Class: QgsApplication¶
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class
qgis.core.QgsApplication¶ Bases:
PyQt5.QtWidgets.QApplicationExtends QApplication to provide access to QGIS specific resources such as theme paths, database paths etc.
This is a subclass of QApplication and should be instantiated in place of QApplication. Most methods are static in keeping with the design of QApplication.
This class hides platform-specific path information and provides a portable way of referencing specific files and directories. Ideally, hard-coded paths should appear only here and not in other modules so that platform-conditional code is minimized and paths are easier to change due to centralization.
Enums
Methods
Converts absolute path to path relative to target
Returns the action scope registry.
Returns the path to the currently active theme directory.
Gets application icon
Apply the skipped drivers list to gdal
Returns the application’s authentication manager instance
Returns the path to the authors file.
Returns path to the build output directory.
Returns path to the source directory.
Emits the signal to collect all the strings of .qgs to be included in ts file
Returns the application’s color scheme registry, used for managing color schemes.
Returns the path to the contributors file.
initialize qgis.db
Create the users theme folder
Custom expression variables for this application.
Returns the application’s data item provider registry, which keeps a list of data item providers that may add items to the browser tree.
Returns the path to default style (works as a starting point).
Returns the path to the default theme directory.
Returns the path to default themes folder from install (works as a starting point).
Returns the path to the developers map file.
Returns the path to the donors file.
Returns whether this machine uses big or little endian
Watch for QFileOpenEvent.
deletes provider registry and map layer registry
Gets the registry of available field formatters.
Helper to get a theme cursor.
Helper to get a theme icon.
Helper to get a theme icon as a pixmap.
Returns the application’s GPS connection registry, used for managing GPS connections.
Returns the path to the translation directory.
Returns path to the desired icon file.
Returns the path to the icons image directory.
Returns the application’s image cache, used for caching resampled versions of raster images.
loads providers
Returns the singleton instance of the QgsApplication.
Indicates whether running from build directory (not installed)
Returns the application’s layout item registry, used for layout item types.
Returns the paths to layout template directories.
Returns the path with utility executables (help viewer, crssync, …)
Returns the path containing qgis_core, qgis_gui, qgispython (and other) libraries
Returns the path to the licence file.
Returns the QGIS locale.
The maximum number of concurrent connections per connections pool.
Gets maximum concurrent thread count
Returns the application’s message log.
Returns the path to the metadata directory.
Returns the application’s network content registry used for fetching temporary files during QGIS session
Catch exceptions when sending event to receiver.
This string is used to represent the value NULL throughout QGIS.
Returns a string name of the operating system QGIS is running on.
Returns the application’s page size registry, used for managing layout page sizes.
Returns the application’s paint effect registry, used for managing paint effects.
Returns the common root path of all application data directories.
Returns the QGIS platform name, e.g., “desktop” or “server”.
Returns the application’s plugin layer registry, used for managing plugin layer types.
Returns the path to the application plugin directory.
Returns the path to the application prefix directory.
Returns the application’s processing registry, used for managing processing providers, algorithms, and various parameters and outputs.
Returns the application runtime profiler.
Returns registry of available project storage implementations.
Returns the path to the user authentication database file: qgis-auth.db.
Returns the path to the master qgis.db file.
Returns the path to the settings directory in user’s home dir
Returns the path to the user qgis.db file.
Returns the path where QML components are installed for QGIS Quick library.
Register OGR drivers ensuring this only happens once.
Converts path relative to target to an absolute path
Returns registry of available 3D renderers.
Returns the application’s renderer registry, used for managing vector layer renderers.
Returns a standard css style sheet for reports.
Calculate the application pkg path
Sets the GDAL_SKIP environment variable to exclude the specified driver and then calls GDALDriverManager.AutoSkipDrivers() to unregister it.
Returns the path to the server resources directory.
Alters authentication data base directory path - used by 3rd party apps
Set a single custom expression variable.
Custom expression variables for this application.
Alters default svg paths - used by 3rd party apps.
