Class: QgsCallout¶
- class qgis.core.QgsCallout¶
Bases:
sip.wrapper
Abstract base class for callout renderers.
Implementations of
QgsCallout
are responsible for performing the actual render of callouts, including determining the desired shape of the callout and using any relevant symbology elements to render them.New in version 3.10.
QgsCallout() Constructor for QgsCallout.
QgsCallout(
QgsCallout
)Enums
Bases:
enum.IntEnum
Methods
Returns the feature's anchor point position.
Returns the blending mode used for drawing callouts.
Returns the anchor point geometry for a label with the given bounding box and
anchor
point mode.Calculates the direct line from a label geometry to an anchor geometry part, respecting the various callout settings which influence how the callout end should be placed in the anchor geometry.
Duplicates a callout by creating a deep copy of the callout.
Returns
True
if the callout requires advanced effects such as blend modes, which require output in raster formats to be fully respected.Returns a reference to the callout's property collection, used for data defined overrides.
Attempts to decode a string representation of an anchor point name to the corresponding anchor point.
Attempts to decode a string representation of a label anchor point name to the corresponding anchor point.
Performs the actual rendering of the callout implementation onto the specified render
context
.Returns the desired drawing order (stacking) to use while rendering this callout.
Returns
True
if the the callout is enabled.Encodes an
anchor
point to its string representation.Encodes a label
anchor
point to its string representation.Returns the anchor point geometry for a label with the given bounding box and
anchor
point mode.Returns the label's anchor point position.
Returns the properties describing the callout encoded in a string format.
Returns the definitions for data defined properties available for use in callouts.
Reads a string map of an callout's properties and restores the callout to the state described by the properties map.
Returns the set of attributes referenced by the callout.
Renders the callout onto the specified render
context
.Restores the callout's properties from a DOM element.
Saves the current state of the callout to a DOM
element
.Sets the feature's
anchor
point position.Sets the blending
mode
used for drawing callouts.Sets the callout's property
collection
, used for data defined overrides.Sets whether the callout is
enabled
.Sets the label's
anchor
point position.Prepares the callout for rendering on the specified render
context
.Finalises the callout after a set of rendering operations on the specified render
context
.Returns a unique string representing the callout type.
Attributes
- class AnchorPoint¶
Bases:
int
- Centroid = 3¶
- class DrawOrder¶
Bases:
int
- class LabelAnchorPoint¶
Bases:
int
- LabelBottomLeft = 7¶
- LabelBottomMiddle = 8¶
- LabelBottomRight = 9¶
- LabelCentroid = 1¶
- LabelMiddleLeft = 5¶
- LabelMiddleRight = 6¶
- LabelPointOnExterior = 0¶
- LabelTopLeft = 2¶
- LabelTopMiddle = 3¶
- LabelTopRight = 4¶
- OrderBelowAllLabels = 0¶
- OrderBelowIndividualLabels = 1¶
- PointOnExterior = 1¶
- PointOnSurface = 2¶
- PoleOfInaccessibility = 0¶
- class Property(value)¶
Bases:
enum.IntEnum
Data definable properties.
MinimumCalloutLength
: Minimum length of calloutsOffsetFromAnchor
: Distance to offset lines from anchor pointsOffsetFromLabel
: Distance to offset lines from label areaDrawCalloutToAllParts
: Whether callout lines should be drawn to all feature partsAnchorPointPosition
: Feature’s anchor point positionLabelAnchorPointPosition
: Label’s anchor point positionOriginX
: X-coordinate of callout origin (label anchor) (since QGIS 3.20)OriginY
: Y-coordinate of callout origin (label anchor) (since QGIS 3.20)DestinationX
: X-coordinate of callout destination (feature anchor) (since QGIS 3.20)DestinationY
: Y-coordinate of callout destination (feature anchor) (since QGIS 3.20)Curvature
: Curvature of curved line callouts (since QGIS 3.20)Orientation
: Orientation of curved line callouts (since QGIS 3.20)Margins
: Margin from text (since QGIS 3.20)WedgeWidth
: Balloon callout wedge width (since QGIS 3.20)CornerRadius
: Balloon callout corner radius (since QGIS 3.20)BlendMode
: Callout blend mode (since QGIS 3.20)
- class QgsCalloutContext¶
Bases:
sip.wrapper
Contains additional contextual information about the context in which a callout is being rendered.
