QGIS API Documentation  3.4.3-Madeira (2f64a3c)
Public Types | Public Member Functions | Static Public Member Functions | Protected Member Functions | List of all members
QgsRuleBasedRenderer::Rule Class Reference

This class keeps data about a rules for rule-based renderer. More...

#include <qgsrulebasedrenderer.h>

Public Types

enum  RenderResult { Filtered = 0, Inactive, Rendered }
 The result of rendering a rule. More...
 

Public Member Functions

 Rule (QgsSymbol *symbol, int maximumScale=0, int minimumScale=0, const QString &filterExp=QString(), const QString &label=QString(), const QString &description=QString(), bool elseRule=false)
 Constructor takes ownership of the symbol. More...
 
 Rule (const Rule &rh)=delete
 Rules cannot be copied. More...
 
 ~Rule ()
 
bool active () const
 Returns if this rule is active. More...
 
void appendChild (QgsRuleBasedRenderer::Rule *rule)
 add child rule, take ownership, sets this as parent More...
 
const QgsRuleBasedRenderer::RuleListchildren ()
 Returns all children rules of this rule. More...
 
QgsRuleBasedRenderer::Ruleclone () const
 clone this rule, return new instance More...
 
QSet< int > collectZLevels ()
 Gets all used z-levels from this rule and children. More...
 
bool dependsOnScale () const
 
QgsRuleBasedRenderer::RuleList descendants () const
 Returns all children, grand-children, grand-grand-children, grand-gra... More...
 
QString description () const
 A human readable description for this rule. More...
 
QString dump (int indent=0) const
 Dump for debug purpose. More...
 
QgsExpressionfilter () const
 A filter that will check if this rule applies. More...
 
QString filterExpression () const
 A filter that will check if this rule applies. More...
 
QgsRuleBasedRenderer::RulefindRuleByKey (const QString &key)
 Try to find a rule given its unique key. More...
 
void insertChild (int i, QgsRuleBasedRenderer::Rule *rule)
 add child rule, take ownership, sets this as parent More...
 
bool isElse () const
 Check if this rule is an ELSE rule. More...
 
bool isFilterOK (const QgsFeature &f, QgsRenderContext *context=nullptr) const
 Check if a given feature shall be rendered by this rule. More...
 
bool isScaleOK (double scale) const
 Check if this rule applies for a given scale. More...
 
QString label () const
 
QSet< QString > legendKeysForFeature (const QgsFeature &feature, QgsRenderContext *context=nullptr)
 Returns which legend keys match the feature. More...
 
QgsLegendSymbolList legendSymbolItems (int currentLevel=-1) const
 
double maximumScale () const
 Returns the maximum map scale (i.e. More...
 
double minimumScale () const
 Returns the minimum map scale (i.e. More...
 
bool needsGeometry () const
 Returns true if this rule or one of its chilren needs the geometry to be applied. More...
 
Ruleoperator= (const Rule &rh)=delete
 Rules cannot be copied. More...
 
QgsRuleBasedRenderer::Ruleparent ()
 The parent rule. More...
 
void removeChild (QgsRuleBasedRenderer::Rule *rule)
 delete child rule More...
 
void removeChildAt (int i)
 delete child rule More...
 
QgsRuleBasedRenderer::Rule::RenderResult renderFeature (QgsRuleBasedRenderer::FeatureToRender &featToRender, QgsRenderContext &context, QgsRuleBasedRenderer::RenderQueue &renderQueue)
 Render a given feature, will recursively call subclasses and only render if the constraints apply. More...
 
QString ruleKey () const
 Unique rule identifier (for identification of rule within renderer) More...
 
QgsRuleBasedRenderer::RuleList rulesForFeature (const QgsFeature &feature, QgsRenderContext *context=nullptr, bool onlyActive=true)
 Returns the list of rules used to render the feature in a specific context. More...
 
