QGIS API Documentation  3.2.0-Bonn (bc43194)
qgsrulebasedlabeling.h
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1 /***************************************************************************
2  qgsrulebasedlabeling.h
3  ---------------------
4  begin : September 2015
5  copyright : (C) 2015 by Martin Dobias
6  email : wonder dot sk at gmail dot com
7  ***************************************************************************
8  * *
9  * This program is free software; you can redistribute it and/or modify *
10  * it under the terms of the GNU General Public License as published by *
11  * the Free Software Foundation; either version 2 of the License, or *
12  * (at your option) any later version. *
13  * *
14  ***************************************************************************/
15 #ifndef QGSRULEBASEDLABELING_H
16 #define QGSRULEBASEDLABELING_H
17 
18 #include "qgis_core.h"
19 #include <QStringList>
20 #include <QMap>
21 
22 #include "qgsvectorlayerlabeling.h"
24 
25 class QDomDocument;
26 class QDomElement;
27 
28 class QgsExpression;
29 class QgsFeature;
31 class QgsRenderContext;
32 class QgsGeometry;
34 
41 {
42  public:
43  class Rule;
44  typedef QList<QgsRuleBasedLabeling::Rule *> RuleList;
45  typedef QMap<QgsRuleBasedLabeling::Rule *, QgsVectorLayerLabelProvider *> RuleToProviderMap;
46 
52  class CORE_EXPORT Rule
53  {
54  public:
56  Rule( QgsPalLayerSettings *settings SIP_TRANSFER, int maximumScale = 0, int minimumScale = 0, const QString &filterExp = QString(), const QString &description = QString(), bool elseRule = false );
57  ~Rule();
58 
60  Rule( const Rule &rh ) = delete;
62  Rule &operator=( const Rule &rh ) = delete;
63 
66  {
67  Filtered = 0,
69  Registered
70  };
71 
75  QgsPalLayerSettings *settings() const { return mSettings; }
76 
82  bool dependsOnScale() const { return mMinimumScale != 0 || mMaximumScale != 0; }
83 
92  double maximumScale() const { return mMaximumScale; }
93 
102  double minimumScale() const { return mMinimumScale; }
103 
108  QString filterExpression() const { return mFilterExp; }
109 
115  QString description() const { return mDescription; }
116 
122  bool active() const { return mIsActive; }
123 
129  bool isElse() const { return mElseRule; }
130 
132  QString ruleKey() const { return mRuleKey; }
133 
135  void setSettings( QgsPalLayerSettings *settings SIP_TRANSFER );
136 
144  void setMinimumScale( double scale ) { mMinimumScale = scale; }
145 
153  void setMaximumScale( double scale ) { mMaximumScale = scale; }
154 
160  void setFilterExpression( const QString &filterExp ) { mFilterExp = filterExp; initFilter(); }
161 
167  void setDescription( const QString &description ) { mDescription = description; }
168 
173  void setActive( bool state ) { mIsActive = state; }
174 
180  void setIsElse( bool iselse ) { mElseRule = iselse; }
181 
183  void setRuleKey( const QString &key ) { mRuleKey = key; }
184 
185  // parent / child operations
186 
192  const QgsRuleBasedLabeling::RuleList &children() const { return mChildren; }
193 
200 
206  QgsRuleBasedLabeling::RuleList descendants() const;
207 
213  const QgsRuleBasedLabeling::Rule *parent() const SIP_SKIP { return mParent; }
214 
220  QgsRuleBasedLabeling::Rule *parent() { return mParent; }
221 
223  void appendChild( QgsRuleBasedLabeling::Rule *rule SIP_TRANSFER );
224 
226  void insertChild( int i, QgsRuleBasedLabeling::Rule *rule SIP_TRANSFER );
227 
229  void removeChildAt( int i );
230 
232  const QgsRuleBasedLabeling::Rule *findRuleByKey( const QString &key ) const;
233 
243  QgsRuleBasedLabeling::Rule *findRuleByKey( const QString &key ) SIP_SKIP;
244 
247 
248  // load / save
249 
256  static QgsRuleBasedLabeling::Rule *create( const QDomElement &ruleElem, const QgsReadWriteContext &context ) SIP_FACTORY;
257 
259  QDomElement save( QDomDocument &doc, const QgsReadWriteContext &context ) const;
260 
261  // evaluation
262 
267  void createSubProviders( QgsVectorLayer *layer, RuleToProviderMap &subProviders, QgsRuleBasedLabelProvider *provider ) SIP_SKIP;
268 
273  void subProviderIds( QStringList &list ) const SIP_SKIP;
274 
279  void prepare( const QgsRenderContext &context, QSet<QString> &attributeNames, RuleToProviderMap &subProviders ) SIP_SKIP;
280 
285  RegisterResult registerFeature( QgsFeature &feature, QgsRenderContext &context, RuleToProviderMap &subProviders, const QgsGeometry &obstacleGeometry = QgsGeometry() ) SIP_SKIP;
286 
291  bool requiresAdvancedEffects() const;
292 
293  private:
294 #ifdef SIP_RUN
295  Rule( const QgsRuleBasedLabeling::Rule &rh );
296 #endif
297 
305  bool isFilterOK( QgsFeature &f, QgsRenderContext &context ) const;
306 
314  bool isScaleOK( double scale ) const;
315 
319  void initFilter();
320 
324  void updateElseRules();
325 
326  private:
327  Rule *mParent; // parent rule (NULL only for root rule)
328  QgsPalLayerSettings *mSettings = nullptr;
329  double mMaximumScale = 0;
330  double mMinimumScale = 0;
331  QString mFilterExp, mDescription;
332  bool mElseRule;
333  RuleList mChildren;
334  RuleList mElseRules;
335  bool mIsActive; // whether it is enabled or not
336 
337  QString mRuleKey; // string used for unique identification of rule within labeling
338 
339  // temporary
340  QgsExpression *mFilter = nullptr;
341 
342  };
343 
344 
