qgsrulebasedlabeling.h

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/***************************************************************************
    qgsrulebasedlabeling.h
    ---------------------
    begin                : September 2015
    copyright            : (C) 2015 by Martin Dobias
    email                : wonder dot sk at gmail dot com
 ***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
#ifndef QGSRULEBASEDLABELING_H
#define QGSRULEBASEDLABELING_H

#include "qgis_core.h"
#include <QStringList>
#include <QMap>

#include "qgsvectorlayerlabeling.h"
#include "qgsvectorlayerlabelprovider.h"

class QDomDocument;
class QDomElement;

class QgsExpression;
class QgsFeature;
class QgsPalLayerSettings;
class QgsRenderContext;
class QgsGeometry;
class QgsRuleBasedLabelProvider;

class CORE_EXPORT QgsRuleBasedLabeling : public QgsAbstractVectorLayerLabeling
{
  public:
    class Rule;
    typedef QList<QgsRuleBasedLabeling::Rule *> RuleList;
    typedef QMap<QgsRuleBasedLabeling::Rule *, QgsVectorLayerLabelProvider *> RuleToProviderMap;

    class CORE_EXPORT Rule
    {
      public:
        Rule( QgsPalLayerSettings *settings SIP_TRANSFER, double maximumScale = 0, double minimumScale = 0, const QString &filterExp = QString(), const QString &description = QString(), bool elseRule = false );
        ~Rule();

        Rule( const Rule &rh ) = delete;
        Rule &operator=( const Rule &rh ) = delete;

        enum RegisterResult
        {
          Filtered = 0, 
          Inactive,     
          Registered    
        };

        QgsPalLayerSettings *settings() const { return mSettings.get(); }

        bool dependsOnScale() const { return !qgsDoubleNear( mMinimumScale, 0.0 ) || !qgsDoubleNear( mMaximumScale, 0 ); }

        double maximumScale() const { return mMaximumScale; }

        double minimumScale() const { return mMinimumScale; }

        QString filterExpression() const { return mFilterExp; }

        QString description() const { return mDescription; }

        bool active() const { return mIsActive; }

        bool isElse() const { return mElseRule; }

        QString ruleKey() const { return mRuleKey; }

        void setSettings( QgsPalLayerSettings *settings SIP_TRANSFER );

        void setMinimumScale( double scale ) { mMinimumScale = scale; }

        void setMaximumScale( double scale ) { mMaximumScale = scale; }

        void setFilterExpression( const QString &filterExp ) { mFilterExp = filterExp; initFilter(); }

        void setDescription( const QString &description ) { mDescription = description; }

        void setActive( bool state ) { mIsActive = state; }

        void setIsElse( bool iselse ) { mElseRule = iselse; }

        void setRuleKey( const QString &key ) { mRuleKey = key; }

        // parent / child operations

        const QgsRuleBasedLabeling::RuleList &children() const { return mChildren; }

        QgsRuleBasedLabeling::RuleList &children() SIP_SKIP { return mChildren; }

        QgsRuleBasedLabeling::RuleList descendants() const;

        const QgsRuleBasedLabeling::Rule *parent() const SIP_SKIP { return mParent; }

        QgsRuleBasedLabeling::Rule *parent() { return mParent; }

        void appendChild( QgsRuleBasedLabeling::Rule *rule SIP_TRANSFER );

        void insertChild( int i, QgsRuleBasedLabeling::Rule *rule SIP_TRANSFER );

        void removeChildAt( int i );

        const QgsRuleBasedLabeling::Rule *findRuleByKey( const QString &key ) const;

        QgsRuleBasedLabeling::Rule *findRuleByKey( const QString &key ) SIP_SKIP;

        QgsRuleBasedLabeling::Rule *clone() const SIP_FACTORY;

        // load / save

        static QgsRuleBasedLabeling::Rule *create( const QDomElement &ruleElem, const QgsReadWriteContext &context ) SIP_FACTORY;

