Class: QgsRenderContext

class qgis.core.QgsRenderContext

Bases: QgsTemporalRangeObject

Contains information about the context of a rendering operation.

The context of a rendering operation defines properties such as the conversion ratio between screen and map units, the extents to be rendered etc.

Enums

Flag	alias of RenderContextFlag
TextRenderFormat	Bases: enum.IntEnum

Methods

clearCustomRenderingFlag	Clears the specified custom rendering flag.
clippingRegions	Returns the list of clipping regions to apply during the render.
convertFromMapUnits	Converts a size from map units to the specified units.
convertMetersToMapUnits	Convert meter distances to active MapUnit values for QgsUnitTypes.RenderMetersInMapUnits note When the sourceCrs() is geographic, the center of the Extent will be used
convertToMapUnits	Converts a size from the specified units to map units.
convertToPainterUnits	Converts a size from the specified units to painter units (pixels).
coordinateTransform	Returns the current coordinate transform for the context.
currentFrame	Returns the current frame number of the map (in frames per second), for maps which are part of an animation.
currentMaskId	Returns the current mask id, which can be used with maskPainter()
customRenderingFlags	Gets custom rendering flags.
deviceOutputSize	Returns the device output size of the render.
devicePixelRatio	Returns the device pixel ratio.
disabledSymbolLayers	When rendering a map layer in a second pass (for selective masking), some symbol layers may be disabled.
distanceArea	A general purpose distance and area calculator, capable of performing ellipsoid based calculations.
dpiTarget	Returns the targeted DPI for rendering.
drawEditingInformation	Returns True if edit markers should be drawn during the render operation.
expressionContext	Gets the expression context.
extent	When rendering a map layer, calling this method returns the "clipping" extent for the layer (in the layer's CRS).
featureClipGeometry	Returns the geometry to use to clip features at render time.
featureFilterProvider	Gets the filter feature provider used for additional filtering of rendered features.
feedback	Returns the feedback object that can be queried regularly during rendering to check if rendering should be canceled, if set.
flags	Returns combination of flags used for rendering.
forceVectorOutput	Returns True if rendering operations should use vector operations instead of any faster raster shortcuts.
frameRate	Returns the frame rate of the map, for maps which are part of an animation.
fromMapSettings	create initialized QgsRenderContext instance from given QgsMapSettings
fromQPainter	Creates a default render context given a pixel based QPainter destination.
geometry	Returns pointer to the unsegmentized geometry
hasRenderedFeatureHandlers	Returns True if the context has any rendered feature handlers.
imageFormat	Returns the QImage format which should be used for QImages created during rendering.
isGuiPreview	Returns the Gui preview mode.
isSymbolLayerEnabled	When rendering a map layer in a second pass (for selective masking), some symbol layers may be disabled.
mapExtent	Returns the original extent of the map being rendered.
mapToPixel	Returns the context's map to pixel transform, which transforms between map coordinates and device coordinates.
maskIdProvider	Returns the mask id provider attached to the context.
maskPainter	Returns a mask QPainter for the render operation.
outputSize	Returns the size of the resulting rendered image, in pixels.
painter	Returns the destination QPainter for the render operation.
pathResolver	Returns the path resolver for conversion between relative and absolute paths during rendering operations, e.g.
renderedFeatureHandlers	Returns the list of rendered feature handlers to use while rendering map layers.
rendererScale	Returns the renderer map scale.
rendererUsage	Returns the renderer usage
renderingStopped	Returns True if the rendering operation has been stopped and any ongoing rendering should be canceled immediately.
scaleFactor	Returns the scaling factor for the render to convert painter units to physical sizes.
segmentationTolerance	Gets the segmentation tolerance applied when rendering curved geometries
segmentationToleranceType	Gets segmentation tolerance type (maximum angle or maximum difference between curve and approximation)
selectionColor	Returns the color to use when rendering selected features.
setCoordinateTransform	Sets the current coordinate transform for the context.
setCurrentFrame	Sets the current frame of the map, for maps which are part of an animation.
setCurrentMaskId	Stores a mask id as the "current" one.