Sets the FileOpen event receiver
Set maximum concurrent thread count
copydoc nullRepresentation()
Alters pkg data path - used by 3rd party apps
Alters plugin path - used by 3rd party apps
Alters prefix path - used by 3rd party apps
Set the active theme to the specified theme.
Set translation
Set the current UI theme used to style the interface.
Returns the short name regular expression for line edit validator
Convenience function to get a summary of the paths used in this application instance useful for debugging mainly.*
Sets the GDAL_SKIP environment variable to include the specified driver and then calls GDALDriverManager.AutoSkipDrivers() to unregister it.
Returns the list of gdal drivers that should be skipped (based on GDAL_SKIP environment variable)
Returns the path to the splash screen image directory.
Returns the path to the sponsors file.
Returns the path to the srs.db file.
Returns the application’s SVG cache, used for caching SVG images and handling parameter replacement within SVG files.
Returns the paths to svg directories.
Returns the application’s symbol layer registry, used for managing symbol layers.
Returns the system environment variables passed to application.
Returns the application’s task manager, used for managing application wide background task handling.
Set the active theme to the specified theme.
Returns the path to the sponsors file.
All themes found in ~/.qgis3/themes folder.
Returns the user’s operating system login account full display name.
Returns the user’s operating system login account name.
Returns the path to user’s style.
Returns the path to user’s themes folder
Returns the application’s validity check registry, used for managing validity checks.
Signals
Emitted whenever a custom global variable changes.
copydoc nullRepresentation() [signal]
Emitted when project strings which require translation are being collected for inclusion in a .ts file.
Attributes
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CapturePoint= 4¶
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CrossHair= 3¶
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class
Cursor¶ Bases:
int
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Identify= 2¶
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NDR= 1¶
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QGIS_APPLICATION_NAME= 'QGIS3'¶
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QGIS_ORGANIZATION_DOMAIN= 'qgis.org'¶
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QGIS_ORGANIZATION_NAME= 'QGIS'¶
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Sampler= 6¶
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Select= 5¶
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XDR= 0¶
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ZoomIn= 0¶
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ZoomOut= 1¶
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absolutePathToRelativePath(apath: str, targetPath: str) → str¶ Converts absolute path to path relative to target
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actionScopeRegistry() → QgsActionScopeRegistry¶ Returns the action scope registry.
New in version 3.0.
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activeThemePath() → str¶ Returns the path to the currently active theme directory.
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appIconPath() → str¶ Gets application icon
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applyGdalSkippedDrivers()¶ Apply the skipped drivers list to gdal
See also
See also
See also
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authManager() → QgsAuthManager¶ Returns the application’s authentication manager instance
Note
this can be a null pointer if called before initQgis
See also
New in version 3.0.
Returns the path to the authors file.
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buildOutputPath() → str¶ Returns path to the build output directory. Valid only when running from build directory
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buildSourcePath() → str¶ Returns path to the source directory. Valid only when running from build directory
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childEvent()¶
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collectTranslatableObjects(self, translationContext: QgsTranslationContext)¶ Emits the signal to collect all the strings of .qgs to be included in ts file
New in version 3.4.
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colorSchemeRegistry() → QgsColorSchemeRegistry¶ Returns the application’s color scheme registry, used for managing color schemes.
New in version 3.0.
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connectNotify()¶
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contributorsFilePath() → str¶ Returns the path to the contributors file. Contributors are people who have submitted patches but don’t have commit access. *
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createDatabase(errorMessage: str = '') → bool¶ initialize qgis.db
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createThemeFolder() → bool¶ Create the users theme folder
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customEvent()¶
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customVariables() → Dict[str, Any]¶ Custom expression variables for this application. This does not include generated variables (like system name, user name etc.)
New in version 3.0.
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customVariablesChanged¶ Emitted whenever a custom global variable changes.
New in version 3.0: [signal]
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dataItemProviderRegistry() → QgsDataItemProviderRegistry¶ Returns the application’s data item provider registry, which keeps a list of data item providers that may add items to the browser tree.
New in version 3.0.
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defaultStylePath() → str¶ Returns the path to default style (works as a starting point).
