Allow to query RpWindow-s frame margins.

ui/platform/mac/ui_window_mac.h

@@ -19,6 +19,7 @@ public:
 	~WindowHelper();
 
 	not_null<RpWidget*> body() override;
+	QMargins frameMargins() override;
 	void setTitle(const QString &title) override;
 	void setTitleStyle(const style::WindowTitle &st) override;
 	void setMinimumSize(QSize size) override;

ui/platform/mac/ui_window_mac.mm

@@ -300,11 +300,9 @@ void WindowHelper::Private::init() {
 WindowHelper::WindowHelper(not_null<RpWidget*> window)
 : BasicWindowHelper(window)
 , _private(std::make_unique<Private>(this))
-, _title(_private->customTitleHeight()
+, _title(Ui::CreateChild<TitleWidget>(
-	? Ui::CreateChild<TitleWidget>(
+	window.get(),
-		window.get(),
+	_private->customTitleHeight()))
-		_private->customTitleHeight())
-	: nullptr)
 , _body(Ui::CreateChild<RpWidget>(window.get())) {
 	if (_title->shouldBeHidden()) {
 		updateCustomTitleVisibility();
@@ -319,26 +317,26 @@ not_null<RpWidget*> WindowHelper::body() {
 	return _body;
 }
 
+QMargins WindowHelper::frameMargins() {
+	const auto titleHeight = !_title->isHidden() ? _title->height() : 0;
+	return QMargins{ 0, titleHeight, 0, 0 };
+}
+
 void WindowHelper::setTitle(const QString &title) {
-	if (_title) {
+	_title->setText(title);
-		_title->setText(title);
+	window()->setWindowTitle(_titleVisible ? QString() : title);
-	}
-	window()->setWindowTitle(
-		(!_title || !_titleVisible) ? title : QString());
 }
 
 void WindowHelper::setTitleStyle(const style::WindowTitle &st) {
-	if (_title) {
+	_title->setStyle(st);
-		_title->setStyle(st);
+	if (_title->shouldBeHidden()) {
-		if (_title->shouldBeHidden()) {
+		updateCustomTitleVisibility();
-			updateCustomTitleVisibility();
-		}
 	}
 }
 
 void WindowHelper::updateCustomTitleVisibility(bool force) {
-	auto visible = !_title->shouldBeHidden() && _titleVisible;
+	const auto visible = !_title->shouldBeHidden() && _titleVisible;
-	if (!_title || (!force && _title->isHidden() != visible)) {
+	if (!force && _title->isHidden() != visible) {
 		return;
 	}
 	_title->setVisible(visible);
@@ -346,15 +344,11 @@ void WindowHelper::updateCustomTitleVisibility(bool force) {
 }
 
 void WindowHelper::setMinimumSize(QSize size) {
-	window()->setMinimumSize(
+	window()->setMinimumSize(size.width(), _title->height() + size.height());
-		size.width(),
-		(_title ? _title->height() : 0) + size.height());
 }
 
 void WindowHelper::setFixedSize(QSize size) {
-	window()->setFixedSize(
+	window()->setFixedSize(size.width(), _title->height() + size.height());
-		size.width(),
-		(_title ? _title->height() : 0) + size.height());
 }
 
 void WindowHelper::setStaysOnTop(bool enabled) {
@@ -362,8 +356,7 @@ void WindowHelper::setStaysOnTop(bool enabled) {
 }
 
 void WindowHelper::setGeometry(QRect rect) {
-	window()->setGeometry(
+	window()->setGeometry(rect.marginsAdded({ 0, _title->height(), 0, 0 }));
-		rect.marginsAdded({ 0, (_title ? _title->height() : 0), 0, 0 }));
 }
 
 void WindowHelper::setupBodyTitleAreaEvents() {

ui/platform/ui_platform_window.cpp

@@ -37,6 +37,10 @@ not_null<RpWidget*> BasicWindowHelper::body() {
 	return _window;
 }
 