setCustomRenderingFlag	Sets a custom rendering flag.
setDevicePixelRatio	Sets the device pixel ratio.
setDisabledSymbolLayers	When rendering a map layer in a second pass (for selective masking), some symbol layers may be disabled.
setDistanceArea	A general purpose distance and area calculator, capable of performing ellipsoid based calculations.
setDpiTarget	Sets the targeted dpi for rendering.
setDrawEditingInformation	Sets whether edit markers should be drawn during the render operation.
setExpressionContext	Sets the expression context.
setExtent	When rendering a map layer, calling this method sets the "clipping" extent for the layer (in the layer's CRS).
setFeatureClipGeometry	Sets a geometry to use to clip features at render time.
setFeatureFilterProvider	Set a filter feature provider used for additional filtering of rendered features.
setFeedback	Attach a feedback object that can be queried regularly during rendering to check if rendering should be canceled.
setFlag	Enable or disable a particular flag (other flags are not affected)
setFlags	Set combination of flags that will be used for rendering.
setForceVectorOutput	Sets whether rendering operations should use vector operations instead of any faster raster shortcuts.
setFrameRate	Sets the frame rate of the map (in frames per second), for maps which are part of an animation.
setGeometry	Sets pointer to original (unsegmentized) geometry
setImageFormat	Sets QImage format which should be used for QImages created during rendering.
setIsGuiPreview	Sets GUI preview mode.
setMapExtent	Sets the original extent of the map being rendered.
setMapToPixel	Sets the context's map to pixel transform, which transforms between map coordinates and device coordinates.
setMaskIdProvider	Attaches a mask id provider to the context.
setMaskPainter	Sets a mask QPainter for the render operation.
setOutputSize	Sets the size of the resulting rendered image, in pixels.
setPainter	Sets the destination QPainter for the render operation.
setPainterFlagsUsingContext	Sets relevant flags on a destination painter, using the flags and settings currently defined for the render context.
setPathResolver	Sets the path resolver for conversion between relative and absolute paths during rendering operations, e.g.
setRendererScale	Sets the renderer map scale.
setRendererUsage	Sets the renderer usage
setRenderingStopped	Sets whether the rendering operation has been stopped and any ongoing rendering should be canceled immediately.
setScaleFactor	Sets the scaling factor for the render to convert painter units to physical sizes.
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	Sets the color to use when rendering selected features.
setShowSelection	Sets whether vector selections should be shown in the rendered map
setSymbologyReferenceScale	Sets the symbology reference scale.
setTextRenderFormat	Sets the text render format, which dictates how text is rendered (e.g.
setTextureOrigin	Sets the texture origin, which should be used as a brush transform when rendering using QBrush objects.
setTransformContext	Sets the context's coordinate transform context, which stores various information regarding which datum transforms should be used when transforming points from a source to destination coordinate reference system.
setUseAdvancedEffects	Used to enable or disable advanced effects such as blend modes
setUseRenderingOptimization	Sets whether the rendering optimization (geometry simplification) should be executed
setVectorSimplifyMethod	Sets the simplification setting to use when rendering vector layers.
setZRange	Sets the range of z-values which should be rendered.
showSelection	Returns True if vector selections should be shown in the rendered map
symbologyReferenceScale	Returns the symbology reference scale.
testFlag	Check whether a particular flag is enabled.
textRenderFormat	Returns the text render format, which dictates how text is rendered (e.g.
textureOrigin	Returns the texture origin, which should be used as a brush transform when rendering using QBrush objects.
transformContext	Returns the context's coordinate transform context, which stores various information regarding which datum transforms should be used when transforming points from a source to destination coordinate reference system.
useAdvancedEffects	Returns True if advanced effects such as blend modes such be used
useRenderingOptimization	Returns True if the rendering optimization (geometry simplification) can be executed
vectorSimplifyMethod	Returns the simplification settings to use when rendering vector layers.
zRange	Returns the range of z-values which should be rendered.

