x11: add XPanelWindow

CMakeLists.txt

@@ -14,6 +14,7 @@ option(SOCKETS "Enable unix socket support" ON)
 option(WAYLAND "Enable wayland support" ON)
 option(WAYLAND_WLR_LAYERSHELL "Support the zwlr_layer_shell_v1 wayland protocol" ON)
 option(WAYLAND_SESSION_LOCK "Support the ext_session_lock_v1 wayland protocol" ON)
+option(X11 "Enable X11 support" ON)
 option(HYPRLAND "Support hyprland specific features" ON)
 option(HYPRLAND_GLOBAL_SHORTCUTS "Hyprland Global Shortcuts" ON)
 option(HYPRLAND_FOCUS_GRAB "Hyprland Focus Grabbing" ON)
@@ -29,6 +30,7 @@ if (WAYLAND)
 	message(STATUS "    Wlroots Layershell: ${WAYLAND_WLR_LAYERSHELL}")
 	message(STATUS "    Session Lock: ${WAYLAND_SESSION_LOCK}")
 endif ()
+message(STATUS "  X11: ${X11}")
 message(STATUS "  Services")
 message(STATUS "    StatusNotifier: ${SERVICE_STATUS_NOTIFIER}")
 message(STATUS "    PipeWire: ${SERVICE_PIPEWIRE}")

README.md

@@ -62,16 +62,22 @@ To build quickshell at all, you will need the following packages (names may vary
 
 - just
 - cmake
-- pkg-config
 - ninja
 - Qt6 [ QtBase, QtDeclarative ]
 
 To build with wayland support you will additionally need:
+- pkg-config
 - wayland
 - wayland-scanner (may be part of wayland on some distros)
 - wayland-protocols
 - Qt6 [ QtWayland ]
 
+To build with x11 support you will additionally need:
+- libxcb
+
+To build with pipewire support you will additionally need:
+- libpipewire
+
 ### Building
 
 To make a release build of quickshell run:

default.nix

@@ -10,6 +10,8 @@
   qt6,
   wayland,
   wayland-protocols,
+  xorg,
+  pipewire,
 
   gitRev ? (let
     headExists = builtins.pathExists ./.git/HEAD;
@@ -24,6 +26,7 @@
 
   debug ? false,
   enableWayland ? true,
+  enableX11 ? true,
   enablePipewire ? true,
   nvidiaCompat ? false,
   svgSupport ? true, # you almost always want this
@@ -42,11 +45,12 @@
     wayland-scanner
   ]);
 
-  buildInputs = with pkgs; [
+  buildInputs = [
     qt6.qtbase
     qt6.qtdeclarative
   ]
   ++ (lib.optionals enableWayland [ qt6.qtwayland wayland ])
+  ++ (lib.optionals enableX11 [ xorg.libxcb ])
   ++ (lib.optionals svgSupport [ qt6.qtsvg ])
   ++ (lib.optionals enablePipewire [ pipewire ]);
 

src/CMakeLists.txt

@@ -11,6 +11,10 @@ endif()
 
 if (WAYLAND)
 	add_subdirectory(wayland)
-endif ()
+endif()
+
+if (X11)
+	add_subdirectory(x11)
+endif()
 
 add_subdirectory(services)

src/core/panelinterface.hpp

@@ -117,6 +117,10 @@ class PanelWindowInterface: public WindowInterface {
 	Q_PROPERTY(qint32 exclusiveZone READ exclusiveZone WRITE setExclusiveZone NOTIFY exclusiveZoneChanged);
 	/// Defaults to `ExclusionMode.Auto`.
 	Q_PROPERTY(ExclusionMode::Enum exclusionMode READ exclusionMode WRITE setExclusionMode NOTIFY exclusionModeChanged);
+	/// If the panel should render above standard windows. Defaults to true.
+	QSDOC_HIDE Q_PROPERTY(bool aboveWindows READ aboveWindows WRITE setAboveWindows NOTIFY aboveWindowsChanged);
+	/// Defaults to false.
+	QSDOC_HIDE Q_PROPERTY(bool focusable READ focusable WRITE setFocusable NOTIFY focusableChanged);
 	// clang-format on
 	QSDOC_NAMED_ELEMENT(PanelWindow);
 
@@ -135,9 +139,17 @@ public:
 	[[nodiscard]] virtual ExclusionMode::Enum exclusionMode() const = 0;
 	virtual void setExclusionMode(ExclusionMode::Enum exclusionMode) = 0;
 
+	[[nodiscard]] virtual bool aboveWindows() const = 0;
+	virtual void setAboveWindows(bool aboveWindows) = 0;
+
+	[[nodiscard]] virtual bool focusable() const = 0;
+	virtual void setFocusable(bool focusable) = 0;
+
 signals:
 	void anchorsChanged();
 	void marginsChanged();
 	void exclusiveZoneChanged();
 	void exclusionModeChanged();
+	void aboveWindowsChanged();
+	void focusableChanged();
 };

src/core/proxywindow.cpp

@@ -46,7 +46,7 @@ ProxyWindowBase::~ProxyWindowBase() { this->deleteWindow(); }
 void ProxyWindowBase::onReload(QObject* oldInstance) {
 	this->window = this->retrieveWindow(oldInstance);
 	auto wasVisible = this->window != nullptr && this->window->isVisible();
-	if (this->window == nullptr) this->window = new QQuickWindow();
+	if (this->window == nullptr) this->window = this->createQQuickWindow();
 