New in version 3.10.
- addCalloutPosition(self, position: QgsCalloutPosition)¶
Adds a rendered callout position.
The position details such as the callout line origin and destination should be populated by the callout subclass during rendering operations.
Note
the feature ID, layer ID and provider ID of the
QgsCalloutPosition
will be automatically populated.New in version 3.20.
- Parameters:
position (QgsCalloutPosition) –
- allFeaturePartsLabeled¶
- originalFeatureCrs¶
- originalFeatureToMapTransform(self, renderContext: QgsRenderContext) QgsCoordinateTransform ¶
Returns the coordinate transform to convert from the original layer associated with the callout to the destination map CRS.
New in version 3.20.
- Parameters:
renderContext (QgsRenderContext) –
- Return type:
- positions(self) List[QgsCalloutPosition] ¶
Returns the list of rendered callout positions.
New in version 3.20.
- Return type:
List[QgsCalloutPosition]
- anchorPoint(self) QgsCallout.AnchorPoint ¶
Returns the feature’s anchor point position.
See also
- Return type:
- blendMode(self) QPainter.CompositionMode ¶
Returns the blending mode used for drawing callouts.
See also
New in version 3.20.
- Return type:
QPainter.CompositionMode
- calloutLabelPoint(self, bodyBoundingBox: QRectF, angle: float, anchor: QgsCallout.LabelAnchorPoint, context: QgsRenderContext, calloutContext: QgsCallout.QgsCalloutContext) Tuple[QgsGeometry, bool] ¶
Returns the anchor point geometry for a label with the given bounding box and
anchor
point mode.The
pinned
argument will be set toTrue
if the callout label point is pinned (manually placed).New in version 3.20.
- Parameters:
bodyBoundingBox (QRectF) –
angle (float) –
anchor (QgsCallout.LabelAnchorPoint) –
context (QgsRenderContext) –
calloutContext (QgsCallout.QgsCalloutContext) –
- Return type:
Tuple[
QgsGeometry
, bool]
- calloutLineToPart(self, labelGeometry: QgsGeometry, partGeometry: QgsAbstractGeometry, context: QgsRenderContext, calloutContext: QgsCallout.QgsCalloutContext) Tuple[QgsGeometry, bool] ¶
Calculates the direct line from a label geometry to an anchor geometry part, respecting the various callout settings which influence how the callout end should be placed in the anchor geometry.
Returns a null geometry if the callout line cannot be calculated.
The
pinned
argument will be set toTrue
if the callout anchor point is pinned (manually placed).New in version 3.20.
- Parameters:
labelGeometry (QgsGeometry) –
partGeometry (QgsAbstractGeometry) –
context (QgsRenderContext) –
calloutContext (QgsCallout.QgsCalloutContext) –
- Return type:
Tuple[
QgsGeometry
, bool]
- clone(self) QgsCallout ¶
Duplicates a callout by creating a deep copy of the callout.
Caller takes ownership of the returned object.
- Return type:
- containsAdvancedEffects(self) bool ¶
Returns
True
if the callout requires advanced effects such as blend modes, which require output in raster formats to be fully respected.New in version 3.20.
- Return type:
bool
- dataDefinedProperties(self) QgsPropertyCollection ¶
Returns a reference to the callout’s property collection, used for data defined overrides.
See also
- Return type:
- decodeAnchorPoint(name: str) Tuple[QgsCallout.AnchorPoint, bool] ¶
Attempts to decode a string representation of an anchor point name to the corresponding anchor point.