Flag

alias of RenderContextFlag

Flags

alias of RenderContextFlags

class TextRenderFormat(value)

Bases: enum.IntEnum

Options for rendering text.

New in version 3.22.

• TextFormatAlwaysOutlines: Always render text using path objects (AKA outlines/curves). This setting guarantees the best quality rendering, even when using a raster paint surface (where sub-pixel path based text rendering is superior to sub-pixel text-based rendering). The downside is that text is converted to paths only, so users cannot open created vector outputs for post-processing in other applications and retain text editability. This setting also guarantees complete compatibility with the full range of formatting options available through QgsTextRenderer and QgsTextFormat, some of which may not be possible to reproduce when using a vector-based paint surface and TextFormatAlwaysText mode. A final benefit to this setting is that vector exports created using text as outlines do not require all users to have the original fonts installed in order to display the text in its original style.

• TextFormatAlwaysText: Always render text as text objects. While this mode preserves text objects as text for post-processing in external vector editing applications, it can result in rendering artifacts or poor quality rendering, depending on the text format settings. Even with raster based paint devices, TextFormatAlwaysText can result in inferior rendering quality to TextFormatAlwaysOutlines. When rendering using TextFormatAlwaysText to a vector based device (e.g. PDF or SVG), care must be taken to ensure that the required fonts are available to users when opening the created files, or default fallback fonts will be used to display the output instead. (Although PDF exports MAY automatically embed some fonts when possible, depending on the user’s platform).

baseClass

alias of Qgis

clearCustomRenderingFlag(self, flag: str)

Clears the specified custom rendering flag.

Parameters:

flag (str) – the flag name

See also

setCustomRenderingFlag()

New in version 3.12.

clippingRegions(self) → List[QgsMapClippingRegion]

Returns the list of clipping regions to apply during the render.

These regions are always in the final destination CRS for the map.

New in version 3.16.

Return type:

List[QgsMapClippingRegion]

convertFromMapUnits(self, sizeInMapUnits: float, outputUnit: QgsUnitTypes.RenderUnit) → float

Converts a size from map units to the specified units.

See also

convertToMapUnits()

New in version 3.0.

Parameters:

• sizeInMapUnits (float) –

• outputUnit (QgsUnitTypes.RenderUnit) –

Return type:

float

convertMetersToMapUnits(self, meters: float) → float

Convert meter distances to active MapUnit values for QgsUnitTypes.RenderMetersInMapUnits note When the sourceCrs() is geographic, the center of the Extent will be used

New in version 3.0.

Parameters:

meters (float) –

Return type:

float

convertToMapUnits(self, size: float, unit: QgsUnitTypes.RenderUnit, scale: QgsMapUnitScale = QgsMapUnitScale()) → float

Converts a size from the specified units to map units. The conversion respects the limits specified by the optional scale parameter.

See also

convertToPainterUnits()

New in version 3.0.

Parameters:

• size (float) –

• unit (QgsUnitTypes.RenderUnit) –

• scale (QgsMapUnitScale = QgsMapUnitScale()) –

Return type:

float

convertToPainterUnits(self, size: float, unit: QgsUnitTypes.RenderUnit, scale: QgsMapUnitScale = QgsMapUnitScale(), property: Qgis.RenderSubcomponentProperty = Qgis.RenderSubcomponentProperty.Generic) → float

Converts a size from the specified units to painter units (pixels). The conversion respects the limits specified by the optional scale parameter.

Since QGIS 3.22 the optional property argument can be used to specify the associated property. This is used in some contexts to refine the converted size. For example, a Qgis.RenderSubcomponentProperty.BlurSize property will be limited to a suitably fast range when the render context has the Qgis.RenderContextFlag.RenderSymbolPreview set.

See also

convertToMapUnits()

New in version 3.0.

Parameters:

• size (float) –

• unit (QgsUnitTypes.RenderUnit) –

• scale (QgsMapUnitScale = QgsMapUnitScale()) –

• property (Qgis.RenderSubcomponentProperty = Qgis.RenderSubcomponentProperty.Generic) –

Return type:

float

coordinateTransform(self) → QgsCoordinateTransform

Returns the current coordinate transform for the context.

This represents the coordinate transform required to transform a layer which is being rendered back to the CRS of the rendered map. If no coordinate transformation is required, or the render context is not associated with a map layer render, then an invalid coordinate transformation is returned.

See also

setCoordinateTransform()

Return type:

QgsCoordinateTransform

currentFrame(self) → int

Returns the current frame number of the map (in frames per second), for maps which are part of an animation.

Returns -1 if the map is not associated with an animation.

See also

setCurrentFrame()

New in version 3.26.

Return type:

int

currentMaskId(self) → int

Returns the current mask id, which can be used with maskPainter()

See also

setCurrentMaskId()

See also

maskPainter()

New in version 3.12.

Return type:

int

customRenderingFlags(self) → Dict[str, Any]

Gets custom rendering flags. Layers might honour these to alter their rendering.

Return type:

Dict[str, Any]

Returns:

a map of custom flags

See also

setCustomRenderingFlag()

New in version 3.12.

deviceOutputSize(self) → QSize

Returns the device output size of the render.

This is equivalent to the output size multiplicated by the device pixel ratio.

See also

outputSize()

See also

devicePixelRatio()

See also

setOutputSize()

New in version 3.22.

Return type:

QSize

devicePixelRatio(self) → float

Returns the device pixel ratio.

Common values are 1 for normal-dpi displays and 2 for high-dpi “retina” displays.

See also

setDevicePixelRatio()

New in version 3.22.

Return type:

float

disabledSymbolLayers(self) → Set[QgsSymbolLayer]

When rendering a map layer in a second pass (for selective masking), some symbol layers may be disabled.

Returns the list of disabled symbol layers.

