core/popupanchor: rework popup anchoring and add PopupAnchor

src/wayland/CMakeLists.txt

@@ -52,6 +52,8 @@ endfunction()
 
 qt_add_library(quickshell-wayland STATIC
 	platformmenu.cpp
+	popupanchor.cpp
+	xdgshell.cpp
 )
 
 # required to make sure the constructor is linked

src/wayland/init.cpp

@@ -4,12 +4,14 @@
 #include <qtenvironmentvariables.h>
 
 #include "../core/plugin.hpp"
-#include "platformmenu.hpp"
 
 #ifdef QS_WAYLAND_WLR_LAYERSHELL
 #include "wlr_layershell.hpp"
 #endif
 
+void installPlatformMenuHook();
+void installPopupPositioner();
+
 namespace {
 
 class WaylandPlugin: public QuickshellPlugin {
@@ -27,7 +29,10 @@ class WaylandPlugin: public QuickshellPlugin {
 		return isWayland;
 	}
 
-	void init() override { installPlatformMenuHook(); }
+	void init() override {
+		installPlatformMenuHook();
+		installPopupPositioner();
+	}
 
 	void registerTypes() override {
 #ifdef QS_WAYLAND_WLR_LAYERSHELL

src/wayland/popupanchor.cpp

@@ -0,0 +1,99 @@
+#include "popupanchor.hpp"
+
+#include <private/qwayland-xdg-shell.h>
+#include <private/qwaylandwindow_p.h>
+#include <private/wayland-xdg-shell-client-protocol.h>
+#include <qvariant.h>
+#include <qwindow.h>
+
+#include "../core/popupanchor.hpp"
+#include "../core/types.hpp"
+#include "xdgshell.hpp"
+
+using QtWaylandClient::QWaylandWindow;
+using XdgPositioner = QtWayland::xdg_positioner;
+using qs::wayland::xdg_shell::XdgWmBase;
+
+void WaylandPopupPositioner::reposition(PopupAnchor* anchor, QWindow* window, bool onlyIfDirty) {
+	if (onlyIfDirty && !anchor->isDirty()) return;
+
+	auto* waylandWindow = dynamic_cast<QWaylandWindow*>(window->handle());
+	auto* popupRole = waylandWindow ? waylandWindow->surfaceRole<::xdg_popup>() : nullptr;
+
+	anchor->markClean();
+
+	if (popupRole) {
+		auto* xdgWmBase = XdgWmBase::instance();
+
+		if (xdgWmBase->QtWayland::xdg_wm_base::version() < XDG_POPUP_REPOSITION_SINCE_VERSION) {
+			window->setVisible(false);
+			WaylandPopupPositioner::setFlags(anchor, window);
+			window->setVisible(true);
+			return;
+		}
+
+		auto positioner = XdgPositioner(xdgWmBase->create_positioner());
+
+		positioner.set_constraint_adjustment(anchor->adjustment().toInt());
+
+		auto anchorRect = anchor->rect();
+		positioner.set_anchor_rect(anchorRect.x, anchorRect.y, anchorRect.w, anchorRect.h);
+
+		XdgPositioner::anchor anchorFlag = XdgPositioner::anchor_none;
+		switch (anchor->edges()) {
+		case Edges::Top: anchorFlag = XdgPositioner::anchor_top; break;
+		case Edges::Top | Edges::Right: anchorFlag = XdgPositioner::anchor_top_right; break;
+		case Edges::Right: anchorFlag = XdgPositioner::anchor_right; break;
+		case Edges::Bottom | Edges::Right: anchorFlag = XdgPositioner::anchor_bottom_right; break;
+		case Edges::Bottom: anchorFlag = XdgPositioner::anchor_bottom; break;
+		case Edges::Bottom | Edges::Left: anchorFlag = XdgPositioner::anchor_bottom_left; break;
+		case Edges::Left: anchorFlag = XdgPositioner::anchor_left; break;
+		case Edges::Top | Edges::Left: anchorFlag = XdgPositioner::anchor_top_left; break;
+		default: break;
+		}
+
+		positioner.set_anchor(anchorFlag);
+
+		XdgPositioner::gravity gravity = XdgPositioner::gravity_none;
+		switch (anchor->gravity()) {
+		case Edges::Top: gravity = XdgPositioner::gravity_top; break;
+		case Edges::Top | Edges::Right: gravity = XdgPositioner::gravity_top_right; break;
+		case Edges::Right: gravity = XdgPositioner::gravity_right; break;
+		case Edges::Bottom | Edges::Right: gravity = XdgPositioner::gravity_bottom_right; break;
+		case Edges::Bottom: gravity = XdgPositioner::gravity_bottom; break;
+		case Edges::Bottom | Edges::Left: gravity = XdgPositioner::gravity_bottom_left; break;
+		case Edges::Left: gravity = XdgPositioner::gravity_left; break;
+		case Edges::Top | Edges::Left: gravity = XdgPositioner::gravity_top_left; break;
+		default: break;
+		}
+
+		positioner.set_gravity(gravity);
+		auto geometry = waylandWindow->geometry();
+		positioner.set_size(geometry.width(), geometry.height());
+
+		// Note: this needs to be set for the initial position as well but no compositor
+		// supports it enough to test
+		positioner.set_reactive();
+
+		xdg_popup_reposition(popupRole, positioner.object(), 0);
+
+		positioner.destroy();
+	} else {
+		WaylandPopupPositioner::setFlags(anchor, window);
+	}
+}
+
+// Should be false but nobody supports set_reactive.
+// This just tries its best when something like a bar gets resized.
+bool WaylandPopupPositioner::shouldRepositionOnMove() const { return true; }
+
+void WaylandPopupPositioner::setFlags(PopupAnchor* anchor, QWindow* window) {
+	// clang-format off
+	window->setProperty("_q_waylandPopupConstraintAdjustment", anchor->adjustment().toInt());
+	window->setProperty("_q_waylandPopupAnchorRect", anchor->rect().qrect());
+	window->setProperty("_q_waylandPopupAnchor", QVariant::fromValue(Edges::toQt(anchor->edges())));
+	window->setProperty("_q_waylandPopupGravity", QVariant::fromValue(Edges::toQt(anchor->gravity())));
+	// clang-format on
+}
+
+void installPopupPositioner() { PopupPositioner::setInstance(new WaylandPopupPositioner()); }