QDomElement save (QDomDocument &doc, QgsSymbolMap &symbolMap) const
 
void setActive (bool state)
 Sets if this rule is active. More...
 
void setDescription (const QString &description)
 Set a human readable description for this rule. More...
 
void setFilterExpression (const QString &filterExp)
 Set the expression used to check if a given feature shall be rendered with this rule. More...
 
void setIsElse (bool iselse)
 Sets if this rule is an ELSE rule. More...
 
void setLabel (const QString &label)
 
void setMaximumScale (double scale)
 Sets the maximum map scale (i.e. More...
 
void setMinimumScale (double scale)
 Sets the minimum map scale (i.e. More...
 
void setNormZLevels (const QMap< int, int > &zLevelsToNormLevels)
 assign normalized z-levels [0..N-1] for this rule's symbol for quick access during rendering More...
 
void setRuleKey (const QString &key)
 Override the assigned rule key (should be used just internally by rule-based renderer) More...
 
void setSymbol (QgsSymbol *sym)
 Sets a new symbol (or NULL). Deletes old symbol. More...
 
bool startRender (QgsRenderContext &context, const QgsFields &fields, QString &filter)
 prepare the rule for rendering and its children (build active children array) More...
 
void stopRender (QgsRenderContext &context)
 Stop a rendering process. More...
 
QgsSymbolsymbol ()
 
QgsSymbolList symbols (const QgsRenderContext &context=QgsRenderContext()) const
 
QgsSymbolList symbolsForFeature (const QgsFeature &feature, QgsRenderContext *context=nullptr)
 tell which symbols will be used to render the feature More...
 
QgsRuleBasedRenderer::RuletakeChild (QgsRuleBasedRenderer::Rule *rule)
 take child rule out, set parent as null More...
 
QgsRuleBasedRenderer::RuletakeChildAt (int i)
 take child rule out, set parent as null More...
 
void toSld (QDomDocument &doc, QDomElement &element, QgsStringMap props) const
 
QSet< QString > usedAttributes (const QgsRenderContext &context) const
 Returns the attributes used to evaluate the expression of this rule. More...
 
bool willRenderFeature (const QgsFeature &feature, QgsRenderContext *context=nullptr)
 only tell whether a feature will be rendered without actually rendering it More...
 

Static Public Member Functions

static QgsRuleBasedRenderer::Rulecreate (QDomElement &ruleElem, QgsSymbolMap &symbolMap)
 Create a rule from an XML definition. More...
 
static QgsRuleBasedRenderer::RulecreateFromSld (QDomElement &element, QgsWkbTypes::GeometryType geomType)
 Create a rule from the SLD provided in element and for the specified geometry type. More...
 

Protected Member Functions

void initFilter ()
 

Detailed Description

This class keeps data about a rules for rule-based renderer.

A rule consists of a symbol, filter expression and range of scales. If filter is empty, it matches all features. If scale range has both values zero, it matches all scales. If one of the min/max scale denominators is zero, there is no lower/upper bound for scales. A rule matches if both filter and scale range match.

Definition at line 131 of file qgsrulebasedrenderer.h.

Member Enumeration Documentation

◆ RenderResult

The result of rendering a rule.

Enumerator
Filtered 

The rule does not apply.

Inactive 

The rule is inactive.

Rendered 

Something was rendered.

Definition at line 135 of file qgsrulebasedrenderer.h.

Constructor & Destructor Documentation

◆ Rule() [1/2]

QgsRuleBasedRenderer::Rule::Rule ( QgsSymbol symbol,
int  maximumScale = 0,
int  minimumScale = 0,
const QString &  filterExp = QString(),
const QString &  label = QString(),
const QString &  description = QString(),
bool  elseRule = false 
)

Constructor takes ownership of the symbol.

Definition at line 38 of file qgsrulebasedrenderer.cpp.

◆ ~Rule()

QgsRuleBasedRenderer::Rule::~Rule ( )

Definition at line 55 of file qgsrulebasedrenderer.cpp.

