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5e4c14cd40
A new control for setting a label's "z-index" has been added to the labeling properties dialog. This control (which also accepts data-defined overrides for individual features) determines the order in which label are rendered. Label layers with a higher z-index are rendered on top of labels from a layer with lower z-index. Additionally, the logic has been tweaks so that if 2 labels have matching z-indexes, then: - if they are from the same layer, a smaller label will be drawn above a larger label - if they are from different layers, the labels will be drawn in the same order as the layers themselves (ie respecting the order set in the legend) Diagrams can also have their z-index set (but not data defined) so that the order of labels and diagrams can be controlled. Note that this does *NOT* allow labels to be drawn below the features from other layers, it just controls the order in which labels are drawn on top of all the layer's features. Fix #13888, #13559
119 lines
5.4 KiB
C++
119 lines
5.4 KiB
C++
/***************************************************************************
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qgsvectorlayerlabelprovider.h
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--------------------------------------
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Date : September 2015
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Copyright : (C) 2015 by Martin Dobias
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Email : wonder dot sk at gmail dot com
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***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************/
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#ifndef QGSVECTORLAYERLABELPROVIDER_H
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#define QGSVECTORLAYERLABELPROVIDER_H
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#include "qgslabelingenginev2.h"
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class QgsAbstractFeatureSource;
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class QgsFeatureRendererV2;
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/**
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* @brief The QgsVectorLayerLabelProvider class implements a label provider
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* for vector layers. Parameters for the labeling are taken from the layer's
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* custom properties or from the given settings.
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*
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* @note added in QGIS 2.12
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* @note this class is not a part of public API yet. See notes in QgsLabelingEngineV2
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* @note not available in Python bindings
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*/
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class CORE_EXPORT QgsVectorLayerLabelProvider : public QgsAbstractLabelProvider
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{
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public:
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//! Convenience constructor to initialize the provider from given vector layer
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explicit QgsVectorLayerLabelProvider( QgsVectorLayer* layer, bool withFeatureLoop = true, const QgsPalLayerSettings* settings = nullptr, const QString& layerName = QString() );
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//! Construct diagram provider with all the necessary configuration parameters
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QgsVectorLayerLabelProvider( const QgsPalLayerSettings& settings,
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const QString& layerId,
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const QgsFields& fields,
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const QgsCoordinateReferenceSystem& crs,
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QgsAbstractFeatureSource* source,
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bool ownsSource,
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QgsFeatureRendererV2* renderer = nullptr );
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~QgsVectorLayerLabelProvider();
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virtual QList<QgsLabelFeature*> labelFeatures( QgsRenderContext& context ) override;
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virtual void drawLabel( QgsRenderContext& context, pal::LabelPosition* label ) const override;
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// new virtual methods
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/**
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* Prepare for registration of features. Must be called after provider has been added to engine (uses its map settings)
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* @param context render context.
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* @param attributeNames list of attribute names to which additional required attributes shall be added
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* @return Whether the preparation was successful - if not, the provider shall not be used
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*/
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virtual bool prepare( const QgsRenderContext& context, QStringList& attributeNames );
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/**
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* Register a feature for labeling as one or more QgsLabelFeature objects stored into mLabels
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*
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* @param feature feature to label
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* @param context render context. The QgsExpressionContext contained within the render context
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* must have already had the feature and fields sets prior to calling this method.
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* @param obstacleGeometry optional obstacle geometry, if a different geometry to the feature's geometry
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* should be used as an obstacle for labels (eg, if the feature has been rendered with an offset point
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* symbol, the obstacle geometry should represent the bounds of the offset symbol). If not set,
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* the feature's original geometry will be used as an obstacle for labels.
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*/
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virtual void registerFeature( QgsFeature& feature, QgsRenderContext &context, QgsGeometry* obstacleGeometry = nullptr );
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/** Returns the geometry for a point feature which should be used as an obstacle for labels. This
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* obstacle geometry will respect the dimensions and offsets of the symbol used to render the
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* point, and ensures that labels will not overlap large or offset points.
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* @param fet point feature
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* @param context render context
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* @param renderer renderer used for layer, required to determine symbols rendered for point feature
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* @note added in QGIS 2.14
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*/
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static QgsGeometry* getPointObstacleGeometry( QgsFeature& fet, QgsRenderContext& context, QgsFeatureRendererV2* renderer );
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protected:
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//! initialization method - called from constructors
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void init();
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//! Internal label drawing method
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void drawLabelPrivate( pal::LabelPosition* label, QgsRenderContext& context, QgsPalLayerSettings& tmpLyr, QgsPalLabeling::DrawLabelType drawType, double dpiRatio = 1.0 ) const;
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protected:
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//! Layer's labeling configuration
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QgsPalLayerSettings mSettings;
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//! Geometry type of layer
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QGis::GeometryType mLayerGeometryType;
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QgsFeatureRendererV2* mRenderer;
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// these are needed only if using own renderer loop
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//! Layer's fields
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QgsFields mFields;
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//! Layer's CRS
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QgsCoordinateReferenceSystem mCrs;
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//! Layer's feature source
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QgsAbstractFeatureSource* mSource;
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//! Whether layer's feature source is owned
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bool mOwnsSource;
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//! List of generated
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QList<QgsLabelFeature*> mLabels;
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};
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#endif // QGSVECTORLAYERLABELPROVIDER_H
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