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defaultThemePath() → str¶ Returns the path to the default theme directory.
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defaultThemesFolder() → str¶ Returns the path to default themes folder from install (works as a starting point).
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developersMapFilePath() → str¶ Returns the path to the developers map file. The developers map was created by using leaflet framework, it shows the contributors.json file.
New in version 2.7.
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disconnectNotify()¶
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donorsFilePath() → str¶ Returns the path to the donors file.
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endian() → QgsApplication.endian_t¶ Returns whether this machine uses big or little endian
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class
endian_t¶ Bases:
int
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event(self, event: QEvent) → bool¶ Watch for QFileOpenEvent.
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exitQgis()¶ deletes provider registry and map layer registry
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fieldFormatterRegistry() → QgsFieldFormatterRegistry¶ Gets the registry of available field formatters.
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getThemeCursor(cursor: QgsApplication.Cursor) → QCursor¶ Helper to get a theme cursor. It will fall back to the default theme if the active theme does not have the required icon. Cursors are automatically scaled to look like a 16px cursor on 96dpi screens.
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getThemeIcon(name: str) → QIcon¶ Helper to get a theme icon. It will fall back to the default theme if the active theme does not have the required icon.
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getThemePixmap(name: str) → QPixmap¶ Helper to get a theme icon as a pixmap. It will fall back to the default theme if the active theme does not have the required icon.
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gpsConnectionRegistry() → QgsGpsConnectionRegistry¶ Returns the application’s GPS connection registry, used for managing GPS connections.
New in version 3.0.
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i18nPath() → str¶ Returns the path to the translation directory.
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iconPath(iconFile: str) → str¶ Returns path to the desired icon file. First it tries to use the active theme path, then default theme path
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iconsPath() → str¶ Returns the path to the icons image directory.
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imageCache() → QgsImageCache¶ Returns the application’s image cache, used for caching resampled versions of raster images.
See also
New in version 3.6.
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initQgis()¶ loads providers
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instance() → QgsApplication¶ Returns the singleton instance of the QgsApplication.
New in version 3.0.
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isRunningFromBuildDir() → bool¶ Indicates whether running from build directory (not installed)
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isSignalConnected()¶
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layoutItemRegistry() → QgsLayoutItemRegistry¶ Returns the application’s layout item registry, used for layout item types.
New in version 3.0.
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layoutTemplatePaths() → List[str]¶ Returns the paths to layout template directories.
New in version 3.0.
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libexecPath() → str¶ Returns the path with utility executables (help viewer, crssync, …)
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libraryPath() → str¶ Returns the path containing qgis_core, qgis_gui, qgispython (and other) libraries
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licenceFilePath() → str¶ Returns the path to the licence file.
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locale() → str¶ Returns the QGIS locale.
New in version 3.0.
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maxConcurrentConnectionsPerPool(self) → int¶ The maximum number of concurrent connections per connections pool.
Note
QGIS may in some situations allocate more than this amount of connections to avoid deadlocks.
New in version 3.4.
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maxThreads() → int¶ Gets maximum concurrent thread count
New in version 2.4.
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messageLog() → QgsMessageLog¶ Returns the application’s message log.
New in version 3.0.
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metadataPath() → str¶ Returns the path to the metadata directory.
New in version 3.0.
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networkContentFetcherRegistry() → QgsNetworkContentFetcherRegistry¶ Returns the application’s network content registry used for fetching temporary files during QGIS session
New in version 3.2.
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notify(self, receiver: QObject, event: QEvent) → bool¶ Catch exceptions when sending event to receiver.
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nullRepresentation() → str¶ This string is used to represent the value NULL throughout QGIS.
In general, when passing values around, prefer to use a null QVariant QVariant( field.type() ) or QVariant( QVariant.Int ). This value should only be used in the final presentation step when showing values in a widget or sending it to a web browser.
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nullRepresentationChanged¶ copydoc nullRepresentation() [signal]
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osName() → str¶ Returns a string name of the operating system QGIS is running on.
See also
New in version 2.14.
