Add datetime components 196-215; Kit.At; inert stepper arrows

Calendars, date and time inputs, pickers, clocks, timers, a sun dial,
a season wheel, an agenda and a day schedule. Kit.At rebuilds at a
moment (relative times, midnight). Stepper and NumberInput arrows stop
under Inert. DateInput parks a popup focus as its own.

datetime/yearview.go

@@ -0,0 +1,41 @@
+package datetime
+
+import (
+	"strconv"
+	"time"
+
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+type YearViewOptions struct{}
+
+// A small month's day cell and box, in dots.
+const miniW, miniH, monthW, monthH = 10, 7, 7*miniW + 4, 6*miniH + pixel.LineHeight + 2
+
+// YearView sets a year's twelve months small; today is marked.
+func YearView(c *ui.Context, year int, o YearViewOptions) *ui.Element {
+	k := pixel.K(c)
+	now := today(c, k)
+	return ui.Box(c).Size(k.D(4*monthW), k.D(3*monthH)).Role(ui.RoleImage).Label(strconv.Itoa(year)).Draw(func(p *ui.Painter, r ui.Rect) {
+		g := k.Canvas(p, r)
+		for m := range 12 {
+			ox, oy := m%4*monthW, m/4*monthH
+			first := time.Date(year, time.Month(m+1), 1, 0, 0, 0, 0, now.Location())
+			g.Text(ox, oy, monthName(k, first.Month()), pixel.Faint, 1)
+			skip := int(first.Weekday())
+			for d := first; d.Month() == first.Month(); d = d.AddDate(0, 0, 1) {
+				i := skip + d.Day() - 1
+				x, y := ox+i%7*miniW, oy+pixel.LineHeight+i/7*miniH
+				n := strconv.Itoa(d.Day())
+				ink := pixel.Ink
+				if sameDay(d, now) {
+					g.Rect(x-1, y-1, miniW, miniH, pixel.Accent)
+					ink = pixel.AccentInk
+				}
+				g.Micro(x+(miniW-1-pixel.MicroWidth(n)), y, n, ink, 1)
+			}
+		}
+	})
+}