◆ Rule() [2/2]

QgsRuleBasedRenderer::Rule::Rule ( const Rule rh)
delete

Rules cannot be copied.

Member Function Documentation

◆ active()

bool QgsRuleBasedRenderer::Rule::active ( ) const
inline

Returns if this rule is active.

Returns
True if the rule is active

Definition at line 242 of file qgsrulebasedrenderer.h.

◆ appendChild()

void QgsRuleBasedRenderer::Rule::appendChild ( QgsRuleBasedRenderer::Rule rule)

add child rule, take ownership, sets this as parent

Definition at line 80 of file qgsrulebasedrenderer.cpp.

◆ children()

const QgsRuleBasedRenderer::RuleList& QgsRuleBasedRenderer::Rule::children ( )
inline

Returns all children rules of this rule.

Returns
A list of rules

Definition at line 377 of file qgsrulebasedrenderer.h.

◆ clone()

QgsRuleBasedRenderer::Rule * QgsRuleBasedRenderer::Rule::clone ( ) const

clone this rule, return new instance

Definition at line 270 of file qgsrulebasedrenderer.cpp.

◆ collectZLevels()

QSet< int > QgsRuleBasedRenderer::Rule::collectZLevels ( )

Gets all used z-levels from this rule and children.

Definition at line 471 of file qgsrulebasedrenderer.cpp.

◆ create()

QgsRuleBasedRenderer::Rule * QgsRuleBasedRenderer::Rule::create ( QDomElement &  ruleElem,
QgsSymbolMap symbolMap 
)
static

Create a rule from an XML definition.

Parameters
ruleElemThe XML rule element
symbolMapSymbol map
Returns
A new rule

Definition at line 681 of file qgsrulebasedrenderer.cpp.

◆ createFromSld()

QgsRuleBasedRenderer::Rule * QgsRuleBasedRenderer::Rule::createFromSld ( QDomElement &  element,
QgsWkbTypes::GeometryType  geomType 
)
static

Create a rule from the SLD provided in element and for the specified geometry type.

Definition at line 739 of file qgsrulebasedrenderer.cpp.

◆ dependsOnScale()

bool QgsRuleBasedRenderer::Rule::dependsOnScale ( ) const
inline

Definition at line 196 of file qgsrulebasedrenderer.h.

◆ descendants()

QgsRuleBasedRenderer::RuleList QgsRuleBasedRenderer::Rule::descendants ( ) const

Returns all children, grand-children, grand-grand-children, grand-gra...

you get it

Returns
A list of descendant rules

Definition at line 728 of file qgsrulebasedrenderer.cpp.

◆ description()

QString QgsRuleBasedRenderer::Rule::description ( ) const
inline

A human readable description for this rule.

Returns
Description

Definition at line 235 of file qgsrulebasedrenderer.h.

◆ dump()

QString QgsRuleBasedRenderer::Rule::dump ( int  indent = 0) const

Dump for debug purpose.

Parameters
indentHow many characters to indent. Will increase by two with every of the recursive calls
Returns
A string representing this rule

Definition at line 157 of file qgsrulebasedrenderer.cpp.

◆ filter()

QgsExpression* QgsRuleBasedRenderer::Rule::filter ( ) const
inline

A filter that will check if this rule applies.

Returns
An expression

Definition at line 222 of file qgsrulebasedrenderer.h.

◆ filterExpression()

QString QgsRuleBasedRenderer::Rule::filterExpression ( ) const
inline

A filter that will check if this rule applies.

Returns
An expression

Definition at line 228 of file qgsrulebasedrenderer.h.

◆ findRuleByKey()

QgsRuleBasedRenderer::Rule * QgsRuleBasedRenderer::Rule::findRuleByKey ( const QString &  key)

Try to find a rule given its unique key.

Since
QGIS 2.6

Definition at line 123 of file qgsrulebasedrenderer.cpp.