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pageSizeRegistry() → QgsPageSizeRegistry¶ Returns the application’s page size registry, used for managing layout page sizes.
New in version 3.0.
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paintEffectRegistry() → QgsPaintEffectRegistry¶ Returns the application’s paint effect registry, used for managing paint effects.
New in version 3.0.
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pkgDataPath() → str¶ Returns the common root path of all application data directories.
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platform() → str¶ Returns the QGIS platform name, e.g., “desktop” or “server”.
See also
New in version 2.14.
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pluginLayerRegistry() → QgsPluginLayerRegistry¶ Returns the application’s plugin layer registry, used for managing plugin layer types.
New in version 3.0.
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pluginPath() → str¶ Returns the path to the application plugin directory.
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prefixPath() → str¶ Returns the path to the application prefix directory.
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processingRegistry() → QgsProcessingRegistry¶ Returns the application’s processing registry, used for managing processing providers, algorithms, and various parameters and outputs.
New in version 3.0.
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profiler() → QgsRuntimeProfiler¶ Returns the application runtime profiler.
New in version 3.0.
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projectStorageRegistry() → QgsProjectStorageRegistry¶ Returns registry of available project storage implementations.
New in version 3.2.
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qgisAuthDatabaseFilePath() → str¶ Returns the path to the user authentication database file: qgis-auth.db.
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qgisMasterDatabaseFilePath() → str¶ Returns the path to the master qgis.db file.
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qgisSettingsDirPath() → str¶ Returns the path to the settings directory in user’s home dir
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qgisUserDatabaseFilePath() → str¶ Returns the path to the user qgis.db file.
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qmlImportPath() → str¶ Returns the path where QML components are installed for QGIS Quick library. Returns empty string when QGIS is built without Quick support
New in version 3.2.
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receivers()¶
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registerOgrDrivers()¶ Register OGR drivers ensuring this only happens once. This is a workaround for an issue with older gdal versions that caused duplicate driver name entries to appear in the list of registered drivers when QgsApplication.registerOgrDrivers was called multiple times.
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relativePathToAbsolutePath(rpath: str, targetPath: str) → str¶ Converts path relative to target to an absolute path
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renderer3DRegistry() → Qgs3DRendererRegistry¶ Returns registry of available 3D renderers.
New in version 3.0.
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rendererRegistry() → QgsRendererRegistry¶ Returns the application’s renderer registry, used for managing vector layer renderers.
New in version 3.0.
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reportStyleSheet() → str¶ Returns a standard css style sheet for reports.
Typically you will use this method by doing: QString myStyle = QgsApplication.reportStyleSheet(); textBrowserReport->document()->setDefaultStyleSheet(myStyle);
- Returns
QString containing the CSS 2.1 compliant stylesheet.
Note
you can use the special Qt extensions too, for example the gradient fills for backgrounds.
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requestForTranslatableObjects¶ Emitted when project strings which require translation are being collected for inclusion in a .ts file. In order to register translatable strings, connect to this signal and register the strings within the specified
translationContext.New in version 3.4: [signal]
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resolvePkgPath() → str¶ Calculate the application pkg path
- Returns
the resolved pkg path
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restoreGdalDriver(driver: str)¶ Sets the GDAL_SKIP environment variable to exclude the specified driver and then calls GDALDriverManager.AutoSkipDrivers() to unregister it. The driver name should be the short format of the Gdal driver name e.g. GTIFF.
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sender()¶
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senderSignalIndex()¶
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serverResourcesPath() → str¶ Returns the path to the server resources directory.
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setAuthDatabaseDirPath(authDbDirPath: str)¶ Alters authentication data base directory path - used by 3rd party apps
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setCustomVariable(name: str, value: Any)¶ Set a single custom expression variable.
New in version 3.0.
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setCustomVariables(customVariables: Dict[str, Any])¶ Custom expression variables for this application. Do not include generated variables (like system name, user name etc.)
New in version 3.0.
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setDefaultSvgPaths(pathList: Iterable[str])¶ Alters default svg paths - used by 3rd party apps.
