Add chart components 216-245; step-aware ticks, font-aware labels

Bars, lines, areas, pies, donuts, radar, histogram, scatter, bubbles,
heatmaps, gauge, bullet, funnel, waterfall, treemap, candles, box
plots, steps, rings, legend, axis, crosshair, polar area, pyramid,
spectrum bars and win-loss strips, each drawn dot by dot. Ticks follow
1-2-5 steps and print as precisely as their step needs; a label row
uses micro letters or the pixel font as a whole. Descriptions carry the
data in numbers. Bad data panics.

chart/winloss.go

@@ -0,0 +1,46 @@
+package chart
+
+import (
+	"fmt"
+
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+type WinLossOptions struct{}
+
+// WinLoss rows blocks: wins up, losses down, draws dashed.
+func WinLoss(c *ui.Context, text string, results []int, o WinLossOptions) *ui.Element {
+	k := pixel.K(c)
+	return ui.Box(c).Size(k.D(len(results)*5), k.D(pixel.LineHeight)).Role(ui.RoleImage).Label(text).
+		Description(record(results)).Draw(func(p *ui.Painter, r ui.Rect) {
+		g := k.Canvas(p, r)
+		mid := pixel.LineHeight / 2
+		for i, res := range results {
+			x := i * 5
+			switch res {
+			case 1:
+				g.Rect(x, mid-6, 4, 5, pixel.Good)
+			case -1:
+				g.Rect(x, mid+1, 4, 5, pixel.Bad)
+			default:
+				g.Rect(x, mid-1, 4, 2, pixel.Faint)
+			}
+		}
+	})
+}
+
+// record is "wins-losses-draws: " then each result, checked.
+func record(results []int) string {
+	var n [3]int
+	all := make([]float64, len(results))
+	for i, r := range results {
+		if r < -1 || r > 1 {
+			panic(fmt.Sprintf("chart: WinLoss result %d is not -1, 0 or 1", r))
+		}
+		n[1-r]++
+		all[i] = float64(r)
+	}
+	return fmt.Sprintf("%d-%d-%d: %s", n[0], n[2], n[1], nums(all))
+}