Make QgsGeometry::offsetCurve handle multi* geometries

qgis · Aug 11, 2016 · 0a2b661 · 0a2b661
1 parent 82f4a82
commit 0a2b661
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Showing 4 changed files with 99 additions and 5 deletions.
diff --git a/python/plugins/processing/tests/testdata/expected/multiline_offset.gml b/python/plugins/processing/tests/testdata/expected/multiline_offset.gml
@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ogr:FeatureCollection
+     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+     xsi:schemaLocation="http://ogr.maptools.org/ multiline_offset.xsd"
+     xmlns:ogr="http://ogr.maptools.org/"
+     xmlns:gml="http://www.opengis.net/gml">
+  <gml:boundedBy>
+    <gml:Box>
+      <gml:coord><gml:X>-1</gml:X><gml:Y>0</gml:Y></gml:coord>
+      <gml:coord><gml:X>6.024038190337471</gml:X><gml:Y>5.119353882875417</gml:Y></gml:coord>
+    </gml:Box>
+  </gml:boundedBy>
+
+  <gml:featureMember>
+    <ogr:multiline_offset fid="lines.1">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>-1,0 1,0</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:multiline_offset>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:multiline_offset fid="lines.2">
+      <ogr:geometryProperty><gml:MultiLineString srsName="EPSG:4326"><gml:lineStringMember><gml:LineString><gml:coordinates>3,2 5,2</gml:coordinates></gml:LineString></gml:lineStringMember><gml:lineStringMember><gml:LineString><gml:coordinates>6.024038190337471,2.397687750474408 5.999853929301003,0.982908479841009</gml:coordinates></gml:LineString></gml:lineStringMember></gml:MultiLineString></ogr:geometryProperty>
+    </ogr:multiline_offset>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:multiline_offset fid="lines.3">
+    </ogr:multiline_offset>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:multiline_offset fid="lines.4">
+      <ogr:geometryProperty><gml:MultiLineString srsName="EPSG:4326"><gml:lineStringMember><gml:LineString><gml:coordinates>1,0 1,2 1.01921471959677,2.195090322016128 1.076120467488713,2.38268343236509 1.168530387697455,2.555570233019602 1.292893218813453,2.707106781186547 1.444429766980398,2.831469612302545 1.61731656763491,2.923879532511287 1.804909677983872,2.98078528040323 2,3</gml:coordinates></gml:LineString></gml:lineStringMember><gml:lineStringMember><gml:LineString><gml:coordinates>2.915503652020259,5.046801099766013 5.430666799812965,5.119353882875417</gml:coordinates></gml:LineString></gml:lineStringMember><gml:lineStringMember><gml:LineString><gml:coordinates>3.020599614854323,3.999787805420657 5.601021879729563,3.946620818856359</gml:coordinates></gml:LineString></gml:lineStringMember></gml:MultiLineString></ogr:geometryProperty>
+    </ogr:multiline_offset>
+  </gml:featureMember>
+</ogr:FeatureCollection>
diff --git a/python/plugins/processing/tests/testdata/expected/multiline_offset.xsd b/python/plugins/processing/tests/testdata/expected/multiline_offset.xsd
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<xs:schema targetNamespace="http://ogr.maptools.org/" xmlns:ogr="http://ogr.maptools.org/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:gml="http://www.opengis.net/gml" elementFormDefault="qualified" version="1.0">
+<xs:import namespace="http://www.opengis.net/gml" schemaLocation="http://schemas.opengis.net/gml/2.1.2/feature.xsd"/>
+<xs:element name="FeatureCollection" type="ogr:FeatureCollectionType" substitutionGroup="gml:_FeatureCollection"/>
+<xs:complexType name="FeatureCollectionType">
+  <xs:complexContent>
+    <xs:extension base="gml:AbstractFeatureCollectionType">
+      <xs:attribute name="lockId" type="xs:string" use="optional"/>
+      <xs:attribute name="scope" type="xs:string" use="optional"/>
+    </xs:extension>
+  </xs:complexContent>
+</xs:complexType>
+<xs:element name="multiline_offset" type="ogr:multiline_offset_Type" substitutionGroup="gml:_Feature"/>
+<xs:complexType name="multiline_offset_Type">
+  <xs:complexContent>
+    <xs:extension base="gml:AbstractFeatureType">
+      <xs:sequence>
+        <xs:element name="geometryProperty" type="gml:GeometryPropertyType" nillable="true" minOccurs="0" maxOccurs="1"/>
+      </xs:sequence>
+    </xs:extension>
+  </xs:complexContent>
+</xs:complexType>
+</xs:schema>
diff --git a/python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml b/python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml
@@ -642,3 +642,18 @@ tests:
       OUTPUT_LAYER:
         name: expected/line_offset_bevel.gml
         type: vector
+
+  - algorithm: qgis:offsetline
+    name: Offset multilines
+    params:
+      DISTANCE: 1.0
+      INPUT_LAYER:
+        name: multilines.gml
+        type: vector
+      JOIN_STYLE: '0'
+      MITRE_LIMIT: 2
+      SEGMENTS: 8
+    results:
+      OUTPUT_LAYER:
+        name: expected/multiline_offset.gml
+        type: vector
diff --git a/src/core/geometry/qgsgeometry.cpp b/src/core/geometry/qgsgeometry.cpp
@@ -1319,13 +1319,36 @@ QgsGeometry QgsGeometry::offsetCurve( double distance, int segments, int joinSty
     return QgsGeometry();
   }
 
-  QgsGeos geos( d->geometry );
-  QgsAbstractGeometry* offsetGeom = geos.offsetCurve( distance, segments, joinStyle, mitreLimit );
-  if ( !offsetGeom )
+  if ( QgsWkbTypes::isMultiType( d->geometry->wkbType() ) )
   {
-    return QgsGeometry();
+    QList<QgsGeometry> parts = asGeometryCollection();
+    QList<QgsGeometry> results;
+    Q_FOREACH ( const QgsGeometry& part, parts )
+    {
+      QgsGeometry result = part.offsetCurve( distance, segments, joinStyle, mitreLimit );
+      if ( result )
+        results << result;
+    }
+    if ( results.isEmpty() )
+      return QgsGeometry();
+
+    QgsGeometry first = results.takeAt( 0 );
+    Q_FOREACH ( const QgsGeometry& result, results )
+    {
+      first.addPart( & result );
+    }
+    return first;
+  }
+  else
+  {
+    QgsGeos geos( d->geometry );
+    QgsAbstractGeometry* offsetGeom = geos.offsetCurve( distance, segments, joinStyle, mitreLimit );
+    if ( !offsetGeom )
+    {
+      return QgsGeometry();
+    }
+    return QgsGeometry( offsetGeom );
   }
-  return QgsGeometry( offsetGeom );
 }
 
 QgsGeometry QgsGeometry::simplify( double tolerance ) const