Set size hints for xdg-shell and xdg-shell-v6

Send minimum and maximum size hints to compositors.

[ChangeLog][QPA plugin] Implement minimum and maximum size in
the xdg-shell and xdg-shell-v6 shell integrations.

Change-Id: I631c3348c8333d7a246b21228a92c436f5adb5dc
Reviewed-by: Johan Helsing <johan.helsing@qt.io>

src/plugins/platforms/wayland/plugins/shellintegration/xdg-shell-v6/qwaylandxdgshellv6.cpp

@@ -46,6 +46,8 @@
 #include <QtWaylandClient/private/qwaylandscreen_p.h>
 #include <QtWaylandClient/private/qwaylandabstractdecoration_p.h>
 
+#include <QtGui/private/qwindow_p.h>
+
 QT_BEGIN_NAMESPACE
 
 namespace QtWaylandClient {
@@ -94,6 +96,9 @@ void QWaylandXdgSurfaceV6::Toplevel::applyConfigure()
 
     QSize windowGeometrySize = m_xdgSurface->m_window->window()->frameGeometry().size();
     m_xdgSurface->set_window_geometry(0, 0, windowGeometrySize.width(), windowGeometrySize.height());
+
+    m_xdgSurface->setSizeHints();
+
     m_applied = m_pending;
     qCDebug(lcQpaWayland) << "Applied pending zxdg_toplevel_v6 configure event:" << m_applied.size << m_applied.states;
 }
@@ -305,6 +310,31 @@ bool QWaylandXdgSurfaceV6::wantsDecorations() const
     return m_toplevel && !(m_toplevel->m_pending.states & Qt::WindowFullScreen);
 }
 
+void QWaylandXdgSurfaceV6::propagateSizeHints()
+{
+    setSizeHints();
+
+    if (m_toplevel && m_window)
+        m_window->commit();
+}
+
+void QWaylandXdgSurfaceV6::setSizeHints()
+{
+    if (m_toplevel && m_window) {
+        const int minWidth = qMax(0, m_window->windowMinimumSize().width());
+        const int minHeight = qMax(0, m_window->windowMinimumSize().height());
+        m_toplevel->set_min_size(minWidth, minHeight);
+
+        int maxWidth = qMax(0, m_window->windowMaximumSize().width());
+        if (maxWidth == QWINDOWSIZE_MAX)
+            maxWidth = 0;
+        int maxHeight = qMax(0, m_window->windowMaximumSize().height());
+        if (maxHeight == QWINDOWSIZE_MAX)
+            maxHeight = 0;
+        m_toplevel->set_max_size(maxWidth, maxHeight);
+    }
+}
+
 void QWaylandXdgSurfaceV6::requestWindowStates(Qt::WindowStates states)
 {
     if (m_toplevel)

src/plugins/platforms/wayland/plugins/shellintegration/xdg-shell-v6/qwaylandxdgshellv6_p.h

@@ -88,6 +88,9 @@ public:
     bool handlesActiveState() const { return m_toplevel; }
     void applyConfigure() override;
     bool wantsDecorations() const override;
+    void propagateSizeHints() override;
+
+    void setSizeHints();
 
 protected:
     void requestWindowStates(Qt::WindowStates states) override;

src/plugins/platforms/wayland/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp

@@ -46,6 +46,8 @@
 #include <QtWaylandClient/private/qwaylandscreen_p.h>
 #include <QtWaylandClient/private/qwaylandabstractdecoration_p.h>
 
+#include <QtGui/private/qwindow_p.h>
+
 QT_BEGIN_NAMESPACE
 
 namespace QtWaylandClient {
@@ -104,6 +106,9 @@ void QWaylandXdgSurface::Toplevel::applyConfigure()
 
