WIP components (as built)

typewriter.go

@@ -2,6 +2,7 @@ package mujica
 
 import (
 	"log/slog"
+	"math"
 	"strings"
 	"time"
 
@@ -12,19 +13,10 @@ import (
 type TypewriterOptions struct {
 	// Speed is characters per second; zero means 40.
 	Speed float64
-	// Skippable adds a Skip button that shows the rest at once.
+	// Skippable adds a Skip button.
 	Skippable bool
 }
 
-// TypewriterResult is a built Typewriter and its events.
-type TypewriterResult struct {
-	Element *ui.Element
-	done    bool
-}
-
-// Finished reports the frame the whole text came into view.
-func (r TypewriterResult) Finished() bool { return r.done }
-
 type typewriterState struct {
 	text    []rune
 	shown   int
@@ -33,26 +25,31 @@ type typewriterState struct {
 	done    bool
 }
 
-// Typewriter reveals text a character at a time; text that grows continues where it was.
-func Typewriter(c *ui.Context, text string, opts TypewriterOptions) TypewriterResult {
+// Typewriter reveals text one character at a time.
+func Typewriter(c *ui.Context, text string, opts TypewriterOptions) ChoiceResult {
 	speed := opts.Speed
 	if speed == 0 {
 		speed = 40
 	}
-	if speed < 0 {
-		panic("mujica: Typewriter Speed is negative")
+	if math.IsNaN(speed) || math.IsInf(speed, 0) || speed < float64(time.Second)/float64(math.MaxInt64) || speed > float64(time.Second) {
+		panic("mujica: Typewriter Speed must give a finite positive interval")
+	}
+	step := time.Duration(float64(time.Second) / speed)
+	if step <= 0 {
+		panic("mujica: Typewriter Speed interval exceeds time.Duration")
 	}
 	col := ui.Column(c).AlignItems(ui.Start).Gap(Density(c).Unit() * 2).Role(ui.RoleGroup).Label(text)
-	res := TypewriterResult{Element: col}
+	res := ChoiceResult{Element: col}
 	st := ui.Local(col, "typing", func() *typewriterState { return &typewriterState{last: c.Now()} })
 	s := *st
 	runes := []rune(text)
 	if !strings.HasPrefix(text, string(s.text)) {
 		s.shown, s.skipped, s.done = 0, false, false
+		s.last = c.Now()
 		slog.Debug("mujica: typewriter restart")
 	}
 	if len(runes) > len(s.text) && s.done {
-		// New text continues from where it stood, at the typing speed.
+		// Appended text continues at the typing speed.
 		s.done, s.skipped, s.last = false, false, c.Now()
 	}
 	s.text = runes
@@ -60,13 +57,12 @@ func Typewriter(c *ui.Context, text string, opts TypewriterOptions) TypewriterRe
 	if c.Preferences().ReduceMotion || s.skipped {
 		s.shown = len(runes)
 	} else if s.shown < len(runes) {
-		step := time.Duration(float64(time.Second) / speed)
 		if n := int(now.Sub(s.last) / step); n > 0 {
 			s.shown = min(len(runes), s.shown+n)
 			s.last = s.last.Add(time.Duration(n) * step)
 		}
 		if s.shown < len(runes) {
-			c.After(s.last.Add(step).Sub(now))
+			col.DrawOver(func(*ui.Painter, ui.Rect) { c.After(s.last.Add(step).Sub(c.Now())) })
 		}
 	} else {
 		s.last = now
@@ -74,14 +70,15 @@ func Typewriter(c *ui.Context, text string, opts TypewriterOptions) TypewriterRe
 	col.Children(func() {
 		ui.Text(c, string(runes[:s.shown]))
 		if opts.Skippable && s.shown < len(runes) {
-			if Button(c, msg(c, "typewriter.skip"), ButtonOptions{Variant: Ghost}).Clicked() {
+			b := Button(c, msg(c, "typewriter.skip"), ButtonOptions{Variant: Ghost})
+			if b.Clicked() && !b.IsDisabled() {
 				s.skipped, s.shown = true, len(runes)
 				slog.Debug("mujica: typewriter skip")
 			}
 		}
 	})
 	if s.shown == len(runes) && !s.done {
-		s.done, res.done = true, true
+		s.done, res.changed = true, true
 	}
 	return res
 }