 	// The qml engine will leave the WindowInterface as owner of everything
 	// nested in an item, so we have to make sure the interface's children

src/wayland/init.cpp

@@ -1,5 +1,7 @@
 #include <qguiapplication.h>
+#include <qlogging.h>
 #include <qqml.h>
+#include <qtenvironmentvariables.h>
 
 #include "../core/plugin.hpp"
 
@@ -10,7 +12,19 @@
 namespace {
 
 class WaylandPlugin: public QuickshellPlugin {
-	bool applies() override { return QGuiApplication::platformName() == "wayland"; }
+	bool applies() override {
+		auto isWayland = QGuiApplication::platformName() == "wayland";
+
+		if (!isWayland && !qEnvironmentVariable("WAYLAND_DISPLAY").isEmpty()) {
+			qWarning() << "--- WARNING ---";
+			qWarning() << "WAYLAND_DISPLAY is present but QT_QPA_PLATFORM is"
+			           << QGuiApplication::platformName();
+			qWarning() << "If you are actually running wayland, set QT_QPA_PLATFORM to \"wayland\" or "
+			              "most functionality will be broken.";
+		}
+
+		return isWayland;
+	}
 
 	void registerTypes() override {
 #ifdef QS_WAYLAND_WLR_LAYERSHELL

src/wayland/wlr_layershell.cpp

@@ -114,6 +114,18 @@ void WlrLayershell::setAnchors(Anchors anchors) {
 	if (!anchors.verticalConstraint()) this->ProxyWindowBase::setHeight(this->mHeight);
 }
 
+bool WlrLayershell::aboveWindows() const { return this->layer() > WlrLayer::Bottom; }
+
+void WlrLayershell::setAboveWindows(bool aboveWindows) {
+	this->setLayer(aboveWindows ? WlrLayer::Top : WlrLayer::Bottom);
+}
+
+bool WlrLayershell::focusable() const { return this->keyboardFocus() != WlrKeyboardFocus::None; }
+
+void WlrLayershell::setFocusable(bool focusable) {
+	this->setKeyboardFocus(focusable ? WlrKeyboardFocus::OnDemand : WlrKeyboardFocus::None);
+}
+
 QString WlrLayershell::ns() const { return this->ext->ns(); }
 
 void WlrLayershell::setNamespace(QString ns) {
@@ -190,6 +202,8 @@ WaylandPanelInterface::WaylandPanelInterface(QObject* parent)
 	QObject::connect(this->layer, &WlrLayershell::marginsChanged, this, &WaylandPanelInterface::marginsChanged);
 	QObject::connect(this->layer, &WlrLayershell::exclusiveZoneChanged, this, &WaylandPanelInterface::exclusiveZoneChanged);
 	QObject::connect(this->layer, &WlrLayershell::exclusionModeChanged, this, &WaylandPanelInterface::exclusionModeChanged);
+	QObject::connect(this->layer, &WlrLayershell::layerChanged, this, &WaylandPanelInterface::aboveWindowsChanged);
+	QObject::connect(this->layer, &WlrLayershell::keyboardFocusChanged, this, &WaylandPanelInterface::focusableChanged);
 	// clang-format on
 }
 
@@ -224,6 +238,8 @@ proxyPair(Anchors, anchors, setAnchors);
 proxyPair(Margins, margins, setMargins);
 proxyPair(qint32, exclusiveZone, setExclusiveZone);
 proxyPair(ExclusionMode::Enum, exclusionMode, setExclusionMode);
+proxyPair(bool, focusable, setFocusable);
+proxyPair(bool, aboveWindows, setAboveWindows);
 
 #undef proxyPair
 // NOLINTEND

src/wayland/wlr_layershell.hpp

@@ -8,6 +8,7 @@
 #include <qtypes.h>
 
 #include "../core/doc.hpp"
+#include "../core/panelinterface.hpp"
 #include "../core/proxywindow.hpp"
 #include "wlr_layershell/window.hpp"
 
