Files
MujicaUI/chat/streaming_text.go
ZacharyZhang-NYandClaude Opus 5.5 bcce34cda1 Upgrade MyGo to v0.5.5
MyGo v0.5.5 returns ui.Element as a checked value handle instead of a
pointer. Migrated with `mygo migrate-ui`, then fixed what the codemod
leaves to review:

- Element nil checks become .Valid(); absent elements are ui.Element{}.
- Input handlers and paint callbacks run outside the build pass, where
  elements expire and Context methods are inert: read IsDisabled into a
  local during the build, keep a ui.Handle for Focus, use c.Services()
  for clipboard access, create ui.Local state during the build.
- Add core.AutoFocus: v0.5.5 records an overlay's opener after its
  content builds, so same-frame autofocus lost focus restore on close.
  It focuses one frame later; cascader rows defer their focus likewise.
- core.OverlayLayer identifies build passes by the root element, not
  c.Now(), which repeats across passes and under the Tester clock.
- Context menus survive the opening press counted as PressedOutside;
  split button tooltip no longer reorders its open menu; disabled
  menubar rows pass presses to the panel; Form defers blur-started
  async checks so the growing message no longer moves Submit away
  from the release; Combobox drops its disabled copy now that MyGo
  blocks typing under a disabled wrapper (canary flipped to a guard).
- The Tester clock is virtual: tests use Advance/Now instead of
  time.Sleep/time.Now and read element state inside the view. The web
  mirror advances the clock to wall time before each frame and input.
- AGENTS.md and docs describe the value Element API and the new pin.

Snapshot goldens are darwin-only and were not re-verified here.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
2026-10-17 01:37:54 -04:00

80 lines
2.1 KiB
Go

package chat
import (
"strings"
"time"
"unicode/utf8"
"github.com/egoist/mygo/ui"
"git.zacharyzhang.com/ZacharyZhang-NY/MujicaUI/core"
)
// StreamingTextOptions configure a StreamingText.
type StreamingTextOptions struct {
// Streaming shows the cursor after the text while more is coming.
Streaming bool
// Smooth reveals new text gradually instead of at once.
Smooth bool
// Rate is the smooth reveal speed in characters per second; zero means 80.
Rate float64
}
// streamingState is how much of the text shows, and since when.
type streamingState struct {
text string
shown float64
at time.Time
}
// StreamingText shows text that grows as it streams; reduced motion shows it at once.
func StreamingText(c *ui.Context, text string, opts StreamingTextOptions) ui.Element {
if opts.Rate < 0 {
panic("mujica: StreamingText Rate must not be negative")
}
rate := opts.Rate
if rate == 0 {
rate = 80
}
k := core.Tokens(c)
e := ui.Box(c).Label(text)
st := ui.Local(e, "stream", func() streamingState {
return streamingState{text: text, shown: float64(utf8.RuneCountInString(text)), at: c.Now()}
})
total := float64(utf8.RuneCountInString(text))
if !strings.HasPrefix(text, st.text) {
// Replaced text starts over from what it shares.
st.shown = min(st.shown, float64(utf8.RuneCountInString(streamingCommon(st.text, text))))
}
st.text = text
now := c.Now()
if !opts.Smooth || core.Motion(c, time.Second) == 0 {
st.shown = total
} else if st.shown < total {
st.shown = min(total, st.shown+now.Sub(st.at).Seconds()*rate)
c.AnimationFrame()
}
st.at = now
shown := text
if n := int(st.shown); n < int(total) {
shown = string([]rune(text)[:n])
}
spans := []ui.Span{{Text: shown}}
if opts.Streaming {
spans = append(spans, ui.Span{Text: "▍", Color: k.AccentText})
}
return e.Children(func() { ui.RichText(c, spans...) })
}
// streamingCommon returns the longest common prefix of a and b, on rune boundaries.
func streamingCommon(a, b string) string {
n := 0
for n < len(a) && n < len(b) && a[n] == b[n] {
n++
}
for n > 0 && n < len(a) && !utf8.RuneStart(a[n]) {
n--
}
return a[:n]
}