feat: add CSI t (windowOptions) handler for size report and title stack

Implement CSI Ps t window manipulation commands:
- CSI 18 t: report terminal size in characters
- CSI 22 ; Ps t: push window title / icon name onto stack
- CSI 23 ; Ps t: pop window title / icon name from stack

Fixes #12

Co-authored-by: Ona <no-reply@ona.com>

Author: ona-automations

inputhandler.go

@@ -83,7 +83,9 @@ type InputHandler struct {
 	parseBuffer     []uint32
 	dirtyRowTracker *DirtyRowTracker
 
-	windowTitle string
+	windowTitle    string
+	windowTitleStack []string
+	iconNameStack    []string
 
 	// Events
 	OnCursorMoveEmitter           EventEmitter[struct{}]
@@ -229,6 +231,7 @@ func NewInputHandler(
 	})
 	p.RegisterCsiHandler(FunctionIdentifier{Intermediates: " ", Final: 'q'}, h.setCursorStyle)
 	p.RegisterCsiHandler(FunctionIdentifier{Final: 'r'}, h.setScrollRegion)
+	p.RegisterCsiHandler(FunctionIdentifier{Final: 't'}, h.windowOptions)
 	p.RegisterCsiHandler(FunctionIdentifier{Final: 's'}, h.csiSaveCursor)
 	p.RegisterCsiHandler(FunctionIdentifier{Final: 'u'}, h.csiRestoreCursor)
 	p.RegisterCsiHandler(FunctionIdentifier{Prefix: '=', Final: 'u'}, h.kittyKeyboardSet)

inputhandler_csi.go

@@ -885,3 +885,57 @@ func (h *InputHandler) kittyKeyboardPop(params *Params) bool {
 	}
 	return true
 }
+
+// --- Window manipulation (CSI Ps t) ---
+
+// windowOptions handles CSI Ps ; Ps ; Ps t — window manipulation commands.
+// Implements sub-commands 18 (report size), 22 (push title), and 23 (pop title).
+func (h *InputHandler) windowOptions(params *Params) bool {
+	if params.Length == 0 {
+		return true
+	}
+	switch params.Params[0] {
+	case 18:
+		// Report terminal size in characters: CSI 8 ; rows ; cols t
+		h.coreService.TriggerDataEvent(
+			fmt.Sprintf("\x1b[8;%d;%dt", h.bufferService.Rows, h.bufferService.Cols),
+			false, false,
+		)
+	case 22:
+		// Push title onto stack.
+		// Ps2: 0 = both icon+title, 1 = icon only, 2 = title only.
+		ps2 := int32(0)
+		if params.Length >= 2 {
+			ps2 = params.Params[1]
+		}
+		if ps2 == 0 || ps2 == 2 {
+			h.windowTitleStack = append(h.windowTitleStack, h.windowTitle)
+		}
+		if ps2 == 0 || ps2 == 1 {
+			// Icon name shares the window title in this implementation.
+			h.iconNameStack = append(h.iconNameStack, h.windowTitle)
+		}
+	case 23:
+		// Pop title from stack.
+		ps2 := int32(0)
+		if params.Length >= 2 {
+			ps2 = params.Params[1]
+		}
+		if ps2 == 0 || ps2 == 2 {
+			if len(h.windowTitleStack) > 0 {
+				title := h.windowTitleStack[len(h.windowTitleStack)-1]
+				h.windowTitleStack = h.windowTitleStack[:len(h.windowTitleStack)-1]
+				h.windowTitle = title
+				h.OnTitleChangeEmitter.Fire(title)
+			}
+		}
+		if ps2 == 0 || ps2 == 1 {
+			if len(h.iconNameStack) > 0 {
+				h.iconNameStack = h.iconNameStack[:len(h.iconNameStack)-1]
+			}
+		}
+	default:
+		// Other sub-commands (14, 16, etc.) are renderer-specific; silently ignore.
+	}
+	return true
+}