@@ -54,6 +55,8 @@ class WlrLayershell: public ProxyWindowBase {
 	QSDOC_HIDE Q_PROPERTY(qint32 exclusiveZone READ exclusiveZone WRITE setExclusiveZone NOTIFY exclusiveZoneChanged);
 	QSDOC_HIDE Q_PROPERTY(ExclusionMode::Enum exclusionMode READ exclusionMode WRITE setExclusionMode NOTIFY exclusionModeChanged);
 	QSDOC_HIDE Q_PROPERTY(Margins margins READ margins WRITE setMargins NOTIFY marginsChanged);
+	QSDOC_HIDE Q_PROPERTY(bool aboveWindows READ aboveWindows WRITE setAboveWindows NOTIFY layerChanged);
+	QSDOC_HIDE Q_PROPERTY(bool focusable READ focusable WRITE setFocusable NOTIFY keyboardFocusChanged);
 	QML_ATTACHED(WlrLayershell);
 	QML_ELEMENT;
 	// clang-format on
@@ -92,6 +95,12 @@ public:
 	[[nodiscard]] Margins margins() const;
 	void setMargins(Margins margins); // NOLINT
 
+	[[nodiscard]] bool aboveWindows() const;
+	void setAboveWindows(bool aboveWindows);
+
+	[[nodiscard]] bool focusable() const;
+	void setFocusable(bool focusable);
+
 	static WlrLayershell* qmlAttachedProperties(QObject* object);
 
 signals:
@@ -161,6 +170,12 @@ public:
 
 	[[nodiscard]] ExclusionMode::Enum exclusionMode() const override;
 	void setExclusionMode(ExclusionMode::Enum exclusionMode) override;
+
+	[[nodiscard]] bool aboveWindows() const override;
+	void setAboveWindows(bool aboveWindows) override;
+
+	[[nodiscard]] bool focusable() const override;
+	void setFocusable(bool focusable) override;
 	// NOLINTEND
 
 private:

src/x11/CMakeLists.txt

@@ -0,0 +1,22 @@
+find_package(XCB REQUIRED COMPONENTS XCB)
+
+qt_add_library(quickshell-x11 STATIC
+	util.cpp
+	panel_window.cpp
+)
+
+qt_add_qml_module(quickshell-x11
+	URI Quickshell.X11
+	VERSION 0.1
+)
+
+add_library(quickshell-x11-init OBJECT init.cpp)
+
+target_link_libraries(quickshell-x11 PRIVATE ${QT_DEPS} ${XCB_LIBRARIES})
+target_link_libraries(quickshell-x11-init PRIVATE ${QT_DEPS} ${XCB_LIBRARIES})
+
+qs_pch(quickshell-x11)
+qs_pch(quickshell-x11plugin)
+qs_pch(quickshell-x11-init)
+
+target_link_libraries(quickshell PRIVATE quickshell-x11plugin quickshell-x11-init)

src/x11/init.cpp

@@ -0,0 +1,29 @@
+#include <qguiapplication.h>
+#include <qqml.h>
+
+#include "../core/plugin.hpp"
+#include "panel_window.hpp"
+#include "util.hpp"
+
+namespace {
+
+class X11Plugin: public QuickshellPlugin {
+	bool applies() override { return QGuiApplication::platformName() == "xcb"; }
+
+	void init() override { XAtom::initAtoms(); }
+
+	void registerTypes() override {
+		qmlRegisterType<XPanelInterface>("Quickshell._X11Overlay", 1, 0, "PanelWindow");
+
+		qmlRegisterModuleImport(
+		    "Quickshell",
+		    QQmlModuleImportModuleAny,
+		    "Quickshell._X11Overlay",
+		    QQmlModuleImportLatest
+		);
+	}
+};
+
+QS_REGISTER_PLUGIN(X11Plugin);
+
+} // namespace

