QGIS API Documentation 3.27.0-Master (95e00c50d2)
qgsalgorithmextractlayoutmapextent.cpp
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1/***************************************************************************
2 qgsalgorithmextractlayoutmapextent.cpp
3 ---------------------
4 begin : March 2019
5 copyright : (C) 2019 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
21#include "layout/qgslayout.h"
24
26
27QString QgsLayoutMapExtentToLayerAlgorithm::name() const
28{
29 return QStringLiteral( "printlayoutmapextenttolayer" );
30}
31
32QString QgsLayoutMapExtentToLayerAlgorithm::displayName() const
33{
34 return QObject::tr( "Print layout map extent to layer" );
35}
36
37QStringList QgsLayoutMapExtentToLayerAlgorithm::tags() const
38{
39 return QObject::tr( "layout,composer,composition,visible" ).split( ',' );
40}
41
42QString QgsLayoutMapExtentToLayerAlgorithm::group() const
43{
44 return QObject::tr( "Cartography" );
45}
46
47QString QgsLayoutMapExtentToLayerAlgorithm::groupId() const
48{
49 return QStringLiteral( "cartography" );
50}
51
52QString QgsLayoutMapExtentToLayerAlgorithm::shortDescription() const
53{
54 return QObject::tr( "Creates a polygon layer containing the extent of a print layout map item." );
55}
56
57void QgsLayoutMapExtentToLayerAlgorithm::initAlgorithm( const QVariantMap & )
58{
59 addParameter( new QgsProcessingParameterLayout( QStringLiteral( "LAYOUT" ), QObject::tr( "Print layout" ) ) );
60 addParameter( new QgsProcessingParameterLayoutItem( QStringLiteral( "MAP" ), QObject::tr( "Map item" ), QVariant(), QStringLiteral( "LAYOUT" ), QgsLayoutItemRegistry::LayoutMap, true ) );
61 auto crsParam = std::make_unique< QgsProcessingParameterCrs >( QStringLiteral( "CRS" ), QObject::tr( "Override CRS" ), QVariant(), true );
62 crsParam->setFlags( crsParam->flags() | QgsProcessingParameterDefinition::FlagAdvanced );
63 addParameter( crsParam.release() );
64 addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "OUTPUT" ), QObject::tr( "Extent" ), QgsProcessing::TypeVectorPolygon ) );
65 addOutput( new QgsProcessingOutputNumber( QStringLiteral( "WIDTH" ), QObject::tr( "Map width" ) ) );
66 addOutput( new QgsProcessingOutputNumber( QStringLiteral( "HEIGHT" ), QObject::tr( "Map height" ) ) );
67 addOutput( new QgsProcessingOutputNumber( QStringLiteral( "SCALE" ), QObject::tr( "Map scale" ) ) );
68 addOutput( new QgsProcessingOutputNumber( QStringLiteral( "ROTATION" ), QObject::tr( "Map rotation" ) ) );
69}
70
71QString QgsLayoutMapExtentToLayerAlgorithm::shortHelpString() const
72{
73 return QObject::tr( "This algorithm creates a polygon layer containing the extent of a print layout map item (or items), "
74 "with attributes specifying the map size (in layout units), scale and rotation.\n\n"
75 "If the map item parameter is specified, then only the matching map extent will be exported. If it "
76 "is not specified, all map extents from the layout will be exported.\n\n"
77 "Optionally, a specific output CRS can be specified. If it is not specified, the original map "
78 "item CRS will be used." );
79}
80
81QgsLayoutMapExtentToLayerAlgorithm *QgsLayoutMapExtentToLayerAlgorithm::createInstance() const
82{
83 return new QgsLayoutMapExtentToLayerAlgorithm();
84}
85
86bool QgsLayoutMapExtentToLayerAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
87{
88 // this needs to be done in main thread, layouts are not thread safe
89 QgsPrintLayout *layout = parameterAsLayout( parameters, QStringLiteral( "LAYOUT" ), context );
90 if ( !layout )
91 throw QgsProcessingException( QObject::tr( "Cannot find layout with name \"%1\"" ).arg( parameters.value( QStringLiteral( "LAYOUT" ) ).toString() ) );
92
93 QgsLayoutItemMap *map = qobject_cast< QgsLayoutItemMap * >( parameterAsLayoutItem( parameters, QStringLiteral( "MAP" ), context, layout ) );
94 if ( !map && parameters.value( QStringLiteral( "MAP" ) ).isValid() )
95 throw QgsProcessingException( QObject::tr( "Cannot find matching map item with ID %1" ).arg( parameters.value( QStringLiteral( "MAP" ) ).toString() ) );
96
97 QList< QgsLayoutItemMap *> maps;
98 if ( map )
99 maps << map;
100 else
101 layout->layoutItems( maps );
102
103 const QgsCoordinateReferenceSystem overrideCrs = parameterAsCrs( parameters, QStringLiteral( "CRS" ), context );
104
105 mFeatures.reserve( maps.size() );
106 for ( QgsLayoutItemMap *map : maps )
107 {
108 if ( !mCrs.isValid() )
109 mCrs = !overrideCrs.isValid() ? map->crs() : overrideCrs;
110
111 QgsGeometry extent = QgsGeometry::fromQPolygonF( map->visibleExtentPolygon() );
112 if ( map->crs() != mCrs )
113 {
114 try
115 {
116 extent.transform( QgsCoordinateTransform( map->crs(), mCrs, context.transformContext() ) );
117 }
118 catch ( QgsCsException & )
119 {
120 feedback->reportError( QObject::tr( "Error reprojecting map to destination CRS" ) );
