First working raster algorithm

Author: Médéric Ribreux

python/plugins/processing/algs/grass7/Grass7Algorithm.py

@@ -59,16 +59,9 @@
                        QgsProcessingOutputHtml)
 from qgis.utils import iface
 
-#from processing.core.GeoAlgorithm import GeoAlgorithm (replaced by QgsProcessingAlgorithm)
 from processing.core.ProcessingConfig import ProcessingConfig
-#from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException (replaced by QgsProcessingException).
 
 from processing.core.parameters import (getParameterFromString)
-#from processing.core.outputs import (getOutputFromString,
-#                                     OutputRaster,
-#                                     OutputVector,
-#                                     OutputFile,
-#                                     OutputHTML)
 
 from .Grass7Utils import Grass7Utils
 
@@ -183,7 +176,6 @@ def initAlgorithm(self, config=None):
     def defineCharacteristicsFromFile(self):
         """
         Create algorithm parameters and outputs from a text file.
-        
         """
         with open(self.descriptionFile) as lines:
             # First line of the file is the Grass algorithm name
@@ -308,6 +300,7 @@ def grabDefaultGrassParameters(self, parameters, context):
         self.region =  self.parameterAsExtent(parameters,
                                               self.GRASS_REGION_EXTENT_PARAMETER,
                                               context)
+        QgsMessageLog.logMessage('processAlgorithm self.region: {}'.format(self.region.isEmpty()), 'Grass7', QgsMessageLog.INFO)                
         # GRASS cell size
         self.cellSize = self.parameterAsString(parameters,
                                          self.GRASS_REGION_CELLSIZE_PARAMETER,
@@ -426,24 +419,25 @@ def processInputs(self, parameters, context):
                 if not paramName in parameters:
                     continue
                 layer = self.parameterAsRasterLayer(parameters, paramName, context)
-                layerSrc = self.parameterAsCompatibleSourceLayerPath(parameters, paramName, context,
-                                                                 QgsVectorFileWriter.supportedFormatExtensions())
-
+                layerSrc = parameters[paramName]
                 # Check if the layer hasn't already been exported in, for
                 # example, previous GRASS calls in this session
                 if paramName in self.exportedLayers:
                     continue
                 else:
+                    layers.append(layer)
                     self.setSessionProjectionFromLayer(layer)
                     self.commands.append(self.exportRasterLayer(paramName, layerSrc))
             # Vector inputs needs to be imported into temp GRASS DB
             if isinstance(param, QgsProcessingParameterVectorLayer):
                 if not paramName in parameters:
                     continue
                 layer = self.parameterAsVectorLayer(parameters, paramName, context)
-                layerSrc = self.parameterAsCompatibleSourceLayerPath(parameters, paramName, context,
-                                                                 QgsVectorFileWriter.supportedFormatExtensions())
-
+                layerSrc = self.parameterAsCompatibleSourceLayerPath(
+                    parameters, paramName, context,
+                    self.provider().supportedOutputVectorLayerExtensions()
+                )
+                                                   
                 if paramName in self.exportedLayers:
                     continue
                 else:
@@ -482,11 +476,11 @@ def processInputs(self, parameters, context):
         self.setSessionProjectionFromProject()
 
         # Build GRASS region
-        if not self.region:
+        if self.region.isEmpty():
             self.region = QgsProcessingUtils.combineLayerExtents(layers)
         command = 'g.region n={} s={} e={} w={}'.format(
             self.region.yMaximum(), self.region.yMinimum(),
-            self.region.xMinimum(), self.region.xMaximum()
+            self.region.xMaximum(), self.region.xMinimum()
         )
         # TODO Handle cell size
         #if not self.cellSize:
@@ -625,7 +619,7 @@ def processOutputs(self, parameters, context):
                     self.commands.append(command)
                     self.outputCommands.append(command)
                 else:
-                    command += ' {} output="{}"'.format(uniqName, fileName)
+                    command += '{} output="{}"'.format(uniqName, fileName)
                     self.commands.append(command)
                     self.outputCommands.append(command)
 
@@ -712,6 +706,10 @@ def setSessionProjectionFromLayer(self, layer):
             Grass7Utils.projectionSet = True
 
     def exportRasterLayer(self, layerKey, layerSrc):
+        """
+        Creates a dedicated command to load a raster into
+        temporary GRASS DB.
+        """
         # TODO: handle multiple bands
         destFilename = 'a' + os.path.basename(self.getTempFilename())
         self.exportedLayers[layerKey] = destFilename

python/plugins/processing/algs/grass7/Grass7AlgorithmProvider.py

@@ -30,13 +30,15 @@
 from qgis.PyQt.QtCore import QCoreApplication
 from qgis.core import (QgsApplication,
                        QgsProcessingProvider,
+                       QgsVectorFileWriter,
                        QgsMessageLog,
                        QgsProcessingUtils)
-from processing.core.ProcessingConfig import ProcessingConfig, Setting
+from processing.core.ProcessingConfig import (ProcessingConfig, Setting)
 from .Grass7Utils import Grass7Utils
 from .Grass7Algorithm import Grass7Algorithm
 from processing.tools.system import isWindows, isMac
 #from .nviz7 import nviz7
+from processing.algs.gdal.GdalUtils import GdalUtils
 
 pluginPath = os.path.normpath(os.path.join(
     os.path.split(os.path.dirname(__file__))[0], os.pardir))
@@ -124,7 +126,18 @@ def svgIconPath(self):
         return QgsApplication.iconPath("providerGrass.svg")
 
     def supportedOutputVectorLayerExtensions(self):
-        return ['shp']
+        # We use the same extensions than QGIS because:
+        # - QGIS is using OGR like GRASS
+        # - There are very chances than OGR version used in GRASS is
+        # different from QGIS OGR version. 
+        return QgsVectorFileWriter.supportedFormatExtensions()
+    
+    def supportedOutputRasterLayerExtensions(self):
+        # We use the same extensions than GDAL because:
+        # - GRASS is also using GDAL for raster imports.
+        # - Chances that GRASS is compiled with another version of
+        # GDAL than QGIS are very limited! 
+        return GdalUtils.getSupportedRasterExtensions()
 
     def canBeActivated(self):
         return not bool(Grass7Utils.checkGrass7IsInstalled())