- Parameters:
name (str) – encoded anchor point name
ok – if specified, will be set to
True
if the anchor point was successfully decoded
- Return type:
Tuple[QgsCallout.AnchorPoint, bool]
- Returns:
decoded name
See also
- decodeLabelAnchorPoint(name: str) Tuple[QgsCallout.LabelAnchorPoint, bool] ¶
Attempts to decode a string representation of a label anchor point name to the corresponding anchor point.
- Parameters:
name (str) – encoded label anchor point name
ok – if specified, will be set to
True
if the anchor point was successfully decoded
- Return type:
Tuple[QgsCallout.LabelAnchorPoint, bool]
- Returns:
decoded name
See also
New in version 3.14.
- draw(self, context: QgsRenderContext, bodyBoundingBox: QRectF, angle: float, anchor: QgsGeometry, calloutContext: QgsCallout.QgsCalloutContext)¶
Performs the actual rendering of the callout implementation onto the specified render
context
.The
bodyBoundingBox
argument gives the desired size and position of the body of the callout (e.g. the actual label geometry). Theangle
argument specifies the rotation of the callout body (in degrees clockwise from horizontal). It is assumed that angle rotation specified viaangle
is applied around the center ofrect
.The
anchor
argument dictates the geometry which the callout should connect to. Depending on the callout subclass and anchor geometry type, the actual shape of the rendered callout may vary. E.g. a subclass may prefer to attach to the centroid of theanchor
, while another subclass may prefer to attach to the closest point onanchor
instead.Both
rect
andanchor
are specified in painter coordinates (i.e. pixels).The
calloutContext
argument is used to specify additional contextual information about how a callout is being rendered.- Parameters:
context (QgsRenderContext) –
bodyBoundingBox (QRectF) –
angle (float) –
anchor (QgsGeometry) –
calloutContext (QgsCallout.QgsCalloutContext) –
- drawOrder(self) QgsCallout.DrawOrder ¶
Returns the desired drawing order (stacking) to use while rendering this callout.
The default order is QgsCallout.OrderBelowIndividualLabels.
- Return type:
- enabled(self) bool ¶
Returns
True
if the the callout is enabled.See also
- Return type:
bool
- encodeAnchorPoint(anchor: QgsCallout.AnchorPoint) str ¶
Encodes an
anchor
point to its string representation.- Return type:
str
- Returns:
encoded string
See also
- Parameters:
anchor (QgsCallout.AnchorPoint) –
- encodeLabelAnchorPoint(anchor: QgsCallout.LabelAnchorPoint) str ¶
Encodes a label
anchor
point to its string representation.- Return type:
str
- Returns:
encoded string
See also
New in version 3.14.
- Parameters:
anchor (QgsCallout.LabelAnchorPoint) –
- labelAnchorGeometry(self, bodyBoundingBox: QRectF, angle: float, anchor: QgsCallout.LabelAnchorPoint) QgsGeometry ¶
Returns the anchor point geometry for a label with the given bounding box and
anchor
point mode.Deprecated since version QGIS: 3.20 use
calloutLabelPoint()
instead- Parameters:
bodyBoundingBox (QRectF) –
angle (float) –
anchor (QgsCallout.LabelAnchorPoint) –
- Return type:
- labelAnchorPoint(self) QgsCallout.LabelAnchorPoint ¶
Returns the label’s anchor point position.
See also
New in version 3.14.
- Return type:
- properties(self, context: QgsReadWriteContext) Dict[str, Any] ¶
Returns the properties describing the callout encoded in a string format.
Subclasses must ensure that they include the base class’
properties()
in their returned value.See also
See also
- Parameters:
context (QgsReadWriteContext) –
- Return type:
Dict[str, Any]
- propertyDefinitions() Dict[int, QgsPropertyDefinition] ¶
Returns the definitions for data defined properties available for use in callouts.
- Return type:
Dict[int, QgsPropertyDefinition]
- readProperties(self, props: Dict[str, Any], context: QgsReadWriteContext)¶
Reads a string map of an callout’s properties and restores the callout to the state described by the properties map.
