QGIS API Documentation 3.39.0-Master (67e056379ed)
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qgsalgorithmarrayoffsetlines.cpp
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1/***************************************************************************
2 qgsalgorithmarrayoffsetlines.cpp
3 ---------------------
4 begin : July 2018
5 copyright : (C) 2018 by Nyall Dawson
6 email : nyall dot dawson at gmail dot com
7 ***************************************************************************/
8
9/***************************************************************************
10 * *
11 * This program is free software; you can redistribute it and/or modify *
12 * it under the terms of the GNU General Public License as published by *
13 * the Free Software Foundation; either version 2 of the License, or *
14 * (at your option) any later version. *
15 * *
16 ***************************************************************************/
17
19
21
22QString QgsCreateArrayOffsetLinesAlgorithm::name() const
23{
24 return QStringLiteral( "arrayoffsetlines" );
25}
26
27QString QgsCreateArrayOffsetLinesAlgorithm::displayName() const
28{
29 return QObject::tr( "Array of offset (parallel) lines" );
30}
31
32QStringList QgsCreateArrayOffsetLinesAlgorithm::tags() const
33{
34 return QObject::tr( "offset,parallel,duplicate,create,spaced,copy,features,objects,step,repeat" ).split( ',' );
35}
36
37QString QgsCreateArrayOffsetLinesAlgorithm::group() const
38{
39 return QObject::tr( "Vector creation" );
40}
41
42QString QgsCreateArrayOffsetLinesAlgorithm::groupId() const
43{
44 return QStringLiteral( "vectorcreation" );
45}
46
47QString QgsCreateArrayOffsetLinesAlgorithm::outputName() const
48{
49 return QObject::tr( "Offset lines" );
50}
51
52QString QgsCreateArrayOffsetLinesAlgorithm::shortHelpString() const
53{
54 return QObject::tr( "This algorithm creates copies of line features in a layer, by creating multiple offset versions of each feature. "
55 "Each copy is offset by a preset distance." );
56}
57
58QString QgsCreateArrayOffsetLinesAlgorithm::shortDescription() const
59{
60 return QObject::tr( "Creates multiple offset copies of lines from a layer." );
61}
62
63QgsCreateArrayOffsetLinesAlgorithm *QgsCreateArrayOffsetLinesAlgorithm::createInstance() const
64{
65 return new QgsCreateArrayOffsetLinesAlgorithm();
66}
67
68void QgsCreateArrayOffsetLinesAlgorithm::initParameters( const QVariantMap & )
69{
70 std::unique_ptr< QgsProcessingParameterNumber > count = std::make_unique< QgsProcessingParameterNumber >( QStringLiteral( "COUNT" ),
71 QObject::tr( "Number of features to create" ), Qgis::ProcessingNumberParameterType::Integer,
72 10, false, 1 );
73 count->setIsDynamic( true );
74 count->setDynamicPropertyDefinition( QgsPropertyDefinition( QStringLiteral( "COUNT" ), QObject::tr( "Number of features to create" ), QgsPropertyDefinition::IntegerPositiveGreaterZero ) );
75 count->setDynamicLayerParameterName( QStringLiteral( "INPUT" ) );
76 addParameter( count.release() );
77
78 std::unique_ptr< QgsProcessingParameterDistance > offset = std::make_unique< QgsProcessingParameterDistance >( QStringLiteral( "OFFSET" ),
79 QObject::tr( "Offset step distance" ),
80 1.0, QStringLiteral( "INPUT" ) );
81 offset->setIsDynamic( true );
82 offset->setDynamicPropertyDefinition( QgsPropertyDefinition( QStringLiteral( "OFFSET" ), QObject::tr( "Step distance" ), QgsPropertyDefinition::Double ) );
83 offset->setDynamicLayerParameterName( QStringLiteral( "INPUT" ) );
84 addParameter( offset.release() );
85
86 auto segmentParam = std::make_unique< QgsProcessingParameterNumber >( QStringLiteral( "SEGMENTS" ), QObject::tr( "Segments" ), Qgis::ProcessingNumberParameterType::Integer, 8, false, 1 );
87 segmentParam->setFlags( segmentParam->flags() | Qgis::ProcessingParameterFlag::Advanced );
88 addParameter( segmentParam.release() );
89
90 auto joinStyleParam = std::make_unique< QgsProcessingParameterEnum>( QStringLiteral( "JOIN_STYLE" ), QObject::tr( "Join style" ), QStringList() << QObject::tr( "Round" ) << QObject::tr( "Miter" ) << QObject::tr( "Bevel" ), false, 0 );
91 joinStyleParam->setFlags( joinStyleParam->flags() | Qgis::ProcessingParameterFlag::Advanced );
92 addParameter( joinStyleParam.release() );
93
94 auto miterLimitParam = std::make_unique< QgsProcessingParameterNumber >( QStringLiteral( "MITER_LIMIT" ), QObject::tr( "Miter limit" ), Qgis::ProcessingNumberParameterType::Double, 2, false, 1 );
95 miterLimitParam->setFlags( miterLimitParam->flags() | Qgis::ProcessingParameterFlag::Advanced );
96 addParameter( miterLimitParam.release() );
97}
98
99QList<int> QgsCreateArrayOffsetLinesAlgorithm::inputLayerTypes() const
100{
101 return QList< int >() << static_cast< int >( Qgis::ProcessingSourceType::VectorLine );
102}
103
104bool QgsCreateArrayOffsetLinesAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
105{
106 mCount = parameterAsInt( parameters, QStringLiteral( "COUNT" ), context );