inputhandler_csi_test.go

@@ -1204,3 +1204,137 @@ func TestRequestModeANSI(t *testing.T) {
 	}
 }
 
+func TestWindowOptionsReportSize(t *testing.T) {
+	t.Parallel()
+	h := newTestInputHandler(80, 24)
+	var response string
+	h.coreService.OnDataEmitter.Event(func(data string) {
+		response = data
+	})
+	h.ParseString("\x1b[18t")
+	expected := "\x1b[8;24;80t"
+	if response != expected {
+		t.Errorf("expected response %q, got %q", expected, response)
+	}
+}
+
+func TestWindowOptionsReportSizeCustom(t *testing.T) {
+	t.Parallel()
+	h := newTestInputHandler(132, 50)
+	var response string
+	h.coreService.OnDataEmitter.Event(func(data string) {
+		response = data
+	})
+	h.ParseString("\x1b[18t")
+	expected := "\x1b[8;50;132t"
+	if response != expected {
+		t.Errorf("expected response %q, got %q", expected, response)
+	}
+}
+
+func TestWindowOptionsPushPopTitle(t *testing.T) {
+	t.Parallel()
+	h := newTestInputHandler(80, 24)
+	var lastTitle string
+	h.OnTitleChangeEmitter.Event(func(title string) {
+		lastTitle = title
+	})
+
+	h.ParseString("\x1b]2;first\x1b\\")
+	if lastTitle != "first" {
+		t.Fatalf("expected title %q, got %q", "first", lastTitle)
+	}
+
+	h.ParseString("\x1b[22;2t")
+
+	h.ParseString("\x1b]2;second\x1b\\")
+	if lastTitle != "second" {
+		t.Fatalf("expected title %q, got %q", "second", lastTitle)
+	}
+
+	h.ParseString("\x1b[23;2t")
+	if lastTitle != "first" {
+		t.Errorf("expected title %q after pop, got %q", "first", lastTitle)
+	}
+}
+
+func TestWindowOptionsPushPopTitleMultiple(t *testing.T) {
+	t.Parallel()
+	h := newTestInputHandler(80, 24)
+	var lastTitle string
+	h.OnTitleChangeEmitter.Event(func(title string) {
+		lastTitle = title
+	})
+
+	h.ParseString("\x1b]2;alpha\x1b\\")
+	h.ParseString("\x1b[22;2t")
+	h.ParseString("\x1b]2;beta\x1b\\")
+	h.ParseString("\x1b[22;2t")
+	h.ParseString("\x1b]2;gamma\x1b\\")
+	h.ParseString("\x1b[22;2t")
+	h.ParseString("\x1b]2;delta\x1b\\")
+
+	h.ParseString("\x1b[23;2t")
+	if lastTitle != "gamma" {
+		t.Errorf("expected %q, got %q", "gamma", lastTitle)
+	}
+	h.ParseString("\x1b[23;2t")
+	if lastTitle != "beta" {
+		t.Errorf("expected %q, got %q", "beta", lastTitle)
+	}
+	h.ParseString("\x1b[23;2t")
+	if lastTitle != "alpha" {
+		t.Errorf("expected %q, got %q", "alpha", lastTitle)
+	}
+}
+
+func TestWindowOptionsPopEmptyStack(t *testing.T) {
+	t.Parallel()
+	h := newTestInputHandler(80, 24)
+	titleChanges := 0
+	h.OnTitleChangeEmitter.Event(func(title string) {
+		titleChanges++
+	})
+
+	h.ParseString("\x1b]2;initial\x1b\\")
+	titleChanges = 0
+
+	h.ParseString("\x1b[23;2t")
+	if titleChanges != 0 {
+		t.Errorf("expected no title change on empty stack pop, got %d changes", titleChanges)
+	}
+}
+
+func TestWindowOptionsPushPopBoth(t *testing.T) {
+	t.Parallel()
+	h := newTestInputHandler(80, 24)
+	var lastTitle string
+	h.OnTitleChangeEmitter.Event(func(title string) {
+		lastTitle = title
+	})
+
+	h.ParseString("\x1b]2;both-test\x1b\\")
+	h.ParseString("\x1b[22;0t")
+	h.ParseString("\x1b]2;replaced\x1b\\")
+
+	h.ParseString("\x1b[23;0t")
+	if lastTitle != "both-test" {
+		t.Errorf("expected %q, got %q", "both-test", lastTitle)
+	}
+}
+
+func TestWindowOptionsUnknownSubcommand(t *testing.T) {
+	t.Parallel()
+	h := newTestInputHandler(80, 24)
+	var response string
+	h.coreService.OnDataEmitter.Event(func(data string) {
+		response = data
+	})
+	h.ParseString("\x1b[99t")
+	if response != "" {
+		t.Errorf("expected no response for unknown subcommand, got %q", response)
+	}
+}
+
+
+