See also

setDisabledSymbolLayers()

See also

isSymbolLayerEnabled()

New in version 3.12.

Return type:

Set[QgsSymbolLayer]

distanceArea(self) → QgsDistanceArea

A general purpose distance and area calculator, capable of performing ellipsoid based calculations.

New in version 3.0.

Return type:

QgsDistanceArea

dpiTarget(self) → float

Returns the targeted DPI for rendering.

See also

setDpiTarget()

New in version 3.20.

Return type:

float

drawEditingInformation(self) → bool

Returns True if edit markers should be drawn during the render operation.

See also

setDrawEditingInformation()

Return type:

bool

expressionContext(self) → QgsExpressionContext

Gets the expression context. This context should be used for all expression evaluation associated with this render context.

See also

setExpressionContext()

New in version 2.12.

Return type:

QgsExpressionContext

extent(self) → QgsRectangle

When rendering a map layer, calling this method returns the “clipping” extent for the layer (in the layer’s CRS).

This extent is a “worst-case” scenario, which is guaranteed to cover the complete visible portion of the layer when it is rendered to a map. It is often larger than the actual visible portion of that layer.

Warning

For some layers, depending on the visible extent and the coordinate transforms involved, this extent will represent the entire globe. This method should never be used to determine the actual visible extent of a map render.

See also

setExtent()

See also

mapExtent()

Return type:

QgsRectangle

featureClipGeometry(self) → QgsGeometry

Returns the geometry to use to clip features at render time.

When vector features are rendered, they should be clipped to this geometry.

Warning

The clipping must take effect for rendering the feature’s symbol only, and should never be applied directly to the feature being rendered. Doing so would impact the results of rendering rules which rely on feature geometry, such as a rule-based renderer using the feature’s area.

See also

setFeatureClipGeometry()

New in version 3.16.

Return type:

QgsGeometry

featureFilterProvider(self) → QgsFeatureFilterProvider

Gets the filter feature provider used for additional filtering of rendered features.

Return type:

QgsFeatureFilterProvider

Returns:

the filter feature provider

See also

setFeatureFilterProvider()

New in version 2.14.

feedback(self) → QgsFeedback

Returns the feedback object that can be queried regularly during rendering to check if rendering should be canceled, if set. Maybe be None.

See also

setFeedback()

New in version 3.22.

Return type:

QgsFeedback

flags(self) → Qgis.RenderContextFlags

Returns combination of flags used for rendering.

New in version 2.14.

Return type:

Qgis.RenderContextFlags

forceVectorOutput(self) → bool

Returns True if rendering operations should use vector operations instead of any faster raster shortcuts.

See also

setForceVectorOutput()

Return type:

bool

frameRate(self) → float

Returns the frame rate of the map, for maps which are part of an animation.

Returns -1 if the map is not associated with an animation.

See also

setFrameRate()

New in version 3.26.

Return type:

float

fromMapSettings(mapSettings: QgsMapSettings) → QgsRenderContext

create initialized QgsRenderContext instance from given QgsMapSettings

New in version 2.4.

Parameters:

mapSettings (QgsMapSettings) –

Return type:

QgsRenderContext

fromQPainter(painter: QPainter) → QgsRenderContext

Creates a default render context given a pixel based QPainter destination. If no painter is specified or the painter has no device, then a default DPI of 88 will be assumed.

New in version 3.0.

Parameters:

painter (QPainter) –

Return type:

QgsRenderContext

geometry(self) → QgsAbstractGeometry

Returns pointer to the unsegmentized geometry

Return type:

QgsAbstractGeometry

hasRenderedFeatureHandlers(self) → bool

Returns True if the context has any rendered feature handlers.

See also

renderedFeatureHandlers()

New in version 3.10.

Return type:

bool

imageFormat(self) → QImage.Format

Returns the QImage format which should be used for QImages created during rendering.

See also

setImageFormat()

New in version 3.22.

Return type:

QImage.Format

isGuiPreview(self) → bool

Returns the Gui preview mode. GUI preview mode is used to change the behavior of some renderings when they are done to preview of symbology in the GUI. This is especially used to display mask symbol layers rather than painting them in a mask painter, which is not meant to be visible, by definition.

See also

isGuiPreview()

See also

setIsGuiPreview()

New in version 3.12.

Return type:

bool

isSymbolLayerEnabled(self, layer: QgsSymbolLayer) → bool

When rendering a map layer in a second pass (for selective masking), some symbol layers may be disabled.

Checks whether a given symbol layer has been disabled for the current pass.

See also

setDisabledSymbolLayers()

See also

disabledSymbolLayers()

New in version 3.12.

