Force correct separate title bar controls geometry.

ui/platform/ui_platform_window.cpp

@@ -41,6 +41,14 @@ QMargins BasicWindowHelper::frameMargins() {
 	return nativeFrameMargins();
 }
 
+int BasicWindowHelper::additionalContentPadding() const {
+	return 0;
+}
+
+rpl::producer<int> BasicWindowHelper::additionalContentPaddingValue() const {
+	return rpl::single(0);
+}
+
 void BasicWindowHelper::setTitle(const QString &title) {
 	_window->setWindowTitle(title);
 }

ui/platform/ui_platform_window.h

@@ -29,6 +29,9 @@ public:
 
 	[[nodiscard]] virtual not_null<RpWidget*> body();
 	[[nodiscard]] virtual QMargins frameMargins();
+	[[nodiscard]] virtual int additionalContentPadding() const;
+	[[nodiscard]] virtual auto additionalContentPaddingValue() const
+		-> rpl::producer<int>;
 	virtual void setTitle(const QString &title);
 	virtual void setTitleStyle(const style::WindowTitle &st);
 	virtual void setNativeFrame(bool enabled);

ui/platform/ui_platform_window_title.cpp

@@ -10,6 +10,7 @@
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/shadow.h"
 #include "ui/ui_utility.h"
+#include "ui/widgets/rp_window.h"
 #include "styles/style_widgets.h"
 #include "styles/palette.h"
 #include "base/algorithm.h"
@@ -438,5 +439,36 @@ void DefaultTitleWidget::mouseDoubleClickEvent(QMouseEvent *e) {
 	}
 }
 
+SeparateTitleControls::SeparateTitleControls(
+	QWidget *parent,
+	const style::WindowTitle &st,
+	Fn<void(bool maximized)> maximize)
+: wrap(parent)
+, controls(&wrap, st, std::move(maximize)) {
+}
+
+std::unique_ptr<SeparateTitleControls> SetupSeparateTitleControls(
+		not_null<RpWindow*> window,
+		const style::WindowTitle &st,
+		Fn<void(bool maximized)> maximize) {
+	auto result = std::make_unique<SeparateTitleControls>(
+		window->body(),
+		st,
+		std::move(maximize));
+
+	rpl::combine(
+		window->body()->widthValue(),
+		window->additionalContentPaddingValue()
+	) | rpl::start_with_next([raw = result.get()](int width, int padding) {
+		raw->wrap.setGeometry(
+			padding,
+			0,
+			width - 2 * padding,
+			raw->controls.geometry().height());
+	}, result->wrap.lifetime());
+
+	return result;
+}
+
 } // namespace Platform
 } // namespace Ui

ui/platform/ui_platform_window_title.h

@@ -20,6 +20,7 @@ namespace Ui {
 
 class IconButton;
 class PlainShadow;
+class RpWindow;
 
 namespace Platform {
 
@@ -122,5 +123,21 @@ private:
 
 };
 
+struct SeparateTitleControls {
+	SeparateTitleControls(
+		QWidget *parent,
+		const style::WindowTitle &st,
+		Fn<void(bool maximized)> maximize);
+
+	RpWidget wrap;
+	TitleControls controls;
+};
+
+[[nodiscard]] auto SetupSeparateTitleControls(
+	not_null<RpWindow*> window,
+	const style::WindowTitle &st,
+	Fn<void(bool maximized)> maximize = nullptr)
+-> std::unique_ptr<SeparateTitleControls>;
+
 } // namespace Platform
 } // namespace Ui

ui/platform/win/ui_window_title_win.cpp

@@ -48,7 +48,7 @@ struct TitleWidget::PaddingHelper {
 	}
 
 	RpWidget controlsParent;
-	int padding = 0;
+	rpl::variable<int> padding = 0;
 };
 
 TitleWidget::TitleWidget(not_null<RpWidget*> parent)
@@ -80,7 +80,7 @@ void TitleWidget::setStyle(const style::WindowTitle &st) {
 }
 
 void TitleWidget::refreshGeometryWithWidth(int width) {
-	const auto add = _paddingHelper ? _paddingHelper->padding : 0;
+	const auto add = additionalPadding();
 	setGeometry(0, 0, width, _controls.st()->height + add);
 	if (_paddingHelper) {
 		_paddingHelper->controlsParent.setGeometry(
@@ -201,10 +201,18 @@ void TitleWidget::refreshAdditionalPaddings(
 	setAdditionalPadding(padding);
 }
 
+int TitleWidget::additionalPadding() const {
+	return _paddingHelper ? _paddingHelper->padding.current() : 0;
+}
+
+rpl::producer<int> TitleWidget::additionalPaddingValue() const {
+	return _paddingHelper ? _paddingHelper->padding.value() : rpl::single(0);
+}
+
 void TitleWidget::setAdditionalPadding(int padding) {
 	Expects(_paddingHelper != nullptr);
 
-	if (_paddingHelper->padding == padding) {
+	if (_paddingHelper->padding.current() == padding) {
 		return;
 	}
 	_paddingHelper->padding = padding;

ui/platform/win/ui_window_title_win.h

@@ -42,6 +42,8 @@ public:
 	void refreshAdditionalPaddings(
 		HWND handle,
 		const WINDOWPLACEMENT &placement);
+	[[nodiscard]] int additionalPadding() const;
+	[[nodiscard]] rpl::producer<int> additionalPaddingValue() const;
 
 	void sysButtonOver(HitTestResult testResult);
 	void sysButtonDown(HitTestResult testResult, bool down);

ui/platform/win/ui_window_win.cpp

@@ -179,6 +179,19 @@ QMargins WindowHelper::frameMargins() {
 		: QMargins{ 0, _title->height(), 0, 0 };
 }
 
+int WindowHelper::additionalContentPadding() const {
+	return _title->isHidden() ? 0 : _title->additionalPadding();
+}
+
+rpl::producer<int> WindowHelper::additionalContentPaddingValue() const {
+	return rpl::combine(
+		_title->shownValue(),
+		_title->additionalPaddingValue()
+	) | rpl::map([](bool shown, int padding) {
+		return shown ? padding : 0;
+	}) | rpl::distinct_until_changed();
+}
+
 void WindowHelper::setTitle(const QString &title) {
 	_title->setText(title);
 	window()->setWindowTitle(title);

ui/platform/win/ui_window_win.h

@@ -24,6 +24,8 @@ public:
 
 	not_null<RpWidget*> body() override;
 	QMargins frameMargins() override;
+	int additionalContentPadding() const override;
+	rpl::producer<int> additionalContentPaddingValue() const override;
 	void setTitle(const QString &title) override;
 	void setTitleStyle(const style::WindowTitle &st) override;
 	void setNativeFrame(bool enabled) override;

ui/widgets/rp_window.cpp

@@ -32,6 +32,14 @@ QMargins RpWindow::frameMargins() const {
 	return _helper->frameMargins();
 }
 
+int RpWindow::additionalContentPadding() const {
+	return _helper->additionalContentPadding();
+}
+
+rpl::producer<int> RpWindow::additionalContentPaddingValue() const {
+	return _helper->additionalContentPaddingValue();
+}
+
 void RpWindow::setTitle(const QString &title) {
 	_helper->setTitle(title);
 }

ui/widgets/rp_window.h

@@ -38,6 +38,14 @@ public:
 	[[nodiscard]] not_null<const RpWidget*> body() const;
 	[[nodiscard]] QMargins frameMargins() const;
 
+	// In Windows 11 the window rounding shadow takes about
+	// round(1px * system_scale) from the window geometry on each side.
+	//
+	// Top shift is made by the TitleWidget height, but the rest of the
+	// side shifts are left for the RpWindow client to consider.
+	[[nodiscard]] int additionalContentPadding() const;
+	[[nodiscard]] rpl::producer<int> additionalContentPaddingValue() const;
+
 	void setTitle(const QString &title);
 	void setTitleStyle(const style::WindowTitle &st);
 	void setNativeFrame(bool enabled);