src/wayland/popupanchor.hpp

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <qwindow.h>
+
+#include "../core/popupanchor.hpp"
+
+class WaylandPopupPositioner: public PopupPositioner {
+public:
+	void reposition(PopupAnchor* anchor, QWindow* window, bool onlyIfDirty = true) override;
+	[[nodiscard]] bool shouldRepositionOnMove() const override;
+
+private:
+	static void setFlags(PopupAnchor* anchor, QWindow* window);
+};
+
+void installPopupPositioner();

src/wayland/xdgshell.cpp

@@ -0,0 +1,14 @@
+#include "xdgshell.hpp"
+
+#include <qwaylandclientextension.h>
+
+namespace qs::wayland::xdg_shell {
+
+XdgWmBase::XdgWmBase(): QWaylandClientExtensionTemplate(6) { this->initialize(); }
+
+XdgWmBase* XdgWmBase::instance() {
+	static auto* instance = new XdgWmBase(); // NOLINT
+	return instance;
+}
+
+} // namespace qs::wayland::xdg_shell

src/wayland/xdgshell.hpp

@@ -0,0 +1,20 @@
+#pragma once
+
+#include <private/qwayland-xdg-shell.h>
+#include <qwaylandclientextension.h>
+
+namespace qs::wayland::xdg_shell {
+
+// Hack that binds xdg_wm_base twice as QtWaylandXdgShell headers are not exported anywhere.
+
+class XdgWmBase
+    : public QWaylandClientExtensionTemplate<XdgWmBase>
+    , public QtWayland::xdg_wm_base {
+public:
+	static XdgWmBase* instance();
+
+private:
+	explicit XdgWmBase();
+};
+
+} // namespace qs::wayland::xdg_shell