Parameters:

layer (QgsSymbolLayer) –

Return type:

bool

mapExtent(self) → QgsRectangle

Returns the original extent of the map being rendered.

Unlike extent(), this extent is always in the final destination CRS for the map render and represents the exact bounds of the map being rendered.

See also

extent()

See also

setMapExtent()

New in version 3.4.8.

Return type:

QgsRectangle

mapToPixel(self) → QgsMapToPixel

Returns the context’s map to pixel transform, which transforms between map coordinates and device coordinates.

See also

setMapToPixel()

Return type:

QgsMapToPixel

maskIdProvider(self) → QgsMaskIdProvider

Returns the mask id provider attached to the context.

See also

setMaskIdProvider()

New in version 3.12.

Return type:

QgsMaskIdProvider

maskPainter(self, id: int = 0) → QPainter

Returns a mask QPainter for the render operation. Multiple mask painters can be defined, each with a unique identifier. None is returned if a mask painter with the given identifier does not exist. This is currently used to implement selective masking.

See also

setMaskPainter()

See also

currentMaskId()

New in version 3.12.

Parameters:

id (int = 0) –

Return type:

QPainter

outputSize(self) → QSize

Returns the size of the resulting rendered image, in pixels.

See also

deviceOutputSize()

See also

setOutputSize()

New in version 3.22.

Return type:

QSize

painter(self) → QPainter

Returns the destination QPainter for the render operation.

See also

setPainter()

Return type:

QPainter

pathResolver(self) → QgsPathResolver

Returns the path resolver for conversion between relative and absolute paths during rendering operations, e.g. for resolving relative symbol paths.

See also

setPathResolver()

New in version 3.0.

Return type:

QgsPathResolver

renderedFeatureHandlers(self) → List[QgsRenderedFeatureHandlerInterface]

Returns the list of rendered feature handlers to use while rendering map layers.

See also

hasRenderedFeatureHandlers()

New in version 3.10.

Return type:

List[QgsRenderedFeatureHandlerInterface]

rendererScale(self) → float

Returns the renderer map scale. This will match the desired scale denominator for the rendered map, eg 1000.0 for a 1:1000 map render.

See also

setRendererScale()

Return type:

float

rendererUsage(self) → Qgis.RendererUsage

Returns the renderer usage

See also

setRendererUsage()

New in version 3.24.

Return type:

Qgis.RendererUsage

renderingStopped(self) → bool

Returns True if the rendering operation has been stopped and any ongoing rendering should be canceled immediately.

Note

Since QGIS 3.22 the feedback() member exists as an alternative means of cancellation support.

See also

setRenderingStopped()

See also

feedback()

Return type:

bool

scaleFactor(self) → float

Returns the scaling factor for the render to convert painter units to physical sizes. This is usually equal to the number of pixels per millimeter.

See also

setScaleFactor()

Return type:

float

segmentationTolerance(self) → float

Gets the segmentation tolerance applied when rendering curved geometries

See also

setSegmentationTolerance()

Return type:

float

segmentationToleranceType(self) → QgsAbstractGeometry.SegmentationToleranceType

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

See also

setSegmentationToleranceType()

Return type:

QgsAbstractGeometry.SegmentationToleranceType

selectionColor(self) → QColor

Returns the color to use when rendering selected features.

See also

setSelectionColor()

Return type:

QColor

setCoordinateTransform(self, t: QgsCoordinateTransform)

Sets the current coordinate transform for the context.

This represents the coordinate transform required to transform the layer which is being rendered back to the CRS of the rendered map.

Set to an invalid QgsCoordinateTransform to indicate that no transformation is required.

See also

coordinateTransform()

Parameters:

t (QgsCoordinateTransform) –

setCurrentFrame(self, frame: int)

Sets the current frame of the map, for maps which are part of an animation.

Defaults to -1 if the map is not associated with an animation.

See also

currentFrame()

New in version 3.26.

Parameters:

frame (int) –

setCurrentMaskId(self, id: int)

Stores a mask id as the “current” one.

See also

currentMaskId()

New in version 3.12.

Parameters:

id (int) –

setCustomRenderingFlag(self, flag: str, value: Any)

Sets a custom rendering flag. Layers might honour these to alter their rendering.

Parameters:

• flag (str) – the flag name

• value (Any) – the flag value

See also

customRenderingFlags()

New in version 3.12.

setDevicePixelRatio(self, ratio: float)

Sets the device pixel ratio.

Common values are 1 for normal-dpi displays and 2 for high-dpi “retina” displays.

See also

devicePixelRatio()

New in version 3.22.

Parameters:

ratio (float) –

setDisabledSymbolLayers(self, symbolLayers: Iterable[QgsSymbolLayer])

When rendering a map layer in a second pass (for selective masking), some symbol layers may be disabled.

Sets the list of disabled symbol layers.

See also

disabledSymbolLayers()

See also

isSymbolLayerEnabled()

New in version 3.12.

Parameters:

symbolLayers (Iterable[QgsSymbolLayer]) –

setDistanceArea(self, distanceArea: QgsDistanceArea)

A general purpose distance and area calculator, capable of performing ellipsoid based calculations. Will be used to convert meter distances to active MapUnit values for QgsUnitTypes.RenderMetersInMapUnits

New in version 3.0.

Parameters:

distanceArea (QgsDistanceArea) –

setDpiTarget(self, dpi: float)

Sets the targeted dpi for rendering.

See also

dpiTarget()

New in version 3.20.

Parameters:

dpi (float) –

setDrawEditingInformation(self, b: bool)

Sets whether edit markers should be drawn during the render operation.

See also

drawEditingInformation()

Parameters:

b (bool) –

setExpressionContext(self, context: QgsExpressionContext)

Sets the expression context. This context is used for all expression evaluation associated with this render context.

See also

expressionContext()

New in version 2.12.

Parameters:

context (QgsExpressionContext) –

setExtent(self, extent: QgsRectangle)

When rendering a map layer, calling this method sets the “clipping” extent for the layer (in the layer’s CRS).

This extent should be a “worst-case” scenario, which is guaranteed to completely cover the entire visible portion of the layer when it is rendered to the map. It may be larger than the actual visible area, but MUST contain at least the entire visible area.

See also

setExtent()

See also

setMapExtent()

Parameters:

extent (QgsRectangle) –

setFeatureClipGeometry(self, geometry: QgsGeometry)

Sets a geometry to use to clip features at render time.

Note

This is not usually set directly, but rather specified by calling QgsMapSettings:addClippingRegion() prior to constructing a QgsRenderContext.

See also

featureClipGeometry()

New in version 3.16.

Parameters:

geometry (QgsGeometry) –

setFeatureFilterProvider(self, ffp: QgsFeatureFilterProvider)

Set a filter feature provider used for additional filtering of rendered features.

Parameters:

ffp (QgsFeatureFilterProvider) – the filter feature provider

See also

featureFilterProvider()

New in version 2.14.

setFeedback(self, feedback: QgsFeedback)

Attach a feedback object that can be queried regularly during rendering to check if rendering should be canceled.

Ownership of feedback is NOT transferred, and the caller must take care that it exists for the lifetime of the render context.

See also

feedback()

New in version 3.22.

Parameters:

feedback (QgsFeedback) –

setFlag(self, flag: Qgis.RenderContextFlag, on: bool = True)

Enable or disable a particular flag (other flags are not affected)

New in version 2.14.

Parameters:

• flag (Qgis.RenderContextFlag) –

• on (bool = True) –

setFlags(self, flags: Qgis.RenderContextFlags | Qgis.RenderContextFlag)

Set combination of flags that will be used for rendering.

New in version 2.14.

Parameters:

flags (Union[Qgis.RenderContextFlags) –

setForceVectorOutput(self, force: bool)

Sets whether rendering operations should use vector operations instead of any faster raster shortcuts.

See also

forceVectorOutput()

Parameters:

force (bool) –

setFrameRate(self, rate: float)

Sets the frame rate of the map (in frames per second), for maps which are part of an animation.

Defaults to -1 if the map is not associated with an animation.

See also

frameRate()

New in version 3.26.

Parameters:

rate (float) –

setGeometry(self, geometry: QgsAbstractGeometry)

Sets pointer to original (unsegmentized) geometry

Parameters:

geometry (QgsAbstractGeometry) –

setImageFormat(self, format: QImage.Format)

Sets QImage format which should be used for QImages created during rendering.

See also

imageFormat()

New in version 3.22.

Parameters:

format (QImage.Format) –

setIsGuiPreview(self, preview: bool)

Sets GUI preview mode. GUI preview mode is used to change the behavior of some renderings when they are done to preview of symbology in the GUI. This is especially used to display mask symbol layers rather than painting them in a mask painter, which is not meant to be visible, by definition.

See also

isGuiPreview()

New in version 3.12.

Parameters:

preview (bool) –

setMapExtent(self, extent: QgsRectangle)

Sets the original extent of the map being rendered.

Unlike setExtent(), this extent is always in the final destination CRS for the map render and represents the exact bounds of the map being rendered.

See also

mapExtent()

See also

setExtent()

New in version 3.4.8.

Parameters:

extent (QgsRectangle) –

setMapToPixel(self, mtp: QgsMapToPixel)

Sets the context’s map to pixel transform, which transforms between map coordinates and device coordinates.

See also

mapToPixel()

Parameters:

mtp (QgsMapToPixel) –

setMaskIdProvider(self, provider: QgsMaskIdProvider)

Attaches a mask id provider to the context. It will allow some rendering operations to set the current mask id based on the context (label layer names and label rules for instance).

See also

QgsMaskIdProvider

See also

setCurrentMaskId()

See also

maskIdProvider()

New in version 3.12.

Parameters:

provider (QgsMaskIdProvider) –

setMaskPainter(self, p: QPainter, id: int = 0)

Sets a mask QPainter for the render operation. Ownership of the painter is not transferred and the QPainter must stay alive for the duration of any rendering operations. Multiple mask painters can be defined and the second parameter gives a unique identifier to each one.

See also

maskPainter()

Parameters:

• p (QPainter) –

• id (int = 0) –

setOutputSize(self, size: QSize)

Sets the size of the resulting rendered image, in pixels.

See also

outputSize()

New in version 3.22.

Parameters:

size (QSize) –

setPainter(self, p: QPainter)

Sets the destination QPainter for the render operation. Ownership of the painter is not transferred and the QPainter destination must stay alive for the duration of any rendering operations.

See also

painter()

Parameters:

p (QPainter) –

setPainterFlagsUsingContext(self, painter: QPainter = None)

Sets relevant flags on a destination painter, using the flags and settings currently defined for the render context.

If no painter is specified, then the flags will be applied to the render context’s painter().

New in version 3.16.

Parameters:

painter (QPainter = None) –

setPathResolver(self, resolver: QgsPathResolver)

Sets the path resolver for conversion between relative and absolute paths during rendering operations, e.g. for resolving relative symbol paths.

See also

pathResolver()

New in version 3.0.

Parameters:

resolver (QgsPathResolver) –

setRendererScale(self, scale: float)

Sets the renderer map scale. This should match the desired scale denominator for the rendered map, eg 1000.0 for a 1:1000 map render.

See also

rendererScale()

Parameters:

scale (float) –

setRendererUsage(self, usage: Qgis.RendererUsage)

Sets the renderer usage

Note

This usage not alter how the map gets rendered but the intention is that data provider knows the context of rendering and may report that to the backend.

See also

rendererUsage()

New in version 3.24.

Parameters:

usage (Qgis.RendererUsage) –

setRenderingStopped(self, stopped: bool)

Sets whether the rendering operation has been stopped and any ongoing rendering should be canceled immediately.

Note

Since QGIS 3.22 the feedback() member exists as an alternative means of cancellation support.

See also

renderingStopped()

See also

feedback()

See also

setFeedback()

Parameters:

stopped (bool) –

setScaleFactor(self, factor: float)

Sets the scaling factor for the render to convert painter units to physical sizes. This should usually be equal to the number of pixels per millimeter.

See also

scaleFactor()

Parameters:

factor (float) –

setSegmentationTolerance(self, tolerance: float)

Sets the segmentation tolerance applied when rendering curved geometries

Parameters:

tolerance (float) – the segmentation tolerance

See also

segmentationTolerance()

See also

segmentationToleranceType()

setSegmentationToleranceType(self, type: QgsAbstractGeometry.SegmentationToleranceType)

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

Parameters:

type (QgsAbstractGeometry.SegmentationToleranceType) – the segmentation tolerance typename

See also

segmentationToleranceType()

See also

segmentationTolerance()

setSelectionColor(self, color: QColor | Qt.GlobalColor | QGradient)

Sets the color to use when rendering selected features.

See also

selectionColor()

Parameters:

color (Union[QColor) –

setShowSelection(self, showSelection: bool)

Sets whether vector selections should be shown in the rendered map

Parameters:

showSelection (bool) – set to True if selections should be shown

See also

showSelection()

See also

setSelectionColor()

New in version 2.4.

setSymbologyReferenceScale(self, scale: float)

Sets the symbology reference scale.

This should match the desired scale denominator for the rendered map, eg 1000.0 for a 1:1000 map render. Set to -1 to disable symbology scaling by reference scale.

The symbology reference scale is an optional property which specifies the reference scale at which symbology in paper units (such a millimeters or points) is fixed to. For instance, if scale is set to 1000 then a 2mm thick line will be rendered at exactly 2mm thick when a map is rendered at 1:1000, or 1mm thick when rendered at 1:2000, or 4mm thick at 1:500.

See also

symbologyReferenceScale()

See also

rendererScale()

New in version 3.22.

Parameters:

scale (float) –

setTextRenderFormat(self, format: Qgis.TextRenderFormat)

Sets the text render format, which dictates how text is rendered (e.g. as paths or real text objects).

See also

textRenderFormat()

New in version 3.4.3.

Parameters:

format (Qgis.TextRenderFormat) –

setTextureOrigin(self, origin: QPointF | QPoint | float)

Sets the texture origin, which should be used as a brush transform when rendering using QBrush objects.

See also

textureOrigin()

New in version 3.16.

Parameters:

origin (Union[QPointF) –

setTransformContext(self, context: QgsCoordinateTransformContext)

Sets the context’s coordinate transform context, which stores various information regarding which datum transforms should be used when transforming points from a source to destination coordinate reference system.

See also

transformContext()

New in version 3.0.

Parameters:

context (QgsCoordinateTransformContext) –

setUseAdvancedEffects(self, enabled: bool)

Used to enable or disable advanced effects such as blend modes

See also

useAdvancedEffects()

Parameters:

enabled (bool) –

setUseRenderingOptimization(self, enabled: bool)

Sets whether the rendering optimization (geometry simplification) should be executed

See also

useRenderingOptimization()

Parameters:

enabled (bool) –

setVectorSimplifyMethod(self, simplifyMethod: QgsVectorSimplifyMethod)

Sets the simplification setting to use when rendering vector layers.

This can be used to specify simplification methods to apply during map exports and renders, e.g. to allow vector layers to be simplified to an appropriate maximum level of detail during PDF exports or to speed up layer rendering

The default is to use no simplification.

See also

vectorSimplifyMethod()

New in version 2.4.

Parameters:

simplifyMethod (QgsVectorSimplifyMethod) –

setZRange(self, range: QgsDoubleRange)

Sets the range of z-values which should be rendered.

See also

zRange()

New in version 3.18.

Parameters:

range (QgsDoubleRange) –

showSelection(self) → bool

Returns True if vector selections should be shown in the rendered map

Return type:

bool

Returns:

True if selections should be shown

See also

setShowSelection()

See also

selectionColor()

New in version 2.4.

symbologyReferenceScale(self) → float

Returns the symbology reference scale.

This represents the desired scale denominator for the rendered map, eg 1000.0 for a 1:1000 map render. A value of -1 indicates that symbology scaling by reference scale is disabled.

The symbology reference scale is an optional property which specifies the reference scale at which symbology in paper units (such a millimeters or points) is fixed to. For instance, if the scale is 1000 then a 2mm thick line will be rendered at exactly 2mm thick when a map is rendered at 1:1000, or 1mm thick when rendered at 1:2000, or 4mm thick at 1:500.

See also

setSymbologyReferenceScale()

See also

rendererScale()

New in version 3.22.

Return type:

float

testFlag(self, flag: Qgis.RenderContextFlag) → bool

Check whether a particular flag is enabled.

New in version 2.14.

Parameters:

flag (Qgis.RenderContextFlag) –

Return type:

bool

textRenderFormat(self) → Qgis.TextRenderFormat

Returns the text render format, which dictates how text is rendered (e.g. as paths or real text objects).

See also

setTextRenderFormat()

New in version 3.4.3.

Return type:

Qgis.TextRenderFormat

textureOrigin(self) → QPointF

Returns the texture origin, which should be used as a brush transform when rendering using QBrush objects.

See also

setTextureOrigin()

New in version 3.16.

Return type:

QPointF

transformContext(self) → QgsCoordinateTransformContext

Returns the context’s coordinate transform context, which stores various information regarding which datum transforms should be used when transforming points from a source to destination coordinate reference system.

See also

setTransformContext()

New in version 3.0.

Return type:

QgsCoordinateTransformContext

useAdvancedEffects(self) → bool

Returns True if advanced effects such as blend modes such be used

See also

setUseAdvancedEffects()

Return type:

bool

useRenderingOptimization(self) → bool

Returns True if the rendering optimization (geometry simplification) can be executed

See also

setUseRenderingOptimization()

Return type:

bool

vectorSimplifyMethod(self) → QgsVectorSimplifyMethod

Returns the simplification settings to use when rendering vector layers.

The default is to use no simplification.

See also

setVectorSimplifyMethod()

New in version 2.4.

Return type:

QgsVectorSimplifyMethod

zRange(self) → QgsDoubleRange

Returns the range of z-values which should be rendered.

See also

setZRange()

New in version 3.18.

Return type:

QgsDoubleRange