4040 QgsProcessingParameterRasterLayer ,
4141 QgsProcessingOutputRasterLayer ,
4242 QgsProcessingParameterString ,
43- QgsCoordinateTransform )
43+ QgsCoordinateTransform ,
44+ QgsMapLayer )
45+ from qgis .PyQt .QtCore import QObject
4446from qgis .analysis import QgsRasterCalculator , QgsRasterCalculatorEntry
4547
4648
@@ -77,23 +79,6 @@ def type(self):
7779 def clone (self ):
7880 return ParameterRasterCalculatorExpression (self .name (), self .description (), self .multiLine ())
7981
80- def evaluateForModeler (self , value , model ):
81- for i in list (model .inputs .values ()):
82- param = i .param
83- if isinstance (param , QgsProcessingParameterRasterLayer ):
84- new = "{}@" .format (os .path .basename (param .value ))
85- old = "{}@" .format (param .name ())
86- value = value .replace (old , new )
87-
88- for alg in list (model .algs .values ()):
89- for out in alg .algorithm .outputs :
90- if isinstance (out , QgsProcessingOutputRasterLayer ):
91- if out .value :
92- new = "{}@" .format (os .path .basename (out .value ))
93- old = "{}:{}@" .format (alg .modeler_name , out .name )
94- value = value .replace (old , new )
95- return value
96-
9782 self .addParameter (ParameterRasterCalculatorExpression (self .EXPRESSION , self .tr ('Expression' ),
9883 multiLine = True ))
9984 self .addParameter (QgsProcessingParameterMultipleLayers (self .LAYERS ,
@@ -122,17 +107,17 @@ def processAlgorithm(self, parameters, context, feedback):
122107
123108 layersDict = {}
124109 if layers :
125- layersDict = {os . path . basename ( lyr .source (). split ( "." )[ 0 ] ): lyr for lyr in layers }
110+ layersDict = {lyr .source (): lyr for lyr in layers }
126111
127112 crs = self .parameterAsCrs (parameters , self .CRS , context )
128- if not layers and not crs .isValid ():
129- raise QgsProcessingException ( self . tr ( "No reference layer selected nor CRS provided" ))
130-
131- if not crs . isValid () and layers :
132- crs = list (layersDict .values ())[0 ].crs ()
113+ if crs is None or not crs .isValid ():
114+ if not layers :
115+ raise QgsProcessingException ( self . tr ( "No reference layer selected nor CRS provided" ))
116+ else :
117+ crs = list (layersDict .values ())[0 ].crs ()
133118
134119 bbox = self .parameterAsExtent (parameters , self .EXTENT , context )
135- if not layers and bbox .isNull ():
120+ if bbox .isNull () and not layers :
136121 raise QgsProcessingException (self .tr ("No reference layer selected nor extent box provided" ))
137122
138123 if not bbox .isNull ():
@@ -145,7 +130,7 @@ def processAlgorithm(self, parameters, context, feedback):
145130 bbox = QgsProcessingUtils .combineLayerExtents (layers , crs )
146131
147132 cellsize = self .parameterAsDouble (parameters , self .CELLSIZE , context )
148- if not layers and cellsize == 0 :
133+ if cellsize == 0 and not layers :
149134 raise QgsProcessingException (self .tr ("No reference layer selected nor cellsize value provided" ))
150135
151136 def _cellsize (layer ):
@@ -157,15 +142,23 @@ def _cellsize(layer):
157142 if cellsize == 0 :
158143 cellsize = min ([_cellsize (lyr ) for lyr in layersDict .values ()])
159144
145+ # check for layers available in the model
146+ layersDictCopy = layersDict .copy () # need a shallow copy because next calls invalidate iterator
147+ for lyr in layersDictCopy .values ():
148+ expression = self .mappedNameToLayer (lyr , expression , layersDict , context )
149+
150+ # check for layers available in the project
160151 for lyr in QgsProcessingUtils .compatibleRasterLayers (context .project ()):
161- name = lyr .name ()
162- if (name + "@" ) in expression :
163- layersDict [name ] = lyr
152+ expression = self .mappedNameToLayer (lyr , expression , layersDict , context )
164153
154+ # create the list of layers to be passed as inputs to RasterCalculaltor
155+ # at this phase expression has been modified to match available layers
156+ # in the current scope
165157 entries = []
166158 for name , lyr in layersDict .items ():
167159 for n in range (lyr .bandCount ()):
168160 ref = '{:s}@{:d}' .format (name , n + 1 )
161+
169162 if ref in expression :
170163 entry = QgsRasterCalculatorEntry ()
171164 entry .ref = ref
@@ -178,6 +171,7 @@ def _cellsize(layer):
178171 width = math .floor ((bbox .xMaximum () - bbox .xMinimum ()) / cellsize )
179172 height = math .floor ((bbox .yMaximum () - bbox .yMinimum ()) / cellsize )
180173 driverName = GdalUtils .getFormatShortNameFromFilename (output )
174+
181175 calc = QgsRasterCalculator (expression ,
182176 output ,
183177 driverName ,
@@ -213,3 +207,80 @@ def processBeforeAddingToModeler(self, algorithm, model):
213207 values .append (ValueFromOutput (alg .modeler_name , out .name ))
214208
215209 algorithm .params [self .LAYERS ] = values
210+
211+ def mappedNameToLayer (self , lyr , expression , layersDict , context ):
212+ '''Try to identify if a real layer is mapped in the expression with a symbolic name.'''
