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| |
| #include <qqmlextensionplugin.h> |
| #include <qqmlengine.h> |
| #include <sharedimageprovider.h> |
| |
| |
| /*! |
| \qmlmodule Qt.labs.sharedimage 1 |
| \title Qt Quick Shared Image Provider |
| \ingroup qmlmodules |
| \brief Adds an image provider which utilizes shared CPU memory |
| |
| \section2 Summary |
| |
| This module provides functionality to save memory in use cases where |
| several Qt Quick applications use the same local image files. It does this |
| by placing the decoded QImage data in shared system memory, making it |
| accessible to all the processes (see QSharedMemory). |
| |
| This module only shares CPU memory. It does not provide sharing of GPU |
| memory or textures. |
| |
| \section2 Usage |
| |
| To use this module, import it like this: |
| \code |
| import Qt.labs.sharedimage 1.0 |
| \endcode |
| |
| The sharing functionality is provided through a QQuickImageProvider. Use |
| the "image:" scheme for the URL source of the image, followed by the |
| identifier \e shared, followed by the image file path. For example: |
| |
| \code |
| Image { source: "image://shared/usr/share/wallpapers/mybackground.jpg" } |
| \endcode |
| |
| This will look for the file \e /usr/share/wallpapers/mybackground.jpg. |
| The first process that does this will read the image file |
| using normal Qt image loading. The decoded image data will then be placed |
| in shared memory, using the full file path as key. Later processes |
| requesting the same image will discover that the data is already available |
| in shared memory. They will then use that instead of loading the image file |
| again. |
| |
| The shared image data will be kept available until the last process has deleted |
| its last reference to the shared image, at which point it is automatically released. |
| |
| If system memory sharing is not available, the shared image provider falls |
| back to normal, unshared image loading. |
| |
| The file path must be absolute. To use a relative path, make it absolute |
| using \e Qt.resolvedUrl() and replace the URL scheme. For example: |
| |
| \code |
| ... |
| property string imagePrefix: Qt.resolvedUrl("../myimages/").replace("file://", "image://shared/") |
| Image { source: imagePrefix + "myimage.png" } |
| \endcode |
| |
| The shared image module does not provide any directly usable QML types. |
| */ |
| |
| extern void qml_register_types_Qt_labs_sharedimage(); |
| |
| QT_BEGIN_NAMESPACE |
| |
| class QtQuickSharedImagePlugin : public QQmlEngineExtensionPlugin |
| { |
| Q_OBJECT |
| Q_PLUGIN_METADATA(IID QQmlEngineExtensionInterface_iid) |
| public: |
| QtQuickSharedImagePlugin(QObject *parent = nullptr) : QQmlEngineExtensionPlugin(parent) |
| { |
| volatile auto registration = &qml_register_types_Qt_labs_sharedimage; |
| Q_UNUSED(registration); |
| } |
| |
| void initializeEngine(QQmlEngine *engine, const char *uri) override |
| { |
| Q_UNUSED(uri); |
| engine->addImageProvider("shared", new SharedImageProvider); |
| } |
| }; |
| |
| QT_END_NAMESPACE |
| |
| #include "plugin.moc" |