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

input/toggle_group.go

@@ -0,0 +1,121 @@
+package input
+
+import (
+	"log/slog"
+	"slices"
+
+	"github.com/egoist/mygo/ui"
+
+	"github.com/ZacharyZhang-NY/MujicaUI/core"
+	"github.com/ZacharyZhang-NY/MujicaUI/internal"
+	"github.com/ZacharyZhang-NY/MujicaUI/theme"
+)
+
+// ToggleItem is one button of a ToggleGroup.
+type ToggleItem[T comparable] struct {
+	Value T
+	Label string
+	Icon  *ui.SVG
+	// Name names an icon-only item for assistive technology.
+	Name     string
+	Disabled bool
+}
+
+// ToggleGroupOptions configure a ToggleGroup.
+type ToggleGroupOptions struct {
+	// Multiple lets several items be pressed at once.
+	Multiple bool
+	// AllowEmpty lets the user release the last pressed item.
+	AllowEmpty bool
+	Vertical   bool
+	Disabled   bool
+	// Label names the group for assistive technology.
+	Label string
+}
+
+// ToggleGroup is a joined row of toggles choosing one item of *value, or several with Multiple.
+func ToggleGroup[T comparable](c *ui.Context, value *[]T, items []ToggleItem[T], opts ToggleGroupOptions) core.ChoiceResult {
+	if !opts.Multiple && len(*value) > 1 {
+		panic("mujica: single ToggleGroup holds more than one value")
+	}
+	k := core.Tokens(c)
+	g := ui.Row(c).Shrink(0).AlignSelf(ui.Start).AlignItems(ui.Stretch).Radius(theme.ControlRadius).
+		Border(theme.BorderWidth, k.ControlBorder).Background(k.Surface).Disabled(opts.Disabled).Role(ui.RoleGroup)
+	if opts.Vertical {
+		g.Column().FocusGroup(ui.Vertical)
+	} else {
+		g.FocusGroup(ui.Horizontal)
+	}
+	if opts.Label != "" {
+		g.Label(opts.Label)
+	}
+	g.Dividers(theme.BorderWidth, k.ControlBorder)
+	changed := false
+	known := ui.Local(g, "values", func() []T { return nil })
+	g.Children(func() {
+		for _, it := range items {
+			on := slices.Contains(*value, it.Value)
+			pressed := on
+			// Keyed by value so focus follows the item, not its position.
+			ui.Box(c).Key(stableKey(known, it.Value)).Children(func() {
+				b := ui.ToggleBase(c, &pressed).Disabled(it.Disabled)
+				// The base took input before Disabled applied: drop a disabled item's press.
+				if b.Changed() && !it.Disabled && !opts.Disabled && toggleGroupApply(value, it.Value, pressed, opts) {
+					changed = true
+					on = pressed
+				}
+				toggleGroupLook(c, k, b, on, it)
+			})
+		}
+	})
+	if changed {
+		slog.Debug("mujica: toggle group changed", "label", opts.Label, "value", *value)
+	}
+	return core.NewChoiceResult(g, changed)
+}
+
+// toggleGroupApply presses or releases v by the group's rules and reports a change.
+func toggleGroupApply[T comparable](value *[]T, v T, pressed bool, opts ToggleGroupOptions) bool {
+	switch {
+	case pressed && opts.Multiple:
+		*value = append(*value, v)
+	case pressed:
+		*value = []T{v}
+	case len(*value) == 1 && !opts.AllowEmpty:
+		return false
+	default:
+		i := slices.Index(*value, v)
+		*value = slices.Delete(slices.Clone(*value), i, i+1)
+	}
+	return true
+}
+
+func toggleGroupLook[T comparable](c *ui.Context, k theme.Tokens, b *ui.Element, on bool, it ToggleItem[T]) {
+	d := core.Density(c)
+	b.MinHeight(d.ControlHeight()-2).MinWidth(d.ControlHeight()).Padding(0, d.Unit()*3).Gap(d.Unit() * 2)
+	internal.Ring(b, k.Focus, theme.ControlRadius)
+	bg, fg := ui.Transparent, k.Text
+	switch {
+	case on:
+		bg, fg = k.Selection, k.AccentText
+	case b.Pressed():
+		bg = k.Selection
+	case b.Hovered():
+		bg = k.SurfaceHover
+	}
+	b.Background(bg).TextColor(fg)
+	if on {
+		toggleMark(b, k)
+	}
+	if it.Name != "" {
+		b.Label(it.Name)
+	}
+	b.Children(func() {
+		if it.Icon != nil {
+			ui.Icon(c, it.Icon).Size(16, 16)
+		}
+		if it.Label != "" {
+			ui.Text(c, it.Label).SingleLine()
+		}
+	})
+}