Add game components 246-268; data.DrawSlot, Canvas.TextVeil

Health, mana and experience bars, quarter hearts, lives, a spinning
coin counter, score board, stage timer, minimap with fog, compass,
hotbar, paper-doll equipment, skill tree, skill buttons with cooldown
wipes, status effects, a boss bar, damage numbers, quest log and
tracker, party frames, character sheet, level-up screen and shop.
data exports DrawSlot so every slot looks alike; pixel adds TextVeil
for dissolving text. Messages the font cannot draw are fixed and
TestMessagesHaveGlyphs holds every message to the font.

game/questtracker.go

@@ -0,0 +1,42 @@
+package game
+
+import (
+	"strings"
+
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/icon"
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+type QuestTrackerOptions struct{}
+
+// QuestTracker lists a quest's objectives with counts, met ones ticked.
+func QuestTracker(c *ui.Context, q Quest, o QuestTrackerOptions) *ui.Element {
+	k := pixel.K(c)
+	q.check()
+	w := icon.Star.W + 2 + pixel.Measure(q.Title)
+	parts := make([]string, len(q.Objectives))
+	for i, ob := range q.Objectives {
+		parts[i] = ob.Text + " " + ratio(ob.Have, ob.Need)
+		w = max(w, 11+pixel.Measure(ob.Text)+6+pixel.MicroWidth(ratio(ob.Have, ob.Need)))
+	}
+	return ui.Box(c).Role(ui.RoleGroup).Label(q.Title).Description(strings.Join(parts, "; ")).Size(k.D(w), k.D((1+len(q.Objectives))*pixel.LineHeight)).Draw(func(p *ui.Painter, r ui.Rect) {
+		g := k.Canvas(p, r)
+		g.Sprite(0, 2, icon.Star, 0, pixel.Warn, 1)
+		g.Text(icon.Star.W+2, 0, q.Title, pixel.Warn, 1)
+		for i, ob := range q.Objectives {
+			y, met := (i+1)*pixel.LineHeight, ob.Have == ob.Need
+			tick(g, 1, y+5, met)
+			ink := pixel.Ink
+			if met {
+				ink = pixel.Faint
+			}
+			g.Text(11, y, ob.Text, ink, 1)
+			if ob.Need > 1 {
+				n := ratio(ob.Have, ob.Need)
+				g.Micro(w-pixel.MicroWidth(n), y+6, n, ink, 1)
+			}
+		}
+	})
+}