Class: QgsMapCanvas

class qgis.gui.QgsMapCanvas(parent: QWidget = None)

Bases: PyQt5.QtWidgets.QGraphicsView

Constructor

Map canvas is a class for displaying all GIS data types on a canvas.

Enums

Methods

actionEvent
annotationItems	Returns a list of all annotation items in the canvas.
annotationsVisible	Returns True if annotations are visible within the map canvas.
antiAliasingEnabled	True if antialising is enabled
canvasColor	Read property of QColor bgColor.
center	Gets map center, in geographical coordinates
changeEvent
childEvent
clearCache	Make sure to remove any rendered images from cache (does nothing if cache is not enabled)
clearExtentHistory
closeEvent
connectNotify
contextMenuEvent
create
currentLayer	returns current layer (set by legend widget)
customEvent
defaultExpressionContextScope	Creates a new scope which contains default variables and functions relating to the map canvas.
destroy
disconnectNotify
dragEnterEvent	Overridden drag enter event
dragLeaveEvent
dragMoveEvent
drawBackground
drawForeground
drawFrame
dropEvent
enableAntiAliasing	used to determine if anti-aliasing is enabled or not
enableMapTileRendering	sets map tile rendering flag
enterEvent
event	Overridden standard event to be gestures aware
eventFilter
expressionContextScope	Returns a reference to the expression context scope for the map canvas.
extent	Returns the current zoom extent of the map canvas
flashFeatureIds	Causes a set of features with matching ids from a vector layer to flash within the canvas.
flashGeometries	Causes a set of geometries to flash within the canvas.
focusInEvent
focusNextChild
focusNextPrevChild
focusOutEvent
focusPreviousChild
freeze	Freeze/thaw the map canvas.
fullExtent	Returns the combined extent for all layers on the map canvas
getCoordinateTransform	Gets the current coordinate transform
hideEvent
initPainter
initStyleOption
inputMethodEvent
isCachingEnabled	Check whether images of rendered layers are curerently being cached
isDrawing	Find out whether rendering is in progress
isFrozen	Returns True if canvas is frozen.
isParallelRenderingEnabled	Check whether the layers are rendered in parallel or sequentially
isSignalConnected
keyPressEvent	Overridden key press event
keyReleaseEvent	Overridden key release event
labelingEngineSettings	Returns global labeling engine settings from the internal map settings
labelingResults	Gets access to the labeling results (may be None)
layer	Returns the map layer at position index in the layer stack
layerCount	Returns number of layers on the map
layerStateChange	This slot is connected to the visibility change of one or more layers
layerStyleOverrides	Returns the stored overrides of styles for layers.
layers	Returns the list of layers shown within the map canvas.
leaveEvent
magnificationFactor	Returns the magnification factor
mapSettings	Gets access to properties used for map rendering
mapTool	Returns the currently active tool
mapUnits	Convenience function for returning the current canvas map units.
mapUnitsPerPixel	Returns the mapUnitsPerPixel (map units per pixel) for the canvas
mapUpdateInterval	Find out how often map preview should be updated while it is being rendered (in milliseconds)
metric
mouseDoubleClickEvent	Overridden mouse double-click event
mouseLastXY	returns last position of mouse cursor
mouseMoveEvent	Overridden mouse move event
mousePressEvent	Overridden mouse press event
mouseReleaseEvent	Overridden mouse release event
moveCanvasContents	called when panning is in action, reset indicates end of panning
moveEvent
nativeEvent
paintEvent	Overridden paint event
panAction	Called when mouse is moving and pan is activated
panActionEnd	Ends pan action and redraws the canvas.
panToFeatureIds	Centers canvas extent to feature ids
panToSelected	Pan to the selected features of current (vector) layer keeping same extent.
previewJobsEnabled	Returns True if canvas map preview jobs (low priority render jobs which render portions of the view just outside of the canvas extent, to allow preview of these out-of-canvas areas when panning or zooming out the map) are enabled for the canvas.
previewMode	Returns the current preview mode for the map canvas.
previewModeEnabled	Returns whether a preview mode is enabled for the map canvas