◆ initFilter()

void QgsRuleBasedRenderer::Rule::initFilter ( )
protected

Definition at line 61 of file qgsrulebasedrenderer.cpp.

◆ insertChild()

void QgsRuleBasedRenderer::Rule::insertChild ( int  i,
QgsRuleBasedRenderer::Rule rule 
)

add child rule, take ownership, sets this as parent

Definition at line 87 of file qgsrulebasedrenderer.cpp.

◆ isElse()

bool QgsRuleBasedRenderer::Rule::isElse ( ) const
inline

Check if this rule is an ELSE rule.

Returns
True if this rule is an else rule

Definition at line 429 of file qgsrulebasedrenderer.h.

◆ isFilterOK()

bool QgsRuleBasedRenderer::Rule::isFilterOK ( const QgsFeature f,
QgsRenderContext context = nullptr 
) const

Check if a given feature shall be rendered by this rule.

Parameters
fThe feature to test
contextThe context in which the rendering happens
Returns
True if the feature shall be rendered

Definition at line 247 of file qgsrulebasedrenderer.cpp.

◆ isScaleOK()

bool QgsRuleBasedRenderer::Rule::isScaleOK ( double  scale) const

Check if this rule applies for a given scale.

The scale value indicates the scale denominator, e.g. 1000.0 for a 1:1000 map. If set to 0, it will always return true.

Returns
If the rule will be evaluated at this scale

Definition at line 257 of file qgsrulebasedrenderer.cpp.

◆ label()

QString QgsRuleBasedRenderer::Rule::label ( ) const
inline

Definition at line 195 of file qgsrulebasedrenderer.h.

◆ legendKeysForFeature()

QSet< QString > QgsRuleBasedRenderer::Rule::legendKeysForFeature ( const QgsFeature feature,
QgsRenderContext context = nullptr 
)

Returns which legend keys match the feature.

Since
QGIS 2.14

Definition at line 614 of file qgsrulebasedrenderer.cpp.

◆ legendSymbolItems()

QgsLegendSymbolList QgsRuleBasedRenderer::Rule::legendSymbolItems ( int  currentLevel = -1) const
Since
QGIS 2.6

Definition at line 230 of file qgsrulebasedrenderer.cpp.

◆ maximumScale()

double QgsRuleBasedRenderer::Rule::maximumScale ( ) const
inline

Returns the maximum map scale (i.e.

most "zoomed in" scale) at which the rule will be active. The scale value indicates the scale denominator, e.g. 1000.0 for a 1:1000 map. A scale of 0 indicates no maximum scale visibility.

See also
minimumScale()
setMaximumScale()
Since
QGIS 3.0

Definition at line 206 of file qgsrulebasedrenderer.h.

◆ minimumScale()

double QgsRuleBasedRenderer::Rule::minimumScale ( ) const
inline

Returns the minimum map scale (i.e.

most "zoomed out" scale) at which the rule will be active. The scale value indicates the scale denominator, e.g. 1000.0 for a 1:1000 map. A scale of 0 indicates no minimum scale visibility.

See also
maximumScale()
setMinimumScale()
Since
QGIS 3.0

Definition at line 216 of file qgsrulebasedrenderer.h.

◆ needsGeometry()

bool QgsRuleBasedRenderer::Rule::needsGeometry ( ) const

Returns true if this rule or one of its chilren needs the geometry to be applied.

Definition at line 192 of file qgsrulebasedrenderer.cpp.

◆ operator=()

Rule& QgsRuleBasedRenderer::Rule::operator= ( const Rule rh)
delete

Rules cannot be copied.

◆ parent()

QgsRuleBasedRenderer::Rule* QgsRuleBasedRenderer::Rule::parent ( )
inline

The parent rule.

Returns
Parent rule

Definition at line 391 of file qgsrulebasedrenderer.h.

