Support multiple output file raster formats:

* A new createopt textbox has been added to the parameters dialog for algorithms which exports to raster files.
* A new metaopt textbox has also been added to the Algorithm parameters dialog.
* Raster file format is detected from output filename extension.
* GdalUtils has been improved to correctly detect raster formats supported for creation.
* QFileDialog for output rasters now display only file filters for supported output raster file formats.

python/plugins/processing/algs/gdal/GdalUtils.py

@@ -61,6 +61,7 @@ class GdalUtils(object):
     GDAL_HELP_PATH = 'GDAL_HELP_PATH'
 
     supportedRasters = None
+    supportedOutputRasters = None
 
     @staticmethod
     def runGdal(commands, feedback=None):
@@ -135,7 +136,10 @@ def getSupportedRasters():
             gdal.AllRegister()
 
         GdalUtils.supportedRasters = {}
+        GdalUtils.supportedOutputRasters = {}
         GdalUtils.supportedRasters['GTiff'] = ['tif']
+        GdalUtils.supportedOutputRasters['GTiff'] = ['tif']
+
         for i in range(gdal.GetDriverCount()):
             driver = gdal.GetDriver(i)
             if driver is None:
@@ -146,18 +150,31 @@ def getSupportedRasters():
                     or metadata[gdal.DCAP_RASTER] != 'YES':
                 continue
 
-            # ===================================================================
-            # if gdal.DCAP_CREATE not in metadata \
-            #         or metadata[gdal.DCAP_CREATE] != 'YES':
-            #     continue
-            # ===================================================================
             if gdal.DMD_EXTENSION in metadata:
                 extensions = metadata[gdal.DMD_EXTENSION].split('/')
                 if extensions:
                     GdalUtils.supportedRasters[shortName] = extensions
+                    # Only creatable rasters can be referenced in output rasters
+                    if ((gdal.DCAP_CREATE in metadata
+                         and metadata[gdal.DCAP_CREATE] == 'YES')
+                        or (gdal.DCAP_CREATECOPY in metadata
+                            and metadata[gdal.DCAP_CREATECOPY] == 'YES')):
+                        GdalUtils.supportedOutputRasters[shortName] = extensions
 
         return GdalUtils.supportedRasters
 
+    @staticmethod
+    def getSupportedOutputRasters():
+        if not gdalAvailable:
+            return {}
+
+        if GdalUtils.supportedOutputRasters is not None:
+            return GdalUtils.supportedOutputRasters
+        else:
+            GdalUtils.getSupportedRasters()
+
+        return GdalUtils.supportedOutputRasters
+
     @staticmethod
     def getSupportedRasterExtensions():
         allexts = ['tif']
@@ -167,6 +184,15 @@ def getSupportedRasterExtensions():
                     allexts.append(ext)
         return allexts
 
+    @staticmethod
+    def getSupportedOutputRasterExtensions():
+        allexts = ['tif']
+        for exts in list(GdalUtils.getSupportedOutputRasters().values()):
+            for ext in exts:
+                if ext not in allexts and ext != '':
+                    allexts.append(ext)
+        return allexts
+
     @staticmethod
     def getVectorDriverFromFileName(filename):
         ext = os.path.splitext(filename)[1]

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

@@ -86,6 +86,8 @@ class Grass7Algorithm(QgsProcessingAlgorithm):
     GRASS_REGION_EXTENT_PARAMETER = 'GRASS_REGION_PARAMETER'
     GRASS_REGION_CELLSIZE_PARAMETER = 'GRASS_REGION_CELLSIZE_PARAMETER'
     GRASS_REGION_ALIGN_TO_RESOLUTION = 'GRASS_REGION_ALIGN_TO_RESOLUTION'
+    GRASS_RASTER_FORMAT_OPT = 'GRASS_RASTER_FORMAT_OPT'
+    GRASS_RASTER_FORMAT_META = 'GRASS_RASTER_FORMAT_META'
 
     OUTPUT_TYPES = ['auto', 'point', 'line', 'area']
     QGIS_OUTPUT_TYPES = {QgsProcessing.TypeVectorAnyGeometry: 'auto',
@@ -227,6 +229,7 @@ def defineCharacteristicsFromFile(self):
         self.params.append(param)
 
         if hasRasterOutput:
+            # Add a cellsize parameter
             param = QgsProcessingParameterNumber(
                 self.GRASS_REGION_CELLSIZE_PARAMETER,
                 self.tr('GRASS GIS 7 region cellsize (leave 0 for default)'),
@@ -236,6 +239,24 @@ def defineCharacteristicsFromFile(self):
             param.setFlags(param.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
             self.params.append(param)
 