readProject	called to read map canvas settings from project
receivers
refresh	Repaints the canvas map
refreshAllLayers	Reload all layers, clear the cache and refresh the canvas
renderFlag	Returns True if canvas render is disabled as a result of user disabling renders via the GUI.
resizeEvent	Overridden resize event
rotation	Gets the current map canvas rotation in clockwise degrees
saveAsImage	Save the contents of the map canvas to disk as an image
scale	Returns the last reported scale of the canvas.
scaleLocked	Returns whether the scale is locked, so zooming can be performed using magnication.
scrollContentsBy
selectionChangedSlot	Receives signal about selection change, and pass it on with layer info
selectionColor	Returns color for selected features
sender
senderSignalIndex
setAnnotationsVisible	Sets whether annotations are visible in the canvas.
setCachingEnabled	Set whether to cache images of rendered layers
setCanvasColor	Write property of QColor bgColor.
setCenter	Set the center of the map canvas, in geographical coordinates
setCurrentLayer
setDestinationCrs	sets destination coordinate reference system
setExpressionContextScope	Sets an expression context scope for the map canvas.
setExtent	Sets the extent of the map canvas
setLabelingEngineSettings	Sets global labeling engine settings in the internal map settings
setLayerStyleOverrides	Sets the stored overrides of styles for rendering layers.
setLayers	Sets the list of layers that should be shown in the canvas.
setMagnificationFactor	Sets the factor of magnification to apply to the map canvas.
setMapSettingsFlags	Resets the flags for the canvas’ map settings.
setMapTool	Sets the map tool currently being used on the canvas
setMapUpdateInterval	Set how often map preview should be updated while it is being rendered (in milliseconds)
setParallelRenderingEnabled	Set whether the layers are rendered in parallel or sequentially
setPreviewJobsEnabled	Sets whether canvas map preview jobs (low priority render jobs which render portions of the view just outside of the canvas extent, to allow preview of these out-of-canvas areas when panning or zooming out the map) are enabled for the canvas.
setPreviewMode	Sets a preview mode for the map canvas.
setPreviewModeEnabled	Enables a preview mode for the map canvas
setRenderFlag	Sets whether a user has disabled canvas renders via the GUI.
setRotation	Set the rotation of the map canvas in clockwise degrees
setScaleLocked	Lock the scale, so zooming can be performed using magnication
setSegmentationTolerance	Sets the segmentation tolerance applied when rendering curved geometries
setSegmentationToleranceType	Sets segmentation tolerance type (maximum angle or maximum difference between curve and approximation)
setSelectionColor	Set color of selected vector features
setSnappingUtils	Assign an instance of snapping utils to the map canvas.
setTheme	Sets a map theme to show in the canvas.
setViewportMargins
setWheelFactor	Sets wheel zoom factor (should be greater than 1)
setupViewport
sharedPainter
showEvent
snappingUtils	Returns snapping utility class that is associated with map canvas.
stopRendering	stop rendering (if there is any right now)
tabletEvent
theme	Returns the map’s theme shown in the canvas, if set.
timerEvent
unsetMapTool	Unset the current map tool or last non zoom tool
updateCanvasItemPositions	called on resize or changed extent to notify canvas items to change their rectangle
updateMicroFocus
updateScale	Emits signal scaleChanged to update scale in main window
viewportEvent
viewportMargins
viewportSizeHint
waitWhileRendering	Blocks until the rendering job has finished.
wheelEvent	Overridden mouse wheel event
writeProject	called to write map canvas settings to project
zoomByFactor	Zoom with the factor supplied.
zoomIn	Zoom in with fixed factor
zoomOut	Zoom out with fixed factor
zoomScale	Zooms the canvas to a specific scale.
zoomToFeatureExtent	Zooms to feature extent.
zoomToFeatureIds	Set canvas extent to the bounding box of a set of features
zoomToFullExtent	Zoom to the full extent of all layers
zoomToNextExtent	Zoom to the next extent (view)
zoomToPreviousExtent	Zoom to the previous extent (view)
zoomToSelected	Zoom to the extent of the selected features of provided (vector) layer.
zoomWithCenter	Zooms in/out with a given center

