Subgroup: Map
Class: QgsMapRendererCache¶
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class
qgis.core.
QgsMapRendererCache
¶ Bases:
PyQt5.QtCore.QObject
This class is responsible for keeping cache of rendered images resulting from a map rendering job.
Once a job has a rendered image stored in the cache (using setCacheImage(…)), the cache listens to repaintRequested() signals from dependent layers. If triggered, the cache removes the rendered image (and disconnects from the layers).
The class is thread-safe (multiple classes can access the same instance safely).
New in version 2.4: Methods
blockSignals
cacheImage
Returns the cached image for the specified cacheKey
.childEvent
children
clear
Invalidates the cache contents, clearing all cached images. clearCacheImage
Removes an image from the cache with matching cacheKey
.connectNotify
customEvent
deleteLater
dependentLayers
Returns a list of map layers on which an image in the cache depends. disconnect
disconnectNotify
dumpObjectInfo
dumpObjectTree
dynamicPropertyNames
event
eventFilter
findChild
findChild(self, Tuple, name: str = ‘’, options: Union[Qt.FindChildOptions, Qt.FindChildOption] = Qt.FindChildrenRecursively) -> QObject findChildren
findChildren(self, Tuple, name: str = ‘’, options: Union[Qt.FindChildOptions, Qt.FindChildOption] = Qt.FindChildrenRecursively) -> List[QObject] hasCacheImage
Returns true if the cache contains an image with the specified cacheKey
.inherits
init
Initialize cache: set new parameters and clears the cache if any parameters have changed since last initialization. installEventFilter
isSignalConnected
isWidgetType
isWindowType
killTimer
metaObject
moveToThread
objectName
parent
property
pyqtConfigure
Each keyword argument is either the name of a Qt property or a Qt signal. receivers
removeEventFilter
sender
senderSignalIndex
setCacheImage
Set the cached image
for a particularcacheKey
.setObjectName
setParent
setProperty
signalsBlocked
startTimer
thread
timerEvent
tr
Attributes
destroyed
destroyed(self, QObject = None) [signal] objectNameChanged
objectNameChanged(self, str) [signal] staticMetaObject
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cacheImage
(self, cacheKey: str) → QImage¶ Returns the cached image for the specified
cacheKey
. ThecacheKey
usually matches the QgsMapLayer.id() which the image is a render of. Returns a null image if it is not cached.See also
See also
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childEvent
()¶
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clear
(self)¶ Invalidates the cache contents, clearing all cached images.
See also
-
clearCacheImage
(self, cacheKey: str)¶ Removes an image from the cache with matching
cacheKey
.See also
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connectNotify
()¶
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customEvent
()¶
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dependentLayers
(self, cacheKey: str) → List[QgsMapLayer]¶ Returns a list of map layers on which an image in the cache depends.
New in version 3.0.
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disconnectNotify
()¶
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hasCacheImage
(self, cacheKey: str) → bool¶ Returns true if the cache contains an image with the specified
cacheKey
.New in version 3.0.
See also
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init
(self, extent: QgsRectangle, scale: float) → bool¶ Initialize cache: set new parameters and clears the cache if any parameters have changed since last initialization.
Returns: flag whether the parameters are the same as last time
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isSignalConnected
()¶
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receivers
()¶
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sender
()¶
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senderSignalIndex
()¶
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setCacheImage
(self, cacheKey: str, image: QImage, dependentLayers: Iterable[QgsMapLayer] = [])¶ Set the cached
image
for a particularcacheKey
. ThecacheKey
usually matches the QgsMapLayer.id() which the image is a render of. A list ofdependentLayers
should be passed containing all layer on which this cache image is dependent. If any of these layers triggers a repaint then the cache image will be cleared.See also
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timerEvent
()¶
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