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39 | |
40 | #include <qqmlextensionplugin.h> |
41 | #include <qqmlengine.h> |
42 | #include <sharedimageprovider.h> |
43 | |
44 | |
45 | /*! |
46 | \qmlmodule Qt.labs.sharedimage 1 |
47 | \title Qt Quick Shared Image Provider |
48 | \ingroup qmlmodules |
49 | \brief Adds an image provider which utilizes shared CPU memory |
50 | |
51 | \section2 Summary |
52 | |
53 | This module provides functionality to save memory in use cases where |
54 | several Qt Quick applications use the same local image files. It does this |
55 | by placing the decoded QImage data in shared system memory, making it |
56 | accessible to all the processes (see QSharedMemory). |
57 | |
58 | This module only shares CPU memory. It does not provide sharing of GPU |
59 | memory or textures. |
60 | |
61 | \section2 Usage |
62 | |
63 | To use this module, import it like this: |
64 | \code |
65 | import Qt.labs.sharedimage 1.0 |
66 | \endcode |
67 | |
68 | The sharing functionality is provided through a QQuickImageProvider. Use |
69 | the "image:" scheme for the URL source of the image, followed by the |
70 | identifier \e shared, followed by the image file path. For example: |
71 | |
72 | \code |
73 | Image { source: "image://shared/usr/share/wallpapers/mybackground.jpg" } |
74 | \endcode |
75 | |
76 | This will look for the file \e /usr/share/wallpapers/mybackground.jpg. |
77 | The first process that does this will read the image file |
78 | using normal Qt image loading. The decoded image data will then be placed |
79 | in shared memory, using the full file path as key. Later processes |
80 | requesting the same image will discover that the data is already available |
81 | in shared memory. They will then use that instead of loading the image file |
82 | again. |
83 | |
84 | The shared image data will be kept available until the last process has deleted |
85 | its last reference to the shared image, at which point it is automatically released. |
86 | |
87 | If system memory sharing is not available, the shared image provider falls |
88 | back to normal, unshared image loading. |
89 | |
90 | The file path must be absolute. To use a relative path, make it absolute |
91 | using \e Qt.resolvedUrl() and replace the URL scheme. For example: |
92 | |
93 | \code |
94 | ... |
95 | property string imagePrefix: Qt.resolvedUrl("../myimages/").replace("file://", "image://shared/") |
96 | Image { source: imagePrefix + "myimage.png" } |
97 | \endcode |
98 | |
99 | The shared image module does not provide any directly usable QML types. |
100 | */ |
101 | |
102 | extern void qml_register_types_Qt_labs_sharedimage(); |
103 | GHS_KEEP_REFERENCE(qml_register_types_Qt_labs_sharedimage); |
104 | |
105 | QT_BEGIN_NAMESPACE |
106 | |
107 | class QtQuickSharedImagePlugin : public QQmlEngineExtensionPlugin |
108 | { |
109 | Q_OBJECT |
110 | Q_PLUGIN_METADATA(IID QQmlEngineExtensionInterface_iid) |
111 | public: |
112 | QtQuickSharedImagePlugin(QObject *parent = nullptr) : QQmlEngineExtensionPlugin(parent) |
113 | { |
114 | volatile auto registration = &qml_register_types_Qt_labs_sharedimage; |
115 | Q_UNUSED(registration); |
116 | } |
117 | |
118 | void initializeEngine(QQmlEngine *engine, const char *uri) override |
119 | { |
120 | Q_UNUSED(uri); |
121 | engine->addImageProvider(id: "shared" , new SharedImageProvider); |
122 | } |
123 | }; |
124 | |
125 | QT_END_NAMESPACE |
126 | |
127 | #include "plugin.moc" |
128 | |