Add tabletop components 486-500 and ten game icons

Fifteen pieces of a games night: Dice, DiceTray, PlayingCard, CardHand,
Deck, Chessboard, GoBoard, MahjongTile, Domino, Roulette, CoinFlip,
BingoCard, TicTacToe, ScoreTrack and Meeple. Component number 500 is
a meeple, which seems right.

Dice tumble, coins turn and wheels spin on a cue, a frame at a time,
and land at once under Reduce Motion. Hands lift the card you point
at and play the one drawn on top; pieces and stones pick the lighter
of Lit and Ink for White, so they read in every palette; the computer
plays a fair O; FREE is a star in every language.

New 12x12 icons: Spade, Club, Diamond, Meeple, King, Queen, Rook,
Bishop, Knight and Pawn.

tabletop/coinflip.go

@@ -0,0 +1,64 @@
+package tabletop
+
+import (
+	"math"
+
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/icon"
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+type CoinFlipOptions struct {
+	// Cue tosses it: a new cue flips, then it lands.
+	Cue int
+}
+
+// The coin's width and lift, a toss's frame by frame.
+var (
+	turns = [...]int{24, 16, 6, 2, 6, 16, 24, 16, 6, 2, 6, 16}
+	toss  = [...]int{0, 6, 11, 14, 16, 16, 14, 11, 7, 4, 2, 0}
+)
+
+const coinUp = 18
+
+// CoinFlip tosses a coin on a new Cue.
+func CoinFlip(c *ui.Context, text string, heads bool, o CoinFlipOptions) *ui.Element {
+	k := pixel.K(c)
+	word := k.Msg("tails")
+	if heads {
+		word = k.Msg("heads")
+	}
+	e := ui.Column(c).Gap(k.D(2)).AlignItems(ui.Center).AlignSelf(ui.Start).Role(ui.RoleGroup).Label(text).Description(word)
+	// A toss turns twelve frames; reduced, it lands at once.
+	f := max(0, k.Shot(c, e, o.Cue, 15, len(turns)))
+	return e.Children(func() {
+		ui.Box(c).Size(k.D(26), k.D(26+coinUp)).Role(ui.RoleNone).Draw(func(p *ui.Painter, r ui.Rect) {
+			g := k.Canvas(p, r)
+			w, y, up := 24, coinUp, heads
+			if f < len(turns) {
+				// Each half turn shows the other face.
+				w, y, up = turns[f], coinUp-toss[f], heads == (f/3%2 == 0)
+			}
+			for dy := -12; dy <= 12; dy++ {
+				half := int(math.Round(float64(w) / 2 * math.Sqrt(1-float64(dy*dy)/144)))
+				g.HLine(13-half, y+12+dy, 2*half, pixel.Edge)
+				if half > 1 {
+					g.HLine(14-half, y+12+dy, 2*half-2, pixel.Warn)
+				}
+			}
+			if w == 24 {
+				face := icon.Star
+				if up {
+					face = icon.Crown
+				}
+				g.Sprite(7, y+6, face, 0, pixel.Ink, 1)
+			}
+		})
+		if f >= len(turns) {
+			pixel.Text(c, word, pixel.TextOptions{})
+		} else {
+			ui.Box(c).Height(k.D(pixel.LineHeight))
+		}
+	})
+}