Introduce krfb-virtualmonitor

It implements a KWin protocol that is oriented towards serving a virtual
display specifically.
It requests KWin a stream that will act as a monitor that we can feed
into remote clients.

framebuffers/pipewire/CMakeLists.txt

@@ -5,8 +5,14 @@ include_directories (${CMAKE_CURRENT_SOURCE_DIR}
 set (krfb_framebuffer_pw_SRCS
      pw_framebuffer.cpp
      pw_framebufferplugin.cpp
+
+     screencasting.cpp
 )
 
+ecm_add_qtwayland_client_protocol(krfb_framebuffer_pw_SRCS
+    PROTOCOL ${PLASMA_WAYLAND_PROTOCOLS_DIR}/screencast.xml
+    BASENAME zkde-screencast-unstable-v1
+)
 
 ecm_qt_declare_logging_category(krfb_framebuffer_pw_SRCS
     HEADER krfb_fb_pipewire_debug.h
@@ -39,6 +45,8 @@ target_link_libraries(krfb_framebuffer_pw
                       Qt5::Gui
                       Qt5::DBus
                       KF5::CoreAddons
+                      KF5::WaylandClient
+                      Wayland::Client
                       krfbprivate
                       PkgConfig::PipeWire
 )

framebuffers/pipewire/pw_framebuffer.cpp

@@ -22,6 +22,9 @@
 #include <QDebug>
 #include <QRandomGenerator>
 
+#include <KWayland/Client/connection_thread.h>
+#include <KWayland/Client/registry.h>
+
 // pipewire
 #include <sys/ioctl.h>
 
@@ -38,6 +41,7 @@
 #include "xdp_dbus_screencast_interface.h"
 #include "xdp_dbus_remotedesktop_interface.h"
 #include "krfb_fb_pipewire_debug.h"
+#include "screencasting.h"
 
 #if HAVE_DMA_BUF
 #include <fcntl.h>
@@ -904,10 +908,6 @@ PWFrameBuffer::PWFrameBuffer(WId winid, QObject *parent)
     : FrameBuffer (winid, parent),
       d(new Private(this))
 {
-    // D-Bus is most important in init chain, no toys for us if something is wrong with XDP
-    // PipeWire connectivity is initialized after D-Bus session is started
-    d->initDbus();
-
     fb = nullptr;
 }
 
@@ -917,6 +917,38 @@ PWFrameBuffer::~PWFrameBuffer()
     fb = nullptr;
 }
 
+void PWFrameBuffer::initDBus()
+{
+    d->initDbus();
+}
+
+void PWFrameBuffer::startVirtualMonitor(const QString& name, const QSize& resolution, qreal dpr)
+{
+    d->videoSize = resolution * dpr;
+    using namespace KWayland::Client;
+    auto connection = ConnectionThread::fromApplication(this);
+    if (!connection) {
+        qWarning() << "Failed getting Wayland connection from QPA";
+        QCoreApplication::exit(1);
+        return;
+    }
+
+    auto registry = new Registry(this);
+    connect(registry, &KWayland::Client::Registry::interfaceAnnounced, this, [this, registry, name, dpr, resolution] (const QByteArray &interfaceName, quint32 wlname, quint32 version) {
+        if (interfaceName != "zkde_screencast_unstable_v1")
+            return;
+
+        auto screencasting = new Screencasting(registry, wlname, version, this);
+        auto r = screencasting->createVirtualMonitorStream(name, resolution, dpr, Screencasting::Metadata);
+        connect(r, &ScreencastingStream::created, this, [this] (quint32 nodeId) {
+            d->pwStreamNodeId = nodeId;
+            d->initPw();
+        });
+    });
+    registry->create(connection);
+    registry->setup();
+}
+
 int PWFrameBuffer::depth()
 {
     return 32;

framebuffers/pipewire/pw_framebuffer.h

@@ -33,6 +33,9 @@ public:
     PWFrameBuffer(WId winid, QObject *parent = nullptr);
     virtual ~PWFrameBuffer() override;
 