121 continue;
122 }
123 }
124
125 mWidth = map->rect().width();
126 mHeight = map->rect().height();
127 mScale = map->scale();
128 mRotation = map->mapRotation();
129
130 QgsFeature f;
131 f.setAttributes( QgsAttributes() << map->displayName() << mWidth << mHeight << mScale << mRotation );
132 f.setGeometry( extent );
133
134 mFeatures << f;
135 }
136 return true;
137}
138
139QVariantMap QgsLayoutMapExtentToLayerAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
140{
141 QgsFields fields;
142 fields.append( QgsField( QStringLiteral( "map" ), QVariant::String ) );
143 fields.append( QgsField( QStringLiteral( "width" ), QVariant::Double ) );
144 fields.append( QgsField( QStringLiteral( "height" ), QVariant::Double ) );
145 fields.append( QgsField( QStringLiteral( "scale" ), QVariant::Double ) );
146 fields.append( QgsField( QStringLiteral( "rotation" ), QVariant::Double ) );
147
148 QString dest;
149 std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, fields, QgsWkbTypes::Polygon, mCrs ) );
150 if ( !sink )
151 throw QgsProcessingException( invalidSinkError( parameters, QStringLiteral( "OUTPUT" ) ) );
152
153 for ( QgsFeature &f : mFeatures )
154 {
155 if ( !sink->addFeature( f, QgsFeatureSink::FastInsert ) )
156 throw QgsProcessingException( writeFeatureError( sink.get(), parameters, QStringLiteral( "OUTPUT" ) ) );
157 }
158
159 feedback->setProgress( 100 );
160
161 QVariantMap outputs;
162 outputs.insert( QStringLiteral( "OUTPUT" ), dest );
163 // these numeric outputs only have value for single-map layouts
164 outputs.insert( QStringLiteral( "WIDTH" ), mFeatures.size() == 1 ? mWidth : QVariant() );
165 outputs.insert( QStringLiteral( "HEIGHT" ), mFeatures.size() == 1 ? mHeight : QVariant() );
166 outputs.insert( QStringLiteral( "SCALE" ), mFeatures.size() == 1 ? mScale : QVariant() );
167 outputs.insert( QStringLiteral( "ROTATION" ), mFeatures.size() == 1 ? mRotation : QVariant() );
168 return outputs;
169}
170
172
A vector of attributes.
Definition: qgsattributes.h:59
This class represents a coordinate reference system (CRS).
bool isValid() const
Returns whether this CRS is correctly initialized and usable.
Class for doing transforms between two map coordinate systems.
Custom exception class for Coordinate Reference System related exceptions.
Definition: qgsexception.h:66
@ FastInsert
Use faster inserts, at the cost of updating the passed features to reflect changes made at the provid...
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Definition: qgsfeature.h:56
void setAttributes(const QgsAttributes &attrs)
Sets the feature's attributes.
Definition: qgsfeature.cpp:160
void setGeometry(const QgsGeometry &geometry)
Set the feature's geometry.
Definition: qgsfeature.cpp:170
void setProgress(double progress)
Sets the current progress for the feedback object.
Definition: qgsfeedback.h:63
Encapsulate a field in an attribute table or data source.
Definition: qgsfield.h:51
Container of fields for a vector layer.
Definition: qgsfields.h:45
bool append(const QgsField &field, FieldOrigin origin=OriginProvider, int originIndex=-1)
Appends a field. The field must have unique name, otherwise it is rejected (returns false)
Definition: qgsfields.cpp:59
A geometry is the spatial representation of a feature.
Definition: qgsgeometry.h:164
Qgis::GeometryOperationResult transform(const QgsCoordinateTransform &ct, Qgis::TransformDirection direction=Qgis::TransformDirection::Forward, bool transformZ=false) SIP_THROW(QgsCsException)
Transforms this geometry as described by the coordinate transform ct.
static QgsGeometry fromQPolygonF(const QPolygonF &polygon)
Construct geometry from a QPolygonF.
Layout graphical items for displaying a map.
void layoutItems(QList< T * > &itemList) const
Returns a list of layout items of a specific type.
Definition: qgslayout.h:122
Print layout, a QgsLayout subclass for static or atlas-based layouts.
Contains information about the context in which a processing algorithm is executed.
QgsCoordinateTransformContext transformContext() const
Returns the coordinate transform context.
Custom exception class for processing related exceptions.
Definition: qgsexception.h:83
Base class for providing feedback from a processing algorithm.
virtual void reportError(const QString &error, bool fatalError=false)
Reports that the algorithm encountered an error while executing.
A numeric output for processing algorithms.
@ FlagAdvanced
Parameter is an advanced parameter which should be hidden from users by default.
A feature sink output for processing algorithms.
A print layout item parameter, allowing users to select a particular item from a print layout.
A print layout parameter, allowing users to select a print layout.
@ TypeVectorPolygon
Vector polygon layers.
Definition: qgsprocessing.h:51