Move variant to CRS resolution out to QgsProcessingUtils for wider

usability
qgis · Dec 20, 2019 · 3e9aaaa · 3e9aaaa
1 parent fe622dd
commit 3e9aaaa
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Showing 4 changed files with 82 additions and 57 deletions.
diff --git a/python/core/auto_generated/processing/qgsprocessingutils.sip.in b/python/core/auto_generated/processing/qgsprocessingutils.sip.in
@@ -125,6 +125,16 @@ The optional ``fallbackValue`` can be used to specify a "default" value which is
 if ``value`` cannot be successfully converted to a source.
 
 This function creates a new object and the caller takes responsibility for deleting the returned object.
+%End
+
+    static QgsCoordinateReferenceSystem variantToCrs( const QVariant &value, QgsProcessingContext &context, const QVariant &fallbackValue = QVariant() );
+%Docstring
+Converts a variant ``value`` to a coordinate reference system.
+
+The optional ``fallbackValue`` can be used to specify a "default" value which is used
+if ``value`` cannot be successfully converted to a CRS.
+
+.. versionadded:: 3.12
 %End
 
     static QString normalizeLayerSource( const QString &source );

diff --git a/src/core/processing/qgsprocessingparameters.cpp b/src/core/processing/qgsprocessingparameters.cpp
@@ -782,63 +782,7 @@ QgsCoordinateReferenceSystem QgsProcessingParameters::parameterAsCrs( const QgsP
   if ( !definition )
     return QgsCoordinateReferenceSystem();
 
-  QVariant val = value;
-
-  if ( val.canConvert<QgsCoordinateReferenceSystem>() )
-  {
-    // input is a QgsCoordinateReferenceSystem - done!
-    return val.value< QgsCoordinateReferenceSystem >();
-  }
-  else if ( val.canConvert<QgsProcessingFeatureSourceDefinition>() )
-  {
-    // input is a QgsProcessingFeatureSourceDefinition - get extra properties from it
-    QgsProcessingFeatureSourceDefinition fromVar = qvariant_cast<QgsProcessingFeatureSourceDefinition>( val );
-    val = fromVar.source;
-  }
-  else if ( val.canConvert<QgsProcessingOutputLayerDefinition>() )
-  {
-    // input is a QgsProcessingOutputLayerDefinition - get extra properties from it
-    QgsProcessingOutputLayerDefinition fromVar = qvariant_cast<QgsProcessingOutputLayerDefinition>( val );
-    val = fromVar.sink;
-  }
-
-  if ( val.canConvert<QgsProperty>() && val.value< QgsProperty >().propertyType() == QgsProperty::StaticProperty )
-  {
-    val = val.value< QgsProperty >().staticValue();
-  }
-
-  // maybe a map layer
-  if ( QgsMapLayer *layer = qobject_cast< QgsMapLayer * >( qvariant_cast<QObject *>( val ) ) )
-    return layer->crs();
-
-  if ( val.canConvert<QgsProperty>() )
-    val = val.value< QgsProperty >().valueAsString( context.expressionContext(), definition->defaultValue().toString() );
-
-  if ( !val.isValid() )
-  {
-    // fall back to default
-    val = definition->defaultValue();
-  }
-
-  QString crsText = val.toString();
-  if ( crsText.isEmpty() )
-    crsText = definition->defaultValue().toString();
-
-  if ( crsText.isEmpty() )
-    return QgsCoordinateReferenceSystem();
-
-  // maybe special string
-  if ( context.project() && crsText.compare( QLatin1String( "ProjectCrs" ), Qt::CaseInsensitive ) == 0 )
-    return context.project()->crs();
-
-  // maybe a map layer reference
-  if ( QgsMapLayer *layer = QgsProcessingUtils::mapLayerFromString( crsText, context ) )
-    return layer->crs();
-
-  // else CRS from string
-  QgsCoordinateReferenceSystem crs;
-  crs.createFromString( crsText );
-  return crs;
+  return QgsProcessingUtils::variantToCrs( value, context, definition->defaultValue() );
 }
 
 QgsRectangle QgsProcessingParameters::parameterAsExtent( const QgsProcessingParameterDefinition *definition, const QVariantMap &parameters, QgsProcessingContext &context,

diff --git a/src/core/processing/qgsprocessingutils.cpp b/src/core/processing/qgsprocessingutils.cpp
@@ -338,6 +338,67 @@ QgsProcessingFeatureSource *QgsProcessingUtils::variantToSource( const QVariant
   }
 }
 
+QgsCoordinateReferenceSystem QgsProcessingUtils::variantToCrs( const QVariant &value, QgsProcessingContext &context, const QVariant &fallbackValue )
+{
+  QVariant val = value;
+
+  if ( val.canConvert<QgsCoordinateReferenceSystem>() )
+  {
+    // input is a QgsCoordinateReferenceSystem - done!
+    return val.value< QgsCoordinateReferenceSystem >();
+  }
+  else if ( val.canConvert<QgsProcessingFeatureSourceDefinition>() )
+  {
+    // input is a QgsProcessingFeatureSourceDefinition - get extra properties from it
+    QgsProcessingFeatureSourceDefinition fromVar = qvariant_cast<QgsProcessingFeatureSourceDefinition>( val );
+    val = fromVar.source;
+  }
+  else if ( val.canConvert<QgsProcessingOutputLayerDefinition>() )
+  {
+    // input is a QgsProcessingOutputLayerDefinition - get extra properties from it
+    QgsProcessingOutputLayerDefinition fromVar = qvariant_cast<QgsProcessingOutputLayerDefinition>( val );
+    val = fromVar.sink;
+  }
+
+  if ( val.canConvert<QgsProperty>() && val.value< QgsProperty >().propertyType() == QgsProperty::StaticProperty )
+  {
+    val = val.value< QgsProperty >().staticValue();
+  }
+
+  // maybe a map layer
+  if ( QgsMapLayer *layer = qobject_cast< QgsMapLayer * >( qvariant_cast<QObject *>( val ) ) )
+    return layer->crs();
+
+  if ( val.canConvert<QgsProperty>() )
+    val = val.value< QgsProperty >().valueAsString( context.expressionContext(), fallbackValue.toString() );
+
+  if ( !val.isValid() )
+  {
+    // fall back to default
+    val = fallbackValue;
+  }
+
+  QString crsText = val.toString();
+  if ( crsText.isEmpty() )
+    crsText = fallbackValue.toString();
+
+  if ( crsText.isEmpty() )
+    return QgsCoordinateReferenceSystem();
+
+  // maybe special string
+  if ( context.project() && crsText.compare( QLatin1String( "ProjectCrs" ), Qt::CaseInsensitive ) == 0 )
+    return context.project()->crs();
+
+  // maybe a map layer reference
+  if ( QgsMapLayer *layer = QgsProcessingUtils::mapLayerFromString( crsText, context ) )
+    return layer->crs();
+
+  // else CRS from string
+  QgsCoordinateReferenceSystem crs;
+  crs.createFromString( crsText );
+  return crs;
+}
+
 bool QgsProcessingUtils::canUseLayer( const QgsMeshLayer *layer )
 {
   return layer && layer->dataProvider();

diff --git a/src/core/processing/qgsprocessingutils.h b/src/core/processing/qgsprocessingutils.h
@@ -144,6 +144,16 @@ class CORE_EXPORT QgsProcessingUtils
      */
     static QgsProcessingFeatureSource *variantToSource( const QVariant &value, QgsProcessingContext &context, const QVariant &fallbackValue = QVariant() ) SIP_FACTORY;
 
+    /**
+     * Converts a variant \a value to a coordinate reference system.
+     *
+     * The optional \a fallbackValue can be used to specify a "default" value which is used
+     * if \a value cannot be successfully converted to a CRS.
+     *
+     * \since QGIS 3.12
+     */
+    static QgsCoordinateReferenceSystem variantToCrs( const QVariant &value, QgsProcessingContext &context, const QVariant &fallbackValue = QVariant() );
+
     /**
      * Normalizes a layer \a source string for safe comparison across different
      * operating system environments.