Subclasses must ensure that they call the base class’
readProperties()
method.See also
- Parameters:
props (Dict[str) –
context (QgsReadWriteContext) –
- referencedFields(self, context: QgsRenderContext) Set[str] ¶
Returns the set of attributes referenced by the callout. This includes attributes required by any data defined properties associated with the callout.
Warning
This must only be called after a corresponding call to
startRender()
with the same rendercontext
.- Parameters:
context (QgsRenderContext) –
- Return type:
Set[str]
- render(self, context: QgsRenderContext, rect: QRectF, angle: float, anchor: QgsGeometry, calloutContext: QgsCallout.QgsCalloutContext)¶
Renders the callout onto the specified render
context
.The
rect
argument gives the desired size and position of the body of the callout (e.g. the actual label geometry). Theangle
argument specifies the rotation of the callout body (in degrees clockwise from horizontal). It is assumed that angle rotation specified viaangle
is applied around the center ofrect
.The
anchor
argument dictates the geometry which the callout should connect to. Depending on the callout subclass and anchor geometry type, the actual shape of the rendered callout may vary. E.g. a subclass may prefer to attach to the centroid of theanchor
, while another subclass may prefer to attach to the closest point onanchor
instead.Both
rect
andanchor
must be specified in painter coordinates (i.e. pixels).The
calloutContext
argument is used to specify additional contextual information about how a callout is being rendered.Warning
A prior call to
startRender()
must have been made before calling this method, and after allrender()
operations are complete a call tostopRender()
must be made.- Parameters:
context (QgsRenderContext) –
rect (QRectF) –
angle (float) –
anchor (QgsGeometry) –
calloutContext (QgsCallout.QgsCalloutContext) –
- restoreProperties(self, element: QDomElement, context: QgsReadWriteContext)¶
Restores the callout’s properties from a DOM element.
The default behavior is the read the DOM contents and call
readProperties()
on the subclass.See also
- Parameters:
element (QDomElement) –
context (QgsReadWriteContext) –
- saveProperties(self, doc: QDomDocument, element: QDomElement, context: QgsReadWriteContext) bool ¶
Saves the current state of the callout to a DOM
element
. The default behavior is to save the properties string map returned byproperties()
.- Return type:
bool
- Returns:
True
if save was successful
See also
- Parameters:
doc (QDomDocument) –
element (QDomElement) –
context (QgsReadWriteContext) –
- setAnchorPoint(self, anchor: QgsCallout.AnchorPoint)¶
Sets the feature’s
anchor
point position.See also
- Parameters:
anchor (QgsCallout.AnchorPoint) –
- setBlendMode(self, mode: QPainter.CompositionMode)¶
Sets the blending
mode
used for drawing callouts.See also
New in version 3.20.
- Parameters:
mode (QPainter.CompositionMode) –
- setDataDefinedProperties(self, collection: QgsPropertyCollection)¶
Sets the callout’s property
collection
, used for data defined overrides.Any existing properties will be discarded.
See also
See also
Property
- Parameters:
collection (QgsPropertyCollection) –
- setEnabled(self, enabled: bool)¶
Sets whether the callout is
enabled
.See also
- Parameters:
enabled (bool) –
- setLabelAnchorPoint(self, anchor: QgsCallout.LabelAnchorPoint)¶
Sets the label’s
anchor
point position.See also
New in version 3.14.
- Parameters:
anchor (QgsCallout.LabelAnchorPoint) –
- startRender(self, context: QgsRenderContext)¶
Prepares the callout for rendering on the specified render
context
.Warning
This MUST be called prior to calling
render()
on the callout, and must always be accompanied by a corresponding call tostopRender()
.See also
- Parameters:
context (QgsRenderContext) –
- stopRender(self, context: QgsRenderContext)¶
Finalises the callout after a set of rendering operations on the specified render
context
.Warning
This MUST be called after to after
render()
operations on the callout, and must always be accompanied by a corresponding prior call tostartRender()
.See also
- Parameters:
context (QgsRenderContext) –
- type(self) str ¶
Returns a unique string representing the callout type.
- Return type:
str