QGIS API Documentation 3.39.0-Master (67e056379ed)
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qgsalgorithmlayouttoimage.cpp
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1/***************************************************************************
2 qgsalgorithmlayouttoimage.cpp
3 ---------------------
4 begin : June 2020
5 copyright : (C) 2020 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#include "qgslayout.h"
20#include "qgslayoutitemmap.h"
21#include "qgsprintlayout.h"
23#include "qgslayoutexporter.h"
24#include <QImageWriter>
25
27
28QString QgsLayoutToImageAlgorithm::name() const
29{
30 return QStringLiteral( "printlayouttoimage" );
31}
32
33QString QgsLayoutToImageAlgorithm::displayName() const
34{
35 return QObject::tr( "Export print layout as image" );
36}
37
38QStringList QgsLayoutToImageAlgorithm::tags() const
39{
40 return QObject::tr( "layout,composer,composition,save,png,jpeg,jpg" ).split( ',' );
41}
42
43QString QgsLayoutToImageAlgorithm::group() const
44{
45 return QObject::tr( "Cartography" );
46}
47
48QString QgsLayoutToImageAlgorithm::groupId() const
49{
50 return QStringLiteral( "cartography" );
51}
52
53QString QgsLayoutToImageAlgorithm::shortDescription() const
54{
55 return QObject::tr( "Exports a print layout as an image." );
56}
57
58QString QgsLayoutToImageAlgorithm::shortHelpString() const
59{
60 return QObject::tr( "This algorithm outputs a print layout as an image file (e.g. PNG or JPEG images)." );
61}
62
63void QgsLayoutToImageAlgorithm::initAlgorithm( const QVariantMap & )
64{
65 addParameter( new QgsProcessingParameterLayout( QStringLiteral( "LAYOUT" ), QObject::tr( "Print layout" ) ) );
66
67 std::unique_ptr< QgsProcessingParameterMultipleLayers > layersParam = std::make_unique< QgsProcessingParameterMultipleLayers>( QStringLiteral( "LAYERS" ), QObject::tr( "Map layers to assign to unlocked map item(s)" ), Qgis::ProcessingSourceType::MapLayer, QVariant(), true );
68 layersParam->setFlags( layersParam->flags() | Qgis::ProcessingParameterFlag::Advanced );
69 addParameter( layersParam.release() );
70
71 std::unique_ptr< QgsProcessingParameterNumber > dpiParam = std::make_unique< QgsProcessingParameterNumber >( QStringLiteral( "DPI" ), QObject::tr( "DPI (leave blank for default layout DPI)" ), Qgis::ProcessingNumberParameterType::Double, QVariant(), true, 0 );
72 dpiParam->setFlags( dpiParam->flags() | Qgis::ProcessingParameterFlag::Advanced );
73 addParameter( dpiParam.release() );
74
75 std::unique_ptr< QgsProcessingParameterBoolean > appendGeorefParam = std::make_unique< QgsProcessingParameterBoolean >( QStringLiteral( "GEOREFERENCE" ), QObject::tr( "Generate world file" ), true );
76 appendGeorefParam->setFlags( appendGeorefParam->flags() | Qgis::ProcessingParameterFlag::Advanced );
77 addParameter( appendGeorefParam.release() );
78
79 std::unique_ptr< QgsProcessingParameterBoolean > exportRDFParam = std::make_unique< QgsProcessingParameterBoolean >( QStringLiteral( "INCLUDE_METADATA" ), QObject::tr( "Export RDF metadata (title, author, etc.)" ), true );
80 exportRDFParam->setFlags( exportRDFParam->flags() | Qgis::ProcessingParameterFlag::Advanced );
81 addParameter( exportRDFParam.release() );
82
83 std::unique_ptr< QgsProcessingParameterBoolean > antialias = std::make_unique< QgsProcessingParameterBoolean >( QStringLiteral( "ANTIALIAS" ), QObject::tr( "Enable antialiasing" ), true );
84 antialias->setFlags( antialias->flags() | Qgis::ProcessingParameterFlag::Advanced );
85 addParameter( antialias.release() );
86
87 QStringList imageFilters;
88 const auto supportedImageFormats { QImageWriter::supportedImageFormats() };
89 for ( const QByteArray &format : supportedImageFormats )
90 {
91 if ( format == "svg" )
92 continue;
93
94 const QString longName = format.toUpper() + QObject::tr( " format" );
95 const QString glob = QStringLiteral( "*." ) + format;
96
97 if ( format == "png" && !imageFilters.empty() )
98 imageFilters.insert( 0, QStringLiteral( "%1 (%2 %3)" ).arg( longName, glob.toLower(), glob.toUpper() ) );
99 else
100 imageFilters.append( QStringLiteral( "%1 (%2 %3)" ).arg( longName, glob.toLower(), glob.toUpper() ) );
101 }
102
103 addParameter( new QgsProcessingParameterFileDestination( QStringLiteral( "OUTPUT" ), QObject::tr( "Image file" ), imageFilters.join( QLatin1String( ";;" ) ) ) );
104}
105
106Qgis::ProcessingAlgorithmFlags QgsLayoutToImageAlgorithm::flags() const
107{
109}
110
111QgsLayoutToImageAlgorithm *QgsLayoutToImageAlgorithm::createInstance() const
112{
113 return new QgsLayoutToImageAlgorithm();
114}
115
116QVariantMap QgsLayoutToImageAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
117{
118 // this needs to be done in main thread, layouts are not thread safe
119 QgsPrintLayout *l = parameterAsLayout( parameters, QStringLiteral( "LAYOUT" ), context );
120 if ( !l )
121 throw QgsProcessingException( QObject::tr( "Cannot find layout with name \"%1\"" ).arg( parameters.value( QStringLiteral( "LAYOUT" ) ).toString() ) );
122 std::unique_ptr< QgsPrintLayout > layout( l->clone() );
123
124 const QList< QgsMapLayer * > layers = parameterAsLayerList( parameters, QStringLiteral( "LAYERS" ), context );