src/x11/panel_window.cpp

@@ -0,0 +1,431 @@
+#include "panel_window.hpp"
+#include <array>
+#include <map>
+
+#include <qevent.h>
+#include <qlist.h>
+#include <qnamespace.h>
+#include <qobject.h>
+#include <qqmlengine.h>
+#include <qqmllist.h>
+#include <qquickwindow.h>
+#include <qscreen.h>
+#include <qtmetamacros.h>
+#include <qtypes.h>
+#include <xcb/xproto.h>
+
+#include "../core/generation.hpp"
+#include "../core/panelinterface.hpp"
+#include "../core/proxywindow.hpp"
+#include "util.hpp"
+
+class XPanelStack {
+public:
+	static XPanelStack* instance() {
+		static XPanelStack* stack = nullptr; // NOLINT
+
+		if (stack == nullptr) {
+			stack = new XPanelStack();
+		}
+
+		return stack;
+	}
+
+	[[nodiscard]] const QList<XPanelWindow*>& panels(XPanelWindow* panel) {
+		return this->mPanels[EngineGeneration::findObjectGeneration(panel)];
+	}
+
+	void addPanel(XPanelWindow* panel) {
+		auto& panels = this->mPanels[EngineGeneration::findObjectGeneration(panel)];
+		if (!panels.contains(panel)) {
+			panels.push_back(panel);
+		}
+	}
+
+	void removePanel(XPanelWindow* panel) {
+		auto& panels = this->mPanels[EngineGeneration::findObjectGeneration(panel)];
+		if (panels.removeOne(panel)) {
+			if (panels.isEmpty()) {
+				this->mPanels.erase(EngineGeneration::findObjectGeneration(panel));
+			}
+
+			// from the bottom up, update all panels
+			for (auto* panel: panels) {
+				panel->updateDimensions();
+			}
+		}
+	}
+
+private:
+	std::map<EngineGeneration*, QList<XPanelWindow*>> mPanels;
+};
+
+bool XPanelEventFilter::eventFilter(QObject* watched, QEvent* event) {
+	if (event->type() == QEvent::PlatformSurface) {
+		auto* surfaceEvent = static_cast<QPlatformSurfaceEvent*>(event); // NOLINT
+
+		if (surfaceEvent->surfaceEventType() == QPlatformSurfaceEvent::SurfaceCreated) {
+			emit this->surfaceCreated();
+		}
+	}
+
+	return this->QObject::eventFilter(watched, event);
+}
+
+XPanelWindow::XPanelWindow(QObject* parent): ProxyWindowBase(parent) {
+	QObject::connect(
+	    &this->eventFilter,
+	    &XPanelEventFilter::surfaceCreated,
+	    this,
+	    &XPanelWindow::xInit
+	);
+}
+
+XPanelWindow::~XPanelWindow() { XPanelStack::instance()->removePanel(this); }
+
+void XPanelWindow::connectWindow() {
+	this->ProxyWindowBase::connectWindow();
+
+	this->window->installEventFilter(&this->eventFilter);
+	this->connectScreen();
+	// clang-format off
+	QObject::connect(this->window, &QQuickWindow::screenChanged, this, &XPanelWindow::connectScreen);
+	QObject::connect(this->window, &QQuickWindow::visibleChanged, this, &XPanelWindow::updatePanelStack);
+	// clang-format on
+
+	// qt overwrites _NET_WM_STATE, so we have to use the qt api
+	// QXcbWindow::WindowType::Dock in qplatformwindow_p.h
+	// see QXcbWindow::setWindowFlags in qxcbwindow.cpp
+	this->window->setProperty("_q_xcb_wm_window_type", 0x000004);
+
+	// at least one flag needs to change for the above property to apply
+	this->window->setFlag(Qt::FramelessWindowHint);
+	this->updateAboveWindows();
+	this->updateFocusable();
+
+	if (this->window->handle() != nullptr) {
+		this->xInit();
+		this->updatePanelStack();
+	}
+}
+
+void XPanelWindow::setWidth(qint32 width) {
+	this->mWidth = width;
+
+	// only update the actual size if not blocked by anchors
+	if (!this->mAnchors.horizontalConstraint()) {
+		this->ProxyWindowBase::setWidth(width);
+		this->updateDimensions();
+	}
+}
+
+void XPanelWindow::setHeight(qint32 height) {
+	this->mHeight = height;
+
+	// only update the actual size if not blocked by anchors
+	if (!this->mAnchors.verticalConstraint()) {
+		this->ProxyWindowBase::setHeight(height);
+		this->updateDimensions();
+	}
+}
+
+Anchors XPanelWindow::anchors() const { return this->mAnchors; }
+
+void XPanelWindow::setAnchors(Anchors anchors) {
+	if (this->mAnchors == anchors) return;
+	this->mAnchors = anchors;
+	this->updateDimensions();
+	emit this->anchorsChanged();
+}
+
+qint32 XPanelWindow::exclusiveZone() const { return this->mExclusiveZone; }
+
+void XPanelWindow::setExclusiveZone(qint32 exclusiveZone) {
+	if (this->mExclusiveZone == exclusiveZone) return;
+	this->mExclusiveZone = exclusiveZone;
+	const bool wasNormal = this->mExclusionMode == ExclusionMode::Normal;
+	this->setExclusionMode(ExclusionMode::Normal);
+	if (wasNormal) this->updateStrut();
+	emit this->exclusiveZoneChanged();
+}
+
+ExclusionMode::Enum XPanelWindow::exclusionMode() const { return this->mExclusionMode; }
+
+void XPanelWindow::setExclusionMode(ExclusionMode::Enum exclusionMode) {
+	if (this->mExclusionMode == exclusionMode) return;
+	this->mExclusionMode = exclusionMode;
+	this->updateStrut();
+	emit this->exclusionModeChanged();
+}
+
+Margins XPanelWindow::margins() const { return this->mMargins; }
+
+void XPanelWindow::setMargins(Margins margins) {