+QMargins BasicWindowHelper::frameMargins() {
+	return nativeFrameMargins();
+}
+
 void BasicWindowHelper::setTitle(const QString &title) {
 	_window->setWindowTitle(title);
 }
@@ -86,6 +90,16 @@ void BasicWindowHelper::setBodyTitleArea(
 	setupBodyTitleAreaEvents();
 }
 
+QMargins BasicWindowHelper::nativeFrameMargins() const {
+	const auto inner = window()->geometry();
+	const auto outer = window()->frameGeometry();
+	return QMargins(
+		inner.x() - outer.x(),
+		inner.y() - outer.y(),
+		outer.x() + outer.width() - inner.x() - inner.width(),
+		outer.y() + outer.height() - inner.y() - inner.height());
+}
+
 void BasicWindowHelper::setupBodyTitleAreaEvents() {
 	// This is not done on macOS, because startSystemMove
 	// doesn't work from event handler there.
@@ -243,6 +257,12 @@ not_null<RpWidget*> DefaultWindowHelper::body() {
 	return _body;
 }
 
+QMargins DefaultWindowHelper::frameMargins() {
+	return _title->isHidden()
+		? BasicWindowHelper::nativeFrameMargins()
+		: QMargins{ 0, _title->height(), 0, 0 };
+}
+
 bool DefaultWindowHelper::hasShadow() const {
 	const auto center = window()->geometry().center();
 	return WindowExtentsSupported() && TranslucentWindowsSupported(center);

ui/platform/ui_platform_window.h

@@ -28,6 +28,7 @@ public:
 	virtual ~BasicWindowHelper() = default;
 
 	[[nodiscard]] virtual not_null<RpWidget*> body();
+	[[nodiscard]] virtual QMargins frameMargins();
 	virtual void setTitle(const QString &title);
 	virtual void setTitleStyle(const style::WindowTitle &st);
 	virtual void setNativeFrame(bool enabled);
@@ -51,6 +52,7 @@ protected:
 			? _bodyTitleAreaTestMethod(point)
 			: WindowTitleHitTestFlag();
 	}
+	[[nodiscard]] QMargins nativeFrameMargins() const;
 
 private:
 	virtual void setupBodyTitleAreaEvents();
@@ -66,6 +68,7 @@ public:
 	explicit DefaultWindowHelper(not_null<RpWidget*> window);
 
 	not_null<RpWidget*> body() override;
+	QMargins frameMargins() override;
 	void setTitle(const QString &title) override;
 	void setTitleStyle(const style::WindowTitle &st) override;
 	void setNativeFrame(bool enabled) override;

ui/platform/win/ui_window_win.cpp

@@ -185,6 +185,12 @@ not_null<RpWidget*> WindowHelper::body() {
 	return _body;
 }
 
+QMargins WindowHelper::frameMargins() {
+	return _title->isHidden()
+		? BasicWindowHelper::nativeFrameMargins()
+		: QMargins{ 0, _title->height(), 0, 0 };
+}
+
 void WindowHelper::setTitle(const QString &title) {
 	_title->setText(title);
 	window()->setWindowTitle(title);

ui/platform/win/ui_window_win.h

@@ -22,6 +22,7 @@ public:
 	~WindowHelper();
 
 	not_null<RpWidget*> body() override;
+	QMargins frameMargins() override;
 	void setTitle(const QString &title) override;
 	void setTitleStyle(const style::WindowTitle &st) override;
 	void setNativeFrame(bool enabled) override;

ui/widgets/rp_window.cpp

@@ -28,6 +28,10 @@ not_null<const RpWidget*> RpWindow::body() const {
 	return _helper->body().get();
 }
 
+QMargins RpWindow::frameMargins() const {
+	return _helper->frameMargins();
+}
+
 void RpWindow::setTitle(const QString &title) {
 	_helper->setTitle(title);
 }

ui/widgets/rp_window.h

@@ -36,6 +36,7 @@ public:
 
 	[[nodiscard]] not_null<RpWidget*> body();
 	[[nodiscard]] not_null<const RpWidget*> body() const;
+	[[nodiscard]] QMargins frameMargins() const;
 
 	void setTitle(const QString &title);
 	void setTitleStyle(const style::WindowTitle &st);