core/menu: add QsMenuAnchor for more control of platform menus

src/core/qsmenuanchor.hpp

@@ -0,0 +1,86 @@
+#pragma once
+
+#include <qqmlintegration.h>
+#include <qtclasshelpermacros.h>
+#include <qtmetamacros.h>
+
+#include "platformmenu.hpp"
+#include "popupanchor.hpp"
+#include "qsmenu.hpp"
+
+namespace qs::menu {
+
+///! Display anchor for platform menus.
+class QsMenuAnchor: public QObject {
+	Q_OBJECT;
+	/// The menu's anchor / positioner relative to another window. The menu will not be
+	/// shown until it has a valid anchor.
+	///
+	/// > [!INFO] *The following is subject to change and NOT a guarantee of future behavior.*
+	/// >
+	/// > A snapshot of the anchor at the time @@opened(s) is emitted will be
+	/// > used to position the menu. Additional changes to the anchor after this point
+	/// > will not affect the placement of the menu.
+	///
+	/// You can set properties of the anchor like so:
+	/// ```qml
+	/// QsMenuAnchor {
+	///   anchor.window: parentwindow
+	///   // or
+	///   anchor {
+	///     window: parentwindow
+	///   }
+	/// }
+	/// ```
+	Q_PROPERTY(PopupAnchor* anchor READ anchor CONSTANT);
+	/// The menu that should be displayed on this anchor.
+	///
+	/// See also: @@Quickshell.Services.SystemTray.SystemTrayItem.menu.
+	Q_PROPERTY(QsMenuHandle* menu READ menu WRITE setMenu NOTIFY menuChanged);
+	/// If the menu is currently open and visible.
+	///
+	/// See also: @@open(), @@close().
+	Q_PROPERTY(bool visible READ isVisible NOTIFY visibleChanged);
+	QML_ELEMENT;
+
+public:
+	explicit QsMenuAnchor(QObject* parent = nullptr): QObject(parent) {}
+	~QsMenuAnchor() override;
+	Q_DISABLE_COPY_MOVE(QsMenuAnchor);
+
+	/// Open the given menu on this menu Requires that @@anchor is valid.
+	Q_INVOKABLE void open();
+	/// Close the open menu.
+	Q_INVOKABLE void close();
+
+	[[nodiscard]] PopupAnchor* anchor();
+
+	[[nodiscard]] QsMenuHandle* menu() const;
+	void setMenu(QsMenuHandle* menu);
+
+	[[nodiscard]] bool isVisible() const;
+
+signals:
+	/// Sent when the menu is displayed onscreen which may be after @@visible
+	/// becomes true.
+	void opened();
+	/// Sent when the menu is closed.
+	void closed();
+
+	void menuChanged();
+	void visibleChanged();
+
+private slots:
+	void onMenuChanged();
+	void onMenuDestroyed();
+
+private:
+	void onClosed();
+
+	PopupAnchor mAnchor {this};
+	QsMenuHandle* mMenu = nullptr;
+	bool mOpen = false;
+	platform::PlatformMenuEntry* platformMenu = nullptr;
+};
+
+} // namespace qs::menu