+	if (this->mMargins == margins) return;
+	this->mMargins = margins;
+	this->updateDimensions();
+	emit this->marginsChanged();
+}
+
+bool XPanelWindow::aboveWindows() const { return this->mAboveWindows; }
+
+void XPanelWindow::setAboveWindows(bool aboveWindows) {
+	if (this->mAboveWindows == aboveWindows) return;
+	this->mAboveWindows = aboveWindows;
+	this->updateAboveWindows();
+	emit this->aboveWindowsChanged();
+}
+
+bool XPanelWindow::focusable() const { return this->mFocusable; }
+
+void XPanelWindow::setFocusable(bool focusable) {
+	if (this->mFocusable == focusable) return;
+	this->mFocusable = focusable;
+	this->updateFocusable();
+	emit this->focusableChanged();
+}
+
+void XPanelWindow::xInit() { this->updateDimensions(); }
+
+void XPanelWindow::connectScreen() {
+	if (this->mTrackedScreen != nullptr) {
+		QObject::disconnect(this->mTrackedScreen, nullptr, this, nullptr);
+	}
+
+	this->mTrackedScreen = this->window->screen();
+
+	if (this->mTrackedScreen != nullptr) {
+		QObject::connect(
+		    this->mTrackedScreen,
+		    &QScreen::geometryChanged,
+		    this,
+		    &XPanelWindow::updateDimensions
+		);
+	}
+}
+
+void XPanelWindow::updateDimensions() {
+	if (this->window == nullptr || this->window->handle() == nullptr) return;
+
+	auto screenGeometry = this->window->screen()->virtualGeometry();
+
+	if (this->mExclusionMode != ExclusionMode::Ignore) {
+		for (auto* panel: XPanelStack::instance()->panels(this)) {
+			// we only care about windows below us
+			if (panel == this) break;
+
+			int side = -1;
+			quint32 exclusiveZone = 0;
+			panel->getExclusion(side, exclusiveZone);
+
+			if (exclusiveZone == 0) continue;
+
+			auto zone = static_cast<qint32>(exclusiveZone);
+
+			screenGeometry.adjust(
+			    side == 0 ? zone : 0,
+			    side == 2 ? zone : 0,
+			    side == 1 ? -zone : 0,
+			    side == 3 ? -zone : 0
+			);
+		}
+	}
+
+	auto geometry = QRect();
+
+	if (this->mAnchors.horizontalConstraint()) {
+		geometry.setX(screenGeometry.x() + this->mMargins.mLeft);
+		geometry.setWidth(screenGeometry.width() - this->mMargins.mLeft - this->mMargins.mRight);
+	} else {
+		if (this->mAnchors.mLeft) {
+			geometry.setX(screenGeometry.x() + this->mMargins.mLeft);
+		} else if (this->mAnchors.mRight) {
+			geometry.setX(
+			    screenGeometry.x() + screenGeometry.width() - this->mWidth - this->mMargins.mRight
+			);
+		} else {
+			geometry.setX(screenGeometry.x() + screenGeometry.width() / 2 - this->mWidth / 2);
+		}
+
+		geometry.setWidth(this->mWidth);
+	}
+
+	if (this->mAnchors.verticalConstraint()) {
+		geometry.setY(screenGeometry.y() + this->mMargins.mTop);
+		geometry.setHeight(screenGeometry.height() - this->mMargins.mTop - this->mMargins.mBottom);
+	} else {
+		if (this->mAnchors.mTop) {
+			geometry.setY(screenGeometry.y() + this->mMargins.mTop);
+		} else if (this->mAnchors.mBottom) {
+			geometry.setY(
+			    screenGeometry.y() + screenGeometry.height() - this->mHeight - this->mMargins.mBottom
+			);
+		} else {
+			geometry.setY(screenGeometry.y() + screenGeometry.height() / 2 - this->mHeight / 2);
+		}
+
+		geometry.setHeight(this->mHeight);
+	}
+
+	this->window->setGeometry(geometry);
+	this->updateStrut();
+}
+
+void XPanelWindow::updatePanelStack() {
+	if (this->window->isVisible()) {
+		XPanelStack::instance()->addPanel(this);
+	} else {
+		XPanelStack::instance()->removePanel(this);
+	}
+}
+
+void XPanelWindow::getExclusion(int& side, quint32& exclusiveZone) {
+	if (this->mExclusionMode == ExclusionMode::Ignore) return;
+
+	auto& anchors = this->mAnchors;
+	if (anchors.mLeft || anchors.mRight || anchors.mTop || anchors.mBottom) {
+		if (!anchors.horizontalConstraint()
+		    && (anchors.verticalConstraint() || (!anchors.mTop && !anchors.mBottom)))
+		{
+			side = anchors.mLeft ? 0 : anchors.mRight ? 1 : -1;
+		} else if (!anchors.verticalConstraint()
+						 && (anchors.horizontalConstraint() || (!anchors.mLeft && !anchors.mRight)))
+		{
+			side = anchors.mTop ? 2 : anchors.mBottom ? 3 : -1;
+		}
+	}
+
+	if (side == -1) return;
+
+	auto autoExclude = this->mExclusionMode == ExclusionMode::Auto;
+
+	if (autoExclude) {
+		if (side == 0 || side == 1) {
+			exclusiveZone = this->mWidth + (side == 0 ? this->mMargins.mLeft : this->mMargins.mRight);
+		} else {
+			exclusiveZone = this->mHeight + (side == 2 ? this->mMargins.mTop : this->mMargins.mBottom);
+		}
+	} else {
+		exclusiveZone = this->mExclusiveZone;
+	}
+}
+
+void XPanelWindow::updateStrut() {
+	if (this->window == nullptr || this->window->handle() == nullptr) return;
+	auto* conn = x11Connection();
+
+	int side = -1;
+	quint32 exclusiveZone = 0;
+
+	this->getExclusion(side, exclusiveZone);
+
+	if (side == -1 || this->mExclusionMode == ExclusionMode::Ignore) {
