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Diffstat (limited to 'examples/wayland/minimal-qml/doc/src')
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diff --git a/examples/wayland/minimal-qml/doc/src/minimal-qml.qdoc b/examples/wayland/minimal-qml/doc/src/minimal-qml.qdoc index 5a435f3fc..2150fece3 100644 --- a/examples/wayland/minimal-qml/doc/src/minimal-qml.qdoc +++ b/examples/wayland/minimal-qml/doc/src/minimal-qml.qdoc @@ -1,36 +1,93 @@ -/**************************************************************************** -** -** Copyright (C) 2017 The Qt Company Ltd. -** Contact: https://www.qt.io/licensing/ -** -** This file is part of the documentation of the Qt Toolkit. -** -** $QT_BEGIN_LICENSE:FDL$ -** Commercial License Usage -** Licensees holding valid commercial Qt licenses may use this file in -** accordance with the commercial license agreement provided with the -** Software or, alternatively, in accordance with the terms contained in -** a written agreement between you and The Qt Company. For licensing terms -** and conditions see https://www.qt.io/terms-conditions. For further -** information use the contact form at https://www.qt.io/contact-us. -** -** GNU Free Documentation License Usage -** Alternatively, this file may be used under the terms of the GNU Free -** Documentation License version 1.3 as published by the Free Software -** Foundation and appearing in the file included in the packaging of -** this file. Please review the following information to ensure -** the GNU Free Documentation License version 1.3 requirements -** will be met: https://www.gnu.org/licenses/fdl-1.3.html. -** $QT_END_LICENSE$ -** -****************************************************************************/ +// Copyright (C) 2021 The Qt Company Ltd. +// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only /*! - * \title Qt Wayland Compositor Examples - Minimal QML + * \title Minimal QML * \example minimal-qml + * \examplecategory {Embedded} * \brief Minimal QML is a simple example that demonstrates how to write a Wayland compositor in QML. * \ingroup qtwaylandcompositor-examples * * Minimal QML is a desktop-style Wayland compositor example implementing a - * complete Qt Wayland Compositor with as little code as possible. + * complete Qt Wayland Compositor with as little code as possible. The compositor is implemented + * with Qt Quick and QML. + * + * \image minimal-qml.png + * + * \section1 The WaylandCompositor Object + * + * The top-level item of the compositor is a \l WaylandCompositor. This represents the Wayland + * server itself and manages the connections to clients as they come in. + * + * \snippet minimal-qml/main.qml compositor + * + * By default, the server supports the core Wayland protocol for communicating with clients. + * Usually, though, you will also want to support one or more extensions to the protocol. This + * gives the client more tools to influence its role in the windowing system. + * + * Qt supports several standard and common extensions. In addition, it is easy to create and support + * custom extensions, as long as support can be added in both the client and server code. + * + * \section1 Shell Extensions + * + * Typically, a compositor will support at least one + * \l{Shell Extensions - Qt Wayland Compositor}{shell extension}. Extensions are added to + * the compositor by instantiating them as direct children of the \l WaylandCompositor object. They + * will automatically be added to its \c extensions property and broadcast to clients when they + * connect. + * + * \snippet minimal-qml/main.qml shells + * + * The \e{Minimal QML} example supports three different shells: \l{WlShell}, \l{XdgShell} and + * \l{IviApplication}. + * + * A client can connect to either of these and it will be used as a channel for communicating + * about certain things between the client and compositor, such as creating new windows, + * negotiating size, and so on. + * + * When a client creates a new surface, its active extension will receive a signal of this. The + * signal contains a \l ShellSurface argument. Depending on which extension received the signal, + * this argument will be of a subclass of \l{ShellSurface}: \l{WlShellSurface}, \l{XdgSurface} + * or \l{IviSurface} respectively. + * + * The \l ShellSurface can be used to access features of the shell extension for the specific + * surface. In the \e{Minimal QML} example, we simply want to add the client to our scene. To + * record existence of the new window, we add it to a simple \l ListModel for safe-keeping. + * + * \snippet minimal-qml/main.qml model + * + * \section1 Creating the Scene + * + * Most of the necessary compositor code is already ready. The final step is to make sure + * applications are actually visible on the screen. + * + * For all compositors, we have to define at least one output. This is done by instantiating + * a \l WaylandOutput object as the direct child of the \l WaylandCompositor. If there is only + * a single output, this will represent the primary screen on the system. (You may also create + * multiple \l WaylandOutput objects to address multiple screens if they are available. See + * the \l{Multi Screen}{Multi Screen example} for more details + * about this.) + * + * \snippet minimal-qml/main.qml output + * + * Inside the \l{WaylandOutput}, we create a \l Window that serves as the container for + * our scene. In the example, we give this a size. The size used if the compositor is running as + * an application inside another windowing system which supports custom-sized windows. In a + * typical use case on an embedded device, where the compositor is the only display server running, + * it will probably be running on a full-screen platform plugin (such as \c{eglfs}) and the size + * set here will not matter. + * + * The final step is to create items for each of the \l ShellSurface objects that have been created. + * For this, we can use the \l ShellSurfaceItem class. + * + * \snippet minimal-qml/main.qml shell surface item + * + * We create a \l ShellSurfaceItem for each of the shell surfaces in our model, and assign them + * to the \c shellSurface property. In addition, we make sure the model is updated when the shell + * surface is destroyed. This can happen when a client manually closes a window, and if it exits + * or crashes. + * + * And this is all the code needed to create a functional Wayland compositor using Qt Quick and + * QML. For another example of a compositor written in QML but which has a few more features, take + * a look at the \l{Fancy Compositor}{Fancy Compositor example}. */ |