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nyalldawsonnyalldawson
committedSep 14, 2017
[FEATURE] New processing algorithm "extract/clip by extent"
Allows extract a subset of another layer using an extent, with optional setting to clip geometries to the extent
·
ltr-3_40final-3_0_0
1 parent ba9cb87 commit d8db3ec

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7 files changed

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7 files changed

+250
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lines changed
 

‎python/plugins/processing/tests/testdata/expected/extract_by_extent.gfs

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<GMLFeatureClassList>
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<GMLFeatureClass>
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<Name>extract_by_extent</Name>
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<ElementPath>extract_by_extent</ElementPath>
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<!--POLYGON-->
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<GeometryType>3</GeometryType>
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<SRSName>EPSG:4326</SRSName>
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<DatasetSpecificInfo>
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<FeatureCount>3</FeatureCount>
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<ExtentXMin>-1.00000</ExtentXMin>
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<ExtentXMax>10.00000</ExtentXMax>
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<ExtentYMin>-3.00000</ExtentYMin>
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<ExtentYMax>3.00000</ExtentYMax>
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</DatasetSpecificInfo>
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<PropertyDefn>
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<Name>name</Name>
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<ElementPath>name</ElementPath>
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<Type>String</Type>
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<Width>5</Width>
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</PropertyDefn>
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<PropertyDefn>
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<Name>intval</Name>
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<ElementPath>intval</ElementPath>
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<Type>Integer</Type>
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</PropertyDefn>
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<PropertyDefn>
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<Name>floatval</Name>
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<ElementPath>floatval</ElementPath>
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<Type>String</Type>
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<Width>18</Width>
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</PropertyDefn>
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</GMLFeatureClass>
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</GMLFeatureClassList>

‎python/plugins/processing/tests/testdata/expected/extract_by_extent.gml

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<?xml version="1.0" encoding="utf-8" ?>
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<ogr:FeatureCollection
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation=""
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xmlns:ogr="http://ogr.maptools.org/"
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xmlns:gml="http://www.opengis.net/gml">
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<gml:boundedBy>
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<gml:Box>
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<gml:coord><gml:X>-1</gml:X><gml:Y>-3</gml:Y></gml:coord>
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<gml:coord><gml:X>6</gml:X><gml:Y>3</gml:Y></gml:coord>
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</gml:Box>
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</gml:boundedBy>
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<gml:featureMember>
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<ogr:extract_by_extent fid="polys.0">
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<ogr:geometryProperty><gml:Polygon srsName="EPSG:4326"><gml:outerBoundaryIs><gml:LinearRing><gml:coordinates>-1,-1 -1,3 3,3 3,2 2,2 2,-1 -1,-1</gml:coordinates></gml:LinearRing></gml:outerBoundaryIs></gml:Polygon></ogr:geometryProperty>
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<ogr:name>aaaaa</ogr:name>
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<ogr:intval>33</ogr:intval>
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<ogr:floatval>44.123456</ogr:floatval>
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</ogr:extract_by_extent>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_by_extent fid="polys.5">
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<ogr:geometryProperty><gml:Polygon srsName="EPSG:4326"><gml:outerBoundaryIs><gml:LinearRing><gml:coordinates>3,2 6,1 6,-3 2,-1 2,2 3,2</gml:coordinates></gml:LinearRing></gml:outerBoundaryIs></gml:Polygon></ogr:geometryProperty>
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<ogr:name>elim</ogr:name>
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<ogr:intval>2</ogr:intval>
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<ogr:floatval>3.33</ogr:floatval>
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</ogr:extract_by_extent>
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</gml:featureMember>
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</ogr:FeatureCollection>

‎python/plugins/processing/tests/testdata/expected/extract_by_extent_clip.gfs

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<GMLFeatureClassList>
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<GMLFeatureClass>
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<Name>extract_by_extent_clip</Name>
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<ElementPath>extract_by_extent_clip</ElementPath>
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<!--MULTIPOLYGON-->
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<GeometryType>6</GeometryType>
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<SRSName>EPSG:4326</SRSName>
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<DatasetSpecificInfo>
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<FeatureCount>2</FeatureCount>
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<ExtentXMin>-1.00000</ExtentXMin>
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<ExtentXMax>4.77500</ExtentXMax>
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<ExtentYMin>-2.38750</ExtentYMin>
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<ExtentYMax>3.00000</ExtentYMax>
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</DatasetSpecificInfo>
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<PropertyDefn>
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<Name>name</Name>
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<ElementPath>name</ElementPath>
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<Type>String</Type>
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<Width>5</Width>
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</PropertyDefn>
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<PropertyDefn>
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<Name>intval</Name>
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<ElementPath>intval</ElementPath>
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<Type>Integer</Type>
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</PropertyDefn>
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<PropertyDefn>
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<Name>floatval</Name>
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<ElementPath>floatval</ElementPath>
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<Type>Real</Type>
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</PropertyDefn>
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</GMLFeatureClass>
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</GMLFeatureClassList>

‎python/plugins/processing/tests/testdata/expected/extract_by_extent_clip.gml

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<?xml version="1.0" encoding="utf-8" ?>
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<ogr:FeatureCollection
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation=""
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xmlns:ogr="http://ogr.maptools.org/"
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xmlns:gml="http://www.opengis.net/gml">
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<gml:boundedBy>
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<gml:Box>
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<gml:coord><gml:X>-1</gml:X><gml:Y>-2.3875</gml:Y></gml:coord>
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<gml:coord><gml:X>4.775</gml:X><gml:Y>3</gml:Y></gml:coord>
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</gml:Box>
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</gml:boundedBy>
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<gml:featureMember>
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<ogr:extract_by_extent_clip fid="polys.0">
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<ogr:geometryProperty><gml:MultiPolygon srsName="EPSG:4326"><gml:polygonMember><gml:Polygon><gml:outerBoundaryIs><gml:LinearRing><gml:coordinates>-1,-1 -1,3 3,3 3,2 2,2 2,-1 -1,-1</gml:coordinates></gml:LinearRing></gml:outerBoundaryIs></gml:Polygon></gml:polygonMember></gml:MultiPolygon></ogr:geometryProperty>
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<ogr:name>aaaaa</ogr:name>
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<ogr:intval>33</ogr:intval>
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<ogr:floatval>44.123456</ogr:floatval>
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</ogr:extract_by_extent_clip>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_by_extent_clip fid="polys.5">
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<ogr:geometryProperty><gml:MultiPolygon srsName="EPSG:4326"><gml:polygonMember><gml:Polygon><gml:outerBoundaryIs><gml:LinearRing><gml:coordinates>3,2 4.775,1.40833333333333 4.775,-2.3875 2,-1 2,2 3,2</gml:coordinates></gml:LinearRing></gml:outerBoundaryIs></gml:Polygon></gml:polygonMember></gml:MultiPolygon></ogr:geometryProperty>
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<ogr:name>elim</ogr:name>
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<ogr:intval>2</ogr:intval>
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<ogr:floatval>3.33</ogr:floatval>
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</ogr:extract_by_extent_clip>
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</gml:featureMember>
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</ogr:FeatureCollection>

‎python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml

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@@ -3937,4 +3937,30 @@ tests:
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- name
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compare:
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fields:
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fid: skip
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fid: skip
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- algorithm: native:extractbyextent
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name: Extract by extent
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params:
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CLIP: false
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EXTENT: -1.1650000000000003,4.775,-2.444285714285715,3.4171428571428573
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INPUT:
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name: polys.gml
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type: vector
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results:
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OUTPUT:
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name: expected/extract_by_extent.gml
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type: vector
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- algorithm: native:extractbyextent
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name: Extract by extent (clipped)
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params:
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CLIP: true
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EXTENT: -1.1650000000000003,4.775,-2.444285714285715,3.4171428571428573
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INPUT:
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name: polys.gml
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type: vector
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results:
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OUTPUT:
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name: expected/extract_by_extent_clip.gml
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type: vector

‎src/core/processing/qgsnativealgorithms.cpp

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@@ -82,6 +82,7 @@ void QgsNativeAlgorithms::loadAlgorithms()
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addAlgorithm( new QgsMergeLinesAlgorithm() );
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addAlgorithm( new QgsSmoothAlgorithm() );
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addAlgorithm( new QgsSimplifyAlgorithm() );
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addAlgorithm( new QgsExtractByExtentAlgorithm() );
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}
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void QgsCentroidAlgorithm::initAlgorithm( const QVariantMap & )
@@ -1811,7 +1812,77 @@ QgsFeature QgsSimplifyAlgorithm::processFeature( const QgsFeature &feature, QgsP
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return f;
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}
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///@endcond
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void QgsExtractByExtentAlgorithm::initAlgorithm( const QVariantMap & )
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{
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addParameter( new QgsProcessingParameterFeatureSource( QStringLiteral( "INPUT" ), QObject::tr( "Input layer" ) ) );
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addParameter( new QgsProcessingParameterExtent( QStringLiteral( "EXTENT" ), QObject::tr( "Extent" ) ) );
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addParameter( new QgsProcessingParameterBoolean( QStringLiteral( "CLIP" ), QObject::tr( "Clip features to extent" ), false ) );
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addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "OUTPUT" ), QObject::tr( "Extracted" ) ) );
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}
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QString QgsExtractByExtentAlgorithm::shortHelpString() const
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{
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return QObject::tr( "This algorithm creates a new vector layer that only contains features which fall within a specified extent. "
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"Any features which intersect the extent will be included.\n\n"
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"Optionally, feature geometries can also be clipped to the extent. If this option is selected, then the output "
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"geometries will automatically be converted to multi geometries to ensure uniform output geometry types." );
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}
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QgsExtractByExtentAlgorithm *QgsExtractByExtentAlgorithm::createInstance() const
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{
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return new QgsExtractByExtentAlgorithm();
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}
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QVariantMap QgsExtractByExtentAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
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{
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std::unique_ptr< QgsFeatureSource > featureSource( parameterAsSource( parameters, QStringLiteral( "INPUT" ), context ) );
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if ( !featureSource )
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return QVariantMap();
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QgsRectangle extent = parameterAsExtent( parameters, QStringLiteral( "EXTENT" ), context );
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bool clip = parameterAsBool( parameters, QStringLiteral( "CLIP" ), context );
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// if clipping, we force multi output
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QgsWkbTypes::Type outType = clip ? QgsWkbTypes::multiType( featureSource->wkbType() ) : featureSource->wkbType();
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QString dest;
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std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, featureSource->fields(), outType, featureSource->sourceCrs() ) );
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if ( !sink )
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return QVariantMap();
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QgsGeometry clipGeom = QgsGeometry::fromRect( extent );
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double step = featureSource->featureCount() > 0 ? 100.0 / featureSource->featureCount() : 1;
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QgsFeatureIterator inputIt = featureSource->getFeatures( QgsFeatureRequest().setFilterRect( extent ).setFlags( QgsFeatureRequest::ExactIntersect ) );
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QgsFeature f;
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int i = -1;
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while ( inputIt.nextFeature( f ) )
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{
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i++;
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if ( feedback->isCanceled() )
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{
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break;
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}
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if ( clip )
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{
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QgsGeometry g = f.geometry().intersection( clipGeom );
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g.convertToMultiType();
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f.setGeometry( g );
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}
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sink->addFeature( f, QgsFeatureSink::FastInsert );
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feedback->setProgress( i * step );
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}
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QVariantMap outputs;
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outputs.insert( QStringLiteral( "OUTPUT" ), dest );
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return outputs;
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}
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///@endcond
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‎src/core/processing/qgsnativealgorithms.h

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@@ -662,6 +662,32 @@ class QgsSimplifyAlgorithm : public QgsProcessingFeatureBasedAlgorithm
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std::unique_ptr< QgsMapToPixelSimplifier > mSimplifier;
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};
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/**
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* Native extract/clip by extent algorithm.
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*/
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class QgsExtractByExtentAlgorithm : public QgsProcessingAlgorithm
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{
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public:
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QgsExtractByExtentAlgorithm() = default;
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void initAlgorithm( const QVariantMap &configuration = QVariantMap() ) override;
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QString name() const override { return QStringLiteral( "extractbyextent" ); }
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QString displayName() const override { return QObject::tr( "Extract/clip by extent" ); }
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virtual QStringList tags() const override { return QObject::tr( "clip,extract,intersect,intersection,mask,extent" ).split( ',' ); }
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QString group() const override { return QObject::tr( "Vector overlay" ); }
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QString shortHelpString() const override;
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QgsExtractByExtentAlgorithm *createInstance() const override SIP_FACTORY;
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protected:
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virtual QVariantMap processAlgorithm( const QVariantMap &parameters,
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QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
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};
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///@endcond PRIVATE
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#endif // QGSNATIVEALGORITHMS_H

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