+		xcb_delete_property(conn, this->window->winId(), XAtom::_NET_WM_STRUT.atom());
+		xcb_delete_property(conn, this->window->winId(), XAtom::_NET_WM_STRUT_PARTIAL.atom());
+		return;
+	}
+
+	auto data = std::array<quint32, 12>();
+	data[side] = exclusiveZone;
+
+	// https://specifications.freedesktop.org/wm-spec/wm-spec-latest.html#idm45573693101552
+	// assuming "specified in root window coordinates" means relative to the window geometry
+	// in which case only the end position should be set, to the opposite extent.
+	data[side * 2 + 5] = side == 0 || side == 1 ? this->window->height() : this->window->width();
+
+	xcb_change_property(
+	    conn,
+	    XCB_PROP_MODE_REPLACE,
+	    this->window->winId(),
+	    XAtom::_NET_WM_STRUT.atom(),
+	    XCB_ATOM_CARDINAL,
+	    32,
+	    4,
+	    data.data()
+	);
+
+	xcb_change_property(
+	    conn,
+	    XCB_PROP_MODE_REPLACE,
+	    this->window->winId(),
+	    XAtom::_NET_WM_STRUT_PARTIAL.atom(),
+	    XCB_ATOM_CARDINAL,
+	    32,
+	    12,
+	    data.data()
+	);
+}
+
+void XPanelWindow::updateAboveWindows() {
+	if (this->window == nullptr) return;
+
+	this->window->setFlag(Qt::WindowStaysOnBottomHint, !this->mAboveWindows);
+	this->window->setFlag(Qt::WindowStaysOnTopHint, this->mAboveWindows);
+}
+
+void XPanelWindow::updateFocusable() {
+	if (this->window == nullptr) return;
+	this->window->setFlag(Qt::WindowDoesNotAcceptFocus, !this->mFocusable);
+}
+
+// XPanelInterface
+
+XPanelInterface::XPanelInterface(QObject* parent)
+    : PanelWindowInterface(parent)
+    , panel(new XPanelWindow(this)) {
+
+	// clang-format off
+	QObject::connect(this->panel, &ProxyWindowBase::windowConnected, this, &XPanelInterface::windowConnected);
+	QObject::connect(this->panel, &ProxyWindowBase::visibleChanged, this, &XPanelInterface::visibleChanged);
+	QObject::connect(this->panel, &ProxyWindowBase::backerVisibilityChanged, this, &XPanelInterface::backingWindowVisibleChanged);
+	QObject::connect(this->panel, &ProxyWindowBase::heightChanged, this, &XPanelInterface::heightChanged);
+	QObject::connect(this->panel, &ProxyWindowBase::widthChanged, this, &XPanelInterface::widthChanged);
+	QObject::connect(this->panel, &ProxyWindowBase::screenChanged, this, &XPanelInterface::screenChanged);
+	QObject::connect(this->panel, &ProxyWindowBase::windowTransformChanged, this, &XPanelInterface::windowTransformChanged);
+	QObject::connect(this->panel, &ProxyWindowBase::colorChanged, this, &XPanelInterface::colorChanged);
+	QObject::connect(this->panel, &ProxyWindowBase::maskChanged, this, &XPanelInterface::maskChanged);
+
+	// panel specific
+	QObject::connect(this->panel, &XPanelWindow::anchorsChanged, this, &XPanelInterface::anchorsChanged);
+	QObject::connect(this->panel, &XPanelWindow::marginsChanged, this, &XPanelInterface::marginsChanged);
+	QObject::connect(this->panel, &XPanelWindow::exclusiveZoneChanged, this, &XPanelInterface::exclusiveZoneChanged);
+	QObject::connect(this->panel, &XPanelWindow::exclusionModeChanged, this, &XPanelInterface::exclusionModeChanged);
+	QObject::connect(this->panel, &XPanelWindow::aboveWindowsChanged, this, &XPanelInterface::aboveWindowsChanged);
+	QObject::connect(this->panel, &XPanelWindow::focusableChanged, this, &XPanelInterface::focusableChanged);
+	// clang-format on
+}
+
+void XPanelInterface::onReload(QObject* oldInstance) {
+	QQmlEngine::setContextForObject(this->panel, QQmlEngine::contextForObject(this));
+
+	auto* old = qobject_cast<XPanelInterface*>(oldInstance);
+	this->panel->reload(old != nullptr ? old->panel : nullptr);
+}
+
+QQmlListProperty<QObject> XPanelInterface::data() { return this->panel->data(); }
+ProxyWindowBase* XPanelInterface::proxyWindow() const { return this->panel; }
+QQuickItem* XPanelInterface::contentItem() const { return this->panel->contentItem(); }
+bool XPanelInterface::isBackingWindowVisible() const { return this->panel->isVisibleDirect(); }
+
+// NOLINTBEGIN
+#define proxyPair(type, get, set)                                                                  \
+	type XPanelInterface::get() const { return this->panel->get(); }                                 \
+	void XPanelInterface::set(type value) { this->panel->set(value); }
+
+proxyPair(bool, isVisible, setVisible);
+proxyPair(qint32, width, setWidth);
+proxyPair(qint32, height, setHeight);
+proxyPair(QuickshellScreenInfo*, screen, setScreen);
+proxyPair(QColor, color, setColor);
+proxyPair(PendingRegion*, mask, setMask);
+
+// panel specific
+proxyPair(Anchors, anchors, setAnchors);
+proxyPair(Margins, margins, setMargins);
+proxyPair(qint32, exclusiveZone, setExclusiveZone);
+proxyPair(ExclusionMode::Enum, exclusionMode, setExclusionMode);
+proxyPair(bool, focusable, setFocusable);
+proxyPair(bool, aboveWindows, setAboveWindows);
+
+#undef proxyPair
+// NOLINTEND