347  ~QgsRuleBasedLabeling() override;
348 
349  QgsRuleBasedLabeling::Rule *rootRule() { return mRootRule; }
350  const Rule *rootRule() const SIP_SKIP { return mRootRule; }
351 
353  static QgsRuleBasedLabeling *create( const QDomElement &element, const QgsReadWriteContext &context ) SIP_FACTORY;
354 
355  // implementation of parent interface
356 
357  QString type() const override;
358  QgsRuleBasedLabeling *clone() const override SIP_FACTORY;
359  QDomElement save( QDomDocument &doc, const QgsReadWriteContext &context ) const override;
361  QgsVectorLayerLabelProvider *provider( QgsVectorLayer *layer ) const override SIP_SKIP;
362  QStringList subProviders() const override;
363  QgsPalLayerSettings settings( const QString &providerId = QString() ) const override;
364 
373  void setSettings( QgsPalLayerSettings *settings SIP_TRANSFER, const QString &providerId = QString() ) override;
374  bool requiresAdvancedEffects() const override;
375  void toSld( QDomNode &parent, const QgsStringMap &props ) const override;
376 
377  protected:
378  Rule *mRootRule = nullptr;
379 };
380 
381 #ifndef SIP_RUN
382 
390 {
391  public:
392  QgsRuleBasedLabelProvider( const QgsRuleBasedLabeling &rules, QgsVectorLayer *layer, bool withFeatureLoop = true );
393 
394  // reimplemented
395 
396  bool prepare( const QgsRenderContext &context, QSet<QString> &attributeNames ) override;
397 
398  void registerFeature( QgsFeature &feature, QgsRenderContext &context, const QgsGeometry &obstacleGeometry = QgsGeometry() ) override;
399 
401  virtual QgsVectorLayerLabelProvider *createProvider( QgsVectorLayer *layer, const QString &providerId, bool withFeatureLoop, const QgsPalLayerSettings *settings );
402 
404  QList<QgsAbstractLabelProvider *> subProviders() override;
405 
406  protected:
408  std::unique_ptr<QgsRuleBasedLabeling> mRules;
411 };
412 
413 #endif
414 
415 #endif // QGSRULEBASEDLABELING_H
Class for parsing and evaluation of expressions (formerly called "search strings").
The class is used as a container of context for various read/write operations on other objects...
double maximumScale() const
Returns the maximum map scale (i.e.
QgsPalLayerSettings * settings() const
Gets the labeling settings.
void setFilterExpression(const QString &filterExp)
Set the expression used to check if a given feature shall be rendered with this rule.
QgsRuleBasedLabeling::RuleToProviderMap mSubProviders
label providers are owned by labeling engine
bool isElse() const
Check if this rule is an ELSE rule.
RegisterResult
The result of registering a rule.
bool dependsOnScale() const
Determines if scale based labeling is active.
const Rule * rootRule() const
QString description() const
A human readable description for this rule.
The QgsVectorLayerLabelProvider class implements a label provider for vector layers.
A geometry is the spatial representation of a feature.
Definition: qgsgeometry.h:104
QString ruleKey() const
Unique rule identifier (for identification of rule within labeling, used as provider ID) ...
The feature class encapsulates a single feature including its id, geometry and a list of field/values...
Definition: qgsfeature.h:62
QMap< QgsRuleBasedLabeling::Rule *, QgsVectorLayerLabelProvider * > RuleToProviderMap
const QgsRuleBasedLabeling::RuleList & children() const
Returns all children rules of this rule.
QMap< QString, QString > QgsStringMap
Definition: qgis.h:501
QList< QgsRuleBasedLabeling::Rule * > RuleList
virtual bool prepare(const QgsRenderContext &context, QSet< QString > &attributeNames)
Prepare for registration of features.
std::unique_ptr< QgsRuleBasedLabeling > mRules
owned copy
#define SIP_SKIP
Definition: qgis_sip.h:119
#define SIP_TRANSFER
Definition: qgis_sip.h:36
QgsRuleBasedLabeling::Rule * rootRule()
double minimumScale() const
Returns the minimum map scale (i.e.
QgsRuleBasedLabeling::RuleList & children()
Returns all children rules of this rule.
#define SIP_FACTORY
Definition: qgis_sip.h:69
virtual void registerFeature(QgsFeature &feature, QgsRenderContext &context, const QgsGeometry &obstacleGeometry=QgsGeometry())
Register a feature for labeling as one or more QgsLabelFeature objects stored into mLabels...
void setActive(bool state)
Sets if this rule is active.
void setMinimumScale(double scale)
Sets the minimum map scale (i.e.
QgsRuleBasedLabeling::Rule * parent()
The parent rule.
void setRuleKey(const QString &key)
Override the assigned rule key (should be used just internally by rule-based labeling) ...
virtual QList< QgsAbstractLabelProvider * > subProviders()
Returns list of child providers - useful if the provider needs to put labels into more layers with di...
Contains information about the context of a rendering operation.
QString filterExpression() const
A filter that will check if this rule applies.
Abstract base class - its implementations define different approaches to the labeling of a vector lay...
bool active() const
Returns if this rule is active.
const QgsRuleBasedLabeling::Rule * parent() const
The parent rule.
void setDescription(const QString &description)
Set a human readable description for this rule.
void setIsElse(bool iselse)
Sets if this rule is an ELSE rule.
Represents a vector layer which manages a vector based data sets.
void setMaximumScale(double scale)
Sets the maximum map scale (i.e.