Signals

canvasColorChanged	Emitted when canvas background color changes
currentLayerChanged	Emitted when the current layer is changed
destinationCrsChanged	Emitted when map CRS has changed
extentsChanged	Emitted when the extents of the map change [signal]
keyPressed	Emit key press event [signal]
keyReleased	Emit key release event [signal]
layerStyleOverridesChanged	Emitted when the configuration of overridden layer styles changes
layersChanged	Emitted when a new set of layers has been received [signal]
magnificationChanged	Emitted when the scale of the map changes
mapCanvasRefreshed	Emitted when canvas finished a refresh request.
mapToolSet	Emit map tool changed with the old tool
messageEmitted	emit a message (usually to be displayed in a message bar) [signal]
renderComplete	TODO: deprecate when decorations are reimplemented as map canvas items - anything related to rendering progress is not visible outside of map canvas - additional drawing shall be done directly within the renderer job or independently as a map canvas item [signal]
renderStarting	Emitted when the canvas is about to be rendered.
rotationChanged	Emitted when the rotation of the map changes
scaleChanged	Emitted when the scale of the map changes [signal]
selectionChanged	Emitted when selection in any layer gets changed [signal]
themeChanged	Emitted when the canvas has been assigned a different map theme.
transformContextChanged	Emitted when the canvas transform context is changed.
xyCoordinates	Emits current mouse position
zoomLastStatusChanged	Emitted when zoom last status changed [signal]
zoomNextStatusChanged	Emitted when zoom next status changed [signal]

Attributes

actionEvent()

annotationItems(self) → List[QgsMapCanvasAnnotationItem]

Returns a list of all annotation items in the canvas.

New in version 3.0.

annotationsVisible(self) → bool

Returns True if annotations are visible within the map canvas.

See also

setAnnotationsVisible()

New in version 3.0.

antiAliasingEnabled(self) → bool

True if antialising is enabled

canvasColor(self) → QColor

Read property of QColor bgColor.

canvasColorChanged

Emitted when canvas background color changes

New in version 3.0: [signal]

center(self) → QgsPointXY

Gets map center, in geographical coordinates

New in version 2.8.

changeEvent()

childEvent()

clearCache(self)

Make sure to remove any rendered images from cache (does nothing if cache is not enabled)

New in version 2.4.

clearExtentHistory(self)

closeEvent()

connectNotify()

contextMenuEvent()

create()

currentLayer(self) → QgsMapLayer

returns current layer (set by legend widget)

currentLayerChanged

Emitted when the current layer is changed

New in version 2.8: [signal]

customEvent()

defaultExpressionContextScope(self) → QgsExpressionContextScope

Creates a new scope which contains default variables and functions relating to the map canvas.

See also

expressionContextScope()

See also

setExpressionContextScope()

New in version 3.4.

destinationCrsChanged

Emitted when map CRS has changed

New in version 2.4: [signal]

destroy()

disconnectNotify()

dragEnterEvent(self, e: QDragEnterEvent)

Overridden drag enter event

dragLeaveEvent()

dragMoveEvent()

drawBackground()

drawForeground()

drawFrame()

dropEvent()

enableAntiAliasing(self, flag: bool)

used to determine if anti-aliasing is enabled or not

enableMapTileRendering(self, flag: bool)

sets map tile rendering flag

enterEvent()

event(self, e: QEvent) → bool

Overridden standard event to be gestures aware

eventFilter()

expressionContextScope(self) → QgsExpressionContextScope

Returns a reference to the expression context scope for the map canvas. This scope is injected into the expression context used for rendering the map, and can be used to apply specific variable overrides for expression evaluation for the map canvas render.

See also

setExpressionContextScope()

See also

defaultExpressionContextScope()

New in version 2.12.

extent(self) → QgsRectangle

Returns the current zoom extent of the map canvas

extentsChanged

Emitted when the extents of the map change [signal]

flashFeatureIds(self, layer: QgsVectorLayer, ids: object, startColor: Union[QColor, Qt.GlobalColor, QGradient] = QColor(255, 0, 0, 255), endColor: Union[QColor, Qt.GlobalColor, QGradient] = QColor(255, 0, 0, 0), flashes: int = 3, duration: int = 500)

Causes a set of features with matching ids from a vector layer to flash within the canvas.

The startColor and endColor can be specified, along with the number of flashes and duration of each flash (in milliseconds).

Note

If the features or geometries are already available, flashGeometries() is much more efficient.