107 mDynamicCount = QgsProcessingParameters::isDynamic( parameters, QStringLiteral( "COUNT" ) );
108 if ( mDynamicCount )
109 mCountProperty = parameters.value( QStringLiteral( "COUNT" ) ).value< QgsProperty >();
110
111 mOffsetStep = parameterAsDouble( parameters, QStringLiteral( "OFFSET" ), context );
112 mDynamicOffset = QgsProcessingParameters::isDynamic( parameters, QStringLiteral( "OFFSET" ) );
113 if ( mDynamicOffset )
114 mOffsetStepProperty = parameters.value( QStringLiteral( "OFFSET" ) ).value< QgsProperty >();
115
116 mSegments = parameterAsInt( parameters, QStringLiteral( "SEGMENTS" ), context );
117 mJoinStyle = static_cast< Qgis::JoinStyle>( 1 + parameterAsInt( parameters, QStringLiteral( "JOIN_STYLE" ), context ) );
118 mMiterLimit = parameterAsDouble( parameters, QStringLiteral( "MITER_LIMIT" ), context );
119
120 return true;
121}
122
123QgsFeatureList QgsCreateArrayOffsetLinesAlgorithm::processFeature( const QgsFeature &feature, QgsProcessingContext &context, QgsProcessingFeedback * )
124{
126
127 if ( feature.hasGeometry() )
128 {
129 const QgsGeometry geometry = feature.geometry();
130 const QgsAttributes attr = feature.attributes();
131
132 int count = mCount;
133 if ( mDynamicCount )
134 count = mCountProperty.valueAsInt( context.expressionContext(), count );
135 result.reserve( count + 1 );
136
137 double offsetStep = mOffsetStep;
138 if ( mDynamicOffset )
139 offsetStep = mOffsetStepProperty.valueAsDouble( context.expressionContext(), offsetStep );
140
141 {
142 QgsFeature original = feature;
143 original.setGeometry( geometry );
144 QgsAttributes outAttrs = attr;
145 outAttrs << QVariant( 0 ) << QVariant( 0 );
146 original.setAttributes( outAttrs );
147 result << original;
148 }
149
150 double offset = 0;
151 for ( int i = 0; i < count; ++i )
152 {
153 offset += offsetStep;
154 // FIXME: shouldn't we use QgsVectorLayerUtils::createFeature?
155 QgsFeature offsetFeature = feature;
156 const QgsGeometry offsetGeometry = geometry.offsetCurve( offset, mSegments, mJoinStyle, mMiterLimit );
157 offsetFeature.setGeometry( offsetGeometry );
158 QgsAttributes outAttrs = attr;
159 outAttrs << QVariant( i + 1 ) << QVariant( offset );
160 offsetFeature.setAttributes( outAttrs );
161 result << offsetFeature;
162 }
163 }
164 else
165 {
166 result << feature;
167 }
168
169 return result;
170}
171
172QgsFields QgsCreateArrayOffsetLinesAlgorithm::outputFields( const QgsFields &inputFields ) const
173{
174 QgsFields output = inputFields;
175 output.append( QgsField( QStringLiteral( "instance" ), QMetaType::Type::Int ) );
176 output.append( QgsField( QStringLiteral( "offset" ), QMetaType::Type::Double ) );
177 return output;
178}
179
180QgsFeatureSink::SinkFlags QgsCreateArrayOffsetLinesAlgorithm::sinkFlags() const
181{
183}
184
186
187
@ VectorLine
Vector line layers.
JoinStyle
Join styles for buffers.
Definition qgis.h:1791
@ Advanced
Parameter is an advanced parameter which should be hidden from users by default.
A vector of attributes.
QFlags< SinkFlag > SinkFlags
@ RegeneratePrimaryKey
This flag indicates, that a primary key field cannot be guaranteed to be unique and the sink should i...
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Definition qgsfeature.h:58
QgsAttributes attributes
Definition qgsfeature.h:67
void setAttributes(const QgsAttributes &attrs)
Sets the feature's attributes.
QgsGeometry geometry
Definition qgsfeature.h:69
bool hasGeometry() const
Returns true if the feature has an associated geometry.
void setGeometry(const QgsGeometry &geometry)
Set the feature's geometry.
Encapsulate a field in an attribute table or data source.
Definition qgsfield.h:53
Container of fields for a vector layer.
Definition qgsfields.h:46
bool append(const QgsField &field, Qgis::FieldOrigin origin=Qgis::FieldOrigin::Provider, int originIndex=-1)
Appends a field.
Definition qgsfields.cpp:69
A geometry is the spatial representation of a feature.
QgsGeometry offsetCurve(double distance, int segments, Qgis::JoinStyle joinStyle, double miterLimit) const
Returns an offset line at a given distance and side from an input line.
Contains information about the context in which a processing algorithm is executed.
QgsExpressionContext & expressionContext()
Returns the expression context.
Base class for providing feedback from a processing algorithm.
static bool isDynamic(const QVariantMap &parameters, const QString &name)
Returns true if the parameter with matching name is a dynamic parameter, and must be evaluated once f...
Definition for a property.
Definition qgsproperty.h:45
@ Double
Double value (including negative values)
Definition qgsproperty.h:55
@ IntegerPositiveGreaterZero
Non-zero positive integer values.
Definition qgsproperty.h:54
A store for object properties.
double valueAsDouble(const QgsExpressionContext &context, double defaultValue=0.0, bool *ok=nullptr) const
Calculates the current value of the property and interprets it as a double.
QList< QgsFeature > QgsFeatureList