Rename AUTO to CYCLE on key c and relay browser keys to stdin

harness/main.go

@@ -169,6 +169,14 @@ func run(runFor time.Duration, at string, out io.Writer, args []string) error {
 		return err
 	}
 	go io.Copy(stdin, os.Stdin)
+	consoleMu.Lock()
+	console = stdin
+	consoleMu.Unlock()
+	defer func() {
+		consoleMu.Lock()
+		console = nil
+		consoleMu.Unlock()
+	}()
 	if err := cmd.Start(); err != nil {
 		return err
 	}

harness/stream.go

@@ -7,6 +7,7 @@ import (
 	"image"
 	"image/color"
 	"image/png"
+	"io"
 	"net"
 	"net/http"
 	"os"
@@ -52,6 +53,12 @@ const page = `<!doctype html>
     await new Promise(r => setTimeout(r, 1000));
   }
 })();
+addEventListener('keydown', e => {
+  if (e.key.length === 1 && !e.ctrlKey && !e.metaKey && !e.altKey) {
+    e.preventDefault();
+    fetch('keys', {method: 'POST', body: e.key});
+  }
+});
 </script>
 `
 
@@ -70,6 +77,9 @@ var (
 
 	clientsMu sync.RWMutex
 	clients   = make(map[chan []byte]bool)
+
+	consoleMu sync.Mutex
+	console   io.Writer
 )
 
 func serveStream() error {
@@ -93,10 +103,27 @@ func serveStream() error {
 		fmt.Fprint(w, page)
 	})
 	mux.HandleFunc("/frames", frames)
+	mux.HandleFunc("/keys", keys)
 	go http.Serve(ln, mux)
 	return nil
 }
 
+func keys(w http.ResponseWriter, r *http.Request) {
+	b, err := io.ReadAll(r.Body)
+	if err != nil {
+		return
+	}
+	consoleMu.Lock()
+	defer consoleMu.Unlock()
+	if console == nil {
+		http.Error(w, "no run to type into", http.StatusServiceUnavailable)
+		return
+	}
+	if _, err := console.Write(b); err != nil {
+		http.Error(w, err.Error(), http.StatusServiceUnavailable)
+	}
+}
+
 // Between runs the crtc scans out the console framebuffer, which is not a
 // dumb buffer and fails to map on every frame; each error reads once, not at
 // frame rate.

main.go

@@ -374,7 +374,7 @@ func run(aName, bName string) (err error) {
 			switch b {
 			case ' ', 'r':
 				kickMeasure()
-			case 'a':
+			case 'c':
 				autoOn, autoAnchor = !autoOn, time.Now()
 			}
 		case <-disp.fb.flips:

ui.go

@@ -277,7 +277,7 @@ func (d *display) drawAutoButton(on bool, frac float64) {
 	if on {
 		c = uiAccent
 	}
-	d.fillButton(d.autoBtn, frac, "AUTO", c, c)
+	d.fillButton(d.autoBtn, frac, "CYCLE", c, c)
 }
 
 func (d *display) tapAuto(x, y int, down bool) bool {