QGIS API Documentation
3.2.0-Bonn (bc43194)
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The QgsLabelFeature class describes a feature that should be used within the labeling engine. More...
#include <qgslabelfeature.h>
Public Member Functions | |
QgsLabelFeature (QgsFeatureId id, geos::unique_ptr geometry, QSizeF size) | |
Create label feature, takes ownership of the geometry instance. More... | |
virtual | ~QgsLabelFeature () |
Clean up geometry and curved label info (if present) More... | |
bool | alwaysShow () const |
Whether label should be always shown (sets very high label priority) More... | |
pal::LabelInfo * | curvedLabelInfo () const |
Gets additional infor required for curved label placement. Returns null if not set. More... | |
double | distLabel () const |
Applies to "around point" placement strategy or linestring features. More... | |
double | fixedAngle () const |
Angle in degrees of the fixed angle (relevant only if hasFixedAngle() returns true) More... | |
QgsPointXY | fixedPosition () const |
Coordinates of the fixed position (relevant only if hasFixedPosition() returns true) More... | |
GEOSGeometry * | geometry () const |
Gets access to the associated geometry. More... | |
bool | hasFixedAngle () const |
Whether the label should use a fixed angle instead of using angle from automatic placement. More... | |
bool | hasFixedPosition () const |
Whether the label should use a fixed position instead of being automatically placed. More... | |
bool | hasFixedQuadrant () const |
Returns whether the quadrant for the label is fixed. More... | |
QgsFeatureId | id () const |
Identifier of the label (unique within the parent label provider) More... | |
bool | isObstacle () const |
Returns whether the feature will act as an obstacle for labels. More... | |
QString | labelText () const |
Text of the label. More... | |
pal::Layer * | layer () const |
Gets PAL layer of the label feature. Should be only used internally in PAL. More... | |
double | obstacleFactor () const |
Returns the obstacle factor for the feature. More... | |
GEOSGeometry * | obstacleGeometry () const |
Returns the label's obstacle geometry, if different to the feature geometry. More... | |
QgsPalLayerSettings::OffsetType | offsetType () const |
Returns the offset type, which determines how offsets and distance to label behaves. More... | |
QgsGeometry | permissibleZone () const |
Returns the label's permissible zone geometry. More... | |
const GEOSPreparedGeometry * | permissibleZonePrepared () const |
Returns a GEOS prepared geometry representing the label's permissibleZone(). More... | |
QgsPointXY | positionOffset () const |
Applies only to "offset from point" placement strategy. More... | |
QVector< QgsPalLayerSettings::PredefinedPointPosition > | predefinedPositionOrder () const |
Returns the priority ordered list of predefined positions for label candidates. More... | |
double | priority () const |
Returns the feature's labeling priority. More... | |
QgsAbstractLabelProvider * | provider () const |
Returns provider of this instance. More... | |
QPointF | quadOffset () const |
Applies to "offset from point" placement strategy and "around point" (in case hasFixedQuadrant() returns true). More... | |
double | repeatDistance () const |
Applies only to linestring features - after what distance (in map units) the labels should be repeated (0 = no repetitions) More... | |
void | setAlwaysShow (bool enabled) |
Sets whether label should be always shown (sets very high label priority) More... | |
void | setCurvedLabelInfo (pal::LabelInfo *info) |
takes ownership of the instance More... | |
void | setDistLabel (double dist) |
Applies to "around point" placement strategy or linestring features. More... | |
void | setFixedAngle (double angle) |
Sets angle in degrees of the fixed angle (relevant only if hasFixedAngle() returns true) More... | |
void | setFixedPosition (const QgsPointXY &point) |
Sets coordinates of the fixed position (relevant only if hasFixedPosition() returns true) More... | |
void | setHasFixedAngle (bool enabled) |
Sets whether the label should use a fixed angle instead of using angle from automatic placement. More... | |
void | setHasFixedPosition (bool enabled) |
Sets whether the label should use a fixed position instead of being automatically placed. More... | |
void | setHasFixedQuadrant (bool enabled) |
Sets whether the quadrant for the label must be respected. More... | |
void | setIsObstacle (bool enabled) |
Sets whether the feature will act as an obstacle for labels. More... | |
void | setLabelText (const QString &text) |
Sets text of the label. More... | |
void | setLayer (pal::Layer *layer) |
Assign PAL layer to the label feature. Should be only used internally in PAL. More... | |
void | setObstacleFactor (double factor) |
Sets the obstacle factor for the feature. More... | |
void | setObstacleGeometry (geos::unique_ptr obstacleGeom) |
Sets the label's obstacle geometry, if different to the feature geometry. More... | |
void | setOffsetType (QgsPalLayerSettings::OffsetType type) |
Sets the offset type, which determines how offsets and distance to label behaves. More... | |
void | setPermissibleZone (const QgsGeometry &geometry) |
Sets the label's permissible zone geometry. More... | |
void | setPositionOffset (const QgsPointXY &offset) |
Applies only to "offset from point" placement strategy. More... | |
void | setPredefinedPositionOrder (const QVector< QgsPalLayerSettings::PredefinedPointPosition > &order) |
Sets the priority ordered list of predefined positions for label candidates. More... | |
void | setPriority (double priority) |
Sets the priority for labeling the feature. More... | |
void | setQuadOffset (QPointF quadOffset) |
Set which side of the point to use. More... | |
void | setRepeatDistance (double dist) |
Applies only to linestring features - set after what distance (in map units) the labels should be repeated (0 = no repetitions) More... | |
void | setSymbolSize (QSizeF size) |
Sets the size of the rendered symbol associated with this feature. More... | |
void | setVisualMargin (const QgsMargins &margin) |
Sets the visual margin for the label feature. More... | |
void | setZIndex (double zIndex) |
Sets the label's z-index. More... | |
QSizeF | size () const |
Size of the label (in map units) More... | |
const QSizeF & | symbolSize () const |
Returns the size of the rendered symbol associated with this feature, if applicable. More... | |
const QgsMargins & | visualMargin () const |
Returns the visual margin for the label feature. More... | |
double | zIndex () const |
Returns the label's z-index. More... | |
Protected Attributes | |
bool | mAlwaysShow |
whether to always show label - even in case of collisions More... | |
double | mDistLabel |
distance of label from the feature (only for "around point" placement or linestrings) More... | |
double | mFixedAngle |
fixed rotation for the label (instead of automatic choice) More... | |
QgsPointXY | mFixedPosition |
fixed position for the label (instead of automatic placement) More... | |
geos::unique_ptr | mGeometry |
Geometry of the feature to be labelled. More... | |
bool | mHasFixedAngle |
whether mFixedAngle should be respected More... | |
bool | mHasFixedPosition |
whether mFixedPosition should be respected More... | |
bool | mHasFixedQuadrant |
whether mQuadOffset should be respected (only for "around point" placement) More... | |
QgsFeatureId | mId |
Associated ID unique within the parent label provider. More... | |
pal::LabelInfo * | mInfo = nullptr |
extra information for curved labels (may be null) More... | |
bool | mIsObstacle |
whether the feature geometry acts as an obstacle for labels More... | |
QString | mLabelText |
text of the label More... | |
pal::Layer * | mLayer = nullptr |
Pointer to PAL layer (assigned when registered to PAL) More... | |
double | mObstacleFactor |
how strong is the geometry acting as obstacle More... | |
geos::unique_ptr | mObstacleGeometry |
Optional geometry to use for label obstacles, if different to mGeometry. More... | |
QgsPalLayerSettings::OffsetType | mOffsetType |
Offset type for certain placement modes. More... | |
QgsGeometry | mPermissibleZone |
Optional geometry to use for label's permissible zone. More... | |
QgsPointXY | mPositionOffset |
offset of label from the feature (only for "offset from point" placement) More... | |
QVector< QgsPalLayerSettings::PredefinedPointPosition > | mPredefinedPositionOrder |
Ordered list of predefined positions for label (only for OrderedPositionsAroundPoint placement) More... | |
double | mPriority |
Priority of the label. More... | |
QPointF | mQuadOffset |
whether the side of the label is fixed (only for "around point" placement) More... | |
double | mRepeatDistance |
distance after which label should be repeated (only for linestrings) More... | |
QSizeF | mSize |
Width and height of the label. More... | |
QSizeF | mSymbolSize |
Size of associated rendered symbol, if applicable. More... | |
QgsMargins | mVisualMargin |
Visual margin of label contents. More... | |
double | mZIndex |
Z-index of label (higher z-index labels are rendered on top of lower z-index labels) More... | |
The QgsLabelFeature class describes a feature that should be used within the labeling engine.
Those may be the usual textual labels, diagrams, or any other custom type of map annotations (generated by custom label providers).
Instances only contain data relevant to the labeling engine (geometry, label size etc.) necessary for the layout. Rendering of labels is done by label providers.
Individual label providers may create subclasses of QgsLabelFeature in order to add more data to the instances that will be later used for drawing of labels.
Definition at line 53 of file qgslabelfeature.h.
QgsLabelFeature::QgsLabelFeature | ( | QgsFeatureId | id, |
geos::unique_ptr | geometry, | ||
QSizeF | size | ||
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Create label feature, takes ownership of the geometry instance.
Definition at line 20 of file qgslabelfeature.cpp.
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Clean up geometry and curved label info (if present)
Definition at line 39 of file qgslabelfeature.cpp.
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Whether label should be always shown (sets very high label priority)
Definition at line 302 of file qgslabelfeature.h.
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Gets additional infor required for curved label placement. Returns null if not set.
Definition at line 348 of file qgslabelfeature.h.
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Applies to "around point" placement strategy or linestring features.
Distance of the label from the feature (in map units)
Definition at line 267 of file qgslabelfeature.h.
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Angle in degrees of the fixed angle (relevant only if hasFixedAngle() returns true)
Definition at line 201 of file qgslabelfeature.h.
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Coordinates of the fixed position (relevant only if hasFixedPosition() returns true)
Definition at line 192 of file qgslabelfeature.h.
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Gets access to the associated geometry.
Definition at line 66 of file qgslabelfeature.h.
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Whether the label should use a fixed angle instead of using angle from automatic placement.
Definition at line 197 of file qgslabelfeature.h.
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Whether the label should use a fixed position instead of being automatically placed.
Definition at line 188 of file qgslabelfeature.h.
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Returns whether the quadrant for the label is fixed.
Applies to "around point" placement strategy.
Definition at line 211 of file qgslabelfeature.h.
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Identifier of the label (unique within the parent label provider)
Definition at line 63 of file qgslabelfeature.h.
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Returns whether the feature will act as an obstacle for labels.
Definition at line 311 of file qgslabelfeature.h.
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Text of the label.
Used also if "merge connected lines to avoid duplicate labels" is enabled to identify which features may be merged.
Definition at line 343 of file qgslabelfeature.h.
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Gets PAL layer of the label feature. Should be only used internally in PAL.
Definition at line 353 of file qgslabelfeature.h.
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Returns the obstacle factor for the feature.
The factor controls the penalty for labels overlapping this feature.
Definition at line 325 of file qgslabelfeature.h.
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Returns the label's obstacle geometry, if different to the feature geometry.
Definition at line 84 of file qgslabelfeature.h.
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Returns the offset type, which determines how offsets and distance to label behaves.
Support depends on which placement mode is used for generating label candidates.
Definition at line 253 of file qgslabelfeature.h.
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Returns the label's permissible zone geometry.
If a valid geometry is returned, the feature's label MUST be fully contained within this zone, and the feature will not be labeled if no candidates can be generated which are not contained within the zone.
Definition at line 105 of file qgslabelfeature.h.
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Returns a GEOS prepared geometry representing the label's permissibleZone().
Definition at line 113 of file qgslabelfeature.h.
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Applies only to "offset from point" placement strategy.
What offset (in map units) to use from the point
Definition at line 239 of file qgslabelfeature.h.
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Returns the priority ordered list of predefined positions for label candidates.
This property is only used for OrderedPositionsAroundPoint placements.
Definition at line 280 of file qgslabelfeature.h.
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Returns the feature's labeling priority.
Definition at line 159 of file qgslabelfeature.h.
QgsAbstractLabelProvider * QgsLabelFeature::provider | ( | ) | const |
Returns provider of this instance.
Definition at line 356 of file qgslabelingengine.cpp.
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Applies to "offset from point" placement strategy and "around point" (in case hasFixedQuadrant() returns true).
Determines which side of the point to use. For X coordinate, values -1, 0, 1 mean left, center, right. For Y coordinate, values -1, 0, 1 mean above, center, below.
Definition at line 227 of file qgslabelfeature.h.
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Applies only to linestring features - after what distance (in map units) the labels should be repeated (0 = no repetitions)
Definition at line 293 of file qgslabelfeature.h.
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Sets whether label should be always shown (sets very high label priority)
Definition at line 304 of file qgslabelfeature.h.
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takes ownership of the instance
Definition at line 350 of file qgslabelfeature.h.
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Applies to "around point" placement strategy or linestring features.
Set distance of the label from the feature (in map units)
Definition at line 273 of file qgslabelfeature.h.
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Sets angle in degrees of the fixed angle (relevant only if hasFixedAngle() returns true)
Definition at line 203 of file qgslabelfeature.h.
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Sets coordinates of the fixed position (relevant only if hasFixedPosition() returns true)
Definition at line 194 of file qgslabelfeature.h.
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Sets whether the label should use a fixed angle instead of using angle from automatic placement.
Definition at line 199 of file qgslabelfeature.h.
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Sets whether the label should use a fixed position instead of being automatically placed.
Definition at line 190 of file qgslabelfeature.h.
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Sets whether the quadrant for the label must be respected.
This can be used to fix the quadrant for specific features when using an "around point" placement.
Definition at line 219 of file qgslabelfeature.h.
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Sets whether the feature will act as an obstacle for labels.
enabled | whether feature will act as an obstacle |
Definition at line 318 of file qgslabelfeature.h.
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Sets text of the label.
Definition at line 345 of file qgslabelfeature.h.
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Assign PAL layer to the label feature. Should be only used internally in PAL.
Definition at line 355 of file qgslabelfeature.h.
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Sets the obstacle factor for the feature.
The factor controls the penalty for labels overlapping this feature.
factor | larger factors ( > 1.0 ) will result in labels which are less likely to cover this feature, smaller factors ( < 1.0 ) mean labels are more likely to cover this feature (where required) |
Definition at line 335 of file qgslabelfeature.h.
void QgsLabelFeature::setObstacleGeometry | ( | geos::unique_ptr | obstacleGeom | ) |
Sets the label's obstacle geometry, if different to the feature geometry.
This can be used to override the shape of the feature for obstacle detection, e.g., to buffer around a point geometry to prevent labels being placed too close to the point itself. It not set, the feature's geometry is used for obstacle detection. Ownership of obstacle geometry is transferred.
Definition at line 50 of file qgslabelfeature.cpp.
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Sets the offset type, which determines how offsets and distance to label behaves.
Support depends on which placement mode is used for generating label candidates.
Definition at line 261 of file qgslabelfeature.h.
void QgsLabelFeature::setPermissibleZone | ( | const QgsGeometry & | geometry | ) |
Sets the label's permissible zone geometry.
If set, the feature's label MUST be fully contained within this zone, and the feature will not be labeled if no candidates can be generated which are not contained within the zone.
geometry | permissible zone geometry. If an invalid QgsGeometry is passed then no zone limit will be applied to the label candidates (this is the default behavior). |
Definition at line 55 of file qgslabelfeature.cpp.
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Applies only to "offset from point" placement strategy.
Set what offset (in map units) to use from the point
Definition at line 245 of file qgslabelfeature.h.
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Sets the priority ordered list of predefined positions for label candidates.
This property is only used for OrderedPositionsAroundPoint placements.
Definition at line 287 of file qgslabelfeature.h.
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Sets the priority for labeling the feature.
priority | feature's priority, as a value between 0 (highest priority) and 1 (lowest priority). Set to -1.0 to use the layer's default priority for this feature. |
Definition at line 168 of file qgslabelfeature.h.
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Set which side of the point to use.
Definition at line 233 of file qgslabelfeature.h.
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Applies only to linestring features - set after what distance (in map units) the labels should be repeated (0 = no repetitions)
Definition at line 299 of file qgslabelfeature.h.
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Sets the size of the rendered symbol associated with this feature.
This size is taken into account in certain label placement modes to avoid placing labels over the rendered symbol for this feature.
Definition at line 142 of file qgslabelfeature.h.
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Sets the visual margin for the label feature.
The visual margin represents a margin within the label which should not be considered when calculating the positions of candidates for the label feature. It is used in certain label placement modes to adjust the position of candidates so that they all appear to be at visually equal distances from a point feature. For instance, this can be used to place labels which sit above a point so that their baseline rather then the descender of the label is at a preset distance from the point.
margin | visual margins for label |
Definition at line 128 of file qgslabelfeature.h.
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Sets the label's z-index.
Higher z-index labels are rendered on top of lower z-index labels.
zIndex | z-index for label |
Definition at line 185 of file qgslabelfeature.h.
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Size of the label (in map units)
Definition at line 116 of file qgslabelfeature.h.
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Returns the size of the rendered symbol associated with this feature, if applicable.
This size is taken into account in certain label placement modes to avoid placing labels over the rendered symbol for this feature. The size will only be set for labels associated with a point feature.
Definition at line 151 of file qgslabelfeature.h.
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Returns the visual margin for the label feature.
Definition at line 134 of file qgslabelfeature.h.
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Returns the label's z-index.
Higher z-index labels are rendered on top of lower z-index labels.
Definition at line 176 of file qgslabelfeature.h.
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whether to always show label - even in case of collisions
Definition at line 405 of file qgslabelfeature.h.
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distance of label from the feature (only for "around point" placement or linestrings)
Definition at line 397 of file qgslabelfeature.h.
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fixed rotation for the label (instead of automatic choice)
Definition at line 389 of file qgslabelfeature.h.
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fixed position for the label (instead of automatic placement)
Definition at line 385 of file qgslabelfeature.h.
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Geometry of the feature to be labelled.
Definition at line 367 of file qgslabelfeature.h.
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whether mFixedAngle should be respected
Definition at line 387 of file qgslabelfeature.h.
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whether mFixedPosition should be respected
Definition at line 383 of file qgslabelfeature.h.
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whether mQuadOffset should be respected (only for "around point" placement)
Definition at line 391 of file qgslabelfeature.h.
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Associated ID unique within the parent label provider.
Definition at line 365 of file qgslabelfeature.h.
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extra information for curved labels (may be null)
Definition at line 413 of file qgslabelfeature.h.
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whether the feature geometry acts as an obstacle for labels
Definition at line 407 of file qgslabelfeature.h.
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text of the label
Definition at line 411 of file qgslabelfeature.h.
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Pointer to PAL layer (assigned when registered to PAL)
Definition at line 362 of file qgslabelfeature.h.
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how strong is the geometry acting as obstacle
Definition at line 409 of file qgslabelfeature.h.
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Optional geometry to use for label obstacles, if different to mGeometry.
Definition at line 369 of file qgslabelfeature.h.
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Offset type for certain placement modes.
Definition at line 399 of file qgslabelfeature.h.
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Optional geometry to use for label's permissible zone.
Definition at line 371 of file qgslabelfeature.h.
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offset of label from the feature (only for "offset from point" placement)
Definition at line 395 of file qgslabelfeature.h.
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Ordered list of predefined positions for label (only for OrderedPositionsAroundPoint placement)
Definition at line 401 of file qgslabelfeature.h.
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Priority of the label.
Definition at line 379 of file qgslabelfeature.h.
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whether the side of the label is fixed (only for "around point" placement)
Definition at line 393 of file qgslabelfeature.h.
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distance after which label should be repeated (only for linestrings)
Definition at line 403 of file qgslabelfeature.h.
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Width and height of the label.
Definition at line 373 of file qgslabelfeature.h.
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Size of associated rendered symbol, if applicable.
Definition at line 377 of file qgslabelfeature.h.
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Visual margin of label contents.
Definition at line 375 of file qgslabelfeature.h.
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Z-index of label (higher z-index labels are rendered on top of lower z-index labels)
Definition at line 381 of file qgslabelfeature.h.