Split into category packages; module github.com/ZacharyZhang-NY/MujicaUI

feedback/stagger.go

@@ -0,0 +1,73 @@
+package feedback
+
+import (
+	"log/slog"
+	"time"
+
+	"github.com/egoist/mygo/ui"
+
+	"github.com/ZacharyZhang-NY/MujicaUI/core"
+	"github.com/ZacharyZhang-NY/MujicaUI/theme"
+)
+
+// StaggerOptions configure a Stagger.
+type StaggerOptions struct {
+	// Interval between items; zero means 60 ms.
+	Interval time.Duration
+	// Duration of each item's entry; zero means PopupDuration.
+	Duration time.Duration
+	// Horizontal lays items in a row.
+	Horizontal bool
+}
+
+type staggerState struct {
+	born time.Time
+	done bool
+}
+
+// Stagger builds n items entering one after another, once.
+func Stagger(c *ui.Context, n int, opts StaggerOptions, item func(i int)) *ui.Element {
+	if n < 0 || opts.Interval < 0 || opts.Duration < 0 {
+		panic("mujica: Stagger needs non-negative n, Interval and Duration")
+	}
+	every, d := opts.Interval, opts.Duration
+	if every == 0 {
+		every = 60 * time.Millisecond
+	}
+	if d == 0 {
+		d = theme.PopupDuration
+	}
+	box := ui.Column(c).AlignItems(ui.Stretch)
+	if opts.Horizontal {
+		box.Row().AlignItems(ui.Start)
+	}
+	st := ui.Local(box, "stagger", func() *staggerState { return &staggerState{born: c.Now()} })
+	s := *st
+	if n == 0 {
+		return box
+	}
+	upto := n
+	if !s.done && !c.Preferences().ReduceMotion {
+		upto = min(n, 1+int(c.Now().Sub(s.born)/every))
+		if upto < n {
+			box.DrawOver(func(*ui.Painter, ui.Rect) { c.After(s.born.Add(time.Duration(upto) * every).Sub(c.Now())) })
+		} else {
+			s.done = true
+			slog.Debug("mujica: stagger done", "items", n)
+		}
+	}
+	if c.Preferences().ReduceMotion {
+		s.done = true
+	}
+	enter := &ui.Motion{Y: 8}
+	if opts.Horizontal {
+		enter = &ui.Motion{X: 8}
+	}
+	box.Children(func() {
+		for i := range upto {
+			ui.Column(c).Key(i).AlignItems(ui.Stretch).
+				Transition(ui.ElementTransition{Duration: core.Motion(c, d), Enter: enter}).Children(func() { item(i) })
+		}
+	})
+	return box
+}