◆ removeChild()

void QgsRuleBasedRenderer::Rule::removeChild ( QgsRuleBasedRenderer::Rule rule)

delete child rule

Definition at line 94 of file qgsrulebasedrenderer.cpp.

◆ removeChildAt()

void QgsRuleBasedRenderer::Rule::removeChildAt ( int  i)

delete child rule

Definition at line 101 of file qgsrulebasedrenderer.cpp.

◆ renderFeature()

QgsRuleBasedRenderer::Rule::RenderResult QgsRuleBasedRenderer::Rule::renderFeature ( QgsRuleBasedRenderer::FeatureToRender featToRender,
QgsRenderContext context,
QgsRuleBasedRenderer::RenderQueue renderQueue 
)

Render a given feature, will recursively call subclasses and only render if the constraints apply.

Parameters
featToRenderThe feature to render
contextThe rendering context
renderQueueThe rendering queue to which the feature should be added
Returns
The result of the rendering. In explicit if the feature is added to the queue or the reason for not rendering the feature.

Definition at line 514 of file qgsrulebasedrenderer.cpp.

◆ ruleKey()

QString QgsRuleBasedRenderer::Rule::ruleKey ( ) const
inline

Unique rule identifier (for identification of rule within renderer)

Since
QGIS 2.6

Definition at line 248 of file qgsrulebasedrenderer.h.

◆ rulesForFeature()

QgsRuleBasedRenderer::RuleList QgsRuleBasedRenderer::Rule::rulesForFeature ( const QgsFeature feature,
QgsRenderContext context = nullptr,
bool  onlyActive = true 
)

Returns the list of rules used to render the feature in a specific context.

Parameters
featureThe feature for which rules have to be find
contextThe rendering context
onlyActiveTrue to search for active rules only, false otherwise

Definition at line 647 of file qgsrulebasedrenderer.cpp.

◆ save()

QDomElement QgsRuleBasedRenderer::Rule::save ( QDomDocument &  doc,
QgsSymbolMap symbolMap 
) const

Definition at line 281 of file qgsrulebasedrenderer.cpp.

◆ setActive()

void QgsRuleBasedRenderer::Rule::setActive ( bool  state)
inline

Sets if this rule is active.

Parameters
stateDetermines if the rule should be activated or deactivated

Definition at line 296 of file qgsrulebasedrenderer.h.

◆ setDescription()

void QgsRuleBasedRenderer::Rule::setDescription ( const QString &  description)
inline

Set a human readable description for this rule.

Parameters
descriptionDescription

Definition at line 290 of file qgsrulebasedrenderer.h.

◆ setFilterExpression()

void QgsRuleBasedRenderer::Rule::setFilterExpression ( const QString &  filterExp)

Set the expression used to check if a given feature shall be rendered with this rule.

Parameters
filterExpAn expression

Definition at line 224 of file qgsrulebasedrenderer.cpp.

◆ setIsElse()

void QgsRuleBasedRenderer::Rule::setIsElse ( bool  iselse)

Sets if this rule is an ELSE rule.

Parameters
iselseIf true, this rule is an ELSE rule

Definition at line 149 of file qgsrulebasedrenderer.cpp.

◆ setLabel()

void QgsRuleBasedRenderer::Rule::setLabel ( const QString &  label)
inline

Definition at line 258 of file qgsrulebasedrenderer.h.

◆ setMaximumScale()

void QgsRuleBasedRenderer::Rule::setMaximumScale ( double  scale)
inline

Sets the maximum map scale (i.e.

most "zoomed in" scale) at which the rule will be active. The scale value indicates the scale denominator, e.g. 1000.0 for a 1:1000 map. A scale of 0 indicates no maximum scale visibility.

See also
maximumScale()
setMinimumScale()

Definition at line 276 of file qgsrulebasedrenderer.h.

