[processing][FEATURE] Port extend lines algorithm to c++, allow dynam…

…ic start/end distance Allows the start and end distance to be data defined
qgis · Jul 23, 2018 · 59ec2e0 · 59ec2e0
1 parent 8a1964f
commit 59ec2e0
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diff --git a/python/plugins/processing/algs/help/qgis.yaml b/python/plugins/processing/algs/help/qgis.yaml
@@ -157,9 +157,6 @@ qgis:exportaddgeometrycolumns: >
 
   Depending on the geometry type of the vector layer, the attributes added to the table will be different.
 
-qgis:extendlines: >
-  This algorithm extends line geometries by a specified amount at the start and end of the line. Lines are extended using the bearing of the first and last segment in the line.
-
 qgis:extractbyattribute: >
   This algorithm creates a new vector layer that only contains matching features from an input layer. The criteria for adding features to the resulting layer is defined based on the values of an attribute from the input layer.
 

diff --git a/python/plugins/processing/algs/qgis/ExtendLines.py b/python/plugins/processing/algs/qgis/ExtendLines.py
diff --git a/python/plugins/processing/algs/qgis/QgisAlgorithmProvider.py b/python/plugins/processing/algs/qgis/QgisAlgorithmProvider.py
@@ -65,7 +65,6 @@
 from .EliminateSelection import EliminateSelection
 from .ExecuteSQL import ExecuteSQL
 from .ExportGeometryInfo import ExportGeometryInfo
-from .ExtendLines import ExtendLines
 from .ExtentFromLayer import ExtentFromLayer
 from .ExtractSpecificVertices import ExtractSpecificVertices
 from .FieldPyculator import FieldsPyculator
@@ -182,7 +181,6 @@ def getAlgs(self):
                 EliminateSelection(),
                 ExecuteSQL(),
                 ExportGeometryInfo(),
-                ExtendLines(),
                 ExtentFromLayer(),
                 ExtractSpecificVertices(),
                 FieldsCalculator(),

diff --git a/python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml b/python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml
@@ -1835,7 +1835,7 @@ tests:
         name: expected/extract_expression.gml
         type: vector
 
-  - algorithm: qgis:extendlines
+  - algorithm: native:extendlines
     name: Extend lines
     params:
       END_DISTANCE: 0.2
@@ -1850,7 +1850,7 @@ tests:
         compare:
           geometry:
             precision: 7
-  - algorithm: qgis:extendlines
+  - algorithm: native:extendlines
     name: Extend multilines
     params:
       END_DISTANCE: 0.4

diff --git a/src/analysis/CMakeLists.txt b/src/analysis/CMakeLists.txt
@@ -33,6 +33,7 @@ SET(QGIS_ANALYSIS_SRCS
   processing/qgsalgorithmdropgeometry.cpp
   processing/qgsalgorithmdropmzvalues.cpp
   processing/qgsalgorithmexplode.cpp
+  processing/qgsalgorithmextendlines.cpp
   processing/qgsalgorithmextenttolayer.cpp
   processing/qgsalgorithmextractbyattribute.cpp
   processing/qgsalgorithmextractbyexpression.cpp

diff --git a/src/analysis/processing/qgsalgorithmextendlines.cpp b/src/analysis/processing/qgsalgorithmextendlines.cpp
@@ -0,0 +1,142 @@
+/***************************************************************************
+                         qgsalgorithmextendlines.cpp
+                         ---------------------
+    begin                : July 2018
+    copyright            : (C) 2018 by Nyall Dawson
+    email                : nyall dot dawson 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.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsalgorithmextendlines.h"
+
+///@cond PRIVATE
+
+QString QgsExtendLinesAlgorithm::name() const
+{
+  return QStringLiteral( "extendlines" );
+}
+
+QString QgsExtendLinesAlgorithm::displayName() const
+{
+  return QObject::tr( "Extend lines" );
+}
+
+QStringList QgsExtendLinesAlgorithm::tags() const
+{
+  return QObject::tr( "linestring,continue,grow,extrapolate" ).split( ',' );
+}
+
+QString QgsExtendLinesAlgorithm::group() const
+{
+  return QObject::tr( "Vector geometry" );
+}
+
+QString QgsExtendLinesAlgorithm::groupId() const
+{
+  return QStringLiteral( "vectorgeometry" );
+}
+
+QString QgsExtendLinesAlgorithm::outputName() const
+{
+  return QObject::tr( "Extended" );
+}
+
+QString QgsExtendLinesAlgorithm::shortHelpString() const
+{
+  return QObject::tr( "This algorithm extends line geometries by a specified amount at the start and end "
+                      "of the line. Lines are extended using the bearing of the first and last segment "
+                      "in the line." );
+}
+
+QString QgsExtendLinesAlgorithm::shortDescription() const
+{
+  return QObject::tr( "Extends LineString geometries by extrapolating the start and end segments." );
+}
+
+QList<int> QgsExtendLinesAlgorithm::inputLayerTypes() const
+{
+  return QList<int>() << QgsProcessing::TypeVectorLine;
+}
+
+QgsProcessing::SourceType QgsExtendLinesAlgorithm::outputLayerType() const
+{
+  return QgsProcessing::TypeVectorLine;
+}
+
+QgsExtendLinesAlgorithm *QgsExtendLinesAlgorithm::createInstance() const
+{
+  return new QgsExtendLinesAlgorithm();
+}
+
+void QgsExtendLinesAlgorithm::initParameters( const QVariantMap & )
+{
+  std::unique_ptr< QgsProcessingParameterDistance> startDistance = qgis::make_unique< QgsProcessingParameterDistance >( QStringLiteral( "START_DISTANCE" ),
+      QObject::tr( "Start distance" ), 0.0, QStringLiteral( "INPUT" ), false, 0 );
+  startDistance->setIsDynamic( true );
+  startDistance->setDynamicPropertyDefinition( QgsPropertyDefinition( QStringLiteral( "Start Distance" ), QObject::tr( "Start distance" ), QgsPropertyDefinition::DoublePositive ) );
+  startDistance->setDynamicLayerParameterName( QStringLiteral( "INPUT" ) );
+  addParameter( startDistance.release() );
+
+  std::unique_ptr< QgsProcessingParameterDistance> endDistance = qgis::make_unique< QgsProcessingParameterDistance >( QStringLiteral( "END_DISTANCE" ),
+      QObject::tr( "End distance" ), 0.0, QStringLiteral( "INPUT" ), false, 0 );
+  endDistance->setIsDynamic( true );
+  endDistance->setDynamicPropertyDefinition( QgsPropertyDefinition( QStringLiteral( "End Distance" ), QObject::tr( "End distance" ), QgsPropertyDefinition::DoublePositive ) );
+  endDistance->setDynamicLayerParameterName( QStringLiteral( "INPUT" ) );
+  addParameter( endDistance.release() );
+}
+
+QgsProcessingFeatureSource::Flag QgsExtendLinesAlgorithm::sourceFlags() const
+{
+  // skip geometry checks - this algorithm doesn't care about invalid geometries
+  return QgsProcessingFeatureSource::FlagSkipGeometryValidityChecks;
+}
+
+bool QgsExtendLinesAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
+{
+  mStartDistance = parameterAsDouble( parameters, QStringLiteral( "START_DISTANCE" ), context );
+  mDynamicStartDistance = QgsProcessingParameters::isDynamic( parameters, QStringLiteral( "START_DISTANCE" ) );
+  if ( mDynamicStartDistance )
+    mStartDistanceProperty = parameters.value( QStringLiteral( "START_DISTANCE" ) ).value< QgsProperty >();
+
+  mEndDistance = parameterAsDouble( parameters, QStringLiteral( "END_DISTANCE" ), context );
+  mDynamicEndDistance = QgsProcessingParameters::isDynamic( parameters, QStringLiteral( "END_DISTANCE" ) );
+  if ( mDynamicEndDistance )
+    mEndDistanceProperty = parameters.value( QStringLiteral( "END_DISTANCE" ) ).value< QgsProperty >();
+
+  return true;
+}
+
+QgsFeatureList QgsExtendLinesAlgorithm::processFeature( const QgsFeature &feature, QgsProcessingContext &context, QgsProcessingFeedback * )
+{
+  QgsFeature f = feature;
+  if ( f.hasGeometry() )
+  {
+    const QgsGeometry geometry = f.geometry();
+    double startDistance = mStartDistance;
+    if ( mDynamicStartDistance )
+      startDistance = mStartDistanceProperty.valueAsDouble( context.expressionContext(), startDistance );
+
+    double endDistance = mEndDistance;
+    if ( mDynamicEndDistance )
+      endDistance = mEndDistanceProperty.valueAsDouble( context.expressionContext(), endDistance );
+
+    const QgsGeometry outGeometry = geometry.extendLine( startDistance, endDistance );
+    if ( !outGeometry )
+      throw QgsProcessingException( QObject::tr( "Error calculating extended line" ) ); // don't think this can actually happen!
+
+    f.setGeometry( outGeometry );
+  }
+  return QgsFeatureList() << f;
+}
+
+///@endcond
+
+
diff --git a/src/analysis/processing/qgsalgorithmextendlines.h b/src/analysis/processing/qgsalgorithmextendlines.h
@@ -0,0 +1,71 @@
+/***************************************************************************
+                         qgsalgorithmextendlines.h
+                         ---------------------
+    begin                : July 2018
+    copyright            : (C) 2018 by Nyall Dawson
+    email                : nyall dot dawson 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 QGSEXTENDLINESALGORITHM_H
+#define QGSEXTENDLINESALGORITHM_H
+
+#define SIP_NO_FILE
+
+#include "qgis.h"
+#include "qgsprocessingalgorithm.h"
+
+///@cond PRIVATE
+
+/**
+ * Native extend lines algorithm.
+ */
+class QgsExtendLinesAlgorithm : public QgsProcessingFeatureBasedAlgorithm
+{
+
+  public:
+
+    QgsExtendLinesAlgorithm() = default;
+    QString name() const override;
+    QString displayName() const override;
+    QStringList tags() const override;
+    QString group() const override;
+    QString groupId() const override;
+    QString shortHelpString() const override;
+    QString shortDescription() const override;
+    QList<int> inputLayerTypes() const override;
+    QgsProcessing::SourceType outputLayerType() const override;
+    QgsExtendLinesAlgorithm *createInstance() const override SIP_FACTORY;
+    void initParameters( const QVariantMap &configuration = QVariantMap() ) override;
+
+  protected:
+    QString outputName() const override;
+    QgsProcessingFeatureSource::Flag sourceFlags() const override;
+    bool prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
+    QgsFeatureList processFeature( const QgsFeature &feature,  QgsProcessingContext &, QgsProcessingFeedback *feedback ) override;
+
+  private:
+
+    double mStartDistance = 0.0;
+    bool mDynamicStartDistance = false;
+    QgsProperty mStartDistanceProperty;
+
+    double mEndDistance = 0.0;
+    bool mDynamicEndDistance = false;
+    QgsProperty mEndDistanceProperty;
+};
+
+
+///@endcond PRIVATE
+
+#endif // QGSEXTENDLINESALGORITHM_H
+
+
diff --git a/src/analysis/processing/qgsnativealgorithms.cpp b/src/analysis/processing/qgsnativealgorithms.cpp
@@ -30,6 +30,7 @@
 #include "qgsalgorithmdropgeometry.h"
 #include "qgsalgorithmdropmzvalues.h"
 #include "qgsalgorithmexplode.h"
+#include "qgsalgorithmextendlines.h"
 #include "qgsalgorithmextenttolayer.h"
 #include "qgsalgorithmextractbyattribute.h"
 #include "qgsalgorithmextractbyexpression.h"
@@ -140,6 +141,7 @@ void QgsNativeAlgorithms::loadAlgorithms()
   addAlgorithm( new QgsDropGeometryAlgorithm() );
   addAlgorithm( new QgsDropMZValuesAlgorithm() );
   addAlgorithm( new QgsExplodeAlgorithm() );
+  addAlgorithm( new QgsExtendLinesAlgorithm() );
   addAlgorithm( new QgsExtentToLayerAlgorithm() );
   addAlgorithm( new QgsExtractByAttributeAlgorithm() );
   addAlgorithm( new QgsExtractByExpressionAlgorithm() );