+    void initDBus();
+    void startVirtualMonitor(const QString &name, const QSize &resolution, qreal dpr);
+
     int  depth() override;
     int  height() override;
     int  width() override;

framebuffers/pipewire/pw_framebufferplugin.cpp

@@ -41,6 +41,13 @@ FrameBuffer *PWFrameBufferPlugin::frameBuffer(WId id, const QVariantMap &args)
     //NOTE WId is irrelevant in Wayland
 
     auto pwfb = new PWFrameBuffer(id);
+    if (args.contains(QLatin1String("name"))) {
+        pwfb->startVirtualMonitor(args[QStringLiteral("name")].toString(), args[QStringLiteral("resolution")].toSize(), args[QStringLiteral("scale")].toDouble());
+    } else {
+        // D-Bus is most important in XDG-Desktop-Portals init chain, no toys for us if something is wrong with XDP
+        // PipeWire connectivity is initialized after D-Bus session is started
+        pwfb->initDBus();
+    }
 
     // sanity check for dbus/wayland/pipewire errors
     if (!pwfb->isValid()) {

framebuffers/pipewire/screencasting.cpp

@@ -0,0 +1,136 @@
+/*
+    SPDX-FileCopyrightText: 2020 Aleix Pol Gonzalez <aleixpol@kde.org>
+
+    SPDX-License-Identifier: LGPL-2.1-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
+*/
+
+#include "screencasting.h"
+#include "qwayland-zkde-screencast-unstable-v1.h"
+#include <KWayland/Client/output.h>
+#include <KWayland/Client/plasmawindowmanagement.h>
+#include <KWayland/Client/registry.h>
+#include <QDebug>
+#include <QRect>
+
+using namespace KWayland::Client;
+
+class ScreencastingStreamPrivate : public QtWayland::zkde_screencast_stream_unstable_v1
+{
+public:
+    ScreencastingStreamPrivate(ScreencastingStream *q)
+        : q(q)
+    {
+    }
+    ~ScreencastingStreamPrivate()
+    {
+        close();
+        q->deleteLater();
+    }
+
+    void zkde_screencast_stream_unstable_v1_created(uint32_t node) override
+    {
+        m_nodeId = node;
+        Q_EMIT q->created(node);
+    }
+
+    void zkde_screencast_stream_unstable_v1_closed() override
+    {
+        Q_EMIT q->closed();
+    }
+
+    void zkde_screencast_stream_unstable_v1_failed(const QString &error) override
+    {
+        Q_EMIT q->failed(error);
+    }
+
+    uint m_nodeId = 0;
+    QPointer<ScreencastingStream> q;
+};
+
+ScreencastingStream::ScreencastingStream(QObject *parent)
+    : QObject(parent)
+    , d(new ScreencastingStreamPrivate(this))
+{
+}
+
+ScreencastingStream::~ScreencastingStream() = default;
+
+quint32 ScreencastingStream::nodeId() const
+{
+    return d->m_nodeId;
+}
+
+class ScreencastingPrivate : public QtWayland::zkde_screencast_unstable_v1
+{
+public:
+    ScreencastingPrivate(Registry *registry, int id, int version, Screencasting *q)
+        : QtWayland::zkde_screencast_unstable_v1(*registry, id, version)
+        , q(q)
+    {
+    }
+
+    ScreencastingPrivate(::zkde_screencast_unstable_v1 *screencasting, Screencasting *q)
+        : QtWayland::zkde_screencast_unstable_v1(screencasting)
+        , q(q)
+    {
+    }
+
+    ~ScreencastingPrivate()
+    {
+        destroy();
+    }
+
+    Screencasting *const q;
+};
+
+Screencasting::Screencasting(QObject *parent)
+    : QObject(parent)
+{
+}
+
+Screencasting::Screencasting(Registry *registry, int id, int version, QObject *parent)
+    : QObject(parent)
+    , d(new ScreencastingPrivate(registry, id, version, this))
+{
+}
+
+Screencasting::~Screencasting() = default;
+
+ScreencastingStream *Screencasting::createOutputStream(Output *output, CursorMode mode)
+{
+    auto stream = new ScreencastingStream(this);
+    stream->setObjectName(output->model());
+    stream->d->init(d->stream_output(*output, mode));
+    return stream;
+}
+
+ScreencastingStream *Screencasting::createWindowStream(PlasmaWindow *window, CursorMode mode)
+{
+    auto stream = createWindowStream(QString::fromUtf8(window->uuid()), mode);
+    stream->setObjectName(window->appId());
+    return stream;
+}
+
+ScreencastingStream *Screencasting::createWindowStream(const QString &uuid, CursorMode mode)
+{
+    auto stream = new ScreencastingStream(this);
+    stream->d->init(d->stream_window(uuid, mode));
+    return stream;
+}
+
+ScreencastingStream * Screencasting::createVirtualMonitorStream(const QString& name, const QSize& resolution, qreal dpr, Screencasting::CursorMode mode)
+{
+    auto stream = new ScreencastingStream(this);
+    stream->d->init(d->stream_virtual_output(name, resolution.width(), resolution.height(), wl_fixed_from_double(dpr), mode));
+    return stream;
+}
+
+void Screencasting::setup(::zkde_screencast_unstable_v1 *screencasting)
+{
+    d.reset(new ScreencastingPrivate(screencasting, this));
+}
+
+void Screencasting::destroy()
+{
+    d.reset(nullptr);
+}