◆ setMinimumScale()

void QgsRuleBasedRenderer::Rule::setMinimumScale ( double  scale)
inline

Sets the minimum map scale (i.e.

most "zoomed out" scale) at which the rule will be active. The scale value indicates the scale denominator, e.g. 1000.0 for a 1:1000 map. A scale of 0 indicates no minimum scale visibility.

See also
minimumScale()
setMaximumScale()

Definition at line 267 of file qgsrulebasedrenderer.h.

◆ setNormZLevels()

void QgsRuleBasedRenderer::Rule::setNormZLevels ( const QMap< int, int > &  zLevelsToNormLevels)

assign normalized z-levels [0..N-1] for this rule's symbol for quick access during rendering

Note
not available in Python bindings

Definition at line 495 of file qgsrulebasedrenderer.cpp.

◆ setRuleKey()

void QgsRuleBasedRenderer::Rule::setRuleKey ( const QString &  key)
inline

Override the assigned rule key (should be used just internally by rule-based renderer)

Since
QGIS 2.6

Definition at line 254 of file qgsrulebasedrenderer.h.

◆ setSymbol()

void QgsRuleBasedRenderer::Rule::setSymbol ( QgsSymbol sym)

Sets a new symbol (or NULL). Deletes old symbol.

Definition at line 219 of file qgsrulebasedrenderer.cpp.

◆ startRender()

bool QgsRuleBasedRenderer::Rule::startRender ( QgsRenderContext context,
const QgsFields fields,
QString &  filter 
)

prepare the rule for rendering and its children (build active children array)

Definition at line 374 of file qgsrulebasedrenderer.cpp.

◆ stopRender()

void QgsRuleBasedRenderer::Rule::stopRender ( QgsRenderContext context)

Stop a rendering process.

Used to clean up the internal state of this rule

Parameters
contextThe rendering context

Definition at line 667 of file qgsrulebasedrenderer.cpp.

◆ symbol()

QgsSymbol* QgsRuleBasedRenderer::Rule::symbol ( )
inline

Definition at line 194 of file qgsrulebasedrenderer.h.

◆ symbols()

QgsSymbolList QgsRuleBasedRenderer::Rule::symbols ( const QgsRenderContext context = QgsRenderContext()) const
Note
available in Python bindings as symbol2

Definition at line 206 of file qgsrulebasedrenderer.cpp.

◆ symbolsForFeature()

QgsSymbolList QgsRuleBasedRenderer::Rule::symbolsForFeature ( const QgsFeature feature,
QgsRenderContext context = nullptr 
)

tell which symbols will be used to render the feature

Definition at line 599 of file qgsrulebasedrenderer.cpp.

◆ takeChild()

QgsRuleBasedRenderer::Rule * QgsRuleBasedRenderer::Rule::takeChild ( QgsRuleBasedRenderer::Rule rule)

take child rule out, set parent as null

Definition at line 107 of file qgsrulebasedrenderer.cpp.

◆ takeChildAt()

QgsRuleBasedRenderer::Rule * QgsRuleBasedRenderer::Rule::takeChildAt ( int  i)

take child rule out, set parent as null

Definition at line 115 of file qgsrulebasedrenderer.cpp.

◆ toSld()

void QgsRuleBasedRenderer::Rule::toSld ( QDomDocument &  doc,
QDomElement &  element,
QgsStringMap  props 
) const

Definition at line 312 of file qgsrulebasedrenderer.cpp.

◆ usedAttributes()

QSet< QString > QgsRuleBasedRenderer::Rule::usedAttributes ( const QgsRenderContext context) const

Returns the attributes used to evaluate the expression of this rule.

Returns
A set of attribute names

Definition at line 175 of file qgsrulebasedrenderer.cpp.

◆ willRenderFeature()

bool QgsRuleBasedRenderer::Rule::willRenderFeature ( const QgsFeature feature,
QgsRenderContext context = nullptr 
)

only tell whether a feature will be rendered without actually rendering it

Definition at line 564 of file qgsrulebasedrenderer.cpp.


The documentation for this class was generated from the following files: