Subgroup: Render
Class: QgsRenderContext¶
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class
qgis.core.
QgsRenderContext
¶ Bases:
sip.wrapper
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. *
Methods
convertFromMapUnits
Converts a size from map units to the specified units. convertMetersToMapUnits
Convert meter distances to active MapUnit values for QgsUnitTypes.RenderMetersInMapUnits 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, or an invalid transform is no coordinate transformation is required. distanceArea
A general purpose distance and area calculator, capable of performing ellipsoid based calculations. drawEditingInformation
expressionContext
Gets the expression context. extent
featureFilterProvider
Get the filter feature provider used for additional filtering of rendered features. flags
Return combination of flags used for rendering. forceVectorOutput
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 mapToPixel
painter
Returns the destination QPainter for the render operation. rendererScale
Returns the renderer map scale. renderingStopped
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
setCoordinateTransform
Sets coordinate transformation. setDistanceArea
A general purpose distance and area calculator, capable of performing ellipsoid based calculations. setDrawEditingInformation
setExpressionContext
Sets the expression context. setExtent
setFeatureFilterProvider
Set a filter feature provider used for additional filtering of rendered features. setFlag
Enable or disable a particular flag (other flags are not affected) setFlags
Set combination of flags that will be used for rendering. setForceVectorOutput
setGeometry
Sets pointer to original (unsegmentized) geometry setMapToPixel
setPainter
Sets the destination QPainter for the render operation. setRendererScale
Sets the renderer map scale. setRenderingStopped
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
setShowSelection
Sets whether vector selections should be shown in the rendered map 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
setVectorSimplifyMethod
showSelection
Returns true if vector selections should be shown in the rendered map testFlag
Check whether a particular flag is enabled. 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
Added in QGIS v2.4 Attributes
Antialiasing
DrawEditingInfo
DrawSelection
DrawSymbolBounds
ForceVectorOutput
RenderMapTile
RenderPartialOutput
RenderPreviewJob
UseAdvancedEffects
UseRenderingOptimization
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Antialiasing
= 128¶
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DrawEditingInfo
= 1¶
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DrawSelection
= 16¶
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DrawSymbolBounds
= 32¶
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class
Flag
¶ Bases:
int
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class
Flags
¶ Bases:
sip.wrapper
QgsRenderContext.Flags(Union[QgsRenderContext.Flags, QgsRenderContext.Flag]) QgsRenderContext.Flags(QgsRenderContext.Flags)
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ForceVectorOutput
= 2¶
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RenderMapTile
= 64¶
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RenderPartialOutput
= 256¶
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RenderPreviewJob
= 512¶
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UseAdvancedEffects
= 4¶
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UseRenderingOptimization
= 8¶
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convertFromMapUnits
(self, sizeInMapUnits: float, outputUnit: QgsUnitTypes.RenderUnit) → float¶ Converts a size from map units to the specified units.
New in version 3.0.
See also
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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.
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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.
New in version 3.0.
See also
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convertToPainterUnits
(self, size: float, unit: QgsUnitTypes.RenderUnit, scale: QgsMapUnitScale = QgsMapUnitScale()) → float¶ Converts a size from the specified units to painter units (pixels). The conversion respects the limits specified by the optional scale parameter.
New in version 3.0.
See also
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coordinateTransform
(self) → QgsCoordinateTransform¶ Returns the current coordinate transform for the context, or an invalid transform is no coordinate transformation is required.
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distanceArea
(self) → QgsDistanceArea¶ A general purpose distance and area calculator, capable of performing ellipsoid based calculations.
New in version 3.0.
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drawEditingInformation
(self) → bool¶
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expressionContext
(self) → QgsExpressionContext¶ Gets the expression context. This context should be used for all expression evaluation associated with this render context.
See also
New in version 2.12.
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extent
(self) → QgsRectangle¶
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featureFilterProvider
(self) → QgsFeatureFilterProvider¶ Get the filter feature provider used for additional filtering of rendered features.
Returns: the filter feature provider New in version 2.14.
See also
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flags
(self) → QgsRenderContext.Flags¶ Return combination of flags used for rendering.
New in version 2.14.
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forceVectorOutput
(self) → bool¶
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fromMapSettings
(mapSettings: QgsMapSettings) → QgsRenderContext¶ create initialized QgsRenderContext instance from given
QgsMapSettings
New in version 2.4.
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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.
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geometry
(self) → QgsAbstractGeometry¶ Returns pointer to the unsegmentized geometry
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mapToPixel
(self) → QgsMapToPixel¶
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painter
(self) → QPainter¶ Returns the destination QPainter for the render operation.
See also
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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
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renderingStopped
(self) → bool¶
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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
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segmentationTolerance
(self) → float¶ Gets the segmentation tolerance applied when rendering curved geometries
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segmentationToleranceType
(self) → QgsAbstractGeometry.SegmentationToleranceType¶ Gets segmentation tolerance type (maximum angle or maximum difference between curve and approximation)
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selectionColor
(self) → QColor¶
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setCoordinateTransform
(self, t: QgsCoordinateTransform)¶ Sets coordinate transformation.
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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.
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setDrawEditingInformation
(self, b: bool)¶
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setExpressionContext
(self, context: QgsExpressionContext)¶ Sets the expression context. This context is used for all expression evaluation associated with this render context.
See also
New in version 2.12.
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setExtent
(self, extent: QgsRectangle)¶
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setFeatureFilterProvider
(self, ffp: QgsFeatureFilterProvider)¶ Set a filter feature provider used for additional filtering of rendered features.
Parameters: ffp – the filter feature provider New in version 2.14.
See also
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setFlag
(self, flag: QgsRenderContext.Flag, on: bool = True)¶ Enable or disable a particular flag (other flags are not affected)
New in version 2.14.
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setFlags
(self, flags: Union[QgsRenderContext.Flags, QgsRenderContext.Flag])¶ Set combination of flags that will be used for rendering.
New in version 2.14.
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setForceVectorOutput
(self, force: bool)¶
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setGeometry
(self, geometry: QgsAbstractGeometry)¶ Sets pointer to original (unsegmentized) geometry
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setMapToPixel
(self, mtp: QgsMapToPixel)¶
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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
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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
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setRenderingStopped
(self, stopped: bool)¶
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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
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setSegmentationTolerance
(self, tolerance: float)¶ Sets the segmentation tolerance applied when rendering curved geometries
Parameters: tolerance – the segmentation tolerance*
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setSegmentationToleranceType
(self, type: QgsAbstractGeometry.SegmentationToleranceType)¶ Sets segmentation tolerance type (maximum angle or maximum difference between curve and approximation)
Parameters: type – the segmentation tolerance typename*
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setSelectionColor
(self, color: Union[QColor, Qt.GlobalColor, QGradient])¶
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setShowSelection
(self, showSelection: bool)¶ Sets whether vector selections should be shown in the rendered map
Parameters: showSelection – set to true if selections should be shown See also
See also
New in version 2.4.
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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.New in version 3.0.
See also
-
setUseAdvancedEffects
(self, enabled: bool)¶ Used to enable or disable advanced effects such as blend modes
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setUseRenderingOptimization
(self, enabled: bool)¶
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setVectorSimplifyMethod
(self, simplifyMethod: QgsVectorSimplifyMethod)¶
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showSelection
(self) → bool¶ Returns true if vector selections should be shown in the rendered map
Returns: true if selections should be shown See also
See also
New in version 2.4.
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testFlag
(self, flag: QgsRenderContext.Flag) → bool¶ Check whether a particular flag is enabled.
New in version 2.14.
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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.
New in version 3.0.
See also
-
useAdvancedEffects
(self) → bool¶ Returns true if advanced effects such as blend modes such be used
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useRenderingOptimization
(self) → bool¶ Returns true if the rendering optimization (geometry simplification) can be executed
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vectorSimplifyMethod
(self) → QgsVectorSimplifyMethod¶ Added in QGIS v2.4
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