feat(agent): add screen blackout feature

- Physical displays blanked via overlay
- Remote video and input keep working
- Exclude overlay from screen capture
- Add blackout API and UI toggle
- Wire flag through capture protocol

lib/capture/client_windows.go

@@ -12,6 +12,7 @@ import (
 	"sync"
 	"time"
 
+	"tea.chunkbyte.com/kato/go-worm/lib/blackout"
 	"tea.chunkbyte.com/kato/go-worm/lib/config"
 	"tea.chunkbyte.com/kato/go-worm/lib/helpers"
 	"tea.chunkbyte.com/kato/go-worm/lib/models"
@@ -80,7 +81,7 @@ func (h *helper) grab(index int, format string, quality int) (models.CapturedIma
 	deadline := time.Now().Add(config.CaptureTimeout)
 	_ = h.stdin.SetWriteDeadline(deadline)
 	_ = h.stdout.SetReadDeadline(deadline)
-	if err := writeRequest(h.stdin, index, format, quality); err != nil {
+	if err := writeRequest(h.stdin, index, format, quality, blackout.Enabled()); err != nil {
 		return models.CapturedImage{}, err
 	}
 	img, err := readResponse(h.reader)

lib/capture/helper_windows.go

@@ -18,7 +18,7 @@ func RunHelper() int {
 	in := bufio.NewReader(os.Stdin)
 	out := bufio.NewWriter(os.Stdout)
 	for {
-		monitor, format, quality, err := readRequest(in)
+		monitor, format, quality, omitLayered, err := readRequest(in)
 		if err == io.EOF {
 			return 0
 		}
@@ -27,7 +27,7 @@ func RunHelper() int {
 			_ = out.Flush()
 			return 1
 		}
-		img, err := grab(monitor, format, quality)
+		img, err := grab(monitor, format, quality, omitLayered)
 		if err != nil {
 			if werr := writeErr(out, err.Error()); werr != nil {
 				return 1
@@ -46,11 +46,12 @@ func RunHelper() int {
 	}
 }
 
-func grab(monitor int, format string, quality int) (img models.CapturedImage, err error) {
+func grab(monitor int, format string, quality int, omitLayered bool) (img models.CapturedImage, err error) {
 	defer func() {
 		if r := recover(); r != nil {
 			err = fmt.Errorf("panic: %v", r)
 		}
 	}()
+	screenshot.SetOmitLayered(omitLayered)
 	return screenshot.CaptureMonitor(monitor, format, quality)
 }

lib/capture/protocol.go

@@ -14,30 +14,38 @@ import (
 
 var ErrMonitorNotFound = errors.New("monitor not found")
 
-func writeRequest(w io.Writer, monitor int, format string, quality int) error {
-	_, err := fmt.Fprintf(w, "C %d %s %d\n", monitor, format, quality)
+func writeRequest(w io.Writer, monitor int, format string, quality int, omitLayered bool) error {
+	flag := 0
+	if omitLayered {
+		flag = 1
+	}
+	_, err := fmt.Fprintf(w, "C %d %s %d %d\n", monitor, format, quality, flag)
 	return err
 }
 
-func readRequest(r *bufio.Reader) (monitor int, format string, quality int, err error) {
+func readRequest(r *bufio.Reader) (monitor int, format string, quality int, omitLayered bool, err error) {
 	line, err := r.ReadString('\n')
 	if err != nil {
-		return 0, "", 0, err
+		return 0, "", 0, false, err
 	}
 	fields := strings.Fields(strings.TrimSpace(line))
-	if len(fields) != 4 || fields[0] != "C" {
-		return 0, "", 0, errors.New("bad capture request")
+	if len(fields) != 5 || fields[0] != "C" {
+		return 0, "", 0, false, errors.New("bad capture request")
 	}
 	monitor, err = strconv.Atoi(fields[1])
 	if err != nil {
-		return 0, "", 0, err
+		return 0, "", 0, false, err
 	}
 	format = fields[2]
 	quality, err = strconv.Atoi(fields[3])
 	if err != nil {
-		return 0, "", 0, err
+		return 0, "", 0, false, err
 	}
-	return monitor, format, quality, nil
+	flag, err := strconv.Atoi(fields[4])
+	if err != nil {
+		return 0, "", 0, false, err
+	}
+	return monitor, format, quality, flag != 0, nil
 }
 
 func writeFrame(w io.Writer, img models.CapturedImage) error {

lib/capture/protocol_test.go

@@ -11,15 +11,15 @@ import (
 func TestCaptureProtocolRoundTrip(t *testing.T) {
 	t.Parallel()
 	var buf bytes.Buffer
-	if err := writeRequest(&buf, 1, "jpeg", 40); err != nil {
+	if err := writeRequest(&buf, 1, "jpeg", 40, true); err != nil {
 		t.Fatal(err)
 	}
-	mon, format, quality, err := readRequest(bufio.NewReader(bytes.NewReader(buf.Bytes())))
+	mon, format, quality, omit, err := readRequest(bufio.NewReader(bytes.NewReader(buf.Bytes())))
 	if err != nil {
 		t.Fatal(err)
 	}
-	if mon != 1 || format != "jpeg" || quality != 40 {
-		t.Fatalf("request = %d %s %d", mon, format, quality)
+	if mon != 1 || format != "jpeg" || quality != 40 || !omit {
+		t.Fatalf("request = %d %s %d omit=%v", mon, format, quality, omit)
 	}
 
 	buf.Reset()