     QSize windowGeometrySize = m_xdgSurface->m_window->window()->frameGeometry().size();
     m_xdgSurface->set_window_geometry(0, 0, windowGeometrySize.width(), windowGeometrySize.height());
+
+    m_xdgSurface->setSizeHints();
+
     m_applied = m_pending;
     qCDebug(lcQpaWayland) << "Applied pending xdg_toplevel configure event:" << m_applied.size << m_applied.states;
 }
@@ -339,6 +344,31 @@ bool QWaylandXdgSurface::wantsDecorations() const
     return m_toplevel && m_toplevel->wantsDecorations();
 }
 
+void QWaylandXdgSurface::propagateSizeHints()
+{
+    setSizeHints();
+
+    if (m_toplevel && m_window)
+        m_window->commit();
+}
+
+void QWaylandXdgSurface::setSizeHints()
+{
+    if (m_toplevel && m_window) {
+        const int minWidth = qMax(0, m_window->windowMinimumSize().width());
+        const int minHeight = qMax(0, m_window->windowMinimumSize().height());
+        m_toplevel->set_min_size(minWidth, minHeight);
+
+        int maxWidth = qMax(0, m_window->windowMaximumSize().width());
+        if (maxWidth == QWINDOWSIZE_MAX)
+            maxWidth = 0;
+        int maxHeight = qMax(0, m_window->windowMaximumSize().height());
+        if (maxHeight == QWINDOWSIZE_MAX)
+            maxHeight = 0;
+        m_toplevel->set_max_size(maxWidth, maxHeight);
+    }
+}
+
 void QWaylandXdgSurface::requestWindowStates(Qt::WindowStates states)
 {
     if (m_toplevel)

src/plugins/platforms/wayland/plugins/shellintegration/xdg-shell/qwaylandxdgshell_p.h

@@ -92,6 +92,9 @@ public:
     bool handlesActiveState() const { return m_toplevel; }
     void applyConfigure() override;
     bool wantsDecorations() const override;
+    void propagateSizeHints() override;
+
+    void setSizeHints();
 
 protected:
     void requestWindowStates(Qt::WindowStates states) override;

src/plugins/platforms/wayland/qwaylandshellsurface_p.h

@@ -97,6 +97,8 @@ public:
     virtual void requestWindowStates(Qt::WindowStates states) {Q_UNUSED(states);}
     virtual bool wantsDecorations() const { return false; }
 
+    virtual void propagateSizeHints() {}
+
 private:
     QWaylandWindow *m_window = nullptr;
     friend class QWaylandWindow;

src/plugins/platforms/wayland/qwaylandwindow.cpp

@@ -605,6 +605,11 @@ void QWaylandWindow::commit(QWaylandBuffer *buffer, const QRegion &damage)
     wl_surface::commit();
 }
 
+void QWaylandWindow::commit()
+{
+    wl_surface::commit();
+}
+
 const wl_callback_listener QWaylandWindow::callbackListener = {
     QWaylandWindow::frameCallback
 };
@@ -1118,6 +1123,12 @@ void QWaylandWindow::addAttachOffset(const QPoint point)
     mOffset += point;
 }
 
+void QWaylandWindow::propagateSizeHints()
+{
+    if (mShellSurface)
+        mShellSurface->propagateSizeHints();
+}
+
 bool QtWaylandClient::QWaylandWindow::startSystemMove(const QPoint &pos)
 {
     Q_UNUSED(pos);

src/plugins/platforms/wayland/qwaylandwindow_p.h

@@ -120,6 +120,8 @@ public:
     void handleExpose(const QRegion &region);
     void commit(QWaylandBuffer *buffer, const QRegion &damage);
 
+    void commit();
+
     void waitForFrameSync();
 
     QMargins frameMargins() const override;
@@ -186,7 +188,7 @@ public:
     QWaylandShmBackingStore *backingStore() const { return mBackingStore; }
 
     bool setKeyboardGrabEnabled(bool) override { return false; }
-    void propagateSizeHints() override { }
+    void propagateSizeHints() override;
     void addAttachOffset(const QPoint point);
 
     bool startSystemMove(const QPoint &pos) override;