Add navigation components 131-150; pixel Pad, Finish, Park, Since

navigation/menubar.go

@@ -0,0 +1,111 @@
+package navigation
+
+import (
+	"log/slog"
+
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/input"
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+type Menu struct {
+	Title string
+	Items []MenuItem
+}
+
+type MenuBarOptions struct {
+	Disabled bool
+}
+
+type MenuBarResult struct {
+	Element *ui.Element
+	// Menu and Item are this frame's choice, else -1.
+	Menu, Item int
+}
+
+type barKey struct{}
+
+// bar is the open menu, its state and the pointer.
+type bar struct {
+	open int
+	m    menu
+	ptr  [2]float32
+}
+
+// MenuBar is a bar of menus; arrows go across, down.
+func MenuBar(c *ui.Context, text string, menus []Menu, o MenuBarOptions) MenuBarResult {
+	k := pixel.K(c)
+	off := o.Disabled || pixel.Current(c).Inert
+	row := ui.Row(c).Gap(k.D(2)).Padding(k.D(2), k.D(4)).AlignItems(ui.Center).FocusGroup(ui.Horizontal).Role(ui.RoleToolbar).Label(text)
+	b := ui.Local(row, barKey{}, func() bar { return bar{open: -1} })
+	res := MenuBarResult{Element: row, Menu: -1, Item: -1}
+	open := func(i int) {
+		b.open = i
+		b.m.show(menus[i].Items)
+	}
+	if off && b.open >= 0 {
+		// Closing on disable must not return focus to it.
+		c.Root().Focus()
+		b.open = -1
+	}
+	if b.open >= 0 && !b.m.open {
+		b.open = -1
+	}
+	n := len(menus)
+	// Left and Right hand an open menu to its neighbor.
+	if b.open >= 0 {
+		left, right := row.Shortcut(0, ui.KeyLeft), row.Shortcut(0, ui.KeyRight)
+		switch {
+		case left:
+			open((b.open + n - 1) % n)
+		case right:
+			open((b.open + 1) % n)
+		}
+	}
+	// Only a moving pointer hands the bar to another title.
+	px, py, over := row.PointerPosition()
+	moved := over && [2]float32{px, py} != b.ptr
+	b.ptr = [2]float32{px, py}
+	var anchor *ui.Element
+	row.Draw(func(p *ui.Painter, r ui.Rect) {
+		g := k.Canvas(p, r)
+		g.Rect(0, 0, g.W, g.H, pixel.Face)
+		g.HLine(0, g.H-1, g.W, pixel.Edge)
+	}).Children(func() {
+		for i, mn := range menus {
+			t := input.Button(c, mn.Title, input.ButtonOptions{Variant: input.Ghost, Size: input.Small, Disabled: o.Disabled})
+			if _, _, on := t.Element.PointerPosition(); on && moved && b.open >= 0 && i != b.open {
+				open(i)
+			}
+			if i == b.open {
+				anchor = t.Element
+			}
+			switch {
+			case t.Clicked && b.open == i:
+				b.open = -1
+			case t.Clicked:
+				open(i)
+				anchor = t.Element
+			case b.open < 0 && !off && t.Element.FocusWithin() && row.Shortcut(0, ui.KeyDown):
+				open(i)
+				anchor = t.Element
+			}
+		}
+	})
+	if b.open >= 0 && anchor != nil {
+		items := menus[b.open].Items
+		res.Item = b.m.keys(row.Shortcut, items)
+		if _, clicked := b.m.list(c, anchor, items); clicked >= 0 {
+			res.Item = clicked
+		}
+		if res.Item >= 0 {
+			res.Menu = b.open
+			b.open = -1
+		}
+	}
+	if res.Item >= 0 {
+		slog.Debug("8bit: menu bar", "menu", menus[res.Menu].Title, "item", menus[res.Menu].Items[res.Item].Label)
+	}
+	return res
+}