src/x11/panel_window.hpp

@@ -0,0 +1,160 @@
+#pragma once
+
+#include <qobject.h>
+#include <qqmlintegration.h>
+#include <qquickwindow.h>
+#include <qscreen.h>
+#include <qtclasshelpermacros.h>
+#include <qtmetamacros.h>
+
+#include "../core/doc.hpp"
+#include "../core/panelinterface.hpp"
+#include "../core/proxywindow.hpp"
+
+class XPanelStack;
+
+class XPanelEventFilter: public QObject {
+	Q_OBJECT;
+
+public:
+	explicit XPanelEventFilter(QObject* parent = nullptr): QObject(parent) {}
+
+signals:
+	void surfaceCreated();
+
+protected:
+	bool eventFilter(QObject* watched, QEvent* event) override;
+};
+
+class XPanelWindow: public ProxyWindowBase {
+	QSDOC_BASECLASS(PanelWindowInterface);
+	Q_OBJECT;
+	// clang-format off
+	QSDOC_HIDE Q_PROPERTY(Anchors anchors READ anchors WRITE setAnchors NOTIFY anchorsChanged);
+	QSDOC_HIDE Q_PROPERTY(qint32 exclusiveZone READ exclusiveZone WRITE setExclusiveZone NOTIFY exclusiveZoneChanged);
+	QSDOC_HIDE Q_PROPERTY(ExclusionMode::Enum exclusionMode READ exclusionMode WRITE setExclusionMode NOTIFY exclusionModeChanged);
+	QSDOC_HIDE Q_PROPERTY(Margins margins READ margins WRITE setMargins NOTIFY marginsChanged);
+	QSDOC_HIDE Q_PROPERTY(bool aboveWindows READ aboveWindows WRITE setAboveWindows NOTIFY aboveWindowsChanged);
+	QSDOC_HIDE Q_PROPERTY(bool focusable READ focusable WRITE setFocusable NOTIFY focusableChanged);
+	// clang-format on
+	QML_ELEMENT;
+
+public:
+	explicit XPanelWindow(QObject* parent = nullptr);
+	~XPanelWindow() override;
+	Q_DISABLE_COPY_MOVE(XPanelWindow);
+
+	void connectWindow() override;
+
+	void setWidth(qint32 width) override;
+	void setHeight(qint32 height) override;
+
+	[[nodiscard]] Anchors anchors() const;
+	void setAnchors(Anchors anchors);
+
+	[[nodiscard]] qint32 exclusiveZone() const;
+	void setExclusiveZone(qint32 exclusiveZone);
+
+	[[nodiscard]] ExclusionMode::Enum exclusionMode() const;
+	void setExclusionMode(ExclusionMode::Enum exclusionMode);
+
+	[[nodiscard]] Margins margins() const;
+	void setMargins(Margins margins);
+
+	[[nodiscard]] bool aboveWindows() const;
+	void setAboveWindows(bool aboveWindows);
+
+	[[nodiscard]] bool focusable() const;
+	void setFocusable(bool focusable);
+
+signals:
+	QSDOC_HIDE void anchorsChanged();
+	QSDOC_HIDE void exclusiveZoneChanged();
+	QSDOC_HIDE void exclusionModeChanged();
+	QSDOC_HIDE void marginsChanged();
+	QSDOC_HIDE void aboveWindowsChanged();
+	QSDOC_HIDE void focusableChanged();
+
+private slots:
+	void xInit();
+	void connectScreen();
+	void updateDimensions();
+	void updatePanelStack();
+
+private:
+	void getExclusion(int& side, quint32& exclusiveZone);
+	void updateStrut();
+	void updateAboveWindows();
+	void updateFocusable();
+
+	QPointer<QScreen> mTrackedScreen = nullptr;
+	bool mAboveWindows = true;
+	bool mFocusable = false;
+	Anchors mAnchors;
+	Margins mMargins;
+	qint32 mExclusiveZone = 0;
+	ExclusionMode::Enum mExclusionMode = ExclusionMode::Auto;
+	XPanelEventFilter eventFilter;
+
+	friend class XPanelStack;
+};
+
+class XPanelInterface: public PanelWindowInterface {
+	Q_OBJECT;
+
+public:
+	explicit XPanelInterface(QObject* parent = nullptr);
+
+	void onReload(QObject* oldInstance) override;
+
+	[[nodiscard]] ProxyWindowBase* proxyWindow() const override;
+	[[nodiscard]] QQuickItem* contentItem() const override;
+
+	// NOLINTBEGIN
+	[[nodiscard]] bool isVisible() const override;
+	[[nodiscard]] bool isBackingWindowVisible() const override;
+	void setVisible(bool visible) override;
+
+	[[nodiscard]] qint32 width() const override;
+	void setWidth(qint32 width) override;
+
+	[[nodiscard]] qint32 height() const override;
+	void setHeight(qint32 height) override;
+
+	[[nodiscard]] QuickshellScreenInfo* screen() const override;
+	void setScreen(QuickshellScreenInfo* screen) override;
+
+	[[nodiscard]] QColor color() const override;
+	void setColor(QColor color) override;
+
+	[[nodiscard]] PendingRegion* mask() const override;
+	void setMask(PendingRegion* mask) override;
+
+	[[nodiscard]] QQmlListProperty<QObject> data() override;
+
+	// panel specific
+
+	[[nodiscard]] Anchors anchors() const override;
+	void setAnchors(Anchors anchors) override;
+
+	[[nodiscard]] Margins margins() const override;
+	void setMargins(Margins margins) override;
+
+	[[nodiscard]] qint32 exclusiveZone() const override;
+	void setExclusiveZone(qint32 exclusiveZone) override;
+
+	[[nodiscard]] ExclusionMode::Enum exclusionMode() const override;
+	void setExclusionMode(ExclusionMode::Enum exclusionMode) override;
+
+	[[nodiscard]] bool aboveWindows() const override;
+	void setAboveWindows(bool aboveWindows) override;
+
+	[[nodiscard]] bool focusable() const override;
+	void setFocusable(bool focusable) override;
+	// NOLINTEND
+
+private:
+	XPanelWindow* panel;
+
+	friend class WlrLayershell;
+};