        QDomElement save( QDomDocument &doc, const QgsReadWriteContext &context ) const;

        // evaluation

        void createSubProviders( QgsVectorLayer *layer, RuleToProviderMap &subProviders, QgsRuleBasedLabelProvider *provider ) SIP_SKIP;

        void subProviderIds( QStringList &list ) const SIP_SKIP;

        void prepare( const QgsRenderContext &context, QSet<QString> &attributeNames, RuleToProviderMap &subProviders ) SIP_SKIP;

        RegisterResult registerFeature( const QgsFeature &feature, QgsRenderContext &context, RuleToProviderMap &subProviders, const QgsGeometry &obstacleGeometry = QgsGeometry() ) SIP_SKIP;

        bool requiresAdvancedEffects() const;

      private:
#ifdef SIP_RUN
        Rule( const QgsRuleBasedLabeling::Rule &rh );
#endif

        bool isFilterOK( const QgsFeature &f, QgsRenderContext &context ) const;

        bool isScaleOK( double scale ) const;

        void initFilter();

        void updateElseRules();

      private:
        Rule *mParent = nullptr; // parent rule (nullptr only for root rule)
        std::unique_ptr<QgsPalLayerSettings> mSettings;
        double mMaximumScale = 0;
        double mMinimumScale = 0;
        QString mFilterExp;
        QString mDescription;
        bool mElseRule = false;
        RuleList mChildren;
        RuleList mElseRules;
        bool mIsActive = true; // whether it is enabled or not

        QString mRuleKey = QUuid::createUuid().toString(); // string used for unique identification of rule within labeling

        std::unique_ptr<QgsExpression> mFilter;

    };


    explicit QgsRuleBasedLabeling( QgsRuleBasedLabeling::Rule *root SIP_TRANSFER );
    ~QgsRuleBasedLabeling() override;

    QgsRuleBasedLabeling::Rule *rootRule();
    const Rule *rootRule() const SIP_SKIP;

    static QgsRuleBasedLabeling *create( const QDomElement &element, const QgsReadWriteContext &context ) SIP_FACTORY;

    // implementation of parent interface

    QString type() const override;
    QgsRuleBasedLabeling *clone() const override SIP_FACTORY;
    QDomElement save( QDomDocument &doc, const QgsReadWriteContext &context ) const override;
    QgsVectorLayerLabelProvider *provider( QgsVectorLayer *layer ) const override SIP_SKIP;
    QStringList subProviders() const override;
    QgsPalLayerSettings settings( const QString &providerId = QString() ) const override;

    void setSettings( QgsPalLayerSettings *settings SIP_TRANSFER, const QString &providerId = QString() ) override;
    bool requiresAdvancedEffects() const override;
    void toSld( QDomNode &parent, const QgsStringMap &props ) const override;

  protected:
    std::unique_ptr<Rule> mRootRule;
};

#ifndef SIP_RUN

class CORE_EXPORT QgsRuleBasedLabelProvider : public QgsVectorLayerLabelProvider
{
  public:
    QgsRuleBasedLabelProvider( const QgsRuleBasedLabeling &rules, QgsVectorLayer *layer, bool withFeatureLoop = true );

    // reimplemented

    bool prepare( const QgsRenderContext &context, QSet<QString> &attributeNames ) override;

    void registerFeature( const QgsFeature &feature, QgsRenderContext &context, const QgsGeometry &obstacleGeometry = QgsGeometry() ) override;

    virtual QgsVectorLayerLabelProvider *createProvider( QgsVectorLayer *layer, const QString &providerId, bool withFeatureLoop, const QgsPalLayerSettings *settings );

    QList<QgsAbstractLabelProvider *> subProviders() override;

  protected:
    std::unique_ptr<QgsRuleBasedLabeling> mRules;
    QgsRuleBasedLabeling::RuleToProviderMap mSubProviders;
};

#endif

#endif // QGSRULEBASEDLABELING_H