213+
214+ nameToMap = lyr .source ()
215+
216+ # check if nameToMap is a file
217+ # TODO: what about URI eg for a COG?
218+ if os .path .isfile (nameToMap ):
219+ # get only the name without extension and path of the file
220+ nameToMap = os .path .splitext (os .path .basename (nameToMap ))[0 ]
221+
222+ # check for layers directly added in the expression
223+ if (nameToMap + "@" ) in expression :
224+ layersDict [nameToMap ] = lyr
225+
226+ # get "algorithm_inputs" scope of the expressionContext related
227+ # with mapped variables
228+ indexOfScope = context .expressionContext ().indexOfScope ("algorithm_inputs" )
229+ if indexOfScope >= 0 :
230+ expContextAlgInputsScope = context .expressionContext ().scope (indexOfScope )
231+
232+ # check for the layers that are mapped as input in a model
233+ # to do this check in the latest scope all passed variables
234+ # to look for a variable that is a layer or a string filename ç
235+ # to a layer
236+ varDescription = None
237+ for varName in expContextAlgInputsScope .variableNames ():
238+
239+ layerInContext = expContextAlgInputsScope .variable (varName )
240+
241+ if not isinstance (layerInContext , str ) and not isinstance (layerInContext , QgsMapLayer ):
242+ continue
243+
244+ if isinstance (layerInContext , QgsMapLayer ) and nameToMap not in layerInContext .source ():
245+ continue
246+
247+ varDescription = expContextAlgInputsScope .description (varName )
248+
249+ # because there can be variable with None or "" description
250+ # then skip them
251+ if not varDescription :
252+ continue
253+
254+ # check if it's description starts with Output as in:
255+ # Output 'Output' from algorithm 'calc1'
256+ # as set in https://github.com/qgis/QGIS/blob/master/src/core/processing/models/qgsprocessingmodelalgorithm.cpp#L516
257+ # but var in expression is called simply
258+ # 'Output' from algorithm 'calc1'
259+
260+ # get the translatin string to use to parse the description
261+ # HAVE to use the same translated string as in
262+ # https://github.com/qgis/QGIS/blob/master/src/core/processing/models/qgsprocessingmodelalgorithm.cpp#L516
263+ translatedDesc = self .tr ("Output '%1' from algorithm '%2'" )
264+ elementZero = translatedDesc .split (" " )[0 ] # For english the string result should be "Output"
265+
266+ elements = varDescription .split (" " )
267+ if len (elements ) > 1 and elements [0 ] == elementZero :
268+ # remove heading QObject.tr"Output ") string. Note adding a space at the end of elementZero!
269+ varDescription = varDescription [len (elementZero ) + 1 :]
270+
271+ # check if cleaned varDescription is present in the expression
272+ # if not skip it
273+ if (varDescription + "@" ) not in expression :
274+ continue
275+
276+ # !!!found!!! => substitute in expression
277+ # and add in the list of layers that will be passed to raster calculator
278+ nameToMap = varName
279+ new = "{}@" .format (nameToMap )
280+ old = "{}@" .format (varDescription )
281+ expression = expression .replace (old , new )
282+
283+ layersDict [nameToMap ] = lyr
284+
285+ # need return the modified expression because it's not a reference
286+ return expression
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