125 if ( layers.size() > 0 )
126 {
127 const QList<QGraphicsItem *> items = layout->items();
128 for ( QGraphicsItem *graphicsItem : items )
129 {
130 QgsLayoutItem *item = dynamic_cast<QgsLayoutItem *>( graphicsItem );
131 QgsLayoutItemMap *map = dynamic_cast<QgsLayoutItemMap *>( item );
132 if ( map && !map->followVisibilityPreset() && !map->keepLayerSet() )
133 {
134 map->setKeepLayerSet( true );
135 map->setLayers( layers );
136 }
137 }
138 }
139
140 const QString dest = parameterAsFileOutput( parameters, QStringLiteral( "OUTPUT" ), context );
141
142 QgsLayoutExporter exporter( layout.get() );
144
145 if ( parameters.value( QStringLiteral( "DPI" ) ).isValid() )
146 {
147 settings.dpi = parameterAsDouble( parameters, QStringLiteral( "DPI" ), context );
148 }
149
150 settings.exportMetadata = parameterAsBool( parameters, QStringLiteral( "INCLUDE_METADATA" ), context );
151 settings.generateWorldFile = parameterAsBool( parameters, QStringLiteral( "GEOREFERENCE" ), context );
152
153 if ( parameterAsBool( parameters, QStringLiteral( "ANTIALIAS" ), context ) )
155 else
156 settings.flags = settings.flags & ~QgsLayoutRenderContext::FlagAntialiasing;
157
158 switch ( exporter.exportToImage( dest, settings ) )
159 {
161 {
162 feedback->pushInfo( QObject::tr( "Successfully exported layout to %1" ).arg( QDir::toNativeSeparators( dest ) ) );
163 break;
164 }
165
167 throw QgsProcessingException( !exporter.errorMessage().isEmpty() ? exporter.errorMessage() : QObject::tr( "Cannot write to %1.\n\nThis file may be open in another application." ).arg( QDir::toNativeSeparators( dest ) ) );
168
170 throw QgsProcessingException( !exporter.errorMessage().isEmpty() ? exporter.errorMessage() : QObject::tr( "Trying to create the image "
171 "resulted in a memory overflow.\n\n"
172 "Please try a lower resolution or a smaller paper size." ) );
173
178 // no meaning for imageexports, will not be encountered
179 break;
180 }
181
182 feedback->setProgress( 100 );
183
184 QVariantMap outputs;
185 outputs.insert( QStringLiteral( "OUTPUT" ), dest );
186 return outputs;
187}
188
190
@ MapLayer
Any map layer type (raster, vector, mesh, point cloud, annotation or plugin layer)
QFlags< ProcessingAlgorithmFlag > ProcessingAlgorithmFlags
Flags indicating how and when an algorithm operates and should be exposed to users.
Definition qgis.h:3076
@ NoThreading
Algorithm is not thread safe and cannot be run in a background thread, e.g. for algorithms which mani...
@ RequiresProject
The algorithm requires that a valid QgsProject is available from the processing context in order to e...
@ Advanced
Parameter is an advanced parameter which should be hidden from users by default.
void setProgress(double progress)
Sets the current progress for the feedback object.
Definition qgsfeedback.h:61
Handles rendering and exports of layouts to various formats.
@ Canceled
Export was canceled.
@ MemoryError
Unable to allocate memory required to export.
@ PrintError
Could not start printing to destination device.
@ IteratorError
Error iterating over layout.
@ FileError
Could not write to destination file, likely due to a lock held by another application.
@ Success
Export was successful.
@ SvgLayerError
Could not create layered SVG file.
Layout graphical items for displaying a map.
bool keepLayerSet() const
Returns whether a stored layer set should be used or the current layer set from the project associate...
void setKeepLayerSet(bool enabled)
Sets whether the stored layer set should be used or the current layer set of the associated project.
bool followVisibilityPreset() const
Returns whether the map should follow a map theme.
void setLayers(const QList< QgsMapLayer * > &layers)
Sets the stored layers set.
Base class for graphical items within a QgsLayout.
Stores information relating to the current rendering settings for a layout.
@ FlagAntialiasing
Use antialiasing when drawing items.
Print layout, a QgsLayout subclass for static or atlas-based layouts.
QgsPrintLayout * clone() const override
Creates a clone of the layout.
virtual Qgis::ProcessingAlgorithmFlags flags() const
Returns the flags indicating how and when the algorithm operates and should be exposed to users.
Contains information about the context in which a processing algorithm is executed.
Custom exception class for processing related exceptions.
Base class for providing feedback from a processing algorithm.
virtual void pushInfo(const QString &info)
Pushes a general informational message from the algorithm.
A generic file based destination parameter, for specifying the destination path for a file (non-map l...
A print layout parameter, allowing users to select a print layout.
Contains settings relating to exporting layouts to raster images.
bool generateWorldFile
Set to true to generate an external world file alongside exported images.
bool exportMetadata
Indicates whether image export should include metadata generated from the layout's project's metadata...
QgsLayoutRenderContext::Flags flags
Layout context flags, which control how the export will be created.
double dpi
Resolution to export layout at. If dpi <= 0 the default layout dpi will be used.