See also

flashGeometries()

New in version 3.0.

flashGeometries(self, geometries: Iterable[QgsGeometry], crs: QgsCoordinateReferenceSystem = QgsCoordinateReferenceSystem(), startColor: Union[QColor, Qt.GlobalColor, QGradient] = QColor(255,0,0,255), endColor: Union[QColor, Qt.GlobalColor, QGradient] = QColor(255,0,0,0), flashes: int = 3, duration: int = 500)

Causes a set of geometries to flash within the canvas.

If crs is a valid coordinate reference system, the geometries will be automatically transformed from this CRS to the canvas CRS.

The startColor and endColor can be specified, along with the number of flashes and duration of each flash (in milliseconds).

See also

flashFeatureIds()

New in version 3.0.

focusInEvent()

focusNextChild()

focusNextPrevChild()

focusOutEvent()

focusPreviousChild()

freeze(self, frozen: bool = True)

Freeze/thaw the map canvas. This is used to prevent the canvas from responding to events while layers are being added/removed etc.

Parameters

frozen – Boolean specifying if the canvas should be frozen (True) or thawed (False). Default is True.

See also

isFrozen()

See also

setRenderFlag() while setRenderFlag() should only be used when users disable rendering via GUI.

fullExtent(self) → QgsRectangle

Returns the combined extent for all layers on the map canvas

getCoordinateTransform(self) → QgsMapToPixel

Gets the current coordinate transform

hideEvent()

initPainter()

initStyleOption()

inputMethodEvent()

isCachingEnabled(self) → bool

Check whether images of rendered layers are curerently being cached

New in version 2.4.

isDrawing(self) → bool

Find out whether rendering is in progress

isFrozen(self) → bool

Returns True if canvas is frozen.

See also

renderFlag()

have been halted programmatically, while renderFlag() should be used to determine whether a user has disabled rendering via GUI.

See also

freeze()

isParallelRenderingEnabled(self) → bool

Check whether the layers are rendered in parallel or sequentially

New in version 2.4.

isSignalConnected()

keyPressEvent(self, e: QKeyEvent)

Overridden key press event

keyPressed

Emit key press event [signal]

keyReleaseEvent(self, e: QKeyEvent)

Overridden key release event

keyReleased

Emit key release event [signal]

labelingEngineSettings(self) → QgsLabelingEngineSettings

Returns global labeling engine settings from the internal map settings

New in version 3.0.

labelingResults(self) → QgsLabelingResults

Gets access to the labeling results (may be None)

New in version 2.4.

layer(self, index: int) → QgsMapLayer

Returns the map layer at position index in the layer stack

layerCount(self) → int

Returns number of layers on the map

layerStateChange(self)

This slot is connected to the visibility change of one or more layers

layerStyleOverrides(self) → Dict[str, str]

Returns the stored overrides of styles for layers.

See also

setLayerStyleOverrides()

New in version 2.12.

layerStyleOverridesChanged

Emitted when the configuration of overridden layer styles changes

New in version 2.12: [signal]

layers(self) → List[QgsMapLayer]

Returns the list of layers shown within the map canvas.

See also

setLayers()

layersChanged

Emitted when a new set of layers has been received [signal]

leaveEvent()

magnificationChanged

Emitted when the scale of the map changes

New in version 2.16: [signal]

magnificationFactor(self) → float

Returns the magnification factor

New in version 2.16.

mapCanvasRefreshed

Emitted when canvas finished a refresh request. [signal]

mapSettings(self) → QgsMapSettings

Gets access to properties used for map rendering

New in version 2.4.

mapTool(self) → QgsMapTool

Returns the currently active tool

mapToolSet

Emit map tool changed with the old tool

New in version 2.3: [signal]

mapUnits(self) → QgsUnitTypes.DistanceUnit

Convenience function for returning the current canvas map units. The map units are dictated by the canvas’ destinationCrs() map units.

mapUnitsPerPixel(self) → float

Returns the mapUnitsPerPixel (map units per pixel) for the canvas

mapUpdateInterval(self) → int

Find out how often map preview should be updated while it is being rendered (in milliseconds)

New in version 2.4.

messageEmitted

emit a message (usually to be displayed in a message bar) [signal]

metric()

mouseDoubleClickEvent(self, e: QMouseEvent)

Overridden mouse double-click event

mouseLastXY(self) → QPoint

returns last position of mouse cursor

mouseMoveEvent(self, e: QMouseEvent)