src/x11/util.cpp

@@ -0,0 +1,55 @@
+#include "util.hpp"
+
+#include <qbytearray.h>
+#include <qguiapplication.h>
+#include <qguiapplication_platform.h>
+#include <xcb/xcb.h>
+#include <xcb/xproto.h>
+
+xcb_connection_t* x11Connection() {
+	static xcb_connection_t* conn = nullptr; // NOLINT
+
+	if (conn == nullptr) {
+		if (auto* x11Application = dynamic_cast<QGuiApplication*>(QGuiApplication::instance())
+		                               ->nativeInterface<QNativeInterface::QX11Application>())
+		{
+			conn = x11Application->connection();
+		}
+	}
+
+	return conn;
+}
+
+// NOLINTBEGIN
+XAtom XAtom::_NET_WM_STRUT {};
+XAtom XAtom::_NET_WM_STRUT_PARTIAL {};
+// NOLINTEND
+
+void XAtom::initAtoms() {
+	_NET_WM_STRUT.init("_NET_WM_STRUT");
+	_NET_WM_STRUT_PARTIAL.init("_NET_WM_STRUT_PARTIAL");
+}
+
+void XAtom::init(const QByteArray& name) {
+	this->cookie = xcb_intern_atom(x11Connection(), 0, name.length(), name.data());
+}
+
+bool XAtom::isValid() {
+	this->resolve();
+	return this->mAtom != XCB_ATOM_NONE;
+}
+
+const xcb_atom_t& XAtom::atom() {
+	this->resolve();
+	return this->mAtom;
+}
+
+void XAtom::resolve() {
+	if (!this->resolved) {
+		this->resolved = true;
+
+		auto* reply = xcb_intern_atom_reply(x11Connection(), this->cookie, nullptr);
+		if (reply != nullptr) this->mAtom = reply->atom;
+		free(reply); // NOLINT
+	}
+}

src/x11/util.hpp

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <qbytearray.h>
+#include <qtclasshelpermacros.h>
+#include <xcb/xcb.h>
+#include <xcb/xproto.h>
+
+xcb_connection_t* x11Connection();
+
+class XAtom {
+public:
+	[[nodiscard]] bool isValid();
+	[[nodiscard]] const xcb_atom_t& atom();
+
+	// NOLINTBEGIN
+	static XAtom _NET_WM_STRUT;
+	static XAtom _NET_WM_STRUT_PARTIAL;
+	// NOLINTEND
+
+	static void initAtoms();
+
+private:
+	void init(const QByteArray& name);
+	void resolve();
+
+	bool resolved = false;
+	xcb_atom_t mAtom = XCB_ATOM_NONE;
+	xcb_intern_atom_cookie_t cookie {};
+};