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setFileOpenEventReceiver(receiver: QObject)¶ Sets the FileOpen event receiver
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setMaxThreads(maxThreads: int)¶ Set maximum concurrent thread count
Note
must be between 1 and #cores, -1 means use all available cores
New in version 2.4.
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setNullRepresentation(nullRepresentation: str)¶ copydoc nullRepresentation()
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setPkgDataPath(pkgDataPath: str)¶ Alters pkg data path - used by 3rd party apps
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setPluginPath(pluginPath: str)¶ Alters plugin path - used by 3rd party apps
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setPrefixPath(prefixPath: str, useDefaultPaths: bool = False)¶ Alters prefix path - used by 3rd party apps
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setThemeName(themeName: str)¶ Set the active theme to the specified theme. The theme name should be a single word e.g. ‘default’,’classic’. The theme search path usually will be pkgDataPath + “/themes/” + themName + “/” but plugin writers etc can use themeName() as a basis for searching for resources in their own datastores e.g. a Qt4 resource bundle.
Note
A basic test will be carried out to ensure the theme search path based on the supplied theme name exists. If it does not the theme name will be reverted to ‘default’.
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setTranslation(translation: str)¶ Set translation
New in version 3.4.
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setUITheme(themeName: str)¶ Set the current UI theme used to style the interface. Use uiThemes() to find valid themes to use. Variables found in variables.qss will be added to the stylesheet on load.
- Parameters
themeName – The name of the theme.
Note
using an invalid theme name will reset to default
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shortNameRegExp() → QRegExp¶ Returns the short name regular expression for line edit validator
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showSettings() → str¶ Convenience function to get a summary of the paths used in this application instance useful for debugging mainly.*
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skipGdalDriver(driver: str)¶ Sets the GDAL_SKIP environment variable to include the specified driver and then calls GDALDriverManager.AutoSkipDrivers() to unregister it. The driver name should be the short format of the Gdal driver name e.g. GTIFF.
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skippedGdalDrivers() → List[str]¶ Returns the list of gdal drivers that should be skipped (based on GDAL_SKIP environment variable)
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splashPath() → str¶ Returns the path to the splash screen image directory.
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sponsorsFilePath() → str¶ Returns the path to the sponsors file.
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srsDatabaseFilePath() → str¶ Returns the path to the srs.db file.
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svgCache() → QgsSvgCache¶ Returns the application’s SVG cache, used for caching SVG images and handling parameter replacement within SVG files.
See also
New in version 3.0.
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svgPaths() → List[str]¶ Returns the paths to svg directories.
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symbolLayerRegistry() → QgsSymbolLayerRegistry¶ Returns the application’s symbol layer registry, used for managing symbol layers.
New in version 3.0.
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systemEnvVars() → Dict[str, str]¶ Returns the system environment variables passed to application.
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taskManager() → QgsTaskManager¶ Returns the application’s task manager, used for managing application wide background task handling.
New in version 3.0.
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themeName() → str¶ Set the active theme to the specified theme. The theme name should be a single word e.g. ‘default’,’classic’. The theme search path usually will be pkgDataPath + “/themes/” + themName + “/” but plugin writers etc can use this method as a basis for searching for resources in their own datastores e.g. a Qt4 resource bundle.
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timerEvent()¶
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translatorsFilePath() → str¶ Returns the path to the sponsors file.
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uiThemes() → object¶ All themes found in ~/.qgis3/themes folder. The path is to the root folder for the theme
- Returns
A hash of theme name and theme path. Valid theme folders contain style.qss
Note
Valid theme folders must contain a style.qss file.
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userFullName() → str¶ Returns the user’s operating system login account full display name.
See also
New in version 2.14.
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userLoginName() → str¶ Returns the user’s operating system login account name.
See also
New in version 2.14.
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userStylePath() → str¶ Returns the path to user’s style.
-
userThemesFolder() → str¶ Returns the path to user’s themes folder
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validityCheckRegistry() → QgsValidityCheckRegistry¶ Returns the application’s validity check registry, used for managing validity checks.
New in version 3.6.
-