Overridden mouse move event

mousePressEvent(self, e: QMouseEvent)

Overridden mouse press event

mouseReleaseEvent(self, e: QMouseEvent)

Overridden mouse release event

moveCanvasContents(self, reset: bool = False)

called when panning is in action, reset indicates end of panning

moveEvent()

nativeEvent()

paintEvent(self, e: QPaintEvent)

Overridden paint event

panAction(self, event: QMouseEvent)

Called when mouse is moving and pan is activated

panActionEnd(self, releasePoint: QPoint)

Ends pan action and redraws the canvas.

panToFeatureIds(self, layer: QgsVectorLayer, ids: object, alwaysRecenter: bool = True)

Centers canvas extent to feature ids

Parameters

• layer – the vector layer

• ids – the feature ids

• alwaysRecenter – if false, the canvas is recentered only if the bounding box is not contained within the current extent

panToSelected(self, layer: QgsVectorLayer = None)

Pan to the selected features of current (vector) layer keeping same extent.

previewJobsEnabled(self) → bool

Returns True if canvas map preview jobs (low priority render jobs which render portions of the view just outside of the canvas extent, to allow preview of these out-of-canvas areas when panning or zooming out the map) are enabled for the canvas.

See also

setPreviewJobsEnabled()

New in version 3.0.

previewMode(self) → QgsPreviewEffect.PreviewMode

Returns the current preview mode for the map canvas. This setting only has an effect if previewModeEnabled is True.

Returns

preview mode for map canvas

See also

setPreviewMode()

See also

previewModeEnabled()

New in version 2.3.

previewModeEnabled(self) → bool

Returns whether a preview mode is enabled for the map canvas

Returns

True if a preview mode is currently enabled

See also

setPreviewModeEnabled()

See also

previewMode()

New in version 2.3.

readProject(self, QDomDocument)

called to read map canvas settings from project

receivers()

refresh(self)

Repaints the canvas map

refreshAllLayers(self)

Reload all layers, clear the cache and refresh the canvas

New in version 2.9.

renderComplete

TODO: deprecate when decorations are reimplemented as map canvas items - anything related to rendering progress is not visible outside of map canvas - additional drawing shall be done directly within the renderer job or independently as a map canvas item [signal]

renderFlag(self) → bool

Returns True if canvas render is disabled as a result of user disabling renders via the GUI.

See also

setRenderFlag()

See also

isFrozen()

have been halted programmatically, while renderFlag() should be used to determine whether a user has disabled rendering via GUI.

renderStarting

Emitted when the canvas is about to be rendered. [signal]

resizeEvent(self, e: QResizeEvent)

Overridden resize event

rotation(self) → float

Gets the current map canvas rotation in clockwise degrees

New in version 2.8.

rotationChanged

Emitted when the rotation of the map changes

New in version 2.8: [signal]

saveAsImage(self, fileName: str, QPixmap: QPixmap = None, a2: str = '')

Save the contents of the map canvas to disk as an image

scale(self) → float

Returns the last reported scale of the canvas. The scale value indicates the scale denominator, e.g. 1000.0 for a 1:1000 map.

scaleChanged

Emitted when the scale of the map changes [signal]

scaleLocked(self) → bool

Returns whether the scale is locked, so zooming can be performed using magnication.

See also

setScaleLocked()

New in version 2.16.

scrollContentsBy()

selectionChanged

Emitted when selection in any layer gets changed [signal]

selectionChangedSlot(self)

Receives signal about selection change, and pass it on with layer info

selectionColor(self) → QColor

Returns color for selected features

New in version 3.0.

sender()

senderSignalIndex()

setAnnotationsVisible(self, visible: bool)

Sets whether annotations are visible in the canvas.

See also

annotationsVisible()

New in version 3.0.

setCachingEnabled(self, enabled: bool)

Set whether to cache images of rendered layers

New in version 2.4.

setCanvasColor(self, _newVal: Union[QColor, Qt.GlobalColor, QGradient])

Write property of QColor bgColor.

setCenter(self, center: QgsPointXY)

Set the center of the map canvas, in geographical coordinates

New in version 2.8.

setCurrentLayer(self, layer: QgsMapLayer)

setDestinationCrs(self, crs: QgsCoordinateReferenceSystem)

sets destination coordinate reference system

New in version 2.4.

setExpressionContextScope(self, scope: QgsExpressionContextScope)

Sets an expression context scope for the map canvas. This scope is injected into the expression context used for rendering the map, and can be used to apply specific variable overrides for expression evaluation for the map canvas render. This method will overwrite the existing expression context scope for the canvas.

Parameters

scope – new expression context scope

See also

expressionContextScope()

See also

defaultExpressionContextScope()

New in version 2.12.

setExtent(self, r: QgsRectangle, magnified: bool = False)

Sets the extent of the map canvas

setLabelingEngineSettings(self, settings: QgsLabelingEngineSettings)

Sets global labeling engine settings in the internal map settings

New in version 3.0.

setLayerStyleOverrides(self, overrides: Dict[str, str])

Sets the stored overrides of styles for rendering layers.

If the map canvas has been associated with a map theme via a call to setTheme(), then any calls to setLayerStyleOverrides() are ignored. It is necessary to first clear the theme association by calling setTheme() with an empty string before setLayerStyleOverrides() calls can be made.

See also

layerStyleOverrides()

New in version 2.12.

setLayers(self, layers: Iterable[QgsMapLayer])

Sets the list of layers that should be shown in the canvas.

If the map canvas has been associated with a map theme via a call to setTheme(), then any calls to setLayers() are ignored. It is necessary to first clear the theme association by calling setTheme() with an empty string before setLayers() calls can be made.

See also

layers()

New in version 3.0.

setMagnificationFactor(self, factor: float)

Sets the factor of magnification to apply to the map canvas. Indeed, we increase/decrease the DPI of the map settings according to this factor in order to render marker point, labels, … bigger.

New in version 2.16.

setMapSettingsFlags(self, flags: Union[QgsMapSettings.Flags, QgsMapSettings.Flag])

Resets the flags for the canvas’ map settings.

New in version 3.0.

setMapTool(self, mapTool: QgsMapTool, clean: bool = False)

Sets the map tool currently being used on the canvas

setMapUpdateInterval(self, timeMilliseconds: int)

Set how often map preview should be updated while it is being rendered (in milliseconds)

New in version 2.4.

setParallelRenderingEnabled(self, enabled: bool)

Set whether the layers are rendered in parallel or sequentially

New in version 2.4.

setPreviewJobsEnabled(self, enabled: bool)

Sets whether canvas map preview jobs (low priority render jobs which render portions of the view just outside of the canvas extent, to allow preview of these out-of-canvas areas when panning or zooming out the map) are enabled for the canvas.

See also

previewJobsEnabled()

New in version 3.0.

setPreviewMode(self, mode: QgsPreviewEffect.PreviewMode)

Sets a preview mode for the map canvas. This setting only has an effect if previewModeEnabled is True.

Parameters

mode – preview mode for the canvas

See also

previewMode()

See also

setPreviewModeEnabled()

See also

previewModeEnabled()

New in version 2.3.

setPreviewModeEnabled(self, previewEnabled: bool)

Enables a preview mode for the map canvas

Parameters

previewEnabled – set to True to enable a preview mode

See also

setPreviewMode()

New in version 2.3.

setRenderFlag(self, flag: bool)

Sets whether a user has disabled canvas renders via the GUI.

Parameters

flag – set to False to indicate that user has disabled renders

See also

renderFlag()

See also

freeze() while setRenderFlag() should only be used when users disable rendering via GUI.

setRotation(self, degrees: float)

Set the rotation of the map canvas in clockwise degrees

New in version 2.8.

setScaleLocked(self, isLocked: bool)

Lock the scale, so zooming can be performed using magnication

See also

scaleLocked()

New in version 2.16.

setSegmentationTolerance(self, tolerance: float)

Sets the segmentation tolerance applied when rendering curved geometries

Parameters

tolerance – the segmentation tolerance*

setSegmentationToleranceType(self, type: QgsAbstractGeometry.SegmentationToleranceType)

Sets segmentation tolerance type (maximum angle or maximum difference between curve and approximation)

Parameters

type – the segmentation tolerance typename*

setSelectionColor(self, color: Union[QColor, Qt.GlobalColor, QGradient])

Set color of selected vector features

New in version 2.4.

setSnappingUtils(self, utils: QgsSnappingUtils)

Assign an instance of snapping utils to the map canvas. The instance is not owned by the canvas, so it is possible to use one instance in multiple canvases.

For main canvas in QGIS, do not associate a different instance from the existing one (it is updated from the project’s snapping configuration).

New in version 2.8.

setTheme(self, theme: str)

Sets a map theme to show in the canvas. The theme name must match a theme present in the associated project’s QgsMapThemeCollection.

When the canvas is associated to a map theme, it will automatically follow the layer selection and layer styles from that theme. Calls to setLayers() or setLayerStyleOverrides() will have no effect, and canvases associated with a QgsLayerTreeMapCanvasBridge will no longer synchronize their state with the layer tree. In these cases it is necessary to call setTheme() with an empty string to clear the theme association and allow map updates with setLayers(), setLayerStyleOverrides(), or via QgsLayerTreeMapCanvasBridge.

If an empty string is passed then the current theme association will be cleared.

See also

theme()

New in version 3.0.

setViewportMargins()

setWheelFactor(self, factor: float)

Sets wheel zoom factor (should be greater than 1)

setupViewport()

sharedPainter()

showEvent()

snappingUtils(self) → QgsSnappingUtils

Returns snapping utility class that is associated with map canvas. If no snapping utils instance has been associated previously, an internal will be created for convenience (so map tools do not need to test for existence of the instance).

Main canvas in QGIS returns an instance which is always up-to-date with the project’s snapping configuration.

New in version 2.8.

stopRendering(self)

stop rendering (if there is any right now)

New in version 2.4.

tabletEvent()

theme(self) → str

Returns the map’s theme shown in the canvas, if set.

See also

setTheme()

New in version 3.0.

themeChanged

Emitted when the canvas has been assigned a different map theme.

See also

setTheme()

New in version 3.0: [signal]

timerEvent()

transformContextChanged

Emitted when the canvas transform context is changed.

New in version 3.0: [signal]

unsetMapTool(self, mapTool: QgsMapTool)

Unset the current map tool or last non zoom tool

This is called from destructor of map tools to make sure that this map tool won’t be used any more. You don’t have to call it manually, QgsMapTool takes care of it.

updateCanvasItemPositions(self)

called on resize or changed extent to notify canvas items to change their rectangle

updateMicroFocus()

updateScale(self)

Emits signal scaleChanged to update scale in main window

viewportEvent()

viewportMargins()

viewportSizeHint()

waitWhileRendering(self)

Blocks until the rendering job has finished.

In almost all cases you do NOT want to call this, as it will hang the UI until the rendering job is complete. It’s included in API solely for unit testing and standalone Python scripts.

New in version 3.0.

wheelEvent(self, e: QWheelEvent)

Overridden mouse wheel event

writeProject(self, QDomDocument)

called to write map canvas settings to project

xyCoordinates

Emits current mouse position

Note

changed in 1.3 * [signal]

zoomByFactor(self, scaleFactor: float, center: QgsPointXY = None)

Zoom with the factor supplied. Factor > 1 zooms out, interval (0,1) zooms in If point is given, re-center on it

zoomIn(self)

Zoom in with fixed factor

zoomLastStatusChanged

Emitted when zoom last status changed [signal]

zoomNextStatusChanged

Emitted when zoom next status changed [signal]

zoomOut(self)

Zoom out with fixed factor

zoomScale(self, scale: float)

Zooms the canvas to a specific scale. The scale value indicates the scale denominator, e.g. 1000.0 for a 1:1000 map.

zoomToFeatureExtent(self, rect: QgsRectangle)

Zooms to feature extent. Adds a small margin around the extent and does a pan if rect is empty (point extent)

zoomToFeatureIds(self, layer: QgsVectorLayer, ids: object)

Set canvas extent to the bounding box of a set of features

Parameters

• layer – the vector layer

• ids – the feature ids*

zoomToFullExtent(self)

Zoom to the full extent of all layers

zoomToNextExtent(self)

Zoom to the next extent (view)

zoomToPreviousExtent(self)

Zoom to the previous extent (view)

zoomToSelected(self, layer: QgsVectorLayer = None)

Zoom to the extent of the selected features of provided (vector) layer.

Parameters

layer – optionally specify different than current layer

zoomWithCenter(self, x: int, y: int, zoomIn: bool)

Zooms in/out with a given center