compositor.h

/*
    SPDX-FileCopyrightText: 2014 Martin Gräßlin <[email protected]>

    SPDX-License-Identifier: LGPL-2.1-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
*/
#ifndef WAYLAND_COMPOSITOR_H
#define WAYLAND_COMPOSITOR_H

#include <QObject>

#include <memory>

#include <KWayland/Client/kwaylandclient_export.h>

struct wl_compositor;

namespace KWayland
{
namespace Client
{
class EventQueue;
class Region;
class Surface;

/**
 * @short Wrapper for the wl_compositor interface.
 *
 * This class provides a convenient wrapper for the wl_compositor interface.
 * It's main purpose is to create a Surface.
 *
 * To use this class one needs to interact with the Registry. There are two
 * possible ways to create the Compositor interface:
 * @code
 * Compositor *c = registry->createCompositor(name, version);
 * @endcode
 *
 * This creates the Compositor and sets it up directly. As an alternative this
 * can also be done in a more low level way:
 * @code
 * Compositor *c = new Compositor;
 * c->setup(registry->bindCompositor(name, version));
 * @endcode
 *
 * The Compositor can be used as a drop-in replacement for any wl_compositor
 * pointer as it provides matching cast operators.
 *
 * @see Registry
 **/
class KWAYLANDCLIENT_EXPORT Compositor : public QObject
{
    Q_OBJECT
public:
    /**
     * Creates a new Compositor.
     * Note: after constructing the Compositor it is not yet valid and one needs
     * to call setup. In order to get a ready to use Compositor prefer using
     * Registry::createCompositor.
     **/
    explicit Compositor(QObject *parent = nullptr);
    virtual ~Compositor();

    /**
     * Creates a Compositor for the used QGuiApplication.
     * This is an integration feature for QtWayland. On non-wayland platforms this method returns
     * @c nullptr.
     *
     * The returned Compositor will be fully setup, which means it manages a wl_compositor.
     * When the created Compositor gets destroyed the managed wl_compositor won't be disconnected
     * as that's managed by Qt.
     * @since 5.4
     **/
    static Compositor *fromApplication(QObject *parent = nullptr);

    /**
     * @returns @c true if managing a wl_compositor.
     **/
    bool isValid() const;
    /**
     * Setup this Compositor to manage the @p compositor.
     * When using Registry::createCompositor there is no need to call this
     * method.
     **/
    void setup(wl_compositor *compositor);
    /**
     * Releases the wl_compositor interface.
     * After the interface has been released the Compositor instance is no
     * longer valid and can be setup with another wl_compositor interface.
     **/
    void release();
    /**
     * Destroys the data held by this Compositor.
     * This method is supposed to be used when the connection to the Wayland
     * server goes away. If the connection is not valid anymore, it's not
     * possible to call release anymore as that calls into the Wayland
     * connection and the call would fail. This method cleans up the data, so
     * that the instance can be deleted or set up to a new wl_compositor interface
     * once there is a new connection available.
     *
     * It is suggested to connect this method to ConnectionThread::connectionDied:
     * @code
     * connect(connection, &ConnectionThread::connectionDied, compositor, &Compositor::destroy);
     * @endcode
     *
     * @see release
     **/
    void destroy();

    /**
     * Sets the @p queue to use for creating a Surface.
     **/
    void setEventQueue(EventQueue *queue);
    /**
     * @returns The event queue to use for creating a Surface.
     **/
    EventQueue *eventQueue();

    /**
     * Creates and setup a new Surface with @p parent.
     * @param parent The parent to pass to the Surface.
     * @returns The new created Surface
     **/
    Surface *createSurface(QObject *parent = nullptr);

    /**
     * Creates and setup a new Region with @p parent.
     * @param parent The parent to pass to the Region.
     * @returns The new created Region
     **/
    Region *createRegion(QObject *parent = nullptr);
    /**
     * Creates and setup a new Region with @p parent.
     *
     * The @p region is directly added to the created Region.
     * @param parent The parent to pass to the Region.
     * @param region The region to install on the newly created Region
     * @returns The new created Region
     **/
    Region *createRegion(const QRegion &region, QObject *parent);
    /**
     * Creates and setup a new Region with @p region installed.
     *
     * This overloaded convenience method is intended to be used in the
     * case that the Region is only needed to setup e.g. input region on
     * a Surface and is afterwards no longer needed. Setting the input
     * region has copy semantics and the Region can be destroyed afterwards.
     * This allows to simplify setting the input region to:
     *
     * @code
     * Surface *s = compositor->createSurface();
     * s->setInputRegion(compositor->createRegion(QRegion(0, 0, 10, 10)).get());
     * @endcode
     *
     * @param region The region to install on the newly created Region
     * @returns The new created Region
     **/
    std::unique_ptr<Region> createRegion(const QRegion &region);

    operator wl_compositor *();
    operator wl_compositor *() const;

Q_SIGNALS:
    /**
     * The corresponding global for this interface on the Registry got removed.
     *
     * This signal gets only emitted if the Compositor got created by
     * Registry::createCompositor
     *
     * @since 5.5
     **/
    void removed();

private:
    class Private;
    QScopedPointer<Private> d;
};

}
}

#endif