framebuffers/pipewire/screencasting.h

@@ -0,0 +1,78 @@
+/*
+    SPDX-FileCopyrightText: 2020 Aleix Pol Gonzalez <aleixpol@kde.org>
+
+    SPDX-License-Identifier: LGPL-2.1-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
+*/
+
+#pragma once
+
+#include <QObject>
+#include <QSharedPointer>
+#include <QVector>
+#include <optional>
+
+struct zkde_screencast_unstable_v1;
+
+namespace KWayland
+{
+namespace Client
+{
+class PlasmaWindow;
+class Registry;
+class Output;
+}
+}
+
+class ScreencastingPrivate;
+class ScreencastingSourcePrivate;
+class ScreencastingStreamPrivate;
+class ScreencastingStream : public QObject
+{
+    Q_OBJECT
+public:
+    ScreencastingStream(QObject *parent);
+    ~ScreencastingStream() override;
+
+    quint32 nodeId() const;
+
+Q_SIGNALS:
+    void created(quint32 nodeid);
+    void failed(const QString &error);
+    void closed();
+
+private:
+    friend class Screencasting;
+    QScopedPointer<ScreencastingStreamPrivate> d;
+};
+
+class Screencasting : public QObject
+{
+    Q_OBJECT
+public:
+    explicit Screencasting(QObject *parent = nullptr);
+    explicit Screencasting(KWayland::Client::Registry *registry, int id, int version, QObject *parent = nullptr);
+    ~Screencasting() override;
+
+    enum CursorMode {
+        Hidden = 1,
+        Embedded = 2,
+        Metadata = 4,
+    };
+    Q_ENUM(CursorMode);
+
+    ScreencastingStream *createOutputStream(KWayland::Client::Output *output, CursorMode mode);
+    ScreencastingStream *createWindowStream(KWayland::Client::PlasmaWindow *window, CursorMode mode);
+    ScreencastingStream *createWindowStream(const QString &uuid, CursorMode mode);
+    ScreencastingStream *createVirtualMonitorStream(const QString &name, const QSize &resolution, qreal dpr, CursorMode mode);
+
+    void setup(zkde_screencast_unstable_v1 *screencasting);
+    void destroy();
+
+Q_SIGNALS:
+    void initialized();
+    void removed();
+    void sourcesChanged();
+
+private:
+    QScopedPointer<ScreencastingPrivate> d;
+};