			for i := range axes {
+				x, y := internal.Polar(cx, cy, rad*float32(t/top), angle(i))
+				if i == 0 {
+					ring.MoveTo(x, y)
+				} else {
+					ring.LineTo(x, y)
+				}
+			}
+			ring.Close()
+			p.StrokePath(&ring, 1, k.Border)
+			chartText(p, internal.FormatTick(t, step), cx-4, cy-rad*float32(t/top), size, k.TextMuted, 1, 0.5)
+		}
+		for i, a := range axes {
+			x, y := internal.Polar(cx, cy, rad, angle(i))
+			w := float32(1)
+			if i == active {
+				w = 2
+			}
+			var spoke ui.Path
+			spoke.MoveTo(cx, cy).LineTo(x, y)
+			p.StrokePath(&spoke, w, k.ControlBorder)
+			lx, ly := internal.Polar(cx, cy, rad+10, angle(i))
+			ax := 0.5 + 0.5*float32(math.Sin(angle(i)))
+			col := k.TextMuted
+			if i == active {
+				col = k.Text
+			}
+			chartText(p, a, lx, ly, size, col, 1-ax, 0.5+0.5*float32(math.Cos(angle(i))))
+		}
+		for si, s := range series {
+			if ch.hidden(s.Name) {
+				continue
+			}
+			var poly ui.Path
+			pt := func(i int) (float32, float32) {
+				v := s.Values[i]
+				if math.IsNaN(v) {
+					v = 0
+				}
+				return internal.Polar(cx, cy, rad*float32(v/top), angle(i))
+			}
+			for i := range axes {
+				if i == 0 {
+					poly.MoveTo(pt(i))
+				} else {
+					poly.LineTo(pt(i))
+				}
+			}
+			poly.Close()
+			p.FillPath(&poly, keys[si].Color.Alpha(0.16))
+			p.StrokePath(&poly, 2, keys[si].Color)
+			for i := range axes {
+				x, y := pt(i)
+				sz := float32(7)
+				if i == active {
+					sz = 11
+				}
+				internal.Marker(p, si, x, y, sz, keys[si].Color)
+			}
+		}
+	}
+	res, _ := ch.build(spec)
+	return res
+}