+            # Add a createopt parameter for format export
+            param = QgsProcessingParameterString(
+                self.GRASS_RASTER_FORMAT_OPT,
+                self.tr('Output Rasters format options (createopt)'),
+                multiLine=True, optional=True
+            )
+            param.setFlags(param.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
+            self.params.append(param)
+
+            # Add a metadata parameter for format export
+            param = QgsProcessingParameterString(
+                self.GRASS_RASTER_FORMAT_META,
+                self.tr('Output Rasters format metadata options (metaopt)'),
+                multiLine=True, optional=True
+            )
+            param.setFlags(param.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
+            self.params.append(param)
+
         if hasVectorInput:
             param = QgsProcessingParameterNumber(self.GRASS_SNAP_TOLERANCE_PARAMETER,
                                                  self.tr('v.in.ogr snap tolerance (-1 = no snap)'),
@@ -459,7 +480,9 @@ def processCommand(self, parameters, context, delOutputs=False):
                              self.GRASS_MIN_AREA_PARAMETER,
                              self.GRASS_SNAP_TOLERANCE_PARAMETER,
                              self.GRASS_OUTPUT_TYPE_PARAMETER,
-                             self.GRASS_REGION_ALIGN_TO_RESOLUTION]:
+                             self.GRASS_REGION_ALIGN_TO_RESOLUTION,
+                             self.GRASS_RASTER_FORMAT_OPT,
+                             self.GRASS_RASTER_FORMAT_META]:
                 continue
 
             # Raster and vector layers
@@ -622,24 +645,39 @@ def exportRasterLayerFromParameter(self, name, parameters, context, colorTable=T
         fileName = os.path.normpath(
             self.parameterAsOutputLayer(parameters, name, context))
         grassName = '{}{}'.format(name, self.uniqueSuffix)
-        self.exportRasterLayer(grassName, fileName, colorTable)
+        outFormat = Grass7Utils.getRasterFormatFromFilename(fileName)
+        createOpt = self.parameterAsString(parameters, self.GRASS_RASTER_FORMAT_OPT, context)
+        metaOpt = self.parameterAsString(parameters, self.GRASS_RASTER_FORMAT_META, context)
+        self.exportRasterLayer(grassName, fileName, colorTable, outFormat, createOpt, metaOpt)
 
-    def exportRasterLayer(self, grassName, fileName, colorTable=True):
+    def exportRasterLayer(self, grassName, fileName,
+                          colorTable=True, outFormat='GTiff',
+                          createOpt=None,
+                          metaOpt=None):
         """
         Creates a dedicated command to export a raster from
         temporary GRASS DB into a file via gdal.
-        :param grassName: name of the parameter
-        :param fileName: file path of raster layer
+        :param grassName: name of the raster to export.
+        :param fileName: file path of raster layer.
         :param colorTable: preserve color Table.
+        :param outFormat: file format for export.
+        :param createOpt: creation options for format.
+        :param metatOpt: metadata options for export.
         """
+        if not createOpt:
+            if outFormat in Grass7Utils.GRASS_RASTER_FORMATS_CREATEOPTS:
+                createOpt = Grass7Utils.GRASS_RASTER_FORMATS_CREATEOPTS[outFormat]
+
         for cmd in [self.commands, self.outputCommands]:
             # Adjust region to layer before exporting
             cmd.append('g.region raster={}'.format(grassName))
             cmd.append(
-                'r.out.gdal -m{0} {3} input="{1}" output="{2}"'.format(
+                'r.out.gdal -c -m{0} input="{1}" output="{2}" format="{3}" {4}{5} --overwrite'.format(
                     ' -t' if colorTable else '',
                     grassName, fileName,
-                    '--overwrite -c createopt="TFW=YES,COMPRESS=LZW"'
+                    outFormat,
+                    ' createopt="{}"'.format(createOpt) if createOpt else '',
+                    ' metaopt="{}"'.format(metaOpt) if metaOpt else ''
                 )
             )
 

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

@@ -38,7 +38,6 @@
 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))
@@ -146,11 +145,7 @@ def supportedOutputVectorLayerExtensions(self):
         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()
+        return Grass7Utils.getSupportedOutputRasterExtensions()
 
     def canBeActivated(self):
         return not bool(Grass7Utils.checkGrass7IsInstalled())

python/plugins/processing/algs/grass7/Grass7Utils.py

@@ -40,6 +40,7 @@
 from processing.core.ProcessingConfig import ProcessingConfig
 from processing.tools.system import userFolder, isWindows, isMac, mkdir
 from processing.tests.TestData import points
+from processing.algs.gdal.GdalUtils import GdalUtils
 
 
 class Grass7Utils(object):
@@ -55,6 +56,13 @@ class Grass7Utils(object):
     GRASS_HELP_PATH = 'GRASS_HELP_PATH'
     GRASS_USE_VEXTERNAL = 'GRASS_USE_VEXTERNAL'
 
