Add files components 406-420; Tree opens to a known choice

Fifteen file components: FileExplorer, FileGrid, FileIcon, PathBar,
MemoryCard, DiskUsage, UploadQueue, Trash, RecentFiles, FilePreview,
ArchiveViewer, FileDetails, SharePanel, SyncStatus and QuotaMeter.

FileIcon draws six kinds as hand-placed 12x12 pages and a folder. The
browsers build on data.Tree, List, GridView and Table; ArchiveViewer
owns its sort and keeps the caller's index on its entry. UploadQueue
keys rows by name so focus stays on its row. SharePanel never logs the
link. SyncStatus turns its arrows on Busy steps, so syncing moves under
Reduce Motion.

data.Tree now opens the closed branches above a chosen path it knows,
so a caller's starting path survives the first frame.

files/memorycard.go

@@ -0,0 +1,98 @@
+package files
+
+import (
+	"fmt"
+	"log/slog"
+
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/input"
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+// Save is a game's save: a title and its icon.
+type Save struct {
+	Title string
+	// Icon is at most 16 dots square.
+	Icon *pixel.Sprite
+	// Slot inks the icon's # dots; zero means Ink.
+	Slot pixel.Slot
+}
+
+type MemoryCardOptions struct {
+	Disabled bool
+}
+
+type MemoryCardResult struct {
+	Element *ui.Element
+	Changed bool
+	// Deleted is the block whose DELETE was pressed, else -1.
+	Deleted int
+}
+
+const blocks, block = 15, 24
+
+// MemoryCard lays fifteen blocks; saves fill them in order.
+func MemoryCard(c *ui.Context, text string, saves []Save, chosen *int, o MemoryCardOptions) MemoryCardResult {
+	k := pixel.K(c)
+	if len(saves) > blocks || *chosen < 0 || *chosen >= blocks {
+		panic(fmt.Sprintf("files: MemoryCard has %d saves, block %d chosen", len(saves), *chosen))
+	}
+	for _, s := range saves {
+		if s.Title == "" || s.Icon == nil || s.Icon.W > 16 || s.Icon.H > 16 {
+			panic(fmt.Sprintf("files: MemoryCard save %q needs an icon of 16 dots at most", s.Title))
+		}
+	}
+	old := *chosen
+	res := MemoryCardResult{Deleted: -1}
+	res.Element = ui.Column(c).Width(k.D(5 * (block + 2))).Gap(k.D(4)).Children(func() {
+		pixel.Text(c, fmt.Sprintf(k.Msg("blocks_used"), len(saves)), pixel.TextOptions{Slot: pixel.Faint})
+		// Arrows choose at once; the cursor is the block.
+		shell, base, st, _ := pixel.Pad(c, text, 5, blocks, block+2, block+2, chosen, o.Disabled)
+		say := k.Msg("free")
+		if *chosen < len(saves) {
+			say = saves[*chosen].Title
+		}
+		base.Description(fmt.Sprintf("%d, %s", *chosen+1, say))
+		at := *chosen
+		shell.Draw(func(p *ui.Painter, r ui.Rect) {
+			g := k.Canvas(p, r)
+			for i := range blocks {
+				x, y := i%5*(block+2)+1, i/5*(block+2)+1
+				g.Frame(x, y, block, block, pixel.Sunken, pixel.Well)
+				if i < len(saves) {
+					s := saves[i]
+					g.Sprite(x+(block-s.Icon.W)/2, y+(block-s.Icon.H)/2, s.Icon, 0, s.Slot, 1)
+				} else {
+					g.Checker(x+2, y+2, block-4, block-4, pixel.Shade)
+				}
+				if i == at {
+					ring(g, x-1, y-1, block+2, block+2)
+				}
+			}
+			g.Finish(st)
+		})
+		ui.Row(c).FillWidth().Gap(k.D(4)).AlignItems(ui.Center).Children(func() {
+			pixel.Text(c, say, pixel.TextOptions{Wrap: true, MaxLines: 1}).Grow(1)
+			free := *chosen >= len(saves)
+			if input.Button(c, k.Msg("delete"), input.ButtonOptions{Size: input.Small, Variant: input.Danger, Disabled: o.Disabled || free, Label: k.Msg("delete") + " " + say}).Clicked {
+				res.Deleted = *chosen
+			}
+		})
+	})
+	res.Changed = *chosen != old
+	if res.Changed || res.Deleted >= 0 {
+		slog.Debug("8bit: memory card", "label", text, "block", *chosen, "deleted", res.Deleted)
+	}
+	return res
+}
+
+// ring draws a two-dot Accent ring inside the box.
+func ring(g pixel.Canvas, x, y, w, h int) {
+	for d := range 2 {
+		g.Rect(x+d, y+d, w-2*d, 1, pixel.Accent)
+		g.Rect(x+d, y+h-1-d, w-2*d, 1, pixel.Accent)
+		g.Rect(x+d, y+d, 1, h-2*d, pixel.Accent)
+		g.Rect(x+w-1-d, y+d, 1, h-2*d, pixel.Accent)
+	}
+}