Add desk components 466-485 and icon.Bomb

Twenty pieces of a retro desktop: Desktop, DesktopIcon, Taskbar,
StartMenu, AppWindow, Calculator, Notepad, Minesweeper, ControlPanel,
TrayIcons, ShutdownScreen, BootScreen, Screensaver, Snake, Dock,
RunDialog, DiskDefrag, WallpaperPicker, ClipboardPanel and LockScreen.

The calculator really adds up and calls division by zero GAME OVER;
Minesweeper and Snake are playable, first click always safe; START
cascades its submenus without moving the rows already open; windows
drag by whole dots; the screensaver's logo changes color at each wall
and sparkles in a corner; the defragmenter is oddly soothing. Clocks
that step back hold at zero, and typed or copied text never reaches
the log.

icon.Bomb is the new 12x12 mine.

desk/bootscreen.go

@@ -0,0 +1,80 @@
+package desk
+
+import (
+	"fmt"
+	"log/slog"
+	"time"
+
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/icon"
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+type BootScreenOptions struct {
+	// Memory counts up in kilobytes; zero means 640.
+	Memory int
+	// Width and Height are dots; zeros mean 320 by 200.
+	Width, Height int
+}
+
+type BootScreenResult struct {
+	Element *ui.Element
+	// Done is the frame the last line shows.
+	Done bool
+}
+
+type bootKey struct{}
+
+// boot is when the screen showed, and if it finished.
+type boot struct {
+	at   time.Time
+	done bool
+}
+
+// BootScreen counts memory, then prints POST lines by the logo.
+func BootScreen(c *ui.Context, title string, lines []string, o BootScreenOptions) BootScreenResult {
+	k := pixel.K(c)
+	mem := pixel.Or("BootScreen Memory", o.Memory, 640)
+	w, h := pixel.Or("BootScreen Width", o.Width, 320), pixel.Or("BootScreen Height", o.Height, 200)
+	if title == "" || mem < 1 || w < 120 || 6+(len(lines)+3)*pixel.LineHeight > h {
+		panic(fmt.Sprintf("desk: BootScreen %q, %dK, %d lines in %d dots", title, mem, len(lines), h))
+	}
+	e := ui.Box(c).Size(k.D(w), k.D(h)).Role(ui.RoleStatus).Label(title)
+	st := ui.Local(e, bootKey{}, func() boot { return boot{at: k.Now()} })
+	// Counting takes 15 steps, a line 4; reduced, at once.
+	total := 15 + 4*max(0, len(lines)-1)
+	n := total
+	if !k.Reduce() {
+		n = max(0, k.Since(c, st.at, 15, total))
+	}
+	res := BootScreenResult{Element: e, Done: n == total && !st.done}
+	st.done = n == total
+	kb := mem / 15 * min(n, 15)
+	if n >= 15 {
+		kb = mem
+	}
+	count := fmt.Sprintf(k.Msg("memory_test"), kb)
+	if n >= 15 {
+		count += " " + k.Msg("ok")
+	}
+	shown := lines[:max(0, min(len(lines), (n-15)/4+1))]
+	if n < 15 {
+		shown = nil
+	}
+	e.Description(count)
+	if res.Done {
+		slog.Debug("8bit: boot screen done", "label", title)
+	}
+	e.Draw(func(p *ui.Painter, r ui.Rect) {
+		g := k.Canvas(p, r)
+		g.Rect(0, 0, w, h, pixel.Well)
+		g.Sprite(w-44, 6, icon.Star, 0, pixel.Warn, 3)
+		g.Text(6, 6, pixel.Wrap(title, w-56, 1)[0], pixel.Ink, 1)
+		g.Text(6, 6+2*pixel.LineHeight, pixel.Wrap(count, w-56, 1)[0], pixel.Ink, 1)
+		for i, l := range shown {
+			g.Text(6, 6+(3+i)*pixel.LineHeight, pixel.Wrap(l, w-12, 1)[0], pixel.Faint, 1)
+		}
+	})
+	return res
+}