+    # TODO Review all default options formats
+    GRASS_RASTER_FORMATS_CREATEOPTS = {
+        'GTiff': 'TFW=YES,COMPRESS=LZW',
+        'PNG': 'ZLEVEL=9',
+        'WEBP': 'QUALITY=85'
+    }
+
     sessionRunning = False
     sessionLayers = {}
     projectionSet = False
@@ -515,3 +523,27 @@ def grassHelpPath():
         else:
             # GRASS not available!
             return 'https://grass.osgeo.org/grass72/manuals/'
+
+    @staticmethod
+    def getSupportedOutputRasterExtensions():
+        # 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.getSupportedOutputRasterExtensions()
+
+    @staticmethod
+    def getRasterFormatFromFilename(filename):
+        """
+        Returns Raster format name from a raster filename.
+        :param filename: The name with extension of the raster.
+        :return: The Gdal short format name for extension.
+        """
+        ext = os.path.splitext(filename)[1].lower()
+        ext = ext.lstrip('.')
+        supported = GdalUtils.getSupportedRasters()
+        for name in list(supported.keys()):
+            exts = supported[name]
+            if ext in exts:
+                return name
+        return 'GTiff'

python/plugins/processing/algs/grass7/TODO.md

@@ -17,7 +17,6 @@ QGIS3 Processing Port
 * TODO Improve unit tests.
 * TODO Use prepareAlgorithm for algorithm preparation.
 * TODO Support ParameterTable.
-* TODO Support multiple output raster formats.
 * TODO Support multiple output vector formats.
   * TODO Try to use v.external.out on simple algorithms.
   * TODO Add an optional/advanced 'format option' textbox if vector output is detected.
@@ -231,6 +230,10 @@ QGIS3 Processing Port
   * v_net_steiner.py
   * v_net_visibility.py
 
+* DONE Support multiple output file raster formats.
+  * DONE Add an optional/advanced 'format option' textbox if raster output is detected.
+  * DONE Detext file format from extension.
+  * DONE Improve GdalUtils to report raster formats that can be created with GDAL.
 * DONE Add GRASS 7.2 new algorithms.
   * DONE Remove r.aspect => r.slope.aspect.
   * DONE Remove r.median.

python/plugins/processing/gui/ParameterGuiUtils.py

@@ -59,9 +59,7 @@ def getFileFilter(param):
     elif param.type() == 'raster':
         return QgsProviderRegistry.instance().fileRasterFilters()
     elif param.type() == 'rasterDestination':
-        exts = dataobjects.getSupportedOutputRasterLayerExtensions()
-        for i in range(len(exts)):
-            exts[i] = tr('{0} files (*.{1})', 'QgsProcessingParameterRasterDestination').format(exts[i].upper(), exts[i].lower())
+        exts = dataobjects.getSupportedOutputRasterFilters()
         return ';;'.join(exts) + ';;' + tr('All files (*.*)')
     elif param.type() == 'table':
         exts = ['csv', 'dbf']

python/plugins/processing/gui/wrappers.py

@@ -220,6 +220,7 @@ def getFileName(self, initial_value=''):
         else:
             path = ''
 
+        # TODO: should use selectedFilter argument for default file format
         filename, selected_filter = QFileDialog.getOpenFileName(self.widget, self.tr('Select file'),
                                                                 path, getFileFilter(self.param))
         if filename:

python/plugins/processing/tools/dataobjects.py

@@ -117,6 +117,24 @@ def getSupportedOutputRasterLayerExtensions():
     return allexts
 
 
+def getSupportedOutputRasterFilters():
+    """
+    Return a list of file filters for supported raster formats.
+    Supported formats come from Gdal.
+    :return: a list of strings for Qt file filters.
+    """
+    allFilters = []
+    supported = GdalUtils.getSupportedOutputRasters()
+    formatList = sorted(supported.keys())
+    # Place GTiff as the first format
+    if 'GTiff' in formatList:
+        formatList.pop(formatList.index('GTiff'))
+    formatList.insert(0, 'GTiff')
+    for f in formatList:
+        allFilters.append('{0} files (*.{1})'.format(f, ' *.'.join(supported[f])))
+    return allFilters
+
+
 def load(fileName, name=None, crs=None, style=None, isRaster=False):
     """Loads a layer/table into the current project, given its file.
     """