Hide titlebar & border when there are no controls

If the user doesn't want to control the window with buttons, then he moves/resizes the window in other way as well

ui/platform/ui_platform_utility.cpp

@@ -10,16 +10,24 @@ namespace Ui {
 namespace Platform {
 namespace {
 
-rpl::event_stream<> TitleControlsLayoutChanges;
+rpl::event_stream<TitleControls::Layout> TitleControlsLayoutChanges;
 
 } // namespace
 
-rpl::producer<> TitleControlsLayoutChanged() {
+rpl::producer<TitleControls::Layout> TitleControlsLayoutValue() {
+	return rpl::single(
+		TitleControlsLayout()
+	) | rpl::then(
+		TitleControlsLayoutChanged()
+	);
+}
+
+rpl::producer<TitleControls::Layout> TitleControlsLayoutChanged() {
 	return TitleControlsLayoutChanges.events();
 }
 
 void NotifyTitleControlsLayoutChanged() {
-	TitleControlsLayoutChanges.fire({});
+	TitleControlsLayoutChanges.fire_copy(TitleControlsLayout());
 }
 
 } // namespace Platform

ui/platform/ui_platform_utility.h

@@ -44,7 +44,8 @@ void UnsetWindowExtents(QWindow *window);
 bool ShowWindowMenu(QWindow *window);
 
 [[nodiscard]] TitleControls::Layout TitleControlsLayout();
-[[nodiscard]] rpl::producer<> TitleControlsLayoutChanged();
+[[nodiscard]] rpl::producer<TitleControls::Layout> TitleControlsLayoutValue();
+[[nodiscard]] rpl::producer<TitleControls::Layout> TitleControlsLayoutChanged();
 void NotifyTitleControlsLayoutChanged();
 
 } // namespace Platform

ui/platform/ui_platform_window.cpp

@@ -202,29 +202,35 @@ void DefaultWindowHelper::init() {
 	rpl::combine(
 		window()->widthValue(),
 		_windowState.value(),
-		_title->shownValue()
+		_title->shownValue(),
+		TitleControlsLayoutValue()
 	) | rpl::start_with_next([=](
 			int width,
 			Qt::WindowStates windowState,
-			bool shown) {
+			bool shown,
+			TitleControls::Layout controlsLayout) {
 		const auto area = resizeArea();
 		_title->setGeometry(
 			area.left(),
 			area.top(),
 			width - area.left() - area.right(),
-			_title->st()->height);
+			_title->controlsGeometry().height()
+				? _title->st()->height
+				: 0);
 	}, _title->lifetime());
 
 	rpl::combine(
 		window()->sizeValue(),
 		_windowState.value(),
 		_title->heightValue(),
-		_title->shownValue()
+		_title->shownValue(),
+		TitleControlsLayoutValue()
 	) | rpl::start_with_next([=](
 			QSize size,
 			Qt::WindowStates windowState,
 			int titleHeight,
-			bool titleShown) {
+			bool titleShown,
+			TitleControls::Layout controlsLayout) {
 		const auto area = resizeArea();
 
 		const auto sizeWithoutMargins = size
@@ -342,7 +348,8 @@ bool DefaultWindowHelper::hasShadow() const {
 QMargins DefaultWindowHelper::resizeArea() const {
 	if (window()->isMaximized()
 		|| window()->isFullScreen()
-		|| _title->isHidden()) {
+		|| _title->isHidden()
+		|| (!hasShadow() && !_title->controlsGeometry().height())) {
 		return QMargins();
 	}
 

ui/platform/ui_platform_window_title.cpp

@@ -167,12 +167,9 @@ void TitleControls::init(Fn<void(bool maximized)> maximize) {
 	});
 	_close->setPointerCursor(false);
 
-	parent()->widthValue(
-	) | rpl::start_with_next([=](int width) {
-		updateControlsPosition();
-	}, _close->lifetime());
-
-	TitleControlsLayoutChanged(
+	rpl::combine(
+		parent()->widthValue(),
+		TitleControlsLayoutValue()
 	) | rpl::start_with_next([=] {
 		updateControlsPosition();
 	}, _close->lifetime());
@@ -417,6 +414,10 @@ not_null<const style::WindowTitle*> DefaultTitleWidget::st() const {
 	return _controls.st();
 }
 
+QRect DefaultTitleWidget::controlsGeometry() const {
+	return _controls.geometry();
+}
+
 void DefaultTitleWidget::setText(const QString &text) {
 	window()->setWindowTitle(text);
 }

ui/platform/ui_platform_window_title.h

@@ -118,6 +118,7 @@ public:
 	explicit DefaultTitleWidget(not_null<RpWidget*> parent);
 
 	[[nodiscard]] not_null<const style::WindowTitle*> st() const;
+	[[nodiscard]] QRect controlsGeometry() const;
 	void setText(const QString &text);
 	void setStyle(const style::WindowTitle &st);
 	void setResizeEnabled(bool enabled);