Add factory method which creates an initialized transformer from meth…

…od and list of GCPs

python/analysis/auto_generated/georeferencing/qgsgcptransformer.sip.in

@@ -68,6 +68,16 @@ Returns a translated string representing the specified transform ``method``.
 %Docstring
 Creates a new QgsGcpTransformerInterface subclass representing the specified transform ``method``.
 
+Caller takes ownership of the returned object.
+%End
+
+    static QgsGcpTransformerInterface *createFromParameters( TransformMethod method, const QVector<QgsPointXY> &mapCoordinates, const QVector<QgsPointXY> &pixelCoordinates ) /Factory/;
+%Docstring
+Creates a new QgsGcpTransformerInterface subclass representing the specified transform ``method``, initialized
+using the given lists of map and pixel coordinates.
+
+If the parameters cannot be fit to a transform ``None`` will be returned.
+
 Caller takes ownership of the returned object.
 %End
 

src/analysis/georeferencing/qgsgcptransformer.cpp

@@ -72,6 +72,18 @@ QgsGcpTransformerInterface *QgsGcpTransformerInterface::create( QgsGcpTransforme
   }
 }
 
+QgsGcpTransformerInterface *QgsGcpTransformerInterface::createFromParameters( QgsGcpTransformerInterface::TransformMethod method, const QVector<QgsPointXY> &mapCoordinates, const QVector<QgsPointXY> &pixelCoordinates )
+{
+  std::unique_ptr< QgsGcpTransformerInterface > transformer( create( method ) );
+  if ( !transformer )
+    return nullptr;
+
+  if ( !transformer->updateParametersFromGcps( mapCoordinates, pixelCoordinates ) )
+    return nullptr;
+
+  return transformer.release();
+}
+
 
 //
 // QgsLinearGeorefTransform

src/analysis/georeferencing/qgsgcptransformer.h

@@ -88,6 +88,16 @@ class ANALYSIS_EXPORT QgsGcpTransformerInterface SIP_ABSTRACT
      */
     static QgsGcpTransformerInterface *create( TransformMethod method ) SIP_FACTORY;
 
+    /**
+     * Creates a new QgsGcpTransformerInterface subclass representing the specified transform \a method, initialized
+     * using the given lists of map and pixel coordinates.
+     *
+     * If the parameters cannot be fit to a transform NULLPTR will be returned.
+     *
+     * Caller takes ownership of the returned object.
+     */
+    static QgsGcpTransformerInterface *createFromParameters( TransformMethod method, const QVector<QgsPointXY> &mapCoordinates, const QVector<QgsPointXY> &pixelCoordinates ) SIP_FACTORY;
+
 #ifndef SIP_RUN
 
     /**