Use native window titlebar on Windows 11

ui/platform/win/ui_window_win.cpp

@@ -9,6 +9,7 @@
 #include "ui/inactive_press.h"
 #include "ui/platform/win/ui_window_title_win.h"
 #include "ui/widgets/rp_window.h"
+#include "ui/painter.h"
 #include "base/platform/win/base_windows_safe_library.h"
 #include "base/platform/base_platform_info.h"
 #include "base/integration.h"
@@ -206,7 +207,9 @@ not_null<RpWidget*> WindowHelper::body() {
 }
 
 QMargins WindowHelper::frameMargins() {
-	return _title->isHidden()
+	return frameMarginsSet()
+		? *_frameMargins.current()
+		: _title->isHidden()
 		? BasicWindowHelper::nativeFrameMargins()
 		: QMargins{ 0, _title->height(), 0, 0 };
 }
@@ -242,6 +245,14 @@ void WindowHelper::setNativeFrame(bool enabled) {
 			GWL_STYLE,
 			enabled ? (style | WS_CAPTION) : (style & ~WS_CAPTION));
 	}
+	if (::Platform::IsWindows11OrGreater()) {
+		if (enabled) {
+			_frameMargins = QMargins();
+			updateFrameMargins();
+		} else {
+			_frameMargins = std::nullopt;
+		}
+	}
 	_title->setVisible(!enabled);
 	if (enabled || ::Platform::IsWindows11OrGreater()) {
 		_shadow.reset();
@@ -352,16 +363,24 @@ void WindowHelper::init() {
 	rpl::combine(
 		window()->sizeValue(),
 		_title->heightValue(),
-		_title->shownValue()
+		_title->shownValue(),
+		_frameMargins.value()
 	) | rpl::start_with_next([=](
 			QSize size,
 			int titleHeight,
-			bool titleShown) {
-		_body->setGeometry(
+			bool titleShown,
+			std::optional<QMargins> frameMargins) {
+		_body->setGeometry(QRect(
+			0,
+			0,
+			size.width(),
+			size.height()
+		).marginsRemoved(QMargins(
 			0,
 			titleShown ? titleHeight : 0,
-			size.width(),
-			size.height() - (titleShown ? titleHeight : 0));
+			0,
+			0
+		)).marginsRemoved(frameMargins ? *frameMargins : QMargins()));
 	}, _body->lifetime());
 
 	hitTestRequests(
@@ -373,21 +392,64 @@ void WindowHelper::init() {
 			const auto style = GetWindowLongPtr(_handle, GWL_STYLE)
 				& ~WS_CAPTION;
 			const auto styleEx = GetWindowLongPtr(_handle, GWL_EXSTYLE);
-			const auto dpi = style::ConvertScale(
-				96 * style::DevicePixelRatio());
+			const auto dpi = frameMarginsSet()
+				? _dpi.current()
+				: style::ConvertScale(96 * style::DevicePixelRatio());
 			if (AdjustWindowRectExForDpiSupported() && dpi) {
 				AdjustWindowRectExForDpi(&r, style, false, styleEx, dpi);
 			} else {
 				AdjustWindowRectEx(&r, style, false, styleEx);
 			}
+			const auto frameMargins = _frameMargins.current()
+				? *_frameMargins.current()
+				: QMargins();
 			const auto maximized = window()->isMaximized()
 				|| window()->isFullScreen();
 			return (!maximized && (request->point.y() < -r.top))
 				? HitTestResult::Top
+				: (request->point.y() < frameMargins.top())
+				? HitTestResult::Caption
 				: HitTestResult::Client;
 		}();
 	}, window()->lifetime());
 
+	_dpi.value(
+	) | rpl::start_with_next([=](uint dpi) {
+		updateFrameMargins();
+	}, window()->lifetime());
+
+	_frameMargins.value(
+	) | rpl::start_with_next([=](std::optional<QMargins> frameMargins) {
+		const auto deviceDependentMargins = frameMargins
+			? *frameMargins * window()->devicePixelRatioF()
+			: QMargins();
+		const MARGINS m{
+			deviceDependentMargins.left(),
+			deviceDependentMargins.right(),
+			deviceDependentMargins.top(),
+			deviceDependentMargins.bottom(),
+		};
+		DwmExtendFrameIntoClientArea(_handle, &m);
+	}, window()->lifetime());
+
+	window()->paintRequest(
+	) | rpl::filter([=](QRect clip) {
+		return frameMarginsSet() && clip.intersects(QRect(
+			0,
+			0,
+			window()->width(),
+			_frameMargins.current()->top()));
+	}) | rpl::start_with_next([=] {
+		Painter p(window());
+		p.setCompositionMode(QPainter::CompositionMode_Clear);
+		p.fillRect(
+			0,
+			0,
+			window()->width(),
+			_frameMargins.current()->top(),
+			Qt::black);
+	}, window()->lifetime());
+
 	if (!::Platform::IsWindows11OrGreater()) {
 		_shadow.emplace(window(), st::windowShadowFg->c);
 	}
@@ -451,7 +513,9 @@ bool WindowHelper::handleNativeEvent(
 	} return true;
 
 	case WM_NCCALCSIZE: {
-		if (_title->isHidden() || window()->isFullScreen() || !wParam) {
+		if ((_title->isHidden() && !frameMarginsSet())
+			|| window()->isFullScreen()
+			|| !wParam) {
 			return false;
 		}
 		const auto r = &((LPNCCALCSIZE_PARAMS)lParam)->rgrc[0];
@@ -474,7 +538,7 @@ bool WindowHelper::handleNativeEvent(
 				- ((style & WS_CAPTION) ? 0 : 1);
 			r->left += borderWidth;
 			r->right -= borderWidth;
-			if (maximized) {
+			if (maximized && !frameMarginsSet()) {
 				r->top += borderWidth;
 			}
 			r->bottom -= borderWidth;
@@ -491,7 +555,9 @@ bool WindowHelper::handleNativeEvent(
 				switch (uEdge) {
 				case ABE_LEFT: r->left += 1; break;
 				case ABE_RIGHT: r->right -= 1; break;
+				if (!frameMarginsSet()) {
 					case ABE_TOP: r->top += 1; break;
+				}
 				case ABE_BOTTOM: r->bottom -= 1; break;
 				}
 			}
@@ -500,7 +566,7 @@ bool WindowHelper::handleNativeEvent(
 	} return true;
 
 	case WM_NCRBUTTONUP: {
-		if (_title->isHidden()) {
+		if (_title->isHidden() && !frameMarginsSet()) {
 			return false;
 		}
 		SendMessage(_handle, 0x313 /* WM_POPUPSYSTEMMENU */, 0, lParam);
@@ -608,7 +674,16 @@ bool WindowHelper::handleNativeEvent(
 	} return false;
 
 	case WM_NCHITTEST: {
-		if (!result || _title->isHidden()) {
+		if (!result) {
+			return false;
+		} else if (frameMarginsSet()) {
+			LRESULT lRet = 0;
+			DwmDefWindowProc(_handle, msg, wParam, lParam, &lRet);
+			if (lRet) {
+				*result = lRet;
+				return true;
+			}
+		} else if (_title->isHidden()) {
 			return false;
 		}
 
@@ -646,6 +721,12 @@ bool WindowHelper::handleNativeEvent(
 		_systemButtonOver.fire(systemButtonHitTest(*result));
 	} return true;
 
+	case WM_NCMOUSELEAVE: {
+		if (result && frameMarginsSet()) {
+			return DwmDefWindowProc(_handle, msg, wParam, lParam, result);
+		}
+	} return false;
+
 	// should return true for Qt not to change window size
 	// when moving the window between screens
 	// change to false once runtime scale change would be supported
@@ -743,7 +824,11 @@ HitTestResult WindowHelper::systemButtonHitTest(int result) const {
 }
 
 int WindowHelper::titleHeight() const {
-	return _title->isHidden() ? 0 : _title->height();
+	return frameMarginsSet()
+		? _frameMargins.current()->top()
+		: _title->isHidden()
+		? 0
+		: _title->height();
 }
 
 void WindowHelper::updateWindowFrameColors() {
@@ -774,6 +859,25 @@ void WindowHelper::updateWindowFrameColors(bool active) {
 		sizeof(COLORREF));
 }
 
+bool WindowHelper::frameMarginsSet() const {
+	return _frameMargins.current() && !_frameMargins.current()->isNull();
+}
+
+void WindowHelper::updateFrameMargins() {
+	if (!_frameMargins.current()) {
+		return;
+	}
+	RECT r{};
+	const auto style = GetWindowLongPtr(_handle, GWL_STYLE);
+	const auto styleEx = GetWindowLongPtr(_handle, GWL_EXSTYLE);
+	if (AdjustWindowRectExForDpiSupported() && _dpi.current()) {
+		AdjustWindowRectExForDpi(&r, style, false, styleEx, _dpi.current());
+	} else {
+		AdjustWindowRectEx(&r, style, false, styleEx);
+	}
+	_frameMargins = QMargins(0, -r.top, 0, 0) / window()->devicePixelRatioF();
+}
+
 not_null<WindowHelper::NativeFilter*> WindowHelper::GetNativeFilter() {
 	Expects(QCoreApplication::instance() != nullptr);
 

ui/platform/win/ui_window_win.h

@@ -49,6 +49,7 @@ private:
 	friend class NativeFilter;
 
 	void init();
+	void updateFrameMargins();
 	void updateWindowFrameColors();
 	void updateWindowFrameColors(bool active);
 	void initialShadowUpdate();
@@ -64,6 +65,7 @@ private:
 		LPARAM lParam,
 		LRESULT *result);
 	[[nodiscard]] bool fixedSize() const;
+	[[nodiscard]] bool frameMarginsSet() const;
 	[[nodiscard]] int systemButtonHitTest(HitTestResult result) const;
 	[[nodiscard]] HitTestResult systemButtonHitTest(int result) const;
 
@@ -78,6 +80,7 @@ private:
 	rpl::event_stream<HitTestResult> _systemButtonDown;
 	std::optional<WindowShadow> _shadow;
 	rpl::variable<uint> _dpi;
+	rpl::variable<std::optional<QMargins>> _frameMargins;
 	bool _isFullScreen = false;
 
 };