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