[wayland] Shadow gains support for a Wayland protocol

For Wayland clients we now are able to get shadows.

Internally this reuses large parts of the X11 implementation. This
could be improved to make the Scene's better aware of the Wayland
shadow, so that less memory is needed.

shadow.cpp

@@ -24,10 +24,19 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "composite.h"
 #include "effects.h"
 #include "toplevel.h"
+#if HAVE_WAYLAND
+#include "wayland_server.h"
+#endif
 
 #include <KDecoration2/Decoration>
 #include <KDecoration2/DecorationShadow>
 
+#if HAVE_WAYLAND
+#include <KWayland/Server/buffer_interface.h>
+#include <KWayland/Server/shadow_interface.h>
+#include <KWayland/Server/surface_interface.h>
+#endif
+
 namespace KWin
 {
 
@@ -49,6 +58,11 @@ Shadow *Shadow::createShadow(Toplevel *toplevel)
         return NULL;
     }
     Shadow *shadow = crateShadowFromDecoration(toplevel);
+#if HAVE_WAYLAND
+    if (!shadow && waylandServer()) {
+        shadow = createShadowFromWayland(toplevel);
+    }
+#endif
     if (!shadow) {
         shadow = createShadowFromX11(toplevel);
     }
@@ -98,6 +112,26 @@ Shadow *Shadow::crateShadowFromDecoration(Toplevel *toplevel)
     return shadow;
 }
 
+Shadow *Shadow::createShadowFromWayland(Toplevel *toplevel)
+{
+#if HAVE_WAYLAND
+    auto surface = toplevel->surface();
+    if (!surface) {
+        return nullptr;
+    }
+    const auto s = surface->shadow();
+    if (!s) {
+        return nullptr;
+    }
+    Shadow *shadow = Compositor::self()->scene()->createShadow(toplevel);
+    if (!shadow->init(s)) {
+        delete shadow;
+        return nullptr;
+    }
+    return shadow;
+#endif
+}
+
 QVector< uint32_t > Shadow::readX11ShadowProperty(xcb_window_t id)
 {
     QVector<uint32_t> ret;
@@ -187,6 +221,36 @@ bool Shadow::init(KDecoration2::Decoration *decoration)
     return true;
 }
 
+bool Shadow::init(const QPointer< KWayland::Server::ShadowInterface > &shadow)
+{
+#if HAVE_WAYLAND
+    if (!shadow) {
+        return false;
+    }
+
+    m_shadowElements[ShadowElementTop] = shadow->top() ? QPixmap::fromImage(shadow->top()->data().copy()) : QPixmap();
+    m_shadowElements[ShadowElementTopRight] = shadow->topRight() ? QPixmap::fromImage(shadow->topRight()->data().copy()) : QPixmap();
+    m_shadowElements[ShadowElementRight] = shadow->right() ? QPixmap::fromImage(shadow->right()->data().copy()) : QPixmap();
+    m_shadowElements[ShadowElementBottomRight] = shadow->bottomRight() ? QPixmap::fromImage(shadow->bottomRight()->data().copy()) : QPixmap();
+    m_shadowElements[ShadowElementBottom] = shadow->bottom() ? QPixmap::fromImage(shadow->bottom()->data().copy()) : QPixmap();
+    m_shadowElements[ShadowElementBottomLeft] = shadow->bottomLeft() ? QPixmap::fromImage(shadow->bottomLeft()->data().copy()) : QPixmap();
+    m_shadowElements[ShadowElementLeft] = shadow->left() ? QPixmap::fromImage(shadow->left()->data().copy()) : QPixmap();
+    m_shadowElements[ShadowElementTopLeft] = shadow->topLeft() ? QPixmap::fromImage(shadow->topLeft()->data().copy()) : QPixmap();
+
+    const QMarginsF &p = shadow->offset();
+    m_topOffset    = p.top();
+    m_rightOffset  = p.right();
+    m_bottomOffset = p.bottom();
+    m_leftOffset   = p.left();
+    updateShadowRegion();
+    if (!prepareBackend()) {
+        return false;
+    }
+    buildQuads();
+    return true;
+#endif
+}
+
 void Shadow::updateShadowRegion()
 {
     const QRect top(0, - m_topOffset, m_topLevel->width(), m_topOffset);
@@ -299,6 +363,20 @@ bool Shadow::updateShadow()
         clear();
         return false;
     }
+#if HAVE_WAYLAND
+    if (waylandServer()) {
+        if (m_topLevel && m_topLevel->surface()) {
+            if (const auto &s = m_topLevel->surface()->shadow()) {
+                if (init(s)) {
+                    if (m_topLevel->effectWindow()) {
+                        m_topLevel->effectWindow()->buildQuads(true);
+                    }
+                    return true;
+                }
+            }
+        }
+    }
+#endif
     auto data = Shadow::readX11ShadowProperty(m_topLevel->window());
     if (data.isEmpty()) {
         clear();

shadow.h

@@ -31,6 +31,14 @@ class Decoration;
 class DecorationShadow;
 }
 
+namespace KWayland
+{
+namespace Server
+{
+class ShadowInterface;
+}
+}
+
 namespace KWin {
 
 class Toplevel;
@@ -160,9 +168,11 @@ protected:
 private:
     static Shadow *createShadowFromX11(Toplevel *toplevel);
     static Shadow *crateShadowFromDecoration(Toplevel *toplevel);
+    static Shadow *createShadowFromWayland(Toplevel *toplevel);
     static QVector<uint32_t> readX11ShadowProperty(xcb_window_t id);
     bool init(const QVector<uint32_t> &data);
     bool init(KDecoration2::Decoration *decoration);
+    bool init(const QPointer<KWayland::Server::ShadowInterface> &shadow);
     Toplevel *m_topLevel;
     // shadow pixmaps
     QPixmap m_shadowElements[ShadowElementsCount];

shell_client.cpp

@@ -31,6 +31,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <KWayland/Server/surface_interface.h>
 #include <KWayland/Server/buffer_interface.h>
 #include <KWayland/Server/plasmashell_interface.h>
+#include <KWayland/Server/shadow_interface.h>
 #include <KWayland/Server/qtsurfaceextension_interface.h>
 
 #include <KDesktopFile>
@@ -88,6 +89,10 @@ ShellClient::ShellClient(ShellSurfaceInterface *surface)
     );
     connect(surface, &ShellSurfaceInterface::windowClassChanged, this, &ShellClient::updateIcon);
     updateIcon();
+
+    // setup shadow integration
+    getShadow();
+    connect(surface->surface(), &SurfaceInterface::shadowChanged, this, &Toplevel::getShadow);
 }
 
 ShellClient::~ShellClient() = default;

wayland_server.cpp

@@ -39,6 +39,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <KWayland/Server/plasmawindowmanagement_interface.h>
 #include <KWayland/Server/qtsurfaceextension_interface.h>
 #include <KWayland/Server/seat_interface.h>
+#include <KWayland/Server/shadow_interface.h>
 #include <KWayland/Server/shell_interface.h>
 
 // Qt
@@ -186,6 +187,8 @@ void WaylandServer::init(const QByteArray &socketName)
             workspace()->setShowingDesktop(set);
         }
     );
+    auto shadowManager = m_display->createShadowManager(m_display);
+    shadowManager->create